diff options
Diffstat (limited to 'security/keys')
| -rw-r--r-- | security/keys/Makefile | 2 | ||||
| -rw-r--r-- | security/keys/compat.c | 67 | ||||
| -rw-r--r-- | security/keys/encrypted.c | 902 | ||||
| -rw-r--r-- | security/keys/encrypted.h | 54 | ||||
| -rw-r--r-- | security/keys/gc.c | 14 | ||||
| -rw-r--r-- | security/keys/internal.h | 44 | ||||
| -rw-r--r-- | security/keys/key.c | 345 | ||||
| -rw-r--r-- | security/keys/keyctl.c | 502 | ||||
| -rw-r--r-- | security/keys/keyring.c | 367 | ||||
| -rw-r--r-- | security/keys/permission.c | 33 | ||||
| -rw-r--r-- | security/keys/proc.c | 19 | ||||
| -rw-r--r-- | security/keys/process_keys.c | 148 | ||||
| -rw-r--r-- | security/keys/request_key.c | 172 | ||||
| -rw-r--r-- | security/keys/request_key_auth.c | 65 | ||||
| -rw-r--r-- | security/keys/trusted.c | 1180 | ||||
| -rw-r--r-- | security/keys/trusted.h | 134 | ||||
| -rw-r--r-- | security/keys/user_defined.c | 53 |
17 files changed, 3413 insertions, 688 deletions
diff --git a/security/keys/Makefile b/security/keys/Makefile index 74d5447d7df7..1bf090a885fe 100644 --- a/security/keys/Makefile +++ b/security/keys/Makefile @@ -13,6 +13,8 @@ obj-y := \ request_key_auth.o \ user_defined.o +obj-$(CONFIG_TRUSTED_KEYS) += trusted.o +obj-$(CONFIG_ENCRYPTED_KEYS) += encrypted.o obj-$(CONFIG_KEYS_COMPAT) += compat.o obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_SYSCTL) += sysctl.o diff --git a/security/keys/compat.c b/security/keys/compat.c index 792c0a611a6d..338b510e9027 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -1,4 +1,4 @@ -/* compat.c: 32-bit compatibility syscall for 64-bit systems +/* 32-bit compatibility syscall for 64-bit systems * * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -12,15 +12,58 @@ #include <linux/syscalls.h> #include <linux/keyctl.h> #include <linux/compat.h> +#include <linux/slab.h> #include "internal.h" -/*****************************************************************************/ /* - * the key control system call, 32-bit compatibility version for 64-bit archs - * - this should only be called if the 64-bit arch uses weird pointers in - * 32-bit mode or doesn't guarantee that the top 32-bits of the argument - * registers on taking a 32-bit syscall are zero - * - if you can, you should call sys_keyctl directly + * Instantiate a key with the specified compatibility multipart payload and + * link the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long compat_keyctl_instantiate_key_iov( + key_serial_t id, + const struct compat_iovec __user *_payload_iov, + unsigned ioc, + key_serial_t ringid) +{ + struct iovec iovstack[UIO_FASTIOV], *iov = iovstack; + long ret; + + if (_payload_iov == 0 || ioc == 0) + goto no_payload; + + ret = compat_rw_copy_check_uvector(WRITE, _payload_iov, ioc, + ARRAY_SIZE(iovstack), + iovstack, &iov); + if (ret < 0) + return ret; + if (ret == 0) + goto no_payload_free; + + ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid); + + if (iov != iovstack) + kfree(iov); + return ret; + +no_payload_free: + if (iov != iovstack) + kfree(iov); +no_payload: + return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); +} + +/* + * The key control system call, 32-bit compatibility version for 64-bit archs + * + * This should only be called if the 64-bit arch uses weird pointers in 32-bit + * mode or doesn't guarantee that the top 32-bits of the argument registers on + * taking a 32-bit syscall are zero. If you can, you should call sys_keyctl() + * directly. */ asmlinkage long compat_sys_keyctl(u32 option, u32 arg2, u32 arg3, u32 arg4, u32 arg5) @@ -85,8 +128,14 @@ asmlinkage long compat_sys_keyctl(u32 option, case KEYCTL_SESSION_TO_PARENT: return keyctl_session_to_parent(); + case KEYCTL_REJECT: + return keyctl_reject_key(arg2, arg3, arg4, arg5); + + case KEYCTL_INSTANTIATE_IOV: + return compat_keyctl_instantiate_key_iov( + arg2, compat_ptr(arg3), arg4, arg5); + default: return -EOPNOTSUPP; } - -} /* end compat_sys_keyctl() */ +} diff --git a/security/keys/encrypted.c b/security/keys/encrypted.c new file mode 100644 index 000000000000..69907a58a683 --- /dev/null +++ b/security/keys/encrypted.c @@ -0,0 +1,902 @@ +/* + * Copyright (C) 2010 IBM Corporation + * + * Author: + * Mimi Zohar <zohar@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * See Documentation/keys-trusted-encrypted.txt + */ + +#include <linux/uaccess.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/parser.h> +#include <linux/string.h> +#include <linux/err.h> +#include <keys/user-type.h> +#include <keys/trusted-type.h> +#include <keys/encrypted-type.h> +#include <linux/key-type.h> +#include <linux/random.h> +#include <linux/rcupdate.h> +#include <linux/scatterlist.h> +#include <linux/crypto.h> +#include <crypto/hash.h> +#include <crypto/sha.h> +#include <crypto/aes.h> + +#include "encrypted.h" + +static const char KEY_TRUSTED_PREFIX[] = "trusted:"; +static const char KEY_USER_PREFIX[] = "user:"; +static const char hash_alg[] = "sha256"; +static const char hmac_alg[] = "hmac(sha256)"; +static const char blkcipher_alg[] = "cbc(aes)"; +static unsigned int ivsize; +static int blksize; + +#define KEY_TRUSTED_PREFIX_LEN (sizeof (KEY_TRUSTED_PREFIX) - 1) +#define KEY_USER_PREFIX_LEN (sizeof (KEY_USER_PREFIX) - 1) +#define HASH_SIZE SHA256_DIGEST_SIZE +#define MAX_DATA_SIZE 4096 +#define MIN_DATA_SIZE 20 + +struct sdesc { + struct shash_desc shash; + char ctx[]; +}; + +static struct crypto_shash *hashalg; +static struct crypto_shash *hmacalg; + +enum { + Opt_err = -1, Opt_new, Opt_load, Opt_update +}; + +static const match_table_t key_tokens = { + {Opt_new, "new"}, + {Opt_load, "load"}, + {Opt_update, "update"}, + {Opt_err, NULL} +}; + +static int aes_get_sizes(void) +{ + struct crypto_blkcipher *tfm; + + tfm = crypto_alloc_blkcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(tfm)) { + pr_err("encrypted_key: failed to alloc_cipher (%ld)\n", + PTR_ERR(tfm)); + return PTR_ERR(tfm); + } + ivsize = crypto_blkcipher_ivsize(tfm); + blksize = crypto_blkcipher_blocksize(tfm); + crypto_free_blkcipher(tfm); + return 0; +} + +/* + * valid_master_desc - verify the 'key-type:desc' of a new/updated master-key + * + * key-type:= "trusted:" | "encrypted:" + * desc:= master-key description + * + * Verify that 'key-type' is valid and that 'desc' exists. On key update, + * only the master key description is permitted to change, not the key-type. + * The key-type remains constant. + * + * On success returns 0, otherwise -EINVAL. + */ +static int valid_master_desc(const char *new_desc, const char *orig_desc) +{ + if (!memcmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) { + if (strlen(new_desc) == KEY_TRUSTED_PREFIX_LEN) + goto out; + if (orig_desc) + if (memcmp(new_desc, orig_desc, KEY_TRUSTED_PREFIX_LEN)) + goto out; + } else if (!memcmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) { + if (strlen(new_desc) == KEY_USER_PREFIX_LEN) + goto out; + if (orig_desc) + if (memcmp(new_desc, orig_desc, KEY_USER_PREFIX_LEN)) + goto out; + } else + goto out; + return 0; +out: + return -EINVAL; +} + +/* + * datablob_parse - parse the keyctl data + * + * datablob format: + * new <master-key name> <decrypted data length> + * load <master-key name> <decrypted data length> <encrypted iv + data> + * update <new-master-key name> + * + * Tokenizes a copy of the keyctl data, returning a pointer to each token, + * which is null terminated. + * + * On success returns 0, otherwise -EINVAL. + */ +static int datablob_parse(char *datablob, char **master_desc, + char **decrypted_datalen, char **hex_encoded_iv) +{ + substring_t args[MAX_OPT_ARGS]; + int ret = -EINVAL; + int key_cmd; + char *p; + + p = strsep(&datablob, " \t"); + if (!p) + return ret; + key_cmd = match_token(p, key_tokens, args); + + *master_desc = strsep(&datablob, " \t"); + if (!*master_desc) + goto out; + + if (valid_master_desc(*master_desc, NULL) < 0) + goto out; + + if (decrypted_datalen) { + *decrypted_datalen = strsep(&datablob, " \t"); + if (!*decrypted_datalen) + goto out; + } + + switch (key_cmd) { + case Opt_new: + if (!decrypted_datalen) + break; + ret = 0; + break; + case Opt_load: + if (!decrypted_datalen) + break; + *hex_encoded_iv = strsep(&datablob, " \t"); + if (!*hex_encoded_iv) + break; + ret = 0; + break; + case Opt_update: + if (decrypted_datalen) + break; + ret = 0; + break; + case Opt_err: + break; + } +out: + return ret; +} + +/* + * datablob_format - format as an ascii string, before copying to userspace + */ +static char *datablob_format(struct encrypted_key_payload *epayload, + size_t asciiblob_len) +{ + char *ascii_buf, *bufp; + u8 *iv = epayload->iv; + int len; + int i; + + ascii_buf = kmalloc(asciiblob_len + 1, GFP_KERNEL); + if (!ascii_buf) + goto out; + + ascii_buf[asciiblob_len] = '\0'; + + /* copy datablob master_desc and datalen strings */ + len = sprintf(ascii_buf, "%s %s ", epayload->master_desc, + epayload->datalen); + + /* convert the hex encoded iv, encrypted-data and HMAC to ascii */ + bufp = &ascii_buf[len]; + for (i = 0; i < (asciiblob_len - len) / 2; i++) + bufp = pack_hex_byte(bufp, iv[i]); +out: + return ascii_buf; +} + +/* + * request_trusted_key - request the trusted key + * + * Trusted keys are sealed to PCRs and other metadata. Although userspace + * manages both trusted/encrypted key-types, like the encrypted key type + * data, trusted key type data is not visible decrypted from userspace. + */ +static struct key *request_trusted_key(const char *trusted_desc, + u8 **master_key, size_t *master_keylen) +{ + struct trusted_key_payload *tpayload; + struct key *tkey; + + tkey = request_key(&key_type_trusted, trusted_desc, NULL); + if (IS_ERR(tkey)) + goto error; + + down_read(&tkey->sem); + tpayload = rcu_dereference(tkey->payload.data); + *master_key = tpayload->key; + *master_keylen = tpayload->key_len; +error: + return tkey; +} + +/* + * request_user_key - request the user key + * + * Use a user provided key to encrypt/decrypt an encrypted-key. + */ +static struct key *request_user_key(const char *master_desc, u8 **master_key, + size_t *master_keylen) +{ + struct user_key_payload *upayload; + struct key *ukey; + + ukey = request_key(&key_type_user, master_desc, NULL); + if (IS_ERR(ukey)) + goto error; + + down_read(&ukey->sem); + upayload = rcu_dereference(ukey->payload.data); + *master_key = upayload->data; + *master_keylen = upayload->datalen; +error: + return ukey; +} + +static struct sdesc *alloc_sdesc(struct crypto_shash *alg) +{ + struct sdesc *sdesc; + int size; + + size = sizeof(struct shash_desc) + crypto_shash_descsize(alg); + sdesc = kmalloc(size, GFP_KERNEL); + if (!sdesc) + return ERR_PTR(-ENOMEM); + sdesc->shash.tfm = alg; + sdesc->shash.flags = 0x0; + return sdesc; +} + +static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen, + const u8 *buf, unsigned int buflen) +{ + struct sdesc *sdesc; + int ret; + + sdesc = alloc_sdesc(hmacalg); + if (IS_ERR(sdesc)) { + pr_info("encrypted_key: can't alloc %s\n", hmac_alg); + return PTR_ERR(sdesc); + } + + ret = crypto_shash_setkey(hmacalg, key, keylen); + if (!ret) + ret = crypto_shash_digest(&sdesc->shash, buf, buflen, digest); + kfree(sdesc); + return ret; +} + +static int calc_hash(u8 *digest, const u8 *buf, unsigned int buflen) +{ + struct sdesc *sdesc; + int ret; + + sdesc = alloc_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("encrypted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + + ret = crypto_shash_digest(&sdesc->shash, buf, buflen, digest); + kfree(sdesc); + return ret; +} + +enum derived_key_type { ENC_KEY, AUTH_KEY }; + +/* Derive authentication/encryption key from trusted key */ +static int get_derived_key(u8 *derived_key, enum derived_key_type key_type, + const u8 *master_key, size_t master_keylen) +{ + u8 *derived_buf; + unsigned int derived_buf_len; + int ret; + + derived_buf_len = strlen("AUTH_KEY") + 1 + master_keylen; + if (derived_buf_len < HASH_SIZE) + derived_buf_len = HASH_SIZE; + + derived_buf = kzalloc(derived_buf_len, GFP_KERNEL); + if (!derived_buf) { + pr_err("encrypted_key: out of memory\n"); + return -ENOMEM; + } + if (key_type) + strcpy(derived_buf, "AUTH_KEY"); + else + strcpy(derived_buf, "ENC_KEY"); + + memcpy(derived_buf + strlen(derived_buf) + 1, master_key, + master_keylen); + ret = calc_hash(derived_key, derived_buf, derived_buf_len); + kfree(derived_buf); + return ret; +} + +static int init_blkcipher_desc(struct blkcipher_desc *desc, const u8 *key, + unsigned int key_len, const u8 *iv, + unsigned int ivsize) +{ + int ret; + + desc->tfm = crypto_alloc_blkcipher(blkcipher_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(desc->tfm)) { + pr_err("encrypted_key: failed to load %s transform (%ld)\n", + blkcipher_alg, PTR_ERR(desc->tfm)); + return PTR_ERR(desc->tfm); + } + desc->flags = 0; + + ret = crypto_blkcipher_setkey(desc->tfm, key, key_len); + if (ret < 0) { + pr_err("encrypted_key: failed to setkey (%d)\n", ret); + crypto_free_blkcipher(desc->tfm); + return ret; + } + crypto_blkcipher_set_iv(desc->tfm, iv, ivsize); + return 0; +} + +static struct key *request_master_key(struct encrypted_key_payload *epayload, + u8 **master_key, size_t *master_keylen) +{ + struct key *mkey = NULL; + + if (!strncmp(epayload->master_desc, KEY_TRUSTED_PREFIX, + KEY_TRUSTED_PREFIX_LEN)) { + mkey = request_trusted_key(epayload->master_desc + + KEY_TRUSTED_PREFIX_LEN, + master_key, master_keylen); + } else if (!strncmp(epayload->master_desc, KEY_USER_PREFIX, + KEY_USER_PREFIX_LEN)) { + mkey = request_user_key(epayload->master_desc + + KEY_USER_PREFIX_LEN, + master_key, master_keylen); + } else + goto out; + + if (IS_ERR(mkey)) + pr_info("encrypted_key: key %s not found", + epayload->master_desc); + if (mkey) + dump_master_key(*master_key, *master_keylen); +out: + return mkey; +} + +/* Before returning data to userspace, encrypt decrypted data. */ +static int derived_key_encrypt(struct encrypted_key_payload *epayload, + const u8 *derived_key, + unsigned int derived_keylen) +{ + struct scatterlist sg_in[2]; + struct scatterlist sg_out[1]; + struct blkcipher_desc desc; + unsigned int encrypted_datalen; + unsigned int padlen; + char pad[16]; + int ret; + + encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); + padlen = encrypted_datalen - epayload->decrypted_datalen; + + ret = init_blkcipher_desc(&desc, derived_key, derived_keylen, + epayload->iv, ivsize); + if (ret < 0) + goto out; + dump_decrypted_data(epayload); + + memset(pad, 0, sizeof pad); + sg_init_table(sg_in, 2); + sg_set_buf(&sg_in[0], epayload->decrypted_data, + epayload->decrypted_datalen); + sg_set_buf(&sg_in[1], pad, padlen); + + sg_init_table(sg_out, 1); + sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen); + + ret = crypto_blkcipher_encrypt(&desc, sg_out, sg_in, encrypted_datalen); + crypto_free_blkcipher(desc.tfm); + if (ret < 0) + pr_err("encrypted_key: failed to encrypt (%d)\n", ret); + else + dump_encrypted_data(epayload, encrypted_datalen); +out: + return ret; +} + +static int datablob_hmac_append(struct encrypted_key_payload *epayload, + const u8 *master_key, size_t master_keylen) +{ + u8 derived_key[HASH_SIZE]; + u8 *digest; + int ret; + + ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen); + if (ret < 0) + goto out; + + digest = epayload->master_desc + epayload->datablob_len; + ret = calc_hmac(digest, derived_key, sizeof derived_key, + epayload->master_desc, epayload->datablob_len); + if (!ret) + dump_hmac(NULL, digest, HASH_SIZE); +out: + return ret; +} + +/* verify HMAC before decrypting encrypted key */ +static int datablob_hmac_verify(struct encrypted_key_payload *epayload, + const u8 *master_key, size_t master_keylen) +{ + u8 derived_key[HASH_SIZE]; + u8 digest[HASH_SIZE]; + int ret; + + ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen); + if (ret < 0) + goto out; + + ret = calc_hmac(digest, derived_key, sizeof derived_key, + epayload->master_desc, epayload->datablob_len); + if (ret < 0) + goto out; + ret = memcmp(digest, epayload->master_desc + epayload->datablob_len, + sizeof digest); + if (ret) { + ret = -EINVAL; + dump_hmac("datablob", + epayload->master_desc + epayload->datablob_len, + HASH_SIZE); + dump_hmac("calc", digest, HASH_SIZE); + } +out: + return ret; +} + +static int derived_key_decrypt(struct encrypted_key_payload *epayload, + const u8 *derived_key, + unsigned int derived_keylen) +{ + struct scatterlist sg_in[1]; + struct scatterlist sg_out[2]; + struct blkcipher_desc desc; + unsigned int encrypted_datalen; + char pad[16]; + int ret; + + encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); + ret = init_blkcipher_desc(&desc, derived_key, derived_keylen, + epayload->iv, ivsize); + if (ret < 0) + goto out; + dump_encrypted_data(epayload, encrypted_datalen); + + memset(pad, 0, sizeof pad); + sg_init_table(sg_in, 1); + sg_init_table(sg_out, 2); + sg_set_buf(sg_in, epayload->encrypted_data, encrypted_datalen); + sg_set_buf(&sg_out[0], epayload->decrypted_data, + epayload->decrypted_datalen); + sg_set_buf(&sg_out[1], pad, sizeof pad); + + ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in, encrypted_datalen); + crypto_free_blkcipher(desc.tfm); + if (ret < 0) + goto out; + dump_decrypted_data(epayload); +out: + return ret; +} + +/* Allocate memory for decrypted key and datablob. */ +static struct encrypted_key_payload *encrypted_key_alloc(struct key *key, + const char *master_desc, + const char *datalen) +{ + struct encrypted_key_payload *epayload = NULL; + unsigned short datablob_len; + unsigned short decrypted_datalen; + unsigned int encrypted_datalen; + long dlen; + int ret; + + ret = strict_strtol(datalen, 10, &dlen); + if (ret < 0 || dlen < MIN_DATA_SIZE || dlen > MAX_DATA_SIZE) + return ERR_PTR(-EINVAL); + + decrypted_datalen = dlen; + encrypted_datalen = roundup(decrypted_datalen, blksize); + + datablob_len = strlen(master_desc) + 1 + strlen(datalen) + 1 + + ivsize + 1 + encrypted_datalen; + + ret = key_payload_reserve(key, decrypted_datalen + datablob_len + + HASH_SIZE + 1); + if (ret < 0) + return ERR_PTR(ret); + + epayload = kzalloc(sizeof(*epayload) + decrypted_datalen + + datablob_len + HASH_SIZE + 1, GFP_KERNEL); + if (!epayload) + return ERR_PTR(-ENOMEM); + + epayload->decrypted_datalen = decrypted_datalen; + epayload->datablob_len = datablob_len; + return epayload; +} + +static int encrypted_key_decrypt(struct encrypted_key_payload *epayload, + const char *hex_encoded_iv) +{ + struct key *mkey; + u8 derived_key[HASH_SIZE]; + u8 *master_key; + u8 *hmac; + const char *hex_encoded_data; + unsigned int encrypted_datalen; + size_t master_keylen; + size_t asciilen; + int ret; + + encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); + asciilen = (ivsize + 1 + encrypted_datalen + HASH_SIZE) * 2; + if (strlen(hex_encoded_iv) != asciilen) + return -EINVAL; + + hex_encoded_data = hex_encoded_iv + (2 * ivsize) + 2; + hex2bin(epayload->iv, hex_encoded_iv, ivsize); + hex2bin(epayload->encrypted_data, hex_encoded_data, encrypted_datalen); + + hmac = epayload->master_desc + epayload->datablob_len; + hex2bin(hmac, hex_encoded_data + (encrypted_datalen * 2), HASH_SIZE); + + mkey = request_master_key(epayload, &master_key, &master_keylen); + if (IS_ERR(mkey)) + return PTR_ERR(mkey); + + ret = datablob_hmac_verify(epayload, master_key, master_keylen); + if (ret < 0) { + pr_err("encrypted_key: bad hmac (%d)\n", ret); + goto out; + } + + ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen); + if (ret < 0) + goto out; + + ret = derived_key_decrypt(epayload, derived_key, sizeof derived_key); + if (ret < 0) + pr_err("encrypted_key: failed to decrypt key (%d)\n", ret); +out: + up_read(&mkey->sem); + key_put(mkey); + return ret; +} + +static void __ekey_init(struct encrypted_key_payload *epayload, + const char *master_desc, const char *datalen) +{ + epayload->master_desc = epayload->decrypted_data + + epayload->decrypted_datalen; + epayload->datalen = epayload->master_desc + strlen(master_desc) + 1; + epayload->iv = epayload->datalen + strlen(datalen) + 1; + epayload->encrypted_data = epayload->iv + ivsize + 1; + + memcpy(epayload->master_desc, master_desc, strlen(master_desc)); + memcpy(epayload->datalen, datalen, strlen(datalen)); +} + +/* + * encrypted_init - initialize an encrypted key + * + * For a new key, use a random number for both the iv and data + * itself. For an old key, decrypt the hex encoded data. + */ +static int encrypted_init(struct encrypted_key_payload *epayload, + const char *master_desc, const char *datalen, + const char *hex_encoded_iv) +{ + int ret = 0; + + __ekey_init(epayload, master_desc, datalen); + if (!hex_encoded_iv) { + get_random_bytes(epayload->iv, ivsize); + + get_random_bytes(epayload->decrypted_data, + epayload->decrypted_datalen); + } else + ret = encrypted_key_decrypt(epayload, hex_encoded_iv); + return ret; +} + +/* + * encrypted_instantiate - instantiate an encrypted key + * + * Decrypt an existing encrypted datablob or create a new encrypted key + * based on a kernel random number. + * + * On success, return 0. Otherwise return errno. + */ +static int encrypted_instantiate(struct key *key, const void *data, + size_t datalen) +{ + struct encrypted_key_payload *epayload = NULL; + char *datablob = NULL; + char *master_desc = NULL; + char *decrypted_datalen = NULL; + char *hex_encoded_iv = NULL; + int ret; + + if (datalen <= 0 || datalen > 32767 || !data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + datablob[datalen] = 0; + memcpy(datablob, data, datalen); + ret = datablob_parse(datablob, &master_desc, &decrypted_datalen, + &hex_encoded_iv); + if (ret < 0) + goto out; + + epayload = encrypted_key_alloc(key, master_desc, decrypted_datalen); + if (IS_ERR(epayload)) { + ret = PTR_ERR(epayload); + goto out; + } + ret = encrypted_init(epayload, master_desc, decrypted_datalen, + hex_encoded_iv); + if (ret < 0) { + kfree(epayload); + goto out; + } + + rcu_assign_pointer(key->payload.data, epayload); +out: + kfree(datablob); + return ret; +} + +static void encrypted_rcu_free(struct rcu_head *rcu) +{ + struct encrypted_key_payload *epayload; + + epayload = container_of(rcu, struct encrypted_key_payload, rcu); + memset(epayload->decrypted_data, 0, epayload->decrypted_datalen); + kfree(epayload); +} + +/* + * encrypted_update - update the master key description + * + * Change the master key description for an existing encrypted key. + * The next read will return an encrypted datablob using the new + * master key description. + * + * On success, return 0. Otherwise return errno. + */ +static int encrypted_update(struct key *key, const void *data, size_t datalen) +{ + struct encrypted_key_payload *epayload = key->payload.data; + struct encrypted_key_payload *new_epayload; + char *buf; + char *new_master_desc = NULL; + int ret = 0; + + if (datalen <= 0 || datalen > 32767 || !data) + return -EINVAL; + + buf = kmalloc(datalen + 1, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + buf[datalen] = 0; + memcpy(buf, data, datalen); + ret = datablob_parse(buf, &new_master_desc, NULL, NULL); + if (ret < 0) + goto out; + + ret = valid_master_desc(new_master_desc, epayload->master_desc); + if (ret < 0) + goto out; + + new_epayload = encrypted_key_alloc(key, new_master_desc, + epayload->datalen); + if (IS_ERR(new_epayload)) { + ret = PTR_ERR(new_epayload); + goto out; + } + + __ekey_init(new_epayload, new_master_desc, epayload->datalen); + + memcpy(new_epayload->iv, epayload->iv, ivsize); + memcpy(new_epayload->decrypted_data, epayload->decrypted_data, + epayload->decrypted_datalen); + + rcu_assign_pointer(key->payload.data, new_epayload); + call_rcu(&epayload->rcu, encrypted_rcu_free); +out: + kfree(buf); + return ret; +} + +/* + * encrypted_read - format and copy the encrypted data to userspace + * + * The resulting datablob format is: + * <master-key name> <decrypted data length> <encrypted iv> <encrypted data> + * + * On success, return to userspace the encrypted key datablob size. + */ +static long encrypted_read(const struct key *key, char __user *buffer, + size_t buflen) +{ + struct encrypted_key_payload *epayload; + struct key *mkey; + u8 *master_key; + size_t master_keylen; + char derived_key[HASH_SIZE]; + char *ascii_buf; + size_t asciiblob_len; + int ret; + + epayload = rcu_dereference_key(key); + + /* returns the hex encoded iv, encrypted-data, and hmac as ascii */ + asciiblob_len = epayload->datablob_len + ivsize + 1 + + roundup(epayload->decrypted_datalen, blksize) + + (HASH_SIZE * 2); + + if (!buffer || buflen < asciiblob_len) + return asciiblob_len; + + mkey = request_master_key(epayload, &master_key, &master_keylen); + if (IS_ERR(mkey)) + return PTR_ERR(mkey); + + ret = get_derived_key(derived_key, ENC_KEY, master_key, master_keylen); + if (ret < 0) + goto out; + + ret = derived_key_encrypt(epayload, derived_key, sizeof derived_key); + if (ret < 0) + goto out; + + ret = datablob_hmac_append(epayload, master_key, master_keylen); + if (ret < 0) + goto out; + + ascii_buf = datablob_format(epayload, asciiblob_len); + if (!ascii_buf) { + ret = -ENOMEM; + goto out; + } + + up_read(&mkey->sem); + key_put(mkey); + + if (copy_to_user(buffer, ascii_buf, asciiblob_len) != 0) + ret = -EFAULT; + kfree(ascii_buf); + + return asciiblob_len; +out: + up_read(&mkey->sem); + key_put(mkey); + return ret; +} + +/* + * encrypted_destroy - before freeing the key, clear the decrypted data + * + * Before freeing the key, clear the memory containing the decrypted + * key data. + */ +static void encrypted_destroy(struct key *key) +{ + struct encrypted_key_payload *epayload = key->payload.data; + + if (!epayload) + return; + + memset(epayload->decrypted_data, 0, epayload->decrypted_datalen); + kfree(key->payload.data); +} + +struct key_type key_type_encrypted = { + .name = "encrypted", + .instantiate = encrypted_instantiate, + .update = encrypted_update, + .match = user_match, + .destroy = encrypted_destroy, + .describe = user_describe, + .read = encrypted_read, +}; +EXPORT_SYMBOL_GPL(key_type_encrypted); + +static void encrypted_shash_release(void) +{ + if (hashalg) + crypto_free_shash(hashalg); + if (hmacalg) + crypto_free_shash(hmacalg); +} + +static int __init encrypted_shash_alloc(void) +{ + int ret; + + hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hmacalg)) { + pr_info("encrypted_key: could not allocate crypto %s\n", + hmac_alg); + return PTR_ERR(hmacalg); + } + + hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hashalg)) { + pr_info("encrypted_key: could not allocate crypto %s\n", + hash_alg); + ret = PTR_ERR(hashalg); + goto hashalg_fail; + } + + return 0; + +hashalg_fail: + crypto_free_shash(hmacalg); + return ret; +} + +static int __init init_encrypted(void) +{ + int ret; + + ret = encrypted_shash_alloc(); + if (ret < 0) + return ret; + ret = register_key_type(&key_type_encrypted); + if (ret < 0) + goto out; + return aes_get_sizes(); +out: + encrypted_shash_release(); + return ret; + +} + +static void __exit cleanup_encrypted(void) +{ + encrypted_shash_release(); + unregister_key_type(&key_type_encrypted); +} + +late_initcall(init_encrypted); +module_exit(cleanup_encrypted); + +MODULE_LICENSE("GPL"); diff --git a/security/keys/encrypted.h b/security/keys/encrypted.h new file mode 100644 index 000000000000..cef5e2f2b7d1 --- /dev/null +++ b/security/keys/encrypted.h @@ -0,0 +1,54 @@ +#ifndef __ENCRYPTED_KEY_H +#define __ENCRYPTED_KEY_H + +#define ENCRYPTED_DEBUG 0 + +#if ENCRYPTED_DEBUG +static inline void dump_master_key(const u8 *master_key, size_t master_keylen) +{ + print_hex_dump(KERN_ERR, "master key: ", DUMP_PREFIX_NONE, 32, 1, + master_key, master_keylen, 0); +} + +static inline void dump_decrypted_data(struct encrypted_key_payload *epayload) +{ + print_hex_dump(KERN_ERR, "decrypted data: ", DUMP_PREFIX_NONE, 32, 1, + epayload->decrypted_data, + epayload->decrypted_datalen, 0); +} + +static inline void dump_encrypted_data(struct encrypted_key_payload *epayload, + unsigned int encrypted_datalen) +{ + print_hex_dump(KERN_ERR, "encrypted data: ", DUMP_PREFIX_NONE, 32, 1, + epayload->encrypted_data, encrypted_datalen, 0); +} + +static inline void dump_hmac(const char *str, const u8 *digest, + unsigned int hmac_size) +{ + if (str) + pr_info("encrypted_key: %s", str); + print_hex_dump(KERN_ERR, "hmac: ", DUMP_PREFIX_NONE, 32, 1, digest, + hmac_size, 0); +} +#else +static inline void dump_master_key(const u8 *master_key, size_t master_keylen) +{ +} + +static inline void dump_decrypted_data(struct encrypted_key_payload *epayload) +{ +} + +static inline void dump_encrypted_data(struct encrypted_key_payload *epayload, + unsigned int encrypted_datalen) +{ +} + +static inline void dump_hmac(const char *str, const u8 *digest, + unsigned int hmac_size) +{ +} +#endif +#endif diff --git a/security/keys/gc.c b/security/keys/gc.c index a46e825cbf02..89df6b5f203c 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -32,8 +32,8 @@ static time_t key_gc_next_run = LONG_MAX; static time_t key_gc_new_timer; /* - * Schedule a garbage collection run - * - precision isn't particularly important + * Schedule a garbage collection run. + * - time precision isn't particularly important */ void key_schedule_gc(time_t gc_at) { @@ -61,8 +61,9 @@ static void key_gc_timer_func(unsigned long data) } /* - * Garbage collect pointers from a keyring - * - return true if we altered the keyring + * Garbage collect pointers from a keyring. + * + * Return true if we altered the keyring. */ static bool key_gc_keyring(struct key *keyring, time_t limit) __releases(key_serial_lock) @@ -107,9 +108,8 @@ do_gc: } /* - * Garbage collector for keys - * - this involves scanning the keyrings for dead, expired and revoked keys - * that have overstayed their welcome + * Garbage collector for keys. This involves scanning the keyrings for dead, + * expired and revoked keys that have overstayed their welcome */ static void key_garbage_collector(struct work_struct *work) { diff --git a/security/keys/internal.h b/security/keys/internal.h index 56a133d8f37d..f375152a2500 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -1,4 +1,4 @@ -/* internal.h: authentication token and access key management internal defs +/* Authentication token and access key management internal defs * * Copyright (C) 2003-5, 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -35,10 +35,12 @@ extern struct key_type key_type_user; /*****************************************************************************/ /* - * keep track of keys for a user - * - this needs to be separate to user_struct to avoid a refcount-loop - * (user_struct pins some keyrings which pin this struct) - * - this also keeps track of keys under request from userspace for this UID + * Keep track of keys for a user. + * + * This needs to be separate to user_struct to avoid a refcount-loop + * (user_struct pins some keyrings which pin this struct). + * + * We also keep track of keys under request from userspace for this UID here. */ struct key_user { struct rb_node node; @@ -62,7 +64,7 @@ extern struct key_user *key_user_lookup(uid_t uid, extern void key_user_put(struct key_user *user); /* - * key quota limits + * Key quota limits. * - root has its own separate limits to everyone else */ extern unsigned key_quota_root_maxkeys; @@ -85,13 +87,13 @@ extern void key_type_put(struct key_type *ktype); extern int __key_link_begin(struct key *keyring, const struct key_type *type, const char *description, - struct keyring_list **_prealloc); + unsigned long *_prealloc); extern int __key_link_check_live_key(struct key *keyring, struct key *key); extern void __key_link(struct key *keyring, struct key *key, - struct keyring_list **_prealloc); + unsigned long *_prealloc); extern void __key_link_end(struct key *keyring, struct key_type *type, - struct keyring_list *prealloc); + unsigned long prealloc); extern key_ref_t __keyring_search_one(key_ref_t keyring_ref, const struct key_type *type, @@ -107,11 +109,13 @@ extern key_ref_t keyring_search_aux(key_ref_t keyring_ref, const struct cred *cred, struct key_type *type, const void *description, - key_match_func_t match); + key_match_func_t match, + bool no_state_check); extern key_ref_t search_my_process_keyrings(struct key_type *type, const void *description, key_match_func_t match, + bool no_state_check, const struct cred *cred); extern key_ref_t search_process_keyrings(struct key_type *type, const void *description, @@ -146,13 +150,13 @@ extern unsigned key_gc_delay; extern void keyring_gc(struct key *keyring, time_t limit); extern void key_schedule_gc(time_t expiry_at); -/* - * check to see whether permission is granted to use a key in the desired way - */ extern int key_task_permission(const key_ref_t key_ref, const struct cred *cred, key_perm_t perm); +/* + * Check to see whether permission is granted to use a key in the desired way. + */ static inline int key_permission(const key_ref_t key_ref, key_perm_t perm) { return key_task_permission(key_ref, current_cred(), perm); @@ -168,7 +172,7 @@ static inline int key_permission(const key_ref_t key_ref, key_perm_t perm) #define KEY_ALL 0x3f /* all the above permissions */ /* - * request_key authorisation + * Authorisation record for request_key(). */ struct request_key_auth { struct key *target_key; @@ -188,7 +192,7 @@ extern struct key *request_key_auth_new(struct key *target, extern struct key *key_get_instantiation_authkey(key_serial_t target_id); /* - * keyctl functions + * keyctl() functions */ extern long keyctl_get_keyring_ID(key_serial_t, int); extern long keyctl_join_session_keyring(const char __user *); @@ -212,9 +216,17 @@ extern long keyctl_assume_authority(key_serial_t); extern long keyctl_get_security(key_serial_t keyid, char __user *buffer, size_t buflen); extern long keyctl_session_to_parent(void); +extern long keyctl_reject_key(key_serial_t, unsigned, unsigned, key_serial_t); +extern long keyctl_instantiate_key_iov(key_serial_t, + const struct iovec __user *, + unsigned, key_serial_t); + +extern long keyctl_instantiate_key_common(key_serial_t, + const struct iovec __user *, + unsigned, size_t, key_serial_t); /* - * debugging key validation + * Debugging key validation */ #ifdef KEY_DEBUGGING extern void __key_check(const struct key *); diff --git a/security/keys/key.c b/security/keys/key.c index c1eac8084ade..f7f9d93f08d9 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -39,10 +39,10 @@ static DECLARE_RWSEM(key_types_sem); static void key_cleanup(struct work_struct *work); static DECLARE_WORK(key_cleanup_task, key_cleanup); -/* we serialise key instantiation and link */ +/* We serialise key instantiation and link */ DEFINE_MUTEX(key_construction_mutex); -/* any key who's type gets unegistered will be re-typed to this */ +/* Any key who's type gets unegistered will be re-typed to this */ static struct key_type key_type_dead = { .name = "dead", }; @@ -56,10 +56,9 @@ void __key_check(const struct key *key) } #endif -/*****************************************************************************/ /* - * get the key quota record for a user, allocating a new record if one doesn't - * already exist + * Get the key quota record for a user, allocating a new record if one doesn't + * already exist. */ struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns) { @@ -67,7 +66,7 @@ struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns) struct rb_node *parent = NULL; struct rb_node **p; - try_again: +try_again: p = &key_user_tree.rb_node; spin_lock(&key_user_lock); @@ -124,18 +123,16 @@ struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns) goto out; /* okay - we found a user record for this UID */ - found: +found: atomic_inc(&user->usage); spin_unlock(&key_user_lock); kfree(candidate); - out: +out: return user; +} -} /* end key_user_lookup() */ - -/*****************************************************************************/ /* - * dispose of a user structure + * Dispose of a user structure */ void key_user_put(struct key_user *user) { @@ -146,14 +143,11 @@ void key_user_put(struct key_user *user) kfree(user); } +} -} /* end key_user_put() */ - -/*****************************************************************************/ /* - * assign a key the next unique serial number - * - these are assigned randomly to avoid security issues through covert - * channel problems + * Allocate a serial number for a key. These are assigned randomly to avoid + * security issues through covert channel problems. */ static inline void key_alloc_serial(struct key *key) { @@ -211,18 +205,36 @@ serial_exists: if (key->serial < xkey->serial) goto attempt_insertion; } +} -} /* end key_alloc_serial() */ - -/*****************************************************************************/ -/* - * allocate a key of the specified type - * - update the user's quota to reflect the existence of the key - * - called from a key-type operation with key_types_sem read-locked by - * key_create_or_update() - * - this prevents unregistration of the key type - * - upon return the key is as yet uninstantiated; the caller needs to either - * instantiate the key or discard it before returning +/** + * key_alloc - Allocate a key of the specified type. + * @type: The type of key to allocate. + * @desc: The key description to allow the key to be searched out. + * @uid: The owner of the new key. + * @gid: The group ID for the new key's group permissions. + * @cred: The credentials specifying UID namespace. + * @perm: The permissions mask of the new key. + * @flags: Flags specifying quota properties. + * + * Allocate a key of the specified type with the attributes given. The key is + * returned in an uninstantiated state and the caller needs to instantiate the + * key before returning. + * + * The user's key count quota is updated to reflect the creation of the key and + * the user's key data quota has the default for the key type reserved. The + * instantiation function should amend this as necessary. If insufficient + * quota is available, -EDQUOT will be returned. + * + * The LSM security modules can prevent a key being created, in which case + * -EACCES will be returned. + * + * Returns a pointer to the new key if successful and an error code otherwise. + * + * Note that the caller needs to ensure the key type isn't uninstantiated. + * Internally this can be done by locking key_types_sem. Externally, this can + * be done by either never unregistering the key type, or making sure + * key_alloc() calls don't race with module unloading. */ struct key *key_alloc(struct key_type *type, const char *desc, uid_t uid, gid_t gid, const struct cred *cred, @@ -237,6 +249,14 @@ struct key *key_alloc(struct key_type *type, const char *desc, if (!desc || !*desc) goto error; + if (type->vet_description) { + ret = type->vet_description(desc); + if (ret < 0) { + key = ERR_PTR(ret); + goto error; + } + } + desclen = strlen(desc) + 1; quotalen = desclen + type->def_datalen; @@ -344,14 +364,19 @@ no_quota: key_user_put(user); key = ERR_PTR(-EDQUOT); goto error; - -} /* end key_alloc() */ - +} EXPORT_SYMBOL(key_alloc); -/*****************************************************************************/ -/* - * reserve an amount of quota for the key's payload +/** + * key_payload_reserve - Adjust data quota reservation for the key's payload + * @key: The key to make the reservation for. + * @datalen: The amount of data payload the caller now wants. + * + * Adjust the amount of the owning user's key data quota that a key reserves. + * If the amount is increased, then -EDQUOT may be returned if there isn't + * enough free quota available. + * + * If successful, 0 is returned. */ int key_payload_reserve(struct key *key, size_t datalen) { @@ -384,22 +409,21 @@ int key_payload_reserve(struct key *key, size_t datalen) key->datalen = datalen; return ret; - -} /* end key_payload_reserve() */ - +} EXPORT_SYMBOL(key_payload_reserve); -/*****************************************************************************/ /* - * instantiate a key and link it into the target keyring atomically - * - called with the target keyring's semaphore writelocked + * Instantiate a key and link it into the target keyring atomically. Must be + * called with the target keyring's semaphore writelocked. The target key's + * semaphore need not be locked as instantiation is serialised by + * key_construction_mutex. */ static int __key_instantiate_and_link(struct key *key, const void *data, size_t datalen, struct key *keyring, struct key *authkey, - struct keyring_list **_prealloc) + unsigned long *_prealloc) { int ret, awaken; @@ -441,12 +465,23 @@ static int __key_instantiate_and_link(struct key *key, wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); return ret; +} -} /* end __key_instantiate_and_link() */ - -/*****************************************************************************/ -/* - * instantiate a key and link it into the target keyring atomically +/** + * key_instantiate_and_link - Instantiate a key and link it into the keyring. + * @key: The key to instantiate. + * @data: The data to use to instantiate the keyring. + * @datalen: The length of @data. + * @keyring: Keyring to create a link in on success (or NULL). + * @authkey: The authorisation token permitting instantiation. + * + * Instantiate a key that's in the uninstantiated state using the provided data + * and, if successful, link it in to the destination keyring if one is + * supplied. + * + * If successful, 0 is returned, the authorisation token is revoked and anyone + * waiting for the key is woken up. If the key was already instantiated, + * -EBUSY will be returned. */ int key_instantiate_and_link(struct key *key, const void *data, @@ -454,7 +489,7 @@ int key_instantiate_and_link(struct key *key, struct key *keyring, struct key *authkey) { - struct keyring_list *prealloc; + unsigned long prealloc; int ret; if (keyring) { @@ -471,21 +506,38 @@ int key_instantiate_and_link(struct key *key, __key_link_end(keyring, key->type, prealloc); return ret; - -} /* end key_instantiate_and_link() */ +} EXPORT_SYMBOL(key_instantiate_and_link); -/*****************************************************************************/ -/* - * negatively instantiate a key and link it into the target keyring atomically +/** + * key_reject_and_link - Negatively instantiate a key and link it into the keyring. + * @key: The key to instantiate. + * @timeout: The timeout on the negative key. + * @error: The error to return when the key is hit. + * @keyring: Keyring to create a link in on success (or NULL). + * @authkey: The authorisation token permitting instantiation. + * + * Negatively instantiate a key that's in the uninstantiated state and, if + * successful, set its timeout and stored error and link it in to the + * destination keyring if one is supplied. The key and any links to the key + * will be automatically garbage collected after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return the stored error code (typically ENOKEY) until the negative + * key expires. + * + * If successful, 0 is returned, the authorisation token is revoked and anyone + * waiting for the key is woken up. If the key was already instantiated, + * -EBUSY will be returned. */ -int key_negate_and_link(struct key *key, +int key_reject_and_link(struct key *key, unsigned timeout, + unsigned error, struct key *keyring, struct key *authkey) { - struct keyring_list *prealloc; + unsigned long prealloc; struct timespec now; int ret, awaken, link_ret = 0; @@ -507,6 +559,7 @@ int key_negate_and_link(struct key *key, atomic_inc(&key->user->nikeys); set_bit(KEY_FLAG_NEGATIVE, &key->flags); set_bit(KEY_FLAG_INSTANTIATED, &key->flags); + key->type_data.reject_error = -error; now = current_kernel_time(); key->expiry = now.tv_sec + timeout; key_schedule_gc(key->expiry + key_gc_delay); @@ -535,22 +588,22 @@ int key_negate_and_link(struct key *key, wake_up_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT); return ret == 0 ? link_ret : ret; +} +EXPORT_SYMBOL(key_reject_and_link); -} /* end key_negate_and_link() */ - -EXPORT_SYMBOL(key_negate_and_link); - -/*****************************************************************************/ /* - * do cleaning up in process context so that we don't have to disable - * interrupts all over the place + * Garbage collect keys in process context so that we don't have to disable + * interrupts all over the place. + * + * key_put() schedules this rather than trying to do the cleanup itself, which + * means key_put() doesn't have to sleep. */ static void key_cleanup(struct work_struct *work) { struct rb_node *_n; struct key *key; - go_again: +go_again: /* look for a dead key in the tree */ spin_lock(&key_serial_lock); @@ -564,7 +617,7 @@ static void key_cleanup(struct work_struct *work) spin_unlock(&key_serial_lock); return; - found_dead_key: +found_dead_key: /* we found a dead key - once we've removed it from the tree, we can * drop the lock */ rb_erase(&key->serial_node, &key_serial_tree); @@ -601,14 +654,15 @@ static void key_cleanup(struct work_struct *work) /* there may, of course, be more than one key to destroy */ goto go_again; +} -} /* end key_cleanup() */ - -/*****************************************************************************/ -/* - * dispose of a reference to a key - * - when all the references are gone, we schedule the cleanup task to come and - * pull it out of the tree in definite process context +/** + * key_put - Discard a reference to a key. + * @key: The key to discard a reference from. + * + * Discard a reference to a key, and when all the references are gone, we + * schedule the cleanup task to come and pull it out of the tree in process + * context at some later time. */ void key_put(struct key *key) { @@ -618,14 +672,11 @@ void key_put(struct key *key) if (atomic_dec_and_test(&key->usage)) schedule_work(&key_cleanup_task); } - -} /* end key_put() */ - +} EXPORT_SYMBOL(key_put); -/*****************************************************************************/ /* - * find a key by its serial number + * Find a key by its serial number. */ struct key *key_lookup(key_serial_t id) { @@ -647,11 +698,11 @@ struct key *key_lookup(key_serial_t id) goto found; } - not_found: +not_found: key = ERR_PTR(-ENOKEY); goto error; - found: +found: /* pretend it doesn't exist if it is awaiting deletion */ if (atomic_read(&key->usage) == 0) goto not_found; @@ -661,16 +712,16 @@ struct key *key_lookup(key_serial_t id) */ atomic_inc(&key->usage); - error: +error: spin_unlock(&key_serial_lock); return key; +} -} /* end key_lookup() */ - -/*****************************************************************************/ /* - * find and lock the specified key type against removal - * - we return with the sem readlocked + * Find and lock the specified key type against removal. + * + * We return with the sem read-locked if successful. If the type wasn't + * available -ENOKEY is returned instead. */ struct key_type *key_type_lookup(const char *type) { @@ -688,26 +739,23 @@ struct key_type *key_type_lookup(const char *type) up_read(&key_types_sem); ktype = ERR_PTR(-ENOKEY); - found_kernel_type: +found_kernel_type: return ktype; +} -} /* end key_type_lookup() */ - -/*****************************************************************************/ /* - * unlock a key type + * Unlock a key type locked by key_type_lookup(). */ void key_type_put(struct key_type *ktype) { up_read(&key_types_sem); +} -} /* end key_type_put() */ - -/*****************************************************************************/ /* - * attempt to update an existing key - * - the key has an incremented refcount - * - we need to put the key if we get an error + * Attempt to update an existing key. + * + * The key is given to us with an incremented refcount that we need to discard + * if we get an error. */ static inline key_ref_t __key_update(key_ref_t key_ref, const void *payload, size_t plen) @@ -742,13 +790,32 @@ error: key_put(key); key_ref = ERR_PTR(ret); goto out; +} -} /* end __key_update() */ - -/*****************************************************************************/ -/* - * search the specified keyring for a key of the same description; if one is - * found, update it, otherwise add a new one +/** + * key_create_or_update - Update or create and instantiate a key. + * @keyring_ref: A pointer to the destination keyring with possession flag. + * @type: The type of key. + * @description: The searchable description for the key. + * @payload: The data to use to instantiate or update the key. + * @plen: The length of @payload. + * @perm: The permissions mask for a new key. + * @flags: The quota flags for a new key. + * + * Search the destination keyring for a key of the same description and if one + * is found, update it, otherwise create and instantiate a new one and create a + * link to it from that keyring. + * + * If perm is KEY_PERM_UNDEF then an appropriate key permissions mask will be + * concocted. + * + * Returns a pointer to the new key if successful, -ENODEV if the key type + * wasn't available, -ENOTDIR if the keyring wasn't a keyring, -EACCES if the + * caller isn't permitted to modify the keyring or the LSM did not permit + * creation of the key. + * + * On success, the possession flag from the keyring ref will be tacked on to + * the key ref before it is returned. */ key_ref_t key_create_or_update(key_ref_t keyring_ref, const char *type, @@ -758,7 +825,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, key_perm_t perm, unsigned long flags) { - struct keyring_list *prealloc; + unsigned long prealloc; const struct cred *cred = current_cred(); struct key_type *ktype; struct key *keyring, *key = NULL; @@ -855,14 +922,21 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, key_ref = __key_update(key_ref, payload, plen); goto error; - -} /* end key_create_or_update() */ - +} EXPORT_SYMBOL(key_create_or_update); -/*****************************************************************************/ -/* - * update a key +/** + * key_update - Update a key's contents. + * @key_ref: The pointer (plus possession flag) to the key. + * @payload: The data to be used to update the key. + * @plen: The length of @payload. + * + * Attempt to update the contents of a key with the given payload data. The + * caller must be granted Write permission on the key. Negative keys can be + * instantiated by this method. + * + * Returns 0 on success, -EACCES if not permitted and -EOPNOTSUPP if the key + * type does not support updating. The key type may return other errors. */ int key_update(key_ref_t key_ref, const void *payload, size_t plen) { @@ -891,14 +965,17 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen) error: return ret; - -} /* end key_update() */ - +} EXPORT_SYMBOL(key_update); -/*****************************************************************************/ -/* - * revoke a key +/** + * key_revoke - Revoke a key. + * @key: The key to be revoked. + * + * Mark a key as being revoked and ask the type to free up its resources. The + * revocation timeout is set and the key and all its links will be + * automatically garbage collected after key_gc_delay amount of time if they + * are not manually dealt with first. */ void key_revoke(struct key *key) { @@ -926,14 +1003,16 @@ void key_revoke(struct key *key) } up_write(&key->sem); - -} /* end key_revoke() */ - +} EXPORT_SYMBOL(key_revoke); -/*****************************************************************************/ -/* - * register a type of key +/** + * register_key_type - Register a type of key. + * @ktype: The new key type. + * + * Register a new key type. + * + * Returns 0 on success or -EEXIST if a type of this name already exists. */ int register_key_type(struct key_type *ktype) { @@ -953,17 +1032,19 @@ int register_key_type(struct key_type *ktype) list_add(&ktype->link, &key_types_list); ret = 0; - out: +out: up_write(&key_types_sem); return ret; - -} /* end register_key_type() */ - +} EXPORT_SYMBOL(register_key_type); -/*****************************************************************************/ -/* - * unregister a type of key +/** + * unregister_key_type - Unregister a type of key. + * @ktype: The key type. + * + * Unregister a key type and mark all the extant keys of this type as dead. + * Those keys of this type are then destroyed to get rid of their payloads and + * they and their links will be garbage collected as soon as possible. */ void unregister_key_type(struct key_type *ktype) { @@ -1010,14 +1091,11 @@ void unregister_key_type(struct key_type *ktype) up_write(&key_types_sem); key_schedule_gc(0); - -} /* end unregister_key_type() */ - +} EXPORT_SYMBOL(unregister_key_type); -/*****************************************************************************/ /* - * initialise the key management stuff + * Initialise the key management state. */ void __init key_init(void) { @@ -1037,5 +1115,4 @@ void __init key_init(void) rb_insert_color(&root_key_user.node, &key_user_tree); - -} /* end key_init() */ +} diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 60924f6a52db..eca51918c951 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1,4 +1,4 @@ -/* keyctl.c: userspace keyctl operations +/* Userspace key control operations * * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -31,28 +31,24 @@ static int key_get_type_from_user(char *type, int ret; ret = strncpy_from_user(type, _type, len); - if (ret < 0) return ret; - if (ret == 0 || ret >= len) return -EINVAL; - if (type[0] == '.') return -EPERM; - type[len - 1] = '\0'; - return 0; } -/*****************************************************************************/ /* - * extract the description of a new key from userspace and either add it as a - * new key to the specified keyring or update a matching key in that keyring - * - the keyring must be writable - * - returns the new key's serial number - * - implements add_key() + * Extract the description of a new key from userspace and either add it as a + * new key to the specified keyring or update a matching key in that keyring. + * + * The keyring must be writable so that we can attach the key to it. + * + * If successful, the new key's serial number is returned, otherwise an error + * code is returned. */ SYSCALL_DEFINE5(add_key, const char __user *, _type, const char __user *, _description, @@ -132,19 +128,20 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type, kfree(description); error: return ret; +} -} /* end sys_add_key() */ - -/*****************************************************************************/ /* - * search the process keyrings for a matching key - * - nested keyrings may also be searched if they have Search permission - * - if a key is found, it will be attached to the destination keyring if - * there's one specified - * - /sbin/request-key will be invoked if _callout_info is non-NULL - * - the _callout_info string will be passed to /sbin/request-key - * - if the _callout_info string is empty, it will be rendered as "-" - * - implements request_key() + * Search the process keyrings and keyring trees linked from those for a + * matching key. Keyrings must have appropriate Search permission to be + * searched. + * + * If a key is found, it will be attached to the destination keyring if there's + * one specified and the serial number of the key will be returned. + * + * If no key is found, /sbin/request-key will be invoked if _callout_info is + * non-NULL in an attempt to create a key. The _callout_info string will be + * passed to /sbin/request-key to aid with completing the request. If the + * _callout_info string is "" then it will be changed to "-". */ SYSCALL_DEFINE4(request_key, const char __user *, _type, const char __user *, _description, @@ -209,8 +206,14 @@ SYSCALL_DEFINE4(request_key, const char __user *, _type, goto error5; } + /* wait for the key to finish being constructed */ + ret = wait_for_key_construction(key, 1); + if (ret < 0) + goto error6; + ret = key->serial; +error6: key_put(key); error5: key_type_put(ktype); @@ -222,14 +225,14 @@ error2: kfree(description); error: return ret; +} -} /* end sys_request_key() */ - -/*****************************************************************************/ /* - * get the ID of the specified process keyring - * - the keyring must have search permission to be found - * - implements keyctl(KEYCTL_GET_KEYRING_ID) + * Get the ID of the specified process keyring. + * + * The requested keyring must have search permission to be found. + * + * If successful, the ID of the requested keyring will be returned. */ long keyctl_get_keyring_ID(key_serial_t id, int create) { @@ -248,13 +251,17 @@ long keyctl_get_keyring_ID(key_serial_t id, int create) key_ref_put(key_ref); error: return ret; +} -} /* end keyctl_get_keyring_ID() */ - -/*****************************************************************************/ /* - * join the session keyring - * - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING) + * Join a (named) session keyring. + * + * Create and join an anonymous session keyring or join a named session + * keyring, creating it if necessary. A named session keyring must have Search + * permission for it to be joined. Session keyrings without this permit will + * be skipped over. + * + * If successful, the ID of the joined session keyring will be returned. */ long keyctl_join_session_keyring(const char __user *_name) { @@ -277,14 +284,17 @@ long keyctl_join_session_keyring(const char __user *_name) error: return ret; +} -} /* end keyctl_join_session_keyring() */ - -/*****************************************************************************/ /* - * update a key's data payload - * - the key must be writable - * - implements keyctl(KEYCTL_UPDATE) + * Update a key's data payload from the given data. + * + * The key must grant the caller Write permission and the key type must support + * updating for this to work. A negative key can be positively instantiated + * with this call. + * + * If successful, 0 will be returned. If the key type does not support + * updating, then -EOPNOTSUPP will be returned. */ long keyctl_update_key(key_serial_t id, const void __user *_payload, @@ -326,14 +336,17 @@ error2: kfree(payload); error: return ret; +} -} /* end keyctl_update_key() */ - -/*****************************************************************************/ /* - * revoke a key - * - the key must be writable - * - implements keyctl(KEYCTL_REVOKE) + * Revoke a key. + * + * The key must be grant the caller Write or Setattr permission for this to + * work. The key type should give up its quota claim when revoked. The key + * and any links to the key will be automatically garbage collected after a + * certain amount of time (/proc/sys/kernel/keys/gc_delay). + * + * If successful, 0 is returned. */ long keyctl_revoke_key(key_serial_t id) { @@ -358,14 +371,14 @@ long keyctl_revoke_key(key_serial_t id) key_ref_put(key_ref); error: return ret; +} -} /* end keyctl_revoke_key() */ - -/*****************************************************************************/ /* - * clear the specified process keyring - * - the keyring must be writable - * - implements keyctl(KEYCTL_CLEAR) + * Clear the specified keyring, creating an empty process keyring if one of the + * special keyring IDs is used. + * + * The keyring must grant the caller Write permission for this to work. If + * successful, 0 will be returned. */ long keyctl_keyring_clear(key_serial_t ringid) { @@ -383,15 +396,18 @@ long keyctl_keyring_clear(key_serial_t ringid) key_ref_put(keyring_ref); error: return ret; +} -} /* end keyctl_keyring_clear() */ - -/*****************************************************************************/ /* - * link a key into a keyring - * - the keyring must be writable - * - the key must be linkable - * - implements keyctl(KEYCTL_LINK) + * Create a link from a keyring to a key if there's no matching key in the + * keyring, otherwise replace the link to the matching key with a link to the + * new key. + * + * The key must grant the caller Link permission and the the keyring must grant + * the caller Write permission. Furthermore, if an additional link is created, + * the keyring's quota will be extended. + * + * If successful, 0 will be returned. */ long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) { @@ -417,15 +433,16 @@ error2: key_ref_put(keyring_ref); error: return ret; +} -} /* end keyctl_keyring_link() */ - -/*****************************************************************************/ /* - * unlink the first attachment of a key from a keyring - * - the keyring must be writable - * - we don't need any permissions on the key - * - implements keyctl(KEYCTL_UNLINK) + * Unlink a key from a keyring. + * + * The keyring must grant the caller Write permission for this to work; the key + * itself need not grant the caller anything. If the last link to a key is + * removed then that key will be scheduled for destruction. + * + * If successful, 0 will be returned. */ long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) { @@ -451,19 +468,20 @@ error2: key_ref_put(keyring_ref); error: return ret; +} -} /* end keyctl_keyring_unlink() */ - -/*****************************************************************************/ /* - * describe a user key - * - the key must have view permission - * - if there's a buffer, we place up to buflen bytes of data into it - * - unless there's an error, we return the amount of description available, - * irrespective of how much we may have copied - * - the description is formatted thus: + * Return a description of a key to userspace. + * + * The key must grant the caller View permission for this to work. + * + * If there's a buffer, we place up to buflen bytes of data into it formatted + * in the following way: + * * type;uid;gid;perm;description<NUL> - * - implements keyctl(KEYCTL_DESCRIBE) + * + * If successful, we return the amount of description available, irrespective + * of how much we may have copied into the buffer. */ long keyctl_describe_key(key_serial_t keyid, char __user *buffer, @@ -531,18 +549,17 @@ error2: key_ref_put(key_ref); error: return ret; +} -} /* end keyctl_describe_key() */ - -/*****************************************************************************/ /* - * search the specified keyring for a matching key - * - the start keyring must be searchable - * - nested keyrings may also be searched if they are searchable - * - only keys with search permission may be found - * - if a key is found, it will be attached to the destination keyring if - * there's one specified - * - implements keyctl(KEYCTL_SEARCH) + * Search the specified keyring and any keyrings it links to for a matching + * key. Only keyrings that grant the caller Search permission will be searched + * (this includes the starting keyring). Only keys with Search permission can + * be found. + * + * If successful, the found key will be linked to the destination keyring if + * supplied and the key has Link permission, and the found key ID will be + * returned. */ long keyctl_keyring_search(key_serial_t ringid, const char __user *_type, @@ -626,18 +643,17 @@ error2: kfree(description); error: return ret; +} -} /* end keyctl_keyring_search() */ - -/*****************************************************************************/ /* - * read a user key's payload - * - the keyring must be readable or the key must be searchable from the - * process's keyrings - * - if there's a buffer, we place up to buflen bytes of data into it - * - unless there's an error, we return the amount of data in the key, - * irrespective of how much we may have copied - * - implements keyctl(KEYCTL_READ) + * Read a key's payload. + * + * The key must either grant the caller Read permission, or it must grant the + * caller Search permission when searched for from the process keyrings. + * + * If successful, we place up to buflen bytes of data into the buffer, if one + * is provided, and return the amount of data that is available in the key, + * irrespective of how much we copied into the buffer. */ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) { @@ -688,15 +704,22 @@ error2: key_put(key); error: return ret; +} -} /* end keyctl_read_key() */ - -/*****************************************************************************/ /* - * change the ownership of a key - * - the keyring owned by the changer - * - if the uid or gid is -1, then that parameter is not changed - * - implements keyctl(KEYCTL_CHOWN) + * Change the ownership of a key + * + * The key must grant the caller Setattr permission for this to work, though + * the key need not be fully instantiated yet. For the UID to be changed, or + * for the GID to be changed to a group the caller is not a member of, the + * caller must have sysadmin capability. If either uid or gid is -1 then that + * attribute is not changed. + * + * If the UID is to be changed, the new user must have sufficient quota to + * accept the key. The quota deduction will be removed from the old user to + * the new user should the attribute be changed. + * + * If successful, 0 will be returned. */ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) { @@ -796,14 +819,14 @@ quota_overrun: zapowner = newowner; ret = -EDQUOT; goto error_put; +} -} /* end keyctl_chown_key() */ - -/*****************************************************************************/ /* - * change the permission mask on a key - * - the keyring owned by the changer - * - implements keyctl(KEYCTL_SETPERM) + * Change the permission mask on a key. + * + * The key must grant the caller Setattr permission for this to work, though + * the key need not be fully instantiated yet. If the caller does not have + * sysadmin capability, it may only change the permission on keys that it owns. */ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) { @@ -838,11 +861,11 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) key_put(key); error: return ret; - -} /* end keyctl_setperm_key() */ +} /* - * get the destination keyring for instantiation + * Get the destination keyring for instantiation and check that the caller has + * Write permission on it. */ static long get_instantiation_keyring(key_serial_t ringid, struct request_key_auth *rka, @@ -879,7 +902,7 @@ static long get_instantiation_keyring(key_serial_t ringid, } /* - * change the request_key authorisation key on the current process + * Change the request_key authorisation key on the current process. */ static int keyctl_change_reqkey_auth(struct key *key) { @@ -895,15 +918,35 @@ static int keyctl_change_reqkey_auth(struct key *key) return commit_creds(new); } -/*****************************************************************************/ /* - * instantiate the key with the specified payload, and, if one is given, link - * the key into the keyring + * Copy the iovec data from userspace */ -long keyctl_instantiate_key(key_serial_t id, - const void __user *_payload, - size_t plen, - key_serial_t ringid) +static long copy_from_user_iovec(void *buffer, const struct iovec *iov, + unsigned ioc) +{ + for (; ioc > 0; ioc--) { + if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0) + return -EFAULT; + buffer += iov->iov_len; + iov++; + } + return 0; +} + +/* + * Instantiate a key with the specified payload and link the key into the + * destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key_common(key_serial_t id, + const struct iovec *payload_iov, + unsigned ioc, + size_t plen, + key_serial_t ringid) { const struct cred *cred = current_cred(); struct request_key_auth *rka; @@ -932,7 +975,7 @@ long keyctl_instantiate_key(key_serial_t id, /* pull the payload in if one was supplied */ payload = NULL; - if (_payload) { + if (payload_iov) { ret = -ENOMEM; payload = kmalloc(plen, GFP_KERNEL); if (!payload) { @@ -944,8 +987,8 @@ long keyctl_instantiate_key(key_serial_t id, goto error; } - ret = -EFAULT; - if (copy_from_user(payload, _payload, plen) != 0) + ret = copy_from_user_iovec(payload, payload_iov, ioc); + if (ret < 0) goto error2; } @@ -973,22 +1016,127 @@ error2: vfree(payload); error: return ret; +} + +/* + * Instantiate a key with the specified payload and link the key into the + * destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key(key_serial_t id, + const void __user *_payload, + size_t plen, + key_serial_t ringid) +{ + if (_payload && plen) { + struct iovec iov[1] = { + [0].iov_base = (void __user *)_payload, + [0].iov_len = plen + }; -} /* end keyctl_instantiate_key() */ + return keyctl_instantiate_key_common(id, iov, 1, plen, ringid); + } + + return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); +} -/*****************************************************************************/ /* - * negatively instantiate the key with the given timeout (in seconds), and, if - * one is given, link the key into the keyring + * Instantiate a key with the specified multipart payload and link the key into + * the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * If successful, 0 will be returned. + */ +long keyctl_instantiate_key_iov(key_serial_t id, + const struct iovec __user *_payload_iov, + unsigned ioc, + key_serial_t ringid) +{ + struct iovec iovstack[UIO_FASTIOV], *iov = iovstack; + long ret; + + if (_payload_iov == 0 || ioc == 0) + goto no_payload; + + ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc, + ARRAY_SIZE(iovstack), iovstack, &iov); + if (ret < 0) + return ret; + if (ret == 0) + goto no_payload_free; + + ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid); + + if (iov != iovstack) + kfree(iov); + return ret; + +no_payload_free: + if (iov != iovstack) + kfree(iov); +no_payload: + return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); +} + +/* + * Negatively instantiate the key with the given timeout (in seconds) and link + * the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * The key and any links to the key will be automatically garbage collected + * after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return -ENOKEY until the negative key expires. + * + * If successful, 0 will be returned. */ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) { + return keyctl_reject_key(id, timeout, ENOKEY, ringid); +} + +/* + * Negatively instantiate the key with the given timeout (in seconds) and error + * code and link the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * The key and any links to the key will be automatically garbage collected + * after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return the specified error code until the negative key expires. + * + * If successful, 0 will be returned. + */ +long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error, + key_serial_t ringid) +{ const struct cred *cred = current_cred(); struct request_key_auth *rka; struct key *instkey, *dest_keyring; long ret; - kenter("%d,%u,%d", id, timeout, ringid); + kenter("%d,%u,%u,%d", id, timeout, error, ringid); + + /* must be a valid error code and mustn't be a kernel special */ + if (error <= 0 || + error >= MAX_ERRNO || + error == ERESTARTSYS || + error == ERESTARTNOINTR || + error == ERESTARTNOHAND || + error == ERESTART_RESTARTBLOCK) + return -EINVAL; /* the appropriate instantiation authorisation key must have been * assumed before calling this */ @@ -1008,7 +1156,7 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) goto error; /* instantiate the key and link it into a keyring */ - ret = key_negate_and_link(rka->target_key, timeout, + ret = key_reject_and_link(rka->target_key, timeout, error, dest_keyring, instkey); key_put(dest_keyring); @@ -1020,13 +1168,14 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) error: return ret; +} -} /* end keyctl_negate_key() */ - -/*****************************************************************************/ /* - * set the default keyring in which request_key() will cache keys - * - return the old setting + * Read or set the default keyring in which request_key() will cache keys and + * return the old setting. + * + * If a process keyring is specified then this will be created if it doesn't + * yet exist. The old setting will be returned if successful. */ long keyctl_set_reqkey_keyring(int reqkey_defl) { @@ -1079,12 +1228,19 @@ set: error: abort_creds(new); return ret; +} -} /* end keyctl_set_reqkey_keyring() */ - -/*****************************************************************************/ /* - * set or clear the timeout for a key + * Set or clear the timeout on a key. + * + * Either the key must grant the caller Setattr permission or else the caller + * must hold an instantiation authorisation token for the key. + * + * The timeout is either 0 to clear the timeout, or a number of seconds from + * the current time. The key and any links to the key will be automatically + * garbage collected after the timeout expires. + * + * If successful, 0 is returned. */ long keyctl_set_timeout(key_serial_t id, unsigned timeout) { @@ -1136,12 +1292,24 @@ okay: ret = 0; error: return ret; +} -} /* end keyctl_set_timeout() */ - -/*****************************************************************************/ /* - * assume the authority to instantiate the specified key + * Assume (or clear) the authority to instantiate the specified key. + * + * This sets the authoritative token currently in force for key instantiation. + * This must be done for a key to be instantiated. It has the effect of making + * available all the keys from the caller of the request_key() that created a + * key to request_key() calls made by the caller of this function. + * + * The caller must have the instantiation key in their process keyrings with a + * Search permission grant available to the caller. + * + * If the ID given is 0, then the setting will be cleared and 0 returned. + * + * If the ID given has a matching an authorisation key, then that key will be + * set and its ID will be returned. The authorisation key can be read to get + * the callout information passed to request_key(). */ long keyctl_assume_authority(key_serial_t id) { @@ -1178,16 +1346,17 @@ long keyctl_assume_authority(key_serial_t id) ret = authkey->serial; error: return ret; - -} /* end keyctl_assume_authority() */ +} /* - * get the security label of a key - * - the key must grant us view permission - * - if there's a buffer, we place up to buflen bytes of data into it - * - unless there's an error, we return the amount of information available, - * irrespective of how much we may have copied (including the terminal NUL) - * - implements keyctl(KEYCTL_GET_SECURITY) + * Get a key's the LSM security label. + * + * The key must grant the caller View permission for this to work. + * + * If there's a buffer, then up to buflen bytes of data will be placed into it. + * + * If successful, the amount of information available will be returned, + * irrespective of how much was copied (including the terminal NUL). */ long keyctl_get_security(key_serial_t keyid, char __user *buffer, @@ -1242,10 +1411,16 @@ long keyctl_get_security(key_serial_t keyid, } /* - * attempt to install the calling process's session keyring on the process's - * parent process - * - the keyring must exist and must grant us LINK permission - * - implements keyctl(KEYCTL_SESSION_TO_PARENT) + * Attempt to install the calling process's session keyring on the process's + * parent process. + * + * The keyring must exist and must grant the caller LINK permission, and the + * parent process must be single-threaded and must have the same effective + * ownership as this process and mustn't be SUID/SGID. + * + * The keyring will be emplaced on the parent when it next resumes userspace. + * + * If successful, 0 will be returned. */ long keyctl_session_to_parent(void) { @@ -1348,9 +1523,8 @@ error_keyring: #endif /* !TIF_NOTIFY_RESUME */ } -/*****************************************************************************/ /* - * the key control system call + * The key control system call */ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, unsigned long, arg4, unsigned long, arg5) @@ -1436,8 +1610,20 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, case KEYCTL_SESSION_TO_PARENT: return keyctl_session_to_parent(); + case KEYCTL_REJECT: + return keyctl_reject_key((key_serial_t) arg2, + (unsigned) arg3, + (unsigned) arg4, + (key_serial_t) arg5); + + case KEYCTL_INSTANTIATE_IOV: + return keyctl_instantiate_key_iov( + (key_serial_t) arg2, + (const struct iovec __user *) arg3, + (unsigned) arg4, + (key_serial_t) arg5); + default: return -EOPNOTSUPP; } - -} /* end sys_keyctl() */ +} diff --git a/security/keys/keyring.c b/security/keys/keyring.c index d37f713e73ce..a06ffab38568 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -25,14 +25,16 @@ (keyring)->payload.subscriptions, \ rwsem_is_locked((struct rw_semaphore *)&(keyring)->sem))) +#define KEY_LINK_FIXQUOTA 1UL + /* - * when plumbing the depths of the key tree, this sets a hard limit set on how - * deep we're willing to go + * When plumbing the depths of the key tree, this sets a hard limit + * set on how deep we're willing to go. */ #define KEYRING_SEARCH_MAX_DEPTH 6 /* - * we keep all named keyrings in a hash to speed looking them up + * We keep all named keyrings in a hash to speed looking them up. */ #define KEYRING_NAME_HASH_SIZE (1 << 5) @@ -50,7 +52,9 @@ static inline unsigned keyring_hash(const char *desc) } /* - * the keyring type definition + * The keyring key type definition. Keyrings are simply keys of this type and + * can be treated as ordinary keys in addition to having their own special + * operations. */ static int keyring_instantiate(struct key *keyring, const void *data, size_t datalen); @@ -71,19 +75,17 @@ struct key_type key_type_keyring = { .describe = keyring_describe, .read = keyring_read, }; - EXPORT_SYMBOL(key_type_keyring); /* - * semaphore to serialise link/link calls to prevent two link calls in parallel - * introducing a cycle + * Semaphore to serialise link/link calls to prevent two link calls in parallel + * introducing a cycle. */ static DECLARE_RWSEM(keyring_serialise_link_sem); -/*****************************************************************************/ /* - * publish the name of a keyring so that it can be found by name (if it has - * one) + * Publish the name of a keyring so that it can be found by name (if it has + * one). */ static void keyring_publish_name(struct key *keyring) { @@ -102,13 +104,12 @@ static void keyring_publish_name(struct key *keyring) write_unlock(&keyring_name_lock); } +} -} /* end keyring_publish_name() */ - -/*****************************************************************************/ /* - * initialise a keyring - * - we object if we were given any data + * Initialise a keyring. + * + * Returns 0 on success, -EINVAL if given any data. */ static int keyring_instantiate(struct key *keyring, const void *data, size_t datalen) @@ -123,23 +124,20 @@ static int keyring_instantiate(struct key *keyring, } return ret; +} -} /* end keyring_instantiate() */ - -/*****************************************************************************/ /* - * match keyrings on their name + * Match keyrings on their name */ static int keyring_match(const struct key *keyring, const void *description) { return keyring->description && strcmp(keyring->description, description) == 0; +} -} /* end keyring_match() */ - -/*****************************************************************************/ /* - * dispose of the data dangling from the corpse of a keyring + * Clean up a keyring when it is destroyed. Unpublish its name if it had one + * and dispose of its data. */ static void keyring_destroy(struct key *keyring) { @@ -164,12 +162,10 @@ static void keyring_destroy(struct key *keyring) key_put(klist->keys[loop]); kfree(klist); } +} -} /* end keyring_destroy() */ - -/*****************************************************************************/ /* - * describe the keyring + * Describe a keyring for /proc. */ static void keyring_describe(const struct key *keyring, struct seq_file *m) { @@ -180,20 +176,21 @@ static void keyring_describe(const struct key *keyring, struct seq_file *m) else seq_puts(m, "[anon]"); - rcu_read_lock(); - klist = rcu_dereference(keyring->payload.subscriptions); - if (klist) - seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys); - else - seq_puts(m, ": empty"); - rcu_read_unlock(); - -} /* end keyring_describe() */ + if (key_is_instantiated(keyring)) { + rcu_read_lock(); + klist = rcu_dereference(keyring->payload.subscriptions); + if (klist) + seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys); + else + seq_puts(m, ": empty"); + rcu_read_unlock(); + } +} -/*****************************************************************************/ /* - * read a list of key IDs from the keyring's contents - * - the keyring's semaphore is read-locked + * Read a list of key IDs from the keyring's contents in binary form + * + * The keyring's semaphore is read-locked by the caller. */ static long keyring_read(const struct key *keyring, char __user *buffer, size_t buflen) @@ -241,12 +238,10 @@ static long keyring_read(const struct key *keyring, error: return ret; +} -} /* end keyring_read() */ - -/*****************************************************************************/ /* - * allocate a keyring and link into the destination keyring + * Allocate a keyring and link into the destination keyring. */ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, const struct cred *cred, unsigned long flags, @@ -269,26 +264,50 @@ struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid, } return keyring; +} -} /* end keyring_alloc() */ - -/*****************************************************************************/ -/* - * search the supplied keyring tree for a key that matches the criterion - * - perform a breadth-then-depth search up to the prescribed limit - * - we only find keys on which we have search permission - * - we use the supplied match function to see if the description (or other - * feature of interest) matches - * - we rely on RCU to prevent the keyring lists from disappearing on us - * - we return -EAGAIN if we didn't find any matching key - * - we return -ENOKEY if we only found negative matching keys - * - we propagate the possession attribute from the keyring ref to the key ref +/** + * keyring_search_aux - Search a keyring tree for a key matching some criteria + * @keyring_ref: A pointer to the keyring with possession indicator. + * @cred: The credentials to use for permissions checks. + * @type: The type of key to search for. + * @description: Parameter for @match. + * @match: Function to rule on whether or not a key is the one required. + * @no_state_check: Don't check if a matching key is bad + * + * Search the supplied keyring tree for a key that matches the criteria given. + * The root keyring and any linked keyrings must grant Search permission to the + * caller to be searchable and keys can only be found if they too grant Search + * to the caller. The possession flag on the root keyring pointer controls use + * of the possessor bits in permissions checking of the entire tree. In + * addition, the LSM gets to forbid keyring searches and key matches. + * + * The search is performed as a breadth-then-depth search up to the prescribed + * limit (KEYRING_SEARCH_MAX_DEPTH). + * + * Keys are matched to the type provided and are then filtered by the match + * function, which is given the description to use in any way it sees fit. The + * match function may use any attributes of a key that it wishes to to + * determine the match. Normally the match function from the key type would be + * used. + * + * RCU is used to prevent the keyring key lists from disappearing without the + * need to take lots of locks. + * + * Returns a pointer to the found key and increments the key usage count if + * successful; -EAGAIN if no matching keys were found, or if expired or revoked + * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the + * specified keyring wasn't a keyring. + * + * In the case of a successful return, the possession attribute from + * @keyring_ref is propagated to the returned key reference. */ key_ref_t keyring_search_aux(key_ref_t keyring_ref, const struct cred *cred, struct key_type *type, const void *description, - key_match_func_t match) + key_match_func_t match, + bool no_state_check) { struct { struct keyring_list *keylist; @@ -330,6 +349,8 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, kflags = keyring->flags; if (keyring->type == type && match(keyring, description)) { key = keyring; + if (no_state_check) + goto found; /* check it isn't negative and hasn't expired or been * revoked */ @@ -337,7 +358,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, goto error_2; if (key->expiry && now.tv_sec >= key->expiry) goto error_2; - key_ref = ERR_PTR(-ENOKEY); + key_ref = ERR_PTR(key->type_data.reject_error); if (kflags & (1 << KEY_FLAG_NEGATIVE)) goto error_2; goto found; @@ -369,11 +390,13 @@ descend: continue; /* skip revoked keys and expired keys */ - if (kflags & (1 << KEY_FLAG_REVOKED)) - continue; + if (!no_state_check) { + if (kflags & (1 << KEY_FLAG_REVOKED)) + continue; - if (key->expiry && now.tv_sec >= key->expiry) - continue; + if (key->expiry && now.tv_sec >= key->expiry) + continue; + } /* keys that don't match */ if (!match(key, description)) @@ -384,9 +407,12 @@ descend: cred, KEY_SEARCH) < 0) continue; + if (no_state_check) + goto found; + /* we set a different error code if we pass a negative key */ if (kflags & (1 << KEY_FLAG_NEGATIVE)) { - err = -ENOKEY; + err = key->type_data.reject_error; continue; } @@ -444,17 +470,16 @@ error_2: rcu_read_unlock(); error: return key_ref; +} -} /* end keyring_search_aux() */ - -/*****************************************************************************/ -/* - * search the supplied keyring tree for a key that matches the criterion - * - perform a breadth-then-depth search up to the prescribed limit - * - we only find keys on which we have search permission - * - we readlock the keyrings as we search down the tree - * - we return -EAGAIN if we didn't find any matching key - * - we return -ENOKEY if we only found negative matching keys +/** + * keyring_search - Search the supplied keyring tree for a matching key + * @keyring: The root of the keyring tree to be searched. + * @type: The type of keyring we want to find. + * @description: The name of the keyring we want to find. + * + * As keyring_search_aux() above, but using the current task's credentials and + * type's default matching function. */ key_ref_t keyring_search(key_ref_t keyring, struct key_type *type, @@ -464,17 +489,24 @@ key_ref_t keyring_search(key_ref_t keyring, return ERR_PTR(-ENOKEY); return keyring_search_aux(keyring, current->cred, - type, description, type->match); - -} /* end keyring_search() */ - + type, description, type->match, false); +} EXPORT_SYMBOL(keyring_search); -/*****************************************************************************/ /* - * search the given keyring only (no recursion) - * - keyring must be locked by caller - * - caller must guarantee that the keyring is a keyring + * Search the given keyring only (no recursion). + * + * The caller must guarantee that the keyring is a keyring and that the + * permission is granted to search the keyring as no check is made here. + * + * RCU is used to make it unnecessary to lock the keyring key list here. + * + * Returns a pointer to the found key with usage count incremented if + * successful and returns -ENOKEY if not found. Revoked keys and keys not + * providing the requested permission are skipped over. + * + * If successful, the possession indicator is propagated from the keyring ref + * to the returned key reference. */ key_ref_t __keyring_search_one(key_ref_t keyring_ref, const struct key_type *ktype, @@ -514,14 +546,18 @@ found: atomic_inc(&key->usage); rcu_read_unlock(); return make_key_ref(key, possessed); +} -} /* end __keyring_search_one() */ - -/*****************************************************************************/ /* - * find a keyring with the specified name - * - all named keyrings are searched - * - normally only finds keyrings with search permission for the current process + * Find a keyring with the specified name. + * + * All named keyrings in the current user namespace are searched, provided they + * grant Search permission directly to the caller (unless this check is + * skipped). Keyrings whose usage points have reached zero or who have been + * revoked are skipped. + * + * Returns a pointer to the keyring with the keyring's refcount having being + * incremented on success. -ENOKEY is returned if a key could not be found. */ struct key *find_keyring_by_name(const char *name, bool skip_perm_check) { @@ -569,15 +605,14 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check) out: read_unlock(&keyring_name_lock); return keyring; +} -} /* end find_keyring_by_name() */ - -/*****************************************************************************/ /* - * see if a cycle will will be created by inserting acyclic tree B in acyclic - * tree A at the topmost level (ie: as a direct child of A) - * - since we are adding B to A at the top level, checking for cycles should - * just be a matter of seeing if node A is somewhere in tree B + * See if a cycle will will be created by inserting acyclic tree B in acyclic + * tree A at the topmost level (ie: as a direct child of A). + * + * Since we are adding B to A at the top level, checking for cycles should just + * be a matter of seeing if node A is somewhere in tree B. */ static int keyring_detect_cycle(struct key *A, struct key *B) { @@ -657,11 +692,10 @@ too_deep: cycle_detected: ret = -EDEADLK; goto error; - -} /* end keyring_detect_cycle() */ +} /* - * dispose of a keyring list after the RCU grace period, freeing the unlinked + * Dispose of a keyring list after the RCU grace period, freeing the unlinked * key */ static void keyring_unlink_rcu_disposal(struct rcu_head *rcu) @@ -675,14 +709,14 @@ static void keyring_unlink_rcu_disposal(struct rcu_head *rcu) } /* - * preallocate memory so that a key can be linked into to a keyring + * Preallocate memory so that a key can be linked into to a keyring. */ int __key_link_begin(struct key *keyring, const struct key_type *type, - const char *description, - struct keyring_list **_prealloc) + const char *description, unsigned long *_prealloc) __acquires(&keyring->sem) { struct keyring_list *klist, *nklist; + unsigned long prealloc; unsigned max; size_t size; int loop, ret; @@ -725,6 +759,7 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, /* note replacement slot */ klist->delkey = nklist->delkey = loop; + prealloc = (unsigned long)nklist; goto done; } } @@ -739,6 +774,7 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, if (klist && klist->nkeys < klist->maxkeys) { /* there's sufficient slack space to append directly */ nklist = NULL; + prealloc = KEY_LINK_FIXQUOTA; } else { /* grow the key list */ max = 4; @@ -773,8 +809,9 @@ int __key_link_begin(struct key *keyring, const struct key_type *type, nklist->keys[nklist->delkey] = NULL; } + prealloc = (unsigned long)nklist | KEY_LINK_FIXQUOTA; done: - *_prealloc = nklist; + *_prealloc = prealloc; kleave(" = 0"); return 0; @@ -792,10 +829,10 @@ error_krsem: } /* - * check already instantiated keys aren't going to be a problem - * - the caller must have called __key_link_begin() - * - don't need to call this for keys that were created since __key_link_begin() - * was called + * Check already instantiated keys aren't going to be a problem. + * + * The caller must have called __key_link_begin(). Don't need to call this for + * keys that were created since __key_link_begin() was called. */ int __key_link_check_live_key(struct key *keyring, struct key *key) { @@ -807,17 +844,20 @@ int __key_link_check_live_key(struct key *keyring, struct key *key) } /* - * link a key into to a keyring - * - must be called with __key_link_begin() having being called - * - discard already extant link to matching key if there is one + * Link a key into to a keyring. + * + * Must be called with __key_link_begin() having being called. Discards any + * already extant link to matching key if there is one, so that each keyring + * holds at most one link to any given key of a particular type+description + * combination. */ void __key_link(struct key *keyring, struct key *key, - struct keyring_list **_prealloc) + unsigned long *_prealloc) { struct keyring_list *klist, *nklist; - nklist = *_prealloc; - *_prealloc = NULL; + nklist = (struct keyring_list *)(*_prealloc & ~KEY_LINK_FIXQUOTA); + *_prealloc = 0; kenter("%d,%d,%p", keyring->serial, key->serial, nklist); @@ -852,34 +892,54 @@ void __key_link(struct key *keyring, struct key *key, } /* - * finish linking a key into to a keyring - * - must be called with __key_link_begin() having being called + * Finish linking a key into to a keyring. + * + * Must be called with __key_link_begin() having being called. */ void __key_link_end(struct key *keyring, struct key_type *type, - struct keyring_list *prealloc) + unsigned long prealloc) __releases(&keyring->sem) { BUG_ON(type == NULL); BUG_ON(type->name == NULL); - kenter("%d,%s,%p", keyring->serial, type->name, prealloc); + kenter("%d,%s,%lx", keyring->serial, type->name, prealloc); if (type == &key_type_keyring) up_write(&keyring_serialise_link_sem); if (prealloc) { - kfree(prealloc); - key_payload_reserve(keyring, - keyring->datalen - KEYQUOTA_LINK_BYTES); + if (prealloc & KEY_LINK_FIXQUOTA) + key_payload_reserve(keyring, + keyring->datalen - + KEYQUOTA_LINK_BYTES); + kfree((struct keyring_list *)(prealloc & ~KEY_LINK_FIXQUOTA)); } up_write(&keyring->sem); } -/* - * link a key to a keyring +/** + * key_link - Link a key to a keyring + * @keyring: The keyring to make the link in. + * @key: The key to link to. + * + * Make a link in a keyring to a key, such that the keyring holds a reference + * on that key and the key can potentially be found by searching that keyring. + * + * This function will write-lock the keyring's semaphore and will consume some + * of the user's key data quota to hold the link. + * + * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, + * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is + * full, -EDQUOT if there is insufficient key data quota remaining to add + * another link or -ENOMEM if there's insufficient memory. + * + * It is assumed that the caller has checked that it is permitted for a link to + * be made (the keyring should have Write permission and the key Link + * permission). */ int key_link(struct key *keyring, struct key *key) { - struct keyring_list *prealloc; + unsigned long prealloc; int ret; key_check(keyring); @@ -895,12 +955,24 @@ int key_link(struct key *keyring, struct key *key) return ret; } - EXPORT_SYMBOL(key_link); -/*****************************************************************************/ -/* - * unlink the first link to a key from a keyring +/** + * key_unlink - Unlink the first link to a key from a keyring. + * @keyring: The keyring to remove the link from. + * @key: The key the link is to. + * + * Remove a link from a keyring to a key. + * + * This function will write-lock the keyring's semaphore. + * + * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if + * the key isn't linked to by the keyring or -ENOMEM if there's insufficient + * memory. + * + * It is assumed that the caller has checked that it is permitted for a link to + * be removed (the keyring should have Write permission; no permissions are + * required on the key). */ int key_unlink(struct key *keyring, struct key *key) { @@ -968,15 +1040,12 @@ nomem: ret = -ENOMEM; up_write(&keyring->sem); goto error; - -} /* end key_unlink() */ - +} EXPORT_SYMBOL(key_unlink); -/*****************************************************************************/ /* - * dispose of a keyring list after the RCU grace period, releasing the keys it - * links to + * Dispose of a keyring list after the RCU grace period, releasing the keys it + * links to. */ static void keyring_clear_rcu_disposal(struct rcu_head *rcu) { @@ -989,13 +1058,15 @@ static void keyring_clear_rcu_disposal(struct rcu_head *rcu) key_put(klist->keys[loop]); kfree(klist); +} -} /* end keyring_clear_rcu_disposal() */ - -/*****************************************************************************/ -/* - * clear the specified process keyring - * - implements keyctl(KEYCTL_CLEAR) +/** + * keyring_clear - Clear a keyring + * @keyring: The keyring to clear. + * + * Clear the contents of the specified keyring. + * + * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. */ int keyring_clear(struct key *keyring) { @@ -1027,15 +1098,13 @@ int keyring_clear(struct key *keyring) } return ret; - -} /* end keyring_clear() */ - +} EXPORT_SYMBOL(keyring_clear); -/*****************************************************************************/ /* - * dispose of the links from a revoked keyring - * - called with the key sem write-locked + * Dispose of the links from a revoked keyring. + * + * This is called with the key sem write-locked. */ static void keyring_revoke(struct key *keyring) { @@ -1050,11 +1119,10 @@ static void keyring_revoke(struct key *keyring) rcu_assign_pointer(keyring->payload.subscriptions, NULL); call_rcu(&klist->rcu, keyring_clear_rcu_disposal); } - -} /* end keyring_revoke() */ +} /* - * Determine whether a key is dead + * Determine whether a key is dead. */ static bool key_is_dead(struct key *key, time_t limit) { @@ -1063,7 +1131,12 @@ static bool key_is_dead(struct key *key, time_t limit) } /* - * Collect garbage from the contents of a keyring + * Collect garbage from the contents of a keyring, replacing the old list with + * a new one with the pointers all shuffled down. + * + * Dead keys are classed as oned that are flagged as being dead or are revoked, + * expired or negative keys that were revoked or expired before the specified + * limit. */ void keyring_gc(struct key *keyring, time_t limit) { diff --git a/security/keys/permission.c b/security/keys/permission.c index 28645502cd0d..c35b5229e3cd 100644 --- a/security/keys/permission.c +++ b/security/keys/permission.c @@ -1,4 +1,4 @@ -/* permission.c: key permission determination +/* Key permission checking * * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -13,18 +13,19 @@ #include <linux/security.h> #include "internal.h" -/*****************************************************************************/ /** * key_task_permission - Check a key can be used - * @key_ref: The key to check - * @cred: The credentials to use - * @perm: The permissions to check for + * @key_ref: The key to check. + * @cred: The credentials to use. + * @perm: The permissions to check for. * * Check to see whether permission is granted to use a key in the desired way, * but permit the security modules to override. * - * The caller must hold either a ref on cred or must hold the RCU readlock or a - * spinlock. + * The caller must hold either a ref on cred or must hold the RCU readlock. + * + * Returns 0 if successful, -EACCES if access is denied based on the + * permissions bits or the LSM check. */ int key_task_permission(const key_ref_t key_ref, const struct cred *cred, key_perm_t perm) @@ -79,14 +80,16 @@ use_these_perms: /* let LSM be the final arbiter */ return security_key_permission(key_ref, cred, perm); - -} /* end key_task_permission() */ - +} EXPORT_SYMBOL(key_task_permission); -/*****************************************************************************/ -/* - * validate a key +/** + * key_validate - Validate a key. + * @key: The key to be validated. + * + * Check that a key is valid, returning 0 if the key is okay, -EKEYREVOKED if + * the key's type has been removed or if the key has been revoked or + * -EKEYEXPIRED if the key has expired. */ int key_validate(struct key *key) { @@ -111,7 +114,5 @@ int key_validate(struct key *key) error: return ret; - -} /* end key_validate() */ - +} EXPORT_SYMBOL(key_validate); diff --git a/security/keys/proc.c b/security/keys/proc.c index 70373966816e..49bbc97943ad 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -1,4 +1,4 @@ -/* proc.c: proc files for key database enumeration +/* procfs files for key database enumeration * * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -60,9 +60,8 @@ static const struct file_operations proc_key_users_fops = { .release = seq_release, }; -/*****************************************************************************/ /* - * declare the /proc files + * Declare the /proc files. */ static int __init key_proc_init(void) { @@ -79,14 +78,13 @@ static int __init key_proc_init(void) panic("Cannot create /proc/key-users\n"); return 0; - -} /* end key_proc_init() */ +} __initcall(key_proc_init); -/*****************************************************************************/ /* - * implement "/proc/keys" to provides a list of the keys on the system + * Implement "/proc/keys" to provide a list of the keys on the system that + * grant View permission to the caller. */ #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS @@ -201,7 +199,7 @@ static int proc_keys_show(struct seq_file *m, void *v) if (key->perm & KEY_POS_VIEW) { skey_ref = search_my_process_keyrings(key->type, key, lookup_user_key_possessed, - cred); + true, cred); if (!IS_ERR(skey_ref)) { key_ref_put(skey_ref); key_ref = make_key_ref(key, 1); @@ -293,9 +291,9 @@ static struct rb_node *key_user_first(struct rb_root *r) return __key_user_next(n); } -/*****************************************************************************/ /* - * implement "/proc/key-users" to provides a list of the key users + * Implement "/proc/key-users" to provides a list of the key users and their + * quotas. */ static int proc_key_users_open(struct inode *inode, struct file *file) { @@ -351,5 +349,4 @@ static int proc_key_users_show(struct seq_file *m, void *v) maxbytes); return 0; - } diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index 504bdd2452bd..a3063eb3dc23 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -1,4 +1,4 @@ -/* Management of a process's keyrings +/* Manage a process's keyrings * * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -21,13 +21,13 @@ #include <asm/uaccess.h> #include "internal.h" -/* session keyring create vs join semaphore */ +/* Session keyring create vs join semaphore */ static DEFINE_MUTEX(key_session_mutex); -/* user keyring creation semaphore */ +/* User keyring creation semaphore */ static DEFINE_MUTEX(key_user_keyring_mutex); -/* the root user's tracking struct */ +/* The root user's tracking struct */ struct key_user root_key_user = { .usage = ATOMIC_INIT(3), .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock), @@ -38,9 +38,8 @@ struct key_user root_key_user = { .user_ns = &init_user_ns, }; -/*****************************************************************************/ /* - * install user and user session keyrings for a particular UID + * Install the user and user session keyrings for the current process's UID. */ int install_user_keyrings(void) { @@ -122,7 +121,8 @@ error: } /* - * install a fresh thread keyring directly to new credentials + * Install a fresh thread keyring directly to new credentials. This keyring is + * allowed to overrun the quota. */ int install_thread_keyring_to_cred(struct cred *new) { @@ -138,7 +138,7 @@ int install_thread_keyring_to_cred(struct cred *new) } /* - * install a fresh thread keyring, discarding the old one + * Install a fresh thread keyring, discarding the old one. */ static int install_thread_keyring(void) { @@ -161,9 +161,10 @@ static int install_thread_keyring(void) } /* - * install a process keyring directly to a credentials struct - * - returns -EEXIST if there was already a process keyring, 0 if one installed, - * and other -ve on any other error + * Install a process keyring directly to a credentials struct. + * + * Returns -EEXIST if there was already a process keyring, 0 if one installed, + * and other value on any other error */ int install_process_keyring_to_cred(struct cred *new) { @@ -192,8 +193,11 @@ int install_process_keyring_to_cred(struct cred *new) } /* - * make sure a process keyring is installed - * - we + * Make sure a process keyring is installed for the current process. The + * existing process keyring is not replaced. + * + * Returns 0 if there is a process keyring by the end of this function, some + * error otherwise. */ static int install_process_keyring(void) { @@ -214,7 +218,7 @@ static int install_process_keyring(void) } /* - * install a session keyring directly to a credentials struct + * Install a session keyring directly to a credentials struct. */ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) { @@ -254,8 +258,8 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) } /* - * install a session keyring, discarding the old one - * - if a keyring is not supplied, an empty one is invented + * Install a session keyring, discarding the old one. If a keyring is not + * supplied, an empty one is invented. */ static int install_session_keyring(struct key *keyring) { @@ -275,9 +279,8 @@ static int install_session_keyring(struct key *keyring) return commit_creds(new); } -/*****************************************************************************/ /* - * the filesystem user ID changed + * Handle the fsuid changing. */ void key_fsuid_changed(struct task_struct *tsk) { @@ -288,12 +291,10 @@ void key_fsuid_changed(struct task_struct *tsk) tsk->cred->thread_keyring->uid = tsk->cred->fsuid; up_write(&tsk->cred->thread_keyring->sem); } +} -} /* end key_fsuid_changed() */ - -/*****************************************************************************/ /* - * the filesystem group ID changed + * Handle the fsgid changing. */ void key_fsgid_changed(struct task_struct *tsk) { @@ -304,20 +305,33 @@ void key_fsgid_changed(struct task_struct *tsk) tsk->cred->thread_keyring->gid = tsk->cred->fsgid; up_write(&tsk->cred->thread_keyring->sem); } +} -} /* end key_fsgid_changed() */ - -/*****************************************************************************/ /* - * search only my process keyrings for the first matching key - * - we use the supplied match function to see if the description (or other - * feature of interest) matches - * - we return -EAGAIN if we didn't find any matching key - * - we return -ENOKEY if we found only negative matching keys + * Search the process keyrings attached to the supplied cred for the first + * matching key. + * + * The search criteria are the type and the match function. The description is + * given to the match function as a parameter, but doesn't otherwise influence + * the search. Typically the match function will compare the description + * parameter to the key's description. + * + * This can only search keyrings that grant Search permission to the supplied + * credentials. Keyrings linked to searched keyrings will also be searched if + * they grant Search permission too. Keys can only be found if they grant + * Search permission to the credentials. + * + * Returns a pointer to the key with the key usage count incremented if + * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only + * matched negative keys. + * + * In the case of a successful return, the possession attribute is set on the + * returned key reference. */ key_ref_t search_my_process_keyrings(struct key_type *type, const void *description, key_match_func_t match, + bool no_state_check, const struct cred *cred) { key_ref_t key_ref, ret, err; @@ -337,7 +351,7 @@ key_ref_t search_my_process_keyrings(struct key_type *type, if (cred->thread_keyring) { key_ref = keyring_search_aux( make_key_ref(cred->thread_keyring, 1), - cred, type, description, match); + cred, type, description, match, no_state_check); if (!IS_ERR(key_ref)) goto found; @@ -358,7 +372,7 @@ key_ref_t search_my_process_keyrings(struct key_type *type, if (cred->tgcred->process_keyring) { key_ref = keyring_search_aux( make_key_ref(cred->tgcred->process_keyring, 1), - cred, type, description, match); + cred, type, description, match, no_state_check); if (!IS_ERR(key_ref)) goto found; @@ -382,7 +396,7 @@ key_ref_t search_my_process_keyrings(struct key_type *type, make_key_ref(rcu_dereference( cred->tgcred->session_keyring), 1), - cred, type, description, match); + cred, type, description, match, no_state_check); rcu_read_unlock(); if (!IS_ERR(key_ref)) @@ -404,7 +418,7 @@ key_ref_t search_my_process_keyrings(struct key_type *type, else if (cred->user->session_keyring) { key_ref = keyring_search_aux( make_key_ref(cred->user->session_keyring, 1), - cred, type, description, match); + cred, type, description, match, no_state_check); if (!IS_ERR(key_ref)) goto found; @@ -428,13 +442,13 @@ found: return key_ref; } -/*****************************************************************************/ /* - * search the process keyrings for the first matching key - * - we use the supplied match function to see if the description (or other - * feature of interest) matches - * - we return -EAGAIN if we didn't find any matching key - * - we return -ENOKEY if we found only negative matching keys + * Search the process keyrings attached to the supplied cred for the first + * matching key in the manner of search_my_process_keyrings(), but also search + * the keys attached to the assumed authorisation key using its credentials if + * one is available. + * + * Return same as search_my_process_keyrings(). */ key_ref_t search_process_keyrings(struct key_type *type, const void *description, @@ -446,7 +460,8 @@ key_ref_t search_process_keyrings(struct key_type *type, might_sleep(); - key_ref = search_my_process_keyrings(type, description, match, cred); + key_ref = search_my_process_keyrings(type, description, match, + false, cred); if (!IS_ERR(key_ref)) goto found; err = key_ref; @@ -489,24 +504,33 @@ key_ref_t search_process_keyrings(struct key_type *type, found: return key_ref; +} -} /* end search_process_keyrings() */ - -/*****************************************************************************/ /* - * see if the key we're looking at is the target key + * See if the key we're looking at is the target key. */ int lookup_user_key_possessed(const struct key *key, const void *target) { return key == target; +} -} /* end lookup_user_key_possessed() */ - -/*****************************************************************************/ /* - * lookup a key given a key ID from userspace with a given permissions mask - * - don't create special keyrings unless so requested - * - partially constructed keys aren't found unless requested + * Look up a key ID given us by userspace with a given permissions mask to get + * the key it refers to. + * + * Flags can be passed to request that special keyrings be created if referred + * to directly, to permit partially constructed keys to be found and to skip + * validity and permission checks on the found key. + * + * Returns a pointer to the key with an incremented usage count if successful; + * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond + * to a key or the best found key was a negative key; -EKEYREVOKED or + * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the + * found key doesn't grant the requested permit or the LSM denied access to it; + * or -ENOMEM if a special keyring couldn't be created. + * + * In the case of a successful return, the possession attribute is set on the + * returned key reference. */ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, key_perm_t perm) @@ -711,15 +735,18 @@ invalid_key: reget_creds: put_cred(cred); goto try_again; +} -} /* end lookup_user_key() */ - -/*****************************************************************************/ /* - * join the named keyring as the session keyring if possible, or attempt to - * create a new one of that name if not - * - if the name is NULL, an empty anonymous keyring is installed instead - * - named session keyring joining is done with a semaphore held + * Join the named keyring as the session keyring if possible else attempt to + * create a new one of that name and join that. + * + * If the name is NULL, an empty anonymous keyring will be installed as the + * session keyring. + * + * Named session keyrings are joined with a semaphore held to prevent the + * keyrings from going away whilst the attempt is made to going them and also + * to prevent a race in creating compatible session keyrings. */ long join_session_keyring(const char *name) { @@ -791,8 +818,8 @@ error: } /* - * Replace a process's session keyring when that process resumes userspace on - * behalf of one of its children + * Replace a process's session keyring on behalf of one of its children when + * the target process is about to resume userspace execution. */ void key_replace_session_keyring(void) { @@ -820,6 +847,7 @@ void key_replace_session_keyring(void) new-> sgid = old-> sgid; new->fsgid = old->fsgid; new->user = get_uid(old->user); + new->user_ns = new->user->user_ns; new->group_info = get_group_info(old->group_info); new->securebits = old->securebits; diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 0088dd8bf68a..b18a71745901 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -39,8 +39,14 @@ static int key_wait_bit_intr(void *flags) return signal_pending(current) ? -ERESTARTSYS : 0; } -/* - * call to complete the construction of a key +/** + * complete_request_key - Complete the construction of a key. + * @cons: The key construction record. + * @error: The success or failute of the construction. + * + * Complete the attempt to construct a key. The key will be negated + * if an error is indicated. The authorisation key will be revoked + * unconditionally. */ void complete_request_key(struct key_construction *cons, int error) { @@ -58,23 +64,33 @@ void complete_request_key(struct key_construction *cons, int error) } EXPORT_SYMBOL(complete_request_key); +/* + * Initialise a usermode helper that is going to have a specific session + * keyring. + * + * This is called in context of freshly forked kthread before kernel_execve(), + * so we can simply install the desired session_keyring at this point. + */ static int umh_keys_init(struct subprocess_info *info) { struct cred *cred = (struct cred*)current_cred(); struct key *keyring = info->data; - /* - * This is called in context of freshly forked kthread before - * kernel_execve(), we can just change our ->session_keyring. - */ + return install_session_keyring_to_cred(cred, keyring); } +/* + * Clean up a usermode helper with session keyring. + */ static void umh_keys_cleanup(struct subprocess_info *info) { struct key *keyring = info->data; key_put(keyring); } +/* + * Call a usermode helper with a specific session keyring. + */ static int call_usermodehelper_keys(char *path, char **argv, char **envp, struct key *session_keyring, enum umh_wait wait) { @@ -91,7 +107,7 @@ static int call_usermodehelper_keys(char *path, char **argv, char **envp, } /* - * request userspace finish the construction of a key + * Request userspace finish the construction of a key * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>" */ static int call_sbin_request_key(struct key_construction *cons, @@ -198,8 +214,9 @@ error_alloc: } /* - * call out to userspace for key construction - * - we ignore program failure and go on key status instead + * Call out to userspace for key construction. + * + * Program failure is ignored in favour of key status. */ static int construct_key(struct key *key, const void *callout_info, size_t callout_len, void *aux, @@ -246,9 +263,10 @@ static int construct_key(struct key *key, const void *callout_info, } /* - * get the appropriate destination keyring for the request - * - we return whatever keyring we select with an extra reference upon it which - * the caller must release + * Get the appropriate destination keyring for the request. + * + * The keyring selected is returned with an extra reference upon it which the + * caller must release. */ static void construct_get_dest_keyring(struct key **_dest_keyring) { @@ -321,9 +339,11 @@ static void construct_get_dest_keyring(struct key **_dest_keyring) } /* - * allocate a new key in under-construction state and attempt to link it in to - * the requested place - * - may return a key that's already under construction instead + * Allocate a new key in under-construction state and attempt to link it in to + * the requested keyring. + * + * May return a key that's already under construction instead if there was a + * race between two thread calling request_key(). */ static int construct_alloc_key(struct key_type *type, const char *description, @@ -332,8 +352,8 @@ static int construct_alloc_key(struct key_type *type, struct key_user *user, struct key **_key) { - struct keyring_list *prealloc; const struct cred *cred = current_cred(); + unsigned long prealloc; struct key *key; key_ref_t key_ref; int ret; @@ -403,7 +423,6 @@ link_check_failed: return ret; link_prealloc_failed: - up_write(&dest_keyring->sem); mutex_unlock(&user->cons_lock); kleave(" = %d [prelink]", ret); return ret; @@ -415,7 +434,7 @@ alloc_failed: } /* - * commence key construction + * Commence key construction. */ static struct key *construct_key_and_link(struct key_type *type, const char *description, @@ -466,12 +485,32 @@ construction_failed: return ERR_PTR(ret); } -/* - * request a key - * - search the process's keyrings - * - check the list of keys being created or updated - * - call out to userspace for a key if supplementary info was provided - * - cache the key in an appropriate keyring +/** + * request_key_and_link - Request a key and cache it in a keyring. + * @type: The type of key we want. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * @callout_len: The length of callout_info. + * @aux: Auxiliary data for the upcall. + * @dest_keyring: Where to cache the key. + * @flags: Flags to key_alloc(). + * + * A key matching the specified criteria is searched for in the process's + * keyrings and returned with its usage count incremented if found. Otherwise, + * if callout_info is not NULL, a key will be allocated and some service + * (probably in userspace) will be asked to instantiate it. + * + * If successfully found or created, the key will be linked to the destination + * keyring if one is provided. + * + * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED + * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was + * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT + * if insufficient key quota was available to create a new key; or -ENOMEM if + * insufficient memory was available. + * + * If the returned key was created, then it may still be under construction, + * and wait_for_key_construction() should be used to wait for that to complete. */ struct key *request_key_and_link(struct key_type *type, const char *description, @@ -491,8 +530,7 @@ struct key *request_key_and_link(struct key_type *type, dest_keyring, flags); /* search all the process keyrings for a key */ - key_ref = search_process_keyrings(type, description, type->match, - cred); + key_ref = search_process_keyrings(type, description, type->match, cred); if (!IS_ERR(key_ref)) { key = key_ref_to_ptr(key_ref); @@ -525,8 +563,16 @@ error: return key; } -/* - * wait for construction of a key to complete +/** + * wait_for_key_construction - Wait for construction of a key to complete + * @key: The key being waited for. + * @intr: Whether to wait interruptibly. + * + * Wait for a key to finish being constructed. + * + * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY + * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was + * revoked or expired. */ int wait_for_key_construction(struct key *key, bool intr) { @@ -538,17 +584,24 @@ int wait_for_key_construction(struct key *key, bool intr) if (ret < 0) return ret; if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) - return -ENOKEY; + return key->type_data.reject_error; return key_validate(key); } EXPORT_SYMBOL(wait_for_key_construction); -/* - * request a key - * - search the process's keyrings - * - check the list of keys being created or updated - * - call out to userspace for a key if supplementary info was provided - * - waits uninterruptible for creation to complete +/** + * request_key - Request a key and wait for construction + * @type: Type of key. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * + * As for request_key_and_link() except that it does not add the returned key + * to a keyring if found, new keys are always allocated in the user's quota, + * the callout_info must be a NUL-terminated string and no auxiliary data can + * be passed. + * + * Furthermore, it then works as wait_for_key_construction() to wait for the + * completion of keys undergoing construction with a non-interruptible wait. */ struct key *request_key(struct key_type *type, const char *description, @@ -573,12 +626,19 @@ struct key *request_key(struct key_type *type, } EXPORT_SYMBOL(request_key); -/* - * request a key with auxiliary data for the upcaller - * - search the process's keyrings - * - check the list of keys being created or updated - * - call out to userspace for a key if supplementary info was provided - * - waits uninterruptible for creation to complete +/** + * request_key_with_auxdata - Request a key with auxiliary data for the upcaller + * @type: The type of key we want. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * @callout_len: The length of callout_info. + * @aux: Auxiliary data for the upcall. + * + * As for request_key_and_link() except that it does not add the returned key + * to a keyring if found and new keys are always allocated in the user's quota. + * + * Furthermore, it then works as wait_for_key_construction() to wait for the + * completion of keys undergoing construction with a non-interruptible wait. */ struct key *request_key_with_auxdata(struct key_type *type, const char *description, @@ -603,10 +663,18 @@ struct key *request_key_with_auxdata(struct key_type *type, EXPORT_SYMBOL(request_key_with_auxdata); /* - * request a key (allow async construction) - * - search the process's keyrings - * - check the list of keys being created or updated - * - call out to userspace for a key if supplementary info was provided + * request_key_async - Request a key (allow async construction) + * @type: Type of key. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * @callout_len: The length of callout_info. + * + * As for request_key_and_link() except that it does not add the returned key + * to a keyring if found, new keys are always allocated in the user's quota and + * no auxiliary data can be passed. + * + * The caller should call wait_for_key_construction() to wait for the + * completion of the returned key if it is still undergoing construction. */ struct key *request_key_async(struct key_type *type, const char *description, @@ -621,9 +689,17 @@ EXPORT_SYMBOL(request_key_async); /* * request a key with auxiliary data for the upcaller (allow async construction) - * - search the process's keyrings - * - check the list of keys being created or updated - * - call out to userspace for a key if supplementary info was provided + * @type: Type of key. + * @description: The searchable description of the key. + * @callout_info: The data to pass to the instantiation upcall (or NULL). + * @callout_len: The length of callout_info. + * @aux: Auxiliary data for the upcall. + * + * As for request_key_and_link() except that it does not add the returned key + * to a keyring if found and new keys are always allocated in the user's quota. + * + * The caller should call wait_for_key_construction() to wait for the + * completion of the returned key if it is still undergoing construction. */ struct key *request_key_async_with_auxdata(struct key_type *type, const char *description, diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c index 86747151ee5b..f6337c9082eb 100644 --- a/security/keys/request_key_auth.c +++ b/security/keys/request_key_auth.c @@ -1,4 +1,4 @@ -/* request_key_auth.c: request key authorisation controlling key def +/* Request key authorisation token key definition. * * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -26,7 +26,7 @@ static void request_key_auth_destroy(struct key *); static long request_key_auth_read(const struct key *, char __user *, size_t); /* - * the request-key authorisation key type definition + * The request-key authorisation key type definition. */ struct key_type key_type_request_key_auth = { .name = ".request_key_auth", @@ -38,9 +38,8 @@ struct key_type key_type_request_key_auth = { .read = request_key_auth_read, }; -/*****************************************************************************/ /* - * instantiate a request-key authorisation key + * Instantiate a request-key authorisation key. */ static int request_key_auth_instantiate(struct key *key, const void *data, @@ -48,12 +47,10 @@ static int request_key_auth_instantiate(struct key *key, { key->payload.data = (struct request_key_auth *) data; return 0; +} -} /* end request_key_auth_instantiate() */ - -/*****************************************************************************/ /* - * reading a request-key authorisation key retrieves the callout information + * Describe an authorisation token. */ static void request_key_auth_describe(const struct key *key, struct seq_file *m) @@ -62,13 +59,12 @@ static void request_key_auth_describe(const struct key *key, seq_puts(m, "key:"); seq_puts(m, key->description); - seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); - -} /* end request_key_auth_describe() */ + if (key_is_instantiated(key)) + seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); +} -/*****************************************************************************/ /* - * read the callout_info data + * Read the callout_info data (retrieves the callout information). * - the key's semaphore is read-locked */ static long request_key_auth_read(const struct key *key, @@ -91,13 +87,12 @@ static long request_key_auth_read(const struct key *key, } return ret; +} -} /* end request_key_auth_read() */ - -/*****************************************************************************/ /* - * handle revocation of an authorisation token key - * - called with the key sem write-locked + * Handle revocation of an authorisation token key. + * + * Called with the key sem write-locked. */ static void request_key_auth_revoke(struct key *key) { @@ -109,12 +104,10 @@ static void request_key_auth_revoke(struct key *key) put_cred(rka->cred); rka->cred = NULL; } +} -} /* end request_key_auth_revoke() */ - -/*****************************************************************************/ /* - * destroy an instantiation authorisation token key + * Destroy an instantiation authorisation token key. */ static void request_key_auth_destroy(struct key *key) { @@ -131,13 +124,11 @@ static void request_key_auth_destroy(struct key *key) key_put(rka->dest_keyring); kfree(rka->callout_info); kfree(rka); +} -} /* end request_key_auth_destroy() */ - -/*****************************************************************************/ /* - * create an authorisation token for /sbin/request-key or whoever to gain - * access to the caller's security data + * Create an authorisation token for /sbin/request-key or whoever to gain + * access to the caller's security data. */ struct key *request_key_auth_new(struct key *target, const void *callout_info, size_t callout_len, struct key *dest_keyring) @@ -228,12 +219,10 @@ error_alloc: kfree(rka); kleave("= %d", ret); return ERR_PTR(ret); +} -} /* end request_key_auth_new() */ - -/*****************************************************************************/ /* - * see if an authorisation key is associated with a particular key + * See if an authorisation key is associated with a particular key. */ static int key_get_instantiation_authkey_match(const struct key *key, const void *_id) @@ -242,16 +231,11 @@ static int key_get_instantiation_authkey_match(const struct key *key, key_serial_t id = (key_serial_t)(unsigned long) _id; return rka->target_key->serial == id; +} -} /* end key_get_instantiation_authkey_match() */ - -/*****************************************************************************/ /* - * get the authorisation key for instantiation of a specific key if attached to - * the current process's keyrings - * - this key is inserted into a keyring and that is set as /sbin/request-key's - * session keyring - * - a target_id of zero specifies any valid token + * Search the current process's keyrings for the authorisation key for + * instantiation of a key. */ struct key *key_get_instantiation_authkey(key_serial_t target_id) { @@ -278,5 +262,4 @@ struct key *key_get_instantiation_authkey(key_serial_t target_id) error: return authkey; - -} /* end key_get_instantiation_authkey() */ +} diff --git a/security/keys/trusted.c b/security/keys/trusted.c new file mode 100644 index 000000000000..c99b9368368c --- /dev/null +++ b/security/keys/trusted.c @@ -0,0 +1,1180 @@ +/* + * Copyright (C) 2010 IBM Corporation + * + * Author: + * David Safford <safford@us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2 of the License. + * + * See Documentation/keys-trusted-encrypted.txt + */ + +#include <linux/uaccess.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/parser.h> +#include <linux/string.h> +#include <linux/err.h> +#include <keys/user-type.h> +#include <keys/trusted-type.h> +#include <linux/key-type.h> +#include <linux/rcupdate.h> +#include <linux/crypto.h> +#include <crypto/hash.h> +#include <crypto/sha.h> +#include <linux/capability.h> +#include <linux/tpm.h> +#include <linux/tpm_command.h> + +#include "trusted.h" + +static const char hmac_alg[] = "hmac(sha1)"; +static const char hash_alg[] = "sha1"; + +struct sdesc { + struct shash_desc shash; + char ctx[]; +}; + +static struct crypto_shash *hashalg; +static struct crypto_shash *hmacalg; + +static struct sdesc *init_sdesc(struct crypto_shash *alg) +{ + struct sdesc *sdesc; + int size; + + size = sizeof(struct shash_desc) + crypto_shash_descsize(alg); + sdesc = kmalloc(size, GFP_KERNEL); + if (!sdesc) + return ERR_PTR(-ENOMEM); + sdesc->shash.tfm = alg; + sdesc->shash.flags = 0x0; + return sdesc; +} + +static int TSS_sha1(const unsigned char *data, unsigned int datalen, + unsigned char *digest) +{ + struct sdesc *sdesc; + int ret; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + + ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest); + kfree(sdesc); + return ret; +} + +static int TSS_rawhmac(unsigned char *digest, const unsigned char *key, + unsigned int keylen, ...) +{ + struct sdesc *sdesc; + va_list argp; + unsigned int dlen; + unsigned char *data; + int ret; + + sdesc = init_sdesc(hmacalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hmac_alg); + return PTR_ERR(sdesc); + } + + ret = crypto_shash_setkey(hmacalg, key, keylen); + if (ret < 0) + goto out; + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + + va_start(argp, keylen); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + data = va_arg(argp, unsigned char *); + if (data == NULL) { + ret = -EINVAL; + break; + } + ret = crypto_shash_update(&sdesc->shash, data, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, digest); +out: + kfree(sdesc); + return ret; +} + +/* + * calculate authorization info fields to send to TPM + */ +static int TSS_authhmac(unsigned char *digest, const unsigned char *key, + unsigned int keylen, unsigned char *h1, + unsigned char *h2, unsigned char h3, ...) +{ + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned char *data; + unsigned char c; + int ret; + va_list argp; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + + c = h3; + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + va_start(argp, h3); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + data = va_arg(argp, unsigned char *); + if (!data) { + ret = -EINVAL; + break; + } + ret = crypto_shash_update(&sdesc->shash, data, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (!ret) + ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, h1, + TPM_NONCE_SIZE, h2, 1, &c, 0, 0); +out: + kfree(sdesc); + return ret; +} + +/* + * verify the AUTH1_COMMAND (Seal) result from TPM + */ +static int TSS_checkhmac1(unsigned char *buffer, + const uint32_t command, + const unsigned char *ononce, + const unsigned char *key, + unsigned int keylen, ...) +{ + uint32_t bufsize; + uint16_t tag; + uint32_t ordinal; + uint32_t result; + unsigned char *enonce; + unsigned char *continueflag; + unsigned char *authdata; + unsigned char testhmac[SHA1_DIGEST_SIZE]; + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned int dpos; + va_list argp; + int ret; + + bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); + tag = LOAD16(buffer, 0); + ordinal = command; + result = LOAD32N(buffer, TPM_RETURN_OFFSET); + if (tag == TPM_TAG_RSP_COMMAND) + return 0; + if (tag != TPM_TAG_RSP_AUTH1_COMMAND) + return -EINVAL; + authdata = buffer + bufsize - SHA1_DIGEST_SIZE; + continueflag = authdata - 1; + enonce = continueflag - TPM_NONCE_SIZE; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result, + sizeof result); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal, + sizeof ordinal); + if (ret < 0) + goto out; + va_start(argp, keylen); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + dpos = va_arg(argp, unsigned int); + ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (ret < 0) + goto out; + + ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest, + TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce, + 1, continueflag, 0, 0); + if (ret < 0) + goto out; + + if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE)) + ret = -EINVAL; +out: + kfree(sdesc); + return ret; +} + +/* + * verify the AUTH2_COMMAND (unseal) result from TPM + */ +static int TSS_checkhmac2(unsigned char *buffer, + const uint32_t command, + const unsigned char *ononce, + const unsigned char *key1, + unsigned int keylen1, + const unsigned char *key2, + unsigned int keylen2, ...) +{ + uint32_t bufsize; + uint16_t tag; + uint32_t ordinal; + uint32_t result; + unsigned char *enonce1; + unsigned char *continueflag1; + unsigned char *authdata1; + unsigned char *enonce2; + unsigned char *continueflag2; + unsigned char *authdata2; + unsigned char testhmac1[SHA1_DIGEST_SIZE]; + unsigned char testhmac2[SHA1_DIGEST_SIZE]; + unsigned char paramdigest[SHA1_DIGEST_SIZE]; + struct sdesc *sdesc; + unsigned int dlen; + unsigned int dpos; + va_list argp; + int ret; + + bufsize = LOAD32(buffer, TPM_SIZE_OFFSET); + tag = LOAD16(buffer, 0); + ordinal = command; + result = LOAD32N(buffer, TPM_RETURN_OFFSET); + + if (tag == TPM_TAG_RSP_COMMAND) + return 0; + if (tag != TPM_TAG_RSP_AUTH2_COMMAND) + return -EINVAL; + authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1 + + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE); + authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE); + continueflag1 = authdata1 - 1; + continueflag2 = authdata2 - 1; + enonce1 = continueflag1 - TPM_NONCE_SIZE; + enonce2 = continueflag2 - TPM_NONCE_SIZE; + + sdesc = init_sdesc(hashalg); + if (IS_ERR(sdesc)) { + pr_info("trusted_key: can't alloc %s\n", hash_alg); + return PTR_ERR(sdesc); + } + ret = crypto_shash_init(&sdesc->shash); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result, + sizeof result); + if (ret < 0) + goto out; + ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal, + sizeof ordinal); + if (ret < 0) + goto out; + + va_start(argp, keylen2); + for (;;) { + dlen = va_arg(argp, unsigned int); + if (dlen == 0) + break; + dpos = va_arg(argp, unsigned int); + ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen); + if (ret < 0) + break; + } + va_end(argp); + if (!ret) + ret = crypto_shash_final(&sdesc->shash, paramdigest); + if (ret < 0) + goto out; + + ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, enonce1, + TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0); + if (ret < 0) + goto out; + if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) { + ret = -EINVAL; + goto out; + } + ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE, + paramdigest, TPM_NONCE_SIZE, enonce2, + TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0); + if (ret < 0) + goto out; + if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE)) + ret = -EINVAL; +out: + kfree(sdesc); + return ret; +} + +/* + * For key specific tpm requests, we will generate and send our + * own TPM command packets using the drivers send function. + */ +static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd, + size_t buflen) +{ + int rc; + + dump_tpm_buf(cmd); + rc = tpm_send(chip_num, cmd, buflen); + dump_tpm_buf(cmd); + if (rc > 0) + /* Can't return positive return codes values to keyctl */ + rc = -EPERM; + return rc; +} + +/* + * get a random value from TPM + */ +static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len) +{ + int ret; + + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_COMMAND); + store32(tb, TPM_GETRANDOM_SIZE); + store32(tb, TPM_ORD_GETRANDOM); + store32(tb, len); + ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data); + if (!ret) + memcpy(buf, tb->data + TPM_GETRANDOM_SIZE, len); + return ret; +} + +static int my_get_random(unsigned char *buf, int len) +{ + struct tpm_buf *tb; + int ret; + + tb = kmalloc(sizeof *tb, GFP_KERNEL); + if (!tb) + return -ENOMEM; + ret = tpm_get_random(tb, buf, len); + + kfree(tb); + return ret; +} + +/* + * Lock a trusted key, by extending a selected PCR. + * + * Prevents a trusted key that is sealed to PCRs from being accessed. + * This uses the tpm driver's extend function. + */ +static int pcrlock(const int pcrnum) +{ + unsigned char hash[SHA1_DIGEST_SIZE]; + int ret; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + ret = my_get_random(hash, SHA1_DIGEST_SIZE); + if (ret < 0) + return ret; + return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0; +} + +/* + * Create an object specific authorisation protocol (OSAP) session + */ +static int osap(struct tpm_buf *tb, struct osapsess *s, + const unsigned char *key, uint16_t type, uint32_t handle) +{ + unsigned char enonce[TPM_NONCE_SIZE]; + unsigned char ononce[TPM_NONCE_SIZE]; + int ret; + + ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE); + if (ret < 0) + return ret; + + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_COMMAND); + store32(tb, TPM_OSAP_SIZE); + store32(tb, TPM_ORD_OSAP); + store16(tb, type); + store32(tb, handle); + storebytes(tb, ononce, TPM_NONCE_SIZE); + + ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE); + if (ret < 0) + return ret; + + s->handle = LOAD32(tb->data, TPM_DATA_OFFSET); + memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]), + TPM_NONCE_SIZE); + memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) + + TPM_NONCE_SIZE]), TPM_NONCE_SIZE); + return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE, + enonce, TPM_NONCE_SIZE, ononce, 0, 0); +} + +/* + * Create an object independent authorisation protocol (oiap) session + */ +static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce) +{ + int ret; + + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_COMMAND); + store32(tb, TPM_OIAP_SIZE); + store32(tb, TPM_ORD_OIAP); + ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE); + if (ret < 0) + return ret; + + *handle = LOAD32(tb->data, TPM_DATA_OFFSET); + memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)], + TPM_NONCE_SIZE); + return 0; +} + +struct tpm_digests { + unsigned char encauth[SHA1_DIGEST_SIZE]; + unsigned char pubauth[SHA1_DIGEST_SIZE]; + unsigned char xorwork[SHA1_DIGEST_SIZE * 2]; + unsigned char xorhash[SHA1_DIGEST_SIZE]; + unsigned char nonceodd[TPM_NONCE_SIZE]; +}; + +/* + * Have the TPM seal(encrypt) the trusted key, possibly based on + * Platform Configuration Registers (PCRs). AUTH1 for sealing key. + */ +static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, + uint32_t keyhandle, const unsigned char *keyauth, + const unsigned char *data, uint32_t datalen, + unsigned char *blob, uint32_t *bloblen, + const unsigned char *blobauth, + const unsigned char *pcrinfo, uint32_t pcrinfosize) +{ + struct osapsess sess; + struct tpm_digests *td; + unsigned char cont; + uint32_t ordinal; + uint32_t pcrsize; + uint32_t datsize; + int sealinfosize; + int encdatasize; + int storedsize; + int ret; + int i; + + /* alloc some work space for all the hashes */ + td = kmalloc(sizeof *td, GFP_KERNEL); + if (!td) + return -ENOMEM; + + /* get session for sealing key */ + ret = osap(tb, &sess, keyauth, keytype, keyhandle); + if (ret < 0) + goto out; + dump_sess(&sess); + + /* calculate encrypted authorization value */ + memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE); + memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE); + ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash); + if (ret < 0) + goto out; + + ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE); + if (ret < 0) + goto out; + ordinal = htonl(TPM_ORD_SEAL); + datsize = htonl(datalen); + pcrsize = htonl(pcrinfosize); + cont = 0; + + /* encrypt data authorization key */ + for (i = 0; i < SHA1_DIGEST_SIZE; ++i) + td->encauth[i] = td->xorhash[i] ^ blobauth[i]; + + /* calculate authorization HMAC value */ + if (pcrinfosize == 0) { + /* no pcr info specified */ + ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, + sess.enonce, td->nonceodd, cont, + sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, + td->encauth, sizeof(uint32_t), &pcrsize, + sizeof(uint32_t), &datsize, datalen, data, 0, + 0); + } else { + /* pcr info specified */ + ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE, + sess.enonce, td->nonceodd, cont, + sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE, + td->encauth, sizeof(uint32_t), &pcrsize, + pcrinfosize, pcrinfo, sizeof(uint32_t), + &datsize, datalen, data, 0, 0); + } + if (ret < 0) + goto out; + + /* build and send the TPM request packet */ + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_AUTH1_COMMAND); + store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen); + store32(tb, TPM_ORD_SEAL); + store32(tb, keyhandle); + storebytes(tb, td->encauth, SHA1_DIGEST_SIZE); + store32(tb, pcrinfosize); + storebytes(tb, pcrinfo, pcrinfosize); + store32(tb, datalen); + storebytes(tb, data, datalen); + store32(tb, sess.handle); + storebytes(tb, td->nonceodd, TPM_NONCE_SIZE); + store8(tb, cont); + storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE); + + ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE); + if (ret < 0) + goto out; + + /* calculate the size of the returned Blob */ + sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t)); + encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) + + sizeof(uint32_t) + sealinfosize); + storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize + + sizeof(uint32_t) + encdatasize; + + /* check the HMAC in the response */ + ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret, + SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0, + 0); + + /* copy the returned blob to caller */ + if (!ret) { + memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize); + *bloblen = storedsize; + } +out: + kfree(td); + return ret; +} + +/* + * use the AUTH2_COMMAND form of unseal, to authorize both key and blob + */ +static int tpm_unseal(struct tpm_buf *tb, + uint32_t keyhandle, const unsigned char *keyauth, + const unsigned char *blob, int bloblen, + const unsigned char *blobauth, + unsigned char *data, unsigned int *datalen) +{ + unsigned char nonceodd[TPM_NONCE_SIZE]; + unsigned char enonce1[TPM_NONCE_SIZE]; + unsigned char enonce2[TPM_NONCE_SIZE]; + unsigned char authdata1[SHA1_DIGEST_SIZE]; + unsigned char authdata2[SHA1_DIGEST_SIZE]; + uint32_t authhandle1 = 0; + uint32_t authhandle2 = 0; + unsigned char cont = 0; + uint32_t ordinal; + uint32_t keyhndl; + int ret; + + /* sessions for unsealing key and data */ + ret = oiap(tb, &authhandle1, enonce1); + if (ret < 0) { + pr_info("trusted_key: oiap failed (%d)\n", ret); + return ret; + } + ret = oiap(tb, &authhandle2, enonce2); + if (ret < 0) { + pr_info("trusted_key: oiap failed (%d)\n", ret); + return ret; + } + + ordinal = htonl(TPM_ORD_UNSEAL); + keyhndl = htonl(SRKHANDLE); + ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE); + if (ret < 0) { + pr_info("trusted_key: tpm_get_random failed (%d)\n", ret); + return ret; + } + ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE, + enonce1, nonceodd, cont, sizeof(uint32_t), + &ordinal, bloblen, blob, 0, 0); + if (ret < 0) + return ret; + ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE, + enonce2, nonceodd, cont, sizeof(uint32_t), + &ordinal, bloblen, blob, 0, 0); + if (ret < 0) + return ret; + + /* build and send TPM request packet */ + INIT_BUF(tb); + store16(tb, TPM_TAG_RQU_AUTH2_COMMAND); + store32(tb, TPM_UNSEAL_SIZE + bloblen); + store32(tb, TPM_ORD_UNSEAL); + store32(tb, keyhandle); + storebytes(tb, blob, bloblen); + store32(tb, authhandle1); + storebytes(tb, nonceodd, TPM_NONCE_SIZE); + store8(tb, cont); + storebytes(tb, authdata1, SHA1_DIGEST_SIZE); + store32(tb, authhandle2); + storebytes(tb, nonceodd, TPM_NONCE_SIZE); + store8(tb, cont); + storebytes(tb, authdata2, SHA1_DIGEST_SIZE); + + ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE); + if (ret < 0) { + pr_info("trusted_key: authhmac failed (%d)\n", ret); + return ret; + } + + *datalen = LOAD32(tb->data, TPM_DATA_OFFSET); + ret = TSS_checkhmac2(tb->data, ordinal, nonceodd, + keyauth, SHA1_DIGEST_SIZE, + blobauth, SHA1_DIGEST_SIZE, + sizeof(uint32_t), TPM_DATA_OFFSET, + *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0, + 0); + if (ret < 0) { + pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret); + return ret; + } + memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen); + return 0; +} + +/* + * Have the TPM seal(encrypt) the symmetric key + */ +static int key_seal(struct trusted_key_payload *p, + struct trusted_key_options *o) +{ + struct tpm_buf *tb; + int ret; + + tb = kzalloc(sizeof *tb, GFP_KERNEL); + if (!tb) + return -ENOMEM; + + /* include migratable flag at end of sealed key */ + p->key[p->key_len] = p->migratable; + + ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth, + p->key, p->key_len + 1, p->blob, &p->blob_len, + o->blobauth, o->pcrinfo, o->pcrinfo_len); + if (ret < 0) + pr_info("trusted_key: srkseal failed (%d)\n", ret); + + kfree(tb); + return ret; +} + +/* + * Have the TPM unseal(decrypt) the symmetric key + */ +static int key_unseal(struct trusted_key_payload *p, + struct trusted_key_options *o) +{ + struct tpm_buf *tb; + int ret; + + tb = kzalloc(sizeof *tb, GFP_KERNEL); + if (!tb) + return -ENOMEM; + + ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len, + o->blobauth, p->key, &p->key_len); + if (ret < 0) + pr_info("trusted_key: srkunseal failed (%d)\n", ret); + else + /* pull migratable flag out of sealed key */ + p->migratable = p->key[--p->key_len]; + + kfree(tb); + return ret; +} + +enum { + Opt_err = -1, + Opt_new, Opt_load, Opt_update, + Opt_keyhandle, Opt_keyauth, Opt_blobauth, + Opt_pcrinfo, Opt_pcrlock, Opt_migratable +}; + +static const match_table_t key_tokens = { + {Opt_new, "new"}, + {Opt_load, "load"}, + {Opt_update, "update"}, + {Opt_keyhandle, "keyhandle=%s"}, + {Opt_keyauth, "keyauth=%s"}, + {Opt_blobauth, "blobauth=%s"}, + {Opt_pcrinfo, "pcrinfo=%s"}, + {Opt_pcrlock, "pcrlock=%s"}, + {Opt_migratable, "migratable=%s"}, + {Opt_err, NULL} +}; + +/* can have zero or more token= options */ +static int getoptions(char *c, struct trusted_key_payload *pay, + struct trusted_key_options *opt) +{ + substring_t args[MAX_OPT_ARGS]; + char *p = c; + int token; + int res; + unsigned long handle; + unsigned long lock; + + while ((p = strsep(&c, " \t"))) { + if (*p == '\0' || *p == ' ' || *p == '\t') + continue; + token = match_token(p, key_tokens, args); + + switch (token) { + case Opt_pcrinfo: + opt->pcrinfo_len = strlen(args[0].from) / 2; + if (opt->pcrinfo_len > MAX_PCRINFO_SIZE) + return -EINVAL; + hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len); + break; + case Opt_keyhandle: + res = strict_strtoul(args[0].from, 16, &handle); + if (res < 0) + return -EINVAL; + opt->keytype = SEAL_keytype; + opt->keyhandle = handle; + break; + case Opt_keyauth: + if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) + return -EINVAL; + hex2bin(opt->keyauth, args[0].from, SHA1_DIGEST_SIZE); + break; + case Opt_blobauth: + if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE) + return -EINVAL; + hex2bin(opt->blobauth, args[0].from, SHA1_DIGEST_SIZE); + break; + case Opt_migratable: + if (*args[0].from == '0') + pay->migratable = 0; + else + return -EINVAL; + break; + case Opt_pcrlock: + res = strict_strtoul(args[0].from, 10, &lock); + if (res < 0) + return -EINVAL; + opt->pcrlock = lock; + break; + default: + return -EINVAL; + } + } + return 0; +} + +/* + * datablob_parse - parse the keyctl data and fill in the + * payload and options structures + * + * On success returns 0, otherwise -EINVAL. + */ +static int datablob_parse(char *datablob, struct trusted_key_payload *p, + struct trusted_key_options *o) +{ + substring_t args[MAX_OPT_ARGS]; + long keylen; + int ret = -EINVAL; + int key_cmd; + char *c; + + /* main command */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + key_cmd = match_token(c, key_tokens, args); + switch (key_cmd) { + case Opt_new: + /* first argument is key size */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + ret = strict_strtol(c, 10, &keylen); + if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE) + return -EINVAL; + p->key_len = keylen; + ret = getoptions(datablob, p, o); + if (ret < 0) + return ret; + ret = Opt_new; + break; + case Opt_load: + /* first argument is sealed blob */ + c = strsep(&datablob, " \t"); + if (!c) + return -EINVAL; + p->blob_len = strlen(c) / 2; + if (p->blob_len > MAX_BLOB_SIZE) + return -EINVAL; + hex2bin(p->blob, c, p->blob_len); + ret = getoptions(datablob, p, o); + if (ret < 0) + return ret; + ret = Opt_load; + break; + case Opt_update: + /* all arguments are options */ + ret = getoptions(datablob, p, o); + if (ret < 0) + return ret; + ret = Opt_update; + break; + case Opt_err: + return -EINVAL; + break; + } + return ret; +} + +static struct trusted_key_options *trusted_options_alloc(void) +{ + struct trusted_key_options *options; + + options = kzalloc(sizeof *options, GFP_KERNEL); + if (options) { + /* set any non-zero defaults */ + options->keytype = SRK_keytype; + options->keyhandle = SRKHANDLE; + } + return options; +} + +static struct trusted_key_payload *trusted_payload_alloc(struct key *key) +{ + struct trusted_key_payload *p = NULL; + int ret; + + ret = key_payload_reserve(key, sizeof *p); + if (ret < 0) + return p; + p = kzalloc(sizeof *p, GFP_KERNEL); + if (p) + p->migratable = 1; /* migratable by default */ + return p; +} + +/* + * trusted_instantiate - create a new trusted key + * + * Unseal an existing trusted blob or, for a new key, get a + * random key, then seal and create a trusted key-type key, + * adding it to the specified keyring. + * + * On success, return 0. Otherwise return errno. + */ +static int trusted_instantiate(struct key *key, const void *data, + size_t datalen) +{ + struct trusted_key_payload *payload = NULL; + struct trusted_key_options *options = NULL; + char *datablob; + int ret = 0; + int key_cmd; + + if (datalen <= 0 || datalen > 32767 || !data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + memcpy(datablob, data, datalen); + datablob[datalen] = '\0'; + + options = trusted_options_alloc(); + if (!options) { + ret = -ENOMEM; + goto out; + } + payload = trusted_payload_alloc(key); + if (!payload) { + ret = -ENOMEM; + goto out; + } + + key_cmd = datablob_parse(datablob, payload, options); + if (key_cmd < 0) { + ret = key_cmd; + goto out; + } + + dump_payload(payload); + dump_options(options); + + switch (key_cmd) { + case Opt_load: + ret = key_unseal(payload, options); + dump_payload(payload); + dump_options(options); + if (ret < 0) + pr_info("trusted_key: key_unseal failed (%d)\n", ret); + break; + case Opt_new: + ret = my_get_random(payload->key, payload->key_len); + if (ret < 0) { + pr_info("trusted_key: key_create failed (%d)\n", ret); + goto out; + } + ret = key_seal(payload, options); + if (ret < 0) + pr_info("trusted_key: key_seal failed (%d)\n", ret); + break; + default: + ret = -EINVAL; + goto out; + } + if (!ret && options->pcrlock) + ret = pcrlock(options->pcrlock); +out: + kfree(datablob); + kfree(options); + if (!ret) + rcu_assign_pointer(key->payload.data, payload); + else + kfree(payload); + return ret; +} + +static void trusted_rcu_free(struct rcu_head *rcu) +{ + struct trusted_key_payload *p; + + p = container_of(rcu, struct trusted_key_payload, rcu); + memset(p->key, 0, p->key_len); + kfree(p); +} + +/* + * trusted_update - reseal an existing key with new PCR values + */ +static int trusted_update(struct key *key, const void *data, size_t datalen) +{ + struct trusted_key_payload *p = key->payload.data; + struct trusted_key_payload *new_p; + struct trusted_key_options *new_o; + char *datablob; + int ret = 0; + + if (!p->migratable) + return -EPERM; + if (datalen <= 0 || datalen > 32767 || !data) + return -EINVAL; + + datablob = kmalloc(datalen + 1, GFP_KERNEL); + if (!datablob) + return -ENOMEM; + new_o = trusted_options_alloc(); + if (!new_o) { + ret = -ENOMEM; + goto out; + } + new_p = trusted_payload_alloc(key); + if (!new_p) { + ret = -ENOMEM; + goto out; + } + + memcpy(datablob, data, datalen); + datablob[datalen] = '\0'; + ret = datablob_parse(datablob, new_p, new_o); + if (ret != Opt_update) { + ret = -EINVAL; + kfree(new_p); + goto out; + } + /* copy old key values, and reseal with new pcrs */ + new_p->migratable = p->migratable; + new_p->key_len = p->key_len; + memcpy(new_p->key, p->key, p->key_len); + dump_payload(p); + dump_payload(new_p); + + ret = key_seal(new_p, new_o); + if (ret < 0) { + pr_info("trusted_key: key_seal failed (%d)\n", ret); + kfree(new_p); + goto out; + } + if (new_o->pcrlock) { + ret = pcrlock(new_o->pcrlock); + if (ret < 0) { + pr_info("trusted_key: pcrlock failed (%d)\n", ret); + kfree(new_p); + goto out; + } + } + rcu_assign_pointer(key->payload.data, new_p); + call_rcu(&p->rcu, trusted_rcu_free); +out: + kfree(datablob); + kfree(new_o); + return ret; +} + +/* + * trusted_read - copy the sealed blob data to userspace in hex. + * On success, return to userspace the trusted key datablob size. + */ +static long trusted_read(const struct key *key, char __user *buffer, + size_t buflen) +{ + struct trusted_key_payload *p; + char *ascii_buf; + char *bufp; + int i; + + p = rcu_dereference_key(key); + if (!p) + return -EINVAL; + if (!buffer || buflen <= 0) + return 2 * p->blob_len; + ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL); + if (!ascii_buf) + return -ENOMEM; + + bufp = ascii_buf; + for (i = 0; i < p->blob_len; i++) + bufp = pack_hex_byte(bufp, p->blob[i]); + if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) { + kfree(ascii_buf); + return -EFAULT; + } + kfree(ascii_buf); + return 2 * p->blob_len; +} + +/* + * trusted_destroy - before freeing the key, clear the decrypted data + */ +static void trusted_destroy(struct key *key) +{ + struct trusted_key_payload *p = key->payload.data; + + if (!p) + return; + memset(p->key, 0, p->key_len); + kfree(key->payload.data); +} + +struct key_type key_type_trusted = { + .name = "trusted", + .instantiate = trusted_instantiate, + .update = trusted_update, + .match = user_match, + .destroy = trusted_destroy, + .describe = user_describe, + .read = trusted_read, +}; + +EXPORT_SYMBOL_GPL(key_type_trusted); + +static void trusted_shash_release(void) +{ + if (hashalg) + crypto_free_shash(hashalg); + if (hmacalg) + crypto_free_shash(hmacalg); +} + +static int __init trusted_shash_alloc(void) +{ + int ret; + + hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hmacalg)) { + pr_info("trusted_key: could not allocate crypto %s\n", + hmac_alg); + return PTR_ERR(hmacalg); + } + + hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hashalg)) { + pr_info("trusted_key: could not allocate crypto %s\n", + hash_alg); + ret = PTR_ERR(hashalg); + goto hashalg_fail; + } + + return 0; + +hashalg_fail: + crypto_free_shash(hmacalg); + return ret; +} + +static int __init init_trusted(void) +{ + int ret; + + ret = trusted_shash_alloc(); + if (ret < 0) + return ret; + ret = register_key_type(&key_type_trusted); + if (ret < 0) + trusted_shash_release(); + return ret; +} + +static void __exit cleanup_trusted(void) +{ + trusted_shash_release(); + unregister_key_type(&key_type_trusted); +} + +late_initcall(init_trusted); +module_exit(cleanup_trusted); + +MODULE_LICENSE("GPL"); diff --git a/security/keys/trusted.h b/security/keys/trusted.h new file mode 100644 index 000000000000..3249fbd2b653 --- /dev/null +++ b/security/keys/trusted.h @@ -0,0 +1,134 @@ +#ifndef __TRUSTED_KEY_H +#define __TRUSTED_KEY_H + +/* implementation specific TPM constants */ +#define MAX_PCRINFO_SIZE 64 +#define MAX_BUF_SIZE 512 +#define TPM_GETRANDOM_SIZE 14 +#define TPM_OSAP_SIZE 36 +#define TPM_OIAP_SIZE 10 +#define TPM_SEAL_SIZE 87 +#define TPM_UNSEAL_SIZE 104 +#define TPM_SIZE_OFFSET 2 +#define TPM_RETURN_OFFSET 6 +#define TPM_DATA_OFFSET 10 + +#define LOAD32(buffer, offset) (ntohl(*(uint32_t *)&buffer[offset])) +#define LOAD32N(buffer, offset) (*(uint32_t *)&buffer[offset]) +#define LOAD16(buffer, offset) (ntohs(*(uint16_t *)&buffer[offset])) + +struct tpm_buf { + int len; + unsigned char data[MAX_BUF_SIZE]; +}; + +#define INIT_BUF(tb) (tb->len = 0) + +struct osapsess { + uint32_t handle; + unsigned char secret[SHA1_DIGEST_SIZE]; + unsigned char enonce[TPM_NONCE_SIZE]; +}; + +/* discrete values, but have to store in uint16_t for TPM use */ +enum { + SEAL_keytype = 1, + SRK_keytype = 4 +}; + +struct trusted_key_options { + uint16_t keytype; + uint32_t keyhandle; + unsigned char keyauth[SHA1_DIGEST_SIZE]; + unsigned char blobauth[SHA1_DIGEST_SIZE]; + uint32_t pcrinfo_len; + unsigned char pcrinfo[MAX_PCRINFO_SIZE]; + int pcrlock; +}; + +#define TPM_DEBUG 0 + +#if TPM_DEBUG +static inline void dump_options(struct trusted_key_options *o) +{ + pr_info("trusted_key: sealing key type %d\n", o->keytype); + pr_info("trusted_key: sealing key handle %0X\n", o->keyhandle); + pr_info("trusted_key: pcrlock %d\n", o->pcrlock); + pr_info("trusted_key: pcrinfo %d\n", o->pcrinfo_len); + print_hex_dump(KERN_INFO, "pcrinfo ", DUMP_PREFIX_NONE, + 16, 1, o->pcrinfo, o->pcrinfo_len, 0); +} + +static inline void dump_payload(struct trusted_key_payload *p) +{ + pr_info("trusted_key: key_len %d\n", p->key_len); + print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE, + 16, 1, p->key, p->key_len, 0); + pr_info("trusted_key: bloblen %d\n", p->blob_len); + print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE, + 16, 1, p->blob, p->blob_len, 0); + pr_info("trusted_key: migratable %d\n", p->migratable); +} + +static inline void dump_sess(struct osapsess *s) +{ + print_hex_dump(KERN_INFO, "trusted-key: handle ", DUMP_PREFIX_NONE, + 16, 1, &s->handle, 4, 0); + pr_info("trusted-key: secret:\n"); + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, + 16, 1, &s->secret, SHA1_DIGEST_SIZE, 0); + pr_info("trusted-key: enonce:\n"); + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, + 16, 1, &s->enonce, SHA1_DIGEST_SIZE, 0); +} + +static inline void dump_tpm_buf(unsigned char *buf) +{ + int len; + + pr_info("\ntrusted-key: tpm buffer\n"); + len = LOAD32(buf, TPM_SIZE_OFFSET); + print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, buf, len, 0); +} +#else +static inline void dump_options(struct trusted_key_options *o) +{ +} + +static inline void dump_payload(struct trusted_key_payload *p) +{ +} + +static inline void dump_sess(struct osapsess *s) +{ +} + +static inline void dump_tpm_buf(unsigned char *buf) +{ +} +#endif + +static inline void store8(struct tpm_buf *buf, const unsigned char value) +{ + buf->data[buf->len++] = value; +} + +static inline void store16(struct tpm_buf *buf, const uint16_t value) +{ + *(uint16_t *) & buf->data[buf->len] = htons(value); + buf->len += sizeof value; +} + +static inline void store32(struct tpm_buf *buf, const uint32_t value) +{ + *(uint32_t *) & buf->data[buf->len] = htonl(value); + buf->len += sizeof value; +} + +static inline void storebytes(struct tpm_buf *buf, const unsigned char *in, + const int len) +{ + memcpy(buf->data + buf->len, in, len); + buf->len += len; +} +#endif diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c index e9aa07929656..5b366d7af3c4 100644 --- a/security/keys/user_defined.c +++ b/security/keys/user_defined.c @@ -35,7 +35,6 @@ struct key_type key_type_user = { EXPORT_SYMBOL_GPL(key_type_user); -/*****************************************************************************/ /* * instantiate a user defined key */ @@ -65,26 +64,10 @@ int user_instantiate(struct key *key, const void *data, size_t datalen) error: return ret; - -} /* end user_instantiate() */ +} EXPORT_SYMBOL_GPL(user_instantiate); -/*****************************************************************************/ -/* - * dispose of the old data from an updated user defined key - */ -static void user_update_rcu_disposal(struct rcu_head *rcu) -{ - struct user_key_payload *upayload; - - upayload = container_of(rcu, struct user_key_payload, rcu); - - kfree(upayload); - -} /* end user_update_rcu_disposal() */ - -/*****************************************************************************/ /* * update a user defined key * - the key's semaphore is write-locked @@ -119,28 +102,24 @@ int user_update(struct key *key, const void *data, size_t datalen) key->expiry = 0; } - call_rcu(&zap->rcu, user_update_rcu_disposal); + kfree_rcu(zap, rcu); error: return ret; - -} /* end user_update() */ +} EXPORT_SYMBOL_GPL(user_update); -/*****************************************************************************/ /* * match users on their name */ int user_match(const struct key *key, const void *description) { return strcmp(key->description, description) == 0; - -} /* end user_match() */ +} EXPORT_SYMBOL_GPL(user_match); -/*****************************************************************************/ /* * dispose of the links from a revoked keyring * - called with the key sem write-locked @@ -154,14 +133,12 @@ void user_revoke(struct key *key) if (upayload) { rcu_assign_pointer(key->payload.data, NULL); - call_rcu(&upayload->rcu, user_update_rcu_disposal); + kfree_rcu(upayload, rcu); } - -} /* end user_revoke() */ +} EXPORT_SYMBOL(user_revoke); -/*****************************************************************************/ /* * dispose of the data dangling from the corpse of a user key */ @@ -170,26 +147,22 @@ void user_destroy(struct key *key) struct user_key_payload *upayload = key->payload.data; kfree(upayload); - -} /* end user_destroy() */ +} EXPORT_SYMBOL_GPL(user_destroy); -/*****************************************************************************/ /* * describe the user key */ void user_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); - - seq_printf(m, ": %u", key->datalen); - -} /* end user_describe() */ + if (key_is_instantiated(key)) + seq_printf(m, ": %u", key->datalen); +} EXPORT_SYMBOL_GPL(user_describe); -/*****************************************************************************/ /* * read the key data * - the key's semaphore is read-locked @@ -199,8 +172,7 @@ long user_read(const struct key *key, char __user *buffer, size_t buflen) struct user_key_payload *upayload; long ret; - upayload = rcu_dereference_protected( - key->payload.data, rwsem_is_locked(&((struct key *)key)->sem)); + upayload = rcu_dereference_key(key); ret = upayload->datalen; /* we can return the data as is */ @@ -213,7 +185,6 @@ long user_read(const struct key *key, char __user *buffer, size_t buflen) } return ret; - -} /* end user_read() */ +} EXPORT_SYMBOL_GPL(user_read); |