diff options
| author | Eric Biggers <ebiggers@google.com> | 2017-06-08 14:48:10 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-14 15:05:55 +0200 |
| commit | d24c1c1977d80dcedf4e469be62f71644bf3383e (patch) | |
| tree | 0194b77add547e7aeef1f774111d948950a95312 /security/keys | |
| parent | 24369761029a791388cf197f4678f8ee37b2a72f (diff) | |
KEYS: encrypted: avoid encrypting/decrypting stack buffers
commit e9ff56ac352446f55141aaef1553cee662b2e310 upstream.
Since v4.9, the crypto API cannot (normally) be used to encrypt/decrypt
stack buffers because the stack may be virtually mapped. Fix this for
the padding buffers in encrypted-keys by using ZERO_PAGE for the
encryption padding and by allocating a temporary heap buffer for the
decryption padding.
Tested with CONFIG_DEBUG_SG=y:
keyctl new_session
keyctl add user master "abcdefghijklmnop" @s
keyid=$(keyctl add encrypted desc "new user:master 25" @s)
datablob="$(keyctl pipe $keyid)"
keyctl unlink $keyid
keyid=$(keyctl add encrypted desc "load $datablob" @s)
datablob2="$(keyctl pipe $keyid)"
[ "$datablob" = "$datablob2" ] && echo "Success!"
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'security/keys')
| -rw-r--r-- | security/keys/encrypted-keys/encrypted.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 17a06105ccb6..56c458dd16a2 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -480,12 +480,9 @@ static int derived_key_encrypt(struct encrypted_key_payload *epayload, struct skcipher_request *req; unsigned int encrypted_datalen; u8 iv[AES_BLOCK_SIZE]; - unsigned int padlen; - char pad[16]; int ret; encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); - padlen = encrypted_datalen - epayload->decrypted_datalen; req = init_skcipher_req(derived_key, derived_keylen); ret = PTR_ERR(req); @@ -493,11 +490,10 @@ static int derived_key_encrypt(struct encrypted_key_payload *epayload, 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_set_page(&sg_in[1], ZERO_PAGE(0), AES_BLOCK_SIZE, 0); sg_init_table(sg_out, 1); sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen); @@ -584,9 +580,14 @@ static int derived_key_decrypt(struct encrypted_key_payload *epayload, struct skcipher_request *req; unsigned int encrypted_datalen; u8 iv[AES_BLOCK_SIZE]; - char pad[16]; + u8 *pad; int ret; + /* Throwaway buffer to hold the unused zero padding at the end */ + pad = kmalloc(AES_BLOCK_SIZE, GFP_KERNEL); + if (!pad) + return -ENOMEM; + encrypted_datalen = roundup(epayload->decrypted_datalen, blksize); req = init_skcipher_req(derived_key, derived_keylen); ret = PTR_ERR(req); @@ -594,13 +595,12 @@ static int derived_key_decrypt(struct encrypted_key_payload *epayload, 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); + sg_set_buf(&sg_out[1], pad, AES_BLOCK_SIZE); memcpy(iv, epayload->iv, sizeof(iv)); skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv); @@ -612,6 +612,7 @@ static int derived_key_decrypt(struct encrypted_key_payload *epayload, goto out; dump_decrypted_data(epayload); out: + kfree(pad); return ret; } |