4.19-stable review patch. If anyone has any objections, please let me know.
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From: Eric Biggers ebiggers@google.com
commit 394a9e044702e6a8958a5e89d2a291605a587a2a upstream.
Like some other block cipher mode implementations, the CFB implementation assumes that while walking through the scatterlist, a partial block does not occur until the end. But the walk is incorrectly being done with a blocksize of 1, as 'cra_blocksize' is set to 1 (since CFB is a stream cipher) but no 'chunksize' is set. This bug causes incorrect encryption/decryption for some scatterlist layouts.
Fix it by setting the 'chunksize'. Also extend the CFB test vectors to cover this bug as well as cases where the message length is not a multiple of the block size.
Fixes: a7d85e06ed80 ("crypto: cfb - add support for Cipher FeedBack mode") Cc: stable@vger.kernel.org # v4.17+ Cc: James Bottomley James.Bottomley@HansenPartnership.com Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- crypto/cfb.c | 6 ++++++ crypto/testmgr.h | 25 +++++++++++++++++++++++++ 2 files changed, 31 insertions(+)
--- a/crypto/cfb.c +++ b/crypto/cfb.c @@ -298,6 +298,12 @@ static int crypto_cfb_create(struct cryp inst->alg.base.cra_blocksize = 1; inst->alg.base.cra_alignmask = alg->cra_alignmask;
+ /* + * To simplify the implementation, configure the skcipher walk to only + * give a partial block at the very end, never earlier. + */ + inst->alg.chunksize = alg->cra_blocksize; + inst->alg.ivsize = alg->cra_blocksize; inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize; inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize; --- a/crypto/testmgr.h +++ b/crypto/testmgr.h @@ -11416,6 +11416,31 @@ static const struct cipher_testvec aes_c "\x75\xa3\x85\x74\x1a\xb9\xce\xf8" "\x20\x31\x62\x3d\x55\xb1\xe4\x71", .len = 64, + .also_non_np = 1, + .np = 2, + .tap = { 31, 33 }, + }, { /* > 16 bytes, not a multiple of 16 bytes */ + .key = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6" + "\xab\xf7\x15\x88\x09\xcf\x4f\x3c", + .klen = 16, + .iv = "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + .ptext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f\x96" + "\xe9\x3d\x7e\x11\x73\x93\x17\x2a" + "\xae", + .ctext = "\x3b\x3f\xd9\x2e\xb7\x2d\xad\x20" + "\x33\x34\x49\xf8\xe8\x3c\xfb\x4a" + "\xc8", + .len = 17, + }, { /* < 16 bytes */ + .key = "\x2b\x7e\x15\x16\x28\xae\xd2\xa6" + "\xab\xf7\x15\x88\x09\xcf\x4f\x3c", + .klen = 16, + .iv = "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + .ptext = "\x6b\xc1\xbe\xe2\x2e\x40\x9f", + .ctext = "\x3b\x3f\xd9\x2e\xb7\x2d\xad", + .len = 7, }, };