diff options
| -rw-r--r-- | crypto/Kconfig | 10 | ||||
| -rw-r--r-- | crypto/Makefile | 1 | ||||
| -rw-r--r-- | crypto/echainiv.c | 531 |
3 files changed, 542 insertions, 0 deletions
diff --git a/crypto/Kconfig b/crypto/Kconfig index 657bb82acd51..b7088d138723 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -227,6 +227,16 @@ config CRYPTO_SEQIV This IV generator generates an IV based on a sequence number by xoring it with a salt. This algorithm is mainly useful for CTR +config CRYPTO_ECHAINIV + tristate "Encrypted Chain IV Generator" + select CRYPTO_AEAD + select CRYPTO_NULL + select CRYPTO_RNG + help + This IV generator generates an IV based on the encryption of + a sequence number xored with a salt. This is the default + algorithm for CBC. + comment "Block modes" config CRYPTO_CBC diff --git a/crypto/Makefile b/crypto/Makefile index 97b7d3ac87e7..df5536309012 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -21,6 +21,7 @@ obj-$(CONFIG_CRYPTO_BLKCIPHER2) += crypto_blkcipher.o obj-$(CONFIG_CRYPTO_BLKCIPHER2) += chainiv.o obj-$(CONFIG_CRYPTO_BLKCIPHER2) += eseqiv.o obj-$(CONFIG_CRYPTO_SEQIV) += seqiv.o +obj-$(CONFIG_CRYPTO_ECHAINIV) += echainiv.o crypto_hash-y += ahash.o crypto_hash-y += shash.o diff --git a/crypto/echainiv.c b/crypto/echainiv.c new file mode 100644 index 000000000000..e5a9878e6532 --- /dev/null +++ b/crypto/echainiv.c @@ -0,0 +1,531 @@ +/* + * echainiv: Encrypted Chain IV Generator + * + * This generator generates an IV based on a sequence number by xoring it + * with a salt and then encrypting it with the same key as used to encrypt + * the plain text. This algorithm requires that the block size be equal + * to the IV size. It is mainly useful for CBC. + * + * This generator can only be used by algorithms where authentication + * is performed after encryption (i.e., authenc). + * + * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> + * + * 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; either version 2 of the License, or (at your option) + * any later version. + * + */ + +#include <crypto/internal/aead.h> +#include <crypto/null.h> +#include <crypto/rng.h> +#include <crypto/scatterwalk.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/percpu.h> +#include <linux/spinlock.h> +#include <linux/string.h> + +#define MAX_IV_SIZE 16 + +struct echainiv_request_ctx { + struct scatterlist src[2]; + struct scatterlist dst[2]; + struct scatterlist ivbuf[2]; + struct scatterlist *ivsg; + struct aead_givcrypt_request subreq; +}; + +struct echainiv_ctx { + struct crypto_aead *child; + spinlock_t lock; + struct crypto_blkcipher *null; + u8 salt[] __attribute__ ((aligned(__alignof__(u32)))); +}; + +static DEFINE_PER_CPU(u32 [MAX_IV_SIZE / sizeof(u32)], echainiv_iv); + +static int echainiv_setkey(struct crypto_aead *tfm, + const u8 *key, unsigned int keylen) +{ + struct echainiv_ctx *ctx = crypto_aead_ctx(tfm); + + return crypto_aead_setkey(ctx->child, key, keylen); +} + +static int echainiv_setauthsize(struct crypto_aead *tfm, + unsigned int authsize) +{ + struct echainiv_ctx *ctx = crypto_aead_ctx(tfm); + + return crypto_aead_setauthsize(ctx->child, authsize); +} + +/* We don't care if we get preempted and read/write IVs from the next CPU. */ +void echainiv_read_iv(u8 *dst, unsigned size) +{ + u32 *a = (u32 *)dst; + u32 __percpu *b = echainiv_iv; + + for (; size >= 4; size -= 4) { + *a++ = this_cpu_read(*b); + b++; + } +} + +void echainiv_write_iv(const u8 *src, unsigned size) +{ + const u32 *a = (const u32 *)src; + u32 __percpu *b = echainiv_iv; + + for (; size >= 4; size -= 4) { + this_cpu_write(*b, *a); + a++; + b++; + } +} + +static void echainiv_encrypt_compat_complete2(struct aead_request *req, + int err) +{ + struct echainiv_request_ctx *rctx = aead_request_ctx(req); + struct aead_givcrypt_request *subreq = &rctx->subreq; + struct crypto_aead *geniv; + + if (err == -EINPROGRESS) + return; + + if (err) + goto out; + + geniv = crypto_aead_reqtfm(req); + scatterwalk_map_and_copy(subreq->giv, rctx->ivsg, 0, + crypto_aead_ivsize(geniv), 1); + +out: + kzfree(subreq->giv); +} + +static void echainiv_encrypt_compat_complete( + struct crypto_async_request *base, int err) +{ + struct aead_request *req = base->data; + + echainiv_encrypt_compat_complete2(req, err); + aead_request_complete(req, err); +} + +static void echainiv_encrypt_complete2(struct aead_request *req, int err) +{ + struct aead_request *subreq = aead_request_ctx(req); + struct crypto_aead *geniv; + unsigned int ivsize; + + if (err == -EINPROGRESS) + return; + + if (err) + goto out; + + geniv = crypto_aead_reqtfm(req); + ivsize = crypto_aead_ivsize(geniv); + + echainiv_write_iv(subreq->iv, ivsize); + + if (req->iv != subreq->iv) + memcpy(req->iv, subreq->iv, ivsize); + +out: + if (req->iv != subreq->iv) + kzfree(subreq->iv); +} + +static void echainiv_encrypt_complete(struct crypto_async_request *base, + int err) +{ + struct aead_request *req = base->data; + + echainiv_encrypt_complete2(req, err); + aead_request_complete(req, err); +} + +static int echainiv_encrypt_compat(struct aead_request *req) +{ + struct crypto_aead *geniv = crypto_aead_reqtfm(req); + struct echainiv_ctx *ctx = crypto_aead_ctx(geniv); + struct echainiv_request_ctx *rctx = aead_request_ctx(req); + struct aead_givcrypt_request *subreq = &rctx->subreq; + unsigned int ivsize = crypto_aead_ivsize(geniv); + crypto_completion_t compl; + void *data; + u8 *info; + __be64 seq; + int err; + + compl = req->base.complete; + data = req->base.data; + + rctx->ivsg = scatterwalk_ffwd(rctx->ivbuf, req->dst, req->assoclen); + info = PageHighMem(sg_page(rctx->ivsg)) ? NULL : sg_virt(rctx->ivsg); + + if (!info) { + info = kmalloc(ivsize, req->base.flags & + CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: + GFP_ATOMIC); + if (!info) + return -ENOMEM; + + compl = echainiv_encrypt_compat_complete; + data = req; + } + + memcpy(&seq, req->iv + ivsize - sizeof(seq), sizeof(seq)); + + aead_givcrypt_set_tfm(subreq, ctx->child); + aead_givcrypt_set_callback(subreq, req->base.flags, + req->base.complete, req->base.data); + aead_givcrypt_set_crypt(subreq, + scatterwalk_ffwd(rctx->src, req->src, + req->assoclen + ivsize), + scatterwalk_ffwd(rctx->dst, rctx->ivsg, + ivsize), + req->cryptlen - ivsize, req->iv); + aead_givcrypt_set_assoc(subreq, req->src, req->assoclen); + aead_givcrypt_set_giv(subreq, info, be64_to_cpu(seq)); + + err = crypto_aead_givencrypt(subreq); + if (unlikely(PageHighMem(sg_page(rctx->ivsg)))) + echainiv_encrypt_compat_complete2(req, err); + return err; +} + +static int echainiv_encrypt(struct aead_request *req) +{ + struct crypto_aead *geniv = crypto_aead_reqtfm(req); + struct echainiv_ctx *ctx = crypto_aead_ctx(geniv); + struct aead_request *subreq = aead_request_ctx(req); + crypto_completion_t compl; + void *data; + u8 *info; + unsigned int ivsize; + int err; + + aead_request_set_tfm(subreq, ctx->child); + + compl = echainiv_encrypt_complete; + data = req; + info = req->iv; + + ivsize = crypto_aead_ivsize(geniv); + + if (req->src != req->dst) { + struct scatterlist src[2]; + struct scatterlist dst[2]; + struct blkcipher_desc desc = { + .tfm = ctx->null, + }; + + err = crypto_blkcipher_encrypt( + &desc, + scatterwalk_ffwd(dst, req->dst, + req->assoclen + ivsize), + scatterwalk_ffwd(src, req->src, + req->assoclen + ivsize), + req->cryptlen - ivsize); + if (err) + return err; + } + + if (unlikely(!IS_ALIGNED((unsigned long)info, + crypto_aead_alignmask(geniv) + 1))) { + info = kmalloc(ivsize, req->base.flags & + CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL: + GFP_ATOMIC); + if (!info) + return -ENOMEM; + + memcpy(info, req->iv, ivsize); + } + + aead_request_set_callback(subreq, req->base.flags, compl, data); + aead_request_set_crypt(subreq, req->dst, req->dst, + req->cryptlen - ivsize, info); + aead_request_set_ad(subreq, req->assoclen + ivsize, 0); + + crypto_xor(info, ctx->salt, ivsize); + scatterwalk_map_and_copy(info, req->dst, req->assoclen, ivsize, 1); + echainiv_read_iv(info, ivsize); + + err = crypto_aead_encrypt(subreq); + echainiv_encrypt_complete2(req, err); + return err; +} + +static int echainiv_decrypt_compat(struct aead_request *req) +{ + struct crypto_aead *geniv = crypto_aead_reqtfm(req); + struct echainiv_ctx *ctx = crypto_aead_ctx(geniv); + struct aead_request *subreq = aead_request_ctx(req); + crypto_completion_t compl; + void *data; + unsigned int ivsize; + + aead_request_set_tfm(subreq, ctx->child); + + compl = req->base.complete; + data = req->base.data; + + ivsize = crypto_aead_ivsize(geniv); + + aead_request_set_callback(subreq, req->base.flags, compl, data); + aead_request_set_crypt(subreq, req->src, req->dst, + req->cryptlen - ivsize, req->iv); + aead_request_set_ad(subreq, req->assoclen, ivsize); + + scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0); + + return crypto_aead_decrypt(subreq); +} + +static int echainiv_decrypt(struct aead_request *req) +{ + struct crypto_aead *geniv = crypto_aead_reqtfm(req); + struct echainiv_ctx *ctx = crypto_aead_ctx(geniv); + struct aead_request *subreq = aead_request_ctx(req); + crypto_completion_t compl; + void *data; + unsigned int ivsize; + + aead_request_set_tfm(subreq, ctx->child); + + compl = req->base.complete; + data = req->base.data; + + ivsize = crypto_aead_ivsize(geniv); + + aead_request_set_callback(subreq, req->base.flags, compl, data); + aead_request_set_crypt(subreq, req->src, req->dst, + req->cryptlen - ivsize, req->iv); + aead_request_set_ad(subreq, req->assoclen + ivsize, 0); + + scatterwalk_map_and_copy(req->iv, req->src, req->assoclen, ivsize, 0); + if (req->src != req->dst) + scatterwalk_map_and_copy(req->iv, req->dst, + req->assoclen, ivsize, 1); + + return crypto_aead_decrypt(subreq); +} + +static int echainiv_encrypt_compat_first(struct aead_request *req) +{ + struct crypto_aead *geniv = crypto_aead_reqtfm(req); + struct echainiv_ctx *ctx = crypto_aead_ctx(geniv); + int err = 0; + + spin_lock_bh(&ctx->lock); + if (geniv->encrypt != echainiv_encrypt_compat_first) + goto unlock; + + geniv->encrypt = echainiv_encrypt_compat; + err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt, + crypto_aead_ivsize(geniv)); + +unlock: + spin_unlock_bh(&ctx->lock); + + if (err) + return err; + + return echainiv_encrypt_compat(req); +} + +static int echainiv_encrypt_first(struct aead_request *req) +{ + struct crypto_aead *geniv = crypto_aead_reqtfm(req); + struct echainiv_ctx *ctx = crypto_aead_ctx(geniv); + int err = 0; + + spin_lock_bh(&ctx->lock); + if (geniv->encrypt != echainiv_encrypt_first) + goto unlock; + + geniv->encrypt = echainiv_encrypt; + err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt, + crypto_aead_ivsize(geniv)); + +unlock: + spin_unlock_bh(&ctx->lock); + + if (err) + return err; + + return echainiv_encrypt(req); +} + +static int echainiv_compat_init(struct crypto_tfm *tfm) +{ + struct crypto_aead *geniv = __crypto_aead_cast(tfm); + struct echainiv_ctx *ctx = crypto_aead_ctx(geniv); + int err; + + spin_lock_init(&ctx->lock); + + crypto_aead_set_reqsize(geniv, sizeof(struct echainiv_request_ctx)); + + err = aead_geniv_init(tfm); + + ctx->child = geniv->child; + geniv->child = geniv; + + return err; +} + +static int echainiv_init(struct crypto_tfm *tfm) +{ + struct crypto_aead *geniv = __crypto_aead_cast(tfm); + struct echainiv_ctx *ctx = crypto_aead_ctx(geniv); + int err; + + spin_lock_init(&ctx->lock); + + crypto_aead_set_reqsize(geniv, sizeof(struct aead_request)); + + ctx->null = crypto_get_default_null_skcipher(); + err = PTR_ERR(ctx->null); + if (IS_ERR(ctx->null)) + goto out; + + err = aead_geniv_init(tfm); + if (err) + goto drop_null; + + ctx->child = geniv->child; + geniv->child = geniv; + +out: + return err; + +drop_null: + crypto_put_default_null_skcipher(); + goto out; +} + +static void echainiv_compat_exit(struct crypto_tfm *tfm) +{ + struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm); + + crypto_free_aead(ctx->child); +} + +static void echainiv_exit(struct crypto_tfm *tfm) +{ + struct echainiv_ctx *ctx = crypto_tfm_ctx(tfm); + + crypto_free_aead(ctx->child); + crypto_put_default_null_skcipher(); +} + +static struct crypto_template echainiv_tmpl; + +static struct crypto_instance *echainiv_aead_alloc(struct rtattr **tb) +{ + struct aead_instance *inst; + struct crypto_aead_spawn *spawn; + struct aead_alg *alg; + + inst = aead_geniv_alloc(&echainiv_tmpl, tb, 0, 0); + + if (IS_ERR(inst)) + goto out; + + if (inst->alg.ivsize < sizeof(u64) || + inst->alg.ivsize & (sizeof(u32) - 1) || + inst->alg.ivsize > MAX_IV_SIZE) { + aead_geniv_free(inst); + inst = ERR_PTR(-EINVAL); + goto out; + } + + spawn = aead_instance_ctx(inst); + alg = crypto_spawn_aead_alg(spawn); + + inst->alg.setkey = echainiv_setkey; + inst->alg.setauthsize = echainiv_setauthsize; + inst->alg.encrypt = echainiv_encrypt_first; + inst->alg.decrypt = echainiv_decrypt; + + inst->alg.base.cra_init = echainiv_init; + inst->alg.base.cra_exit = echainiv_exit; + + inst->alg.base.cra_alignmask |= __alignof__(u32) - 1; + inst->alg.base.cra_ctxsize = sizeof(struct echainiv_ctx); + inst->alg.base.cra_ctxsize += inst->alg.base.cra_aead.ivsize; + + if (alg->base.cra_aead.encrypt) { + inst->alg.encrypt = echainiv_encrypt_compat_first; + inst->alg.decrypt = echainiv_decrypt_compat; + + inst->alg.base.cra_init = echainiv_compat_init; + inst->alg.base.cra_exit = echainiv_compat_exit; + } + +out: + return aead_crypto_instance(inst); +} + +static struct crypto_instance *echainiv_alloc(struct rtattr **tb) +{ + struct crypto_instance *inst; + int err; + + err = crypto_get_default_rng(); + if (err) + return ERR_PTR(err); + + inst = echainiv_aead_alloc(tb); + + if (IS_ERR(inst)) + goto put_rng; + +out: + return inst; + +put_rng: + crypto_put_default_rng(); + goto out; +} + +static void echainiv_free(struct crypto_instance *inst) +{ + aead_geniv_free(aead_instance(inst)); + crypto_put_default_rng(); +} + +static struct crypto_template echainiv_tmpl = { + .name = "echainiv", + .alloc = echainiv_alloc, + .free = echainiv_free, + .module = THIS_MODULE, +}; + +static int __init echainiv_module_init(void) +{ + return crypto_register_template(&echainiv_tmpl); +} + +static void __exit echainiv_module_exit(void) +{ + crypto_unregister_template(&echainiv_tmpl); +} + +module_init(echainiv_module_init); +module_exit(echainiv_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Encrypted Chain IV Generator"); +MODULE_ALIAS_CRYPTO("echainiv"); |