diff options
| author | Eric Biggers <ebiggers@google.com> | 2019-01-14 15:21:45 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-16 22:16:12 +0100 |
| commit | 6b22de54346b5d00e3fcf3b0bd0bc2958cc52c41 (patch) | |
| tree | ec8d55fb662e7f90c7e8c6144c630a7272f76ee7 /crypto | |
| parent | 61dd99c3788d9752453c5406b8ae6d6e2197cf34 (diff) | |
crypto: cts - fix crash on short inputs
[It's a minimal fix for a bug that was fixed incidentally by a large
refactoring in v4.8.]
In the CTS template, when the input length is <= one block cipher block
(e.g. <= 16 bytes for AES) pass the correct length to the underlying CBC
transform rather than one block. This matches the upstream behavior and
makes the encryption/decryption operation correctly return -EINVAL when
1 <= nbytes < bsize or succeed when nbytes == 0, rather than crashing.
This was fixed upstream incidentally by a large refactoring,
commit 0605c41cc53c ("crypto: cts - Convert to skcipher"). But
syzkaller easily trips over this when running on older kernels, as it's
easily reachable via AF_ALG. Therefore, this patch makes the minimal
fix for older kernels.
Cc: linux-crypto@vger.kernel.org
Fixes: 76cb9521795a ("[CRYPTO] cts: Add CTS mode required for Kerberos AES support")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/cts.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/crypto/cts.c b/crypto/cts.c index e467ec0acf9f..e65688d6a4ca 100644 --- a/crypto/cts.c +++ b/crypto/cts.c @@ -137,8 +137,8 @@ static int crypto_cts_encrypt(struct blkcipher_desc *desc, lcldesc.info = desc->info; lcldesc.flags = desc->flags; - if (tot_blocks == 1) { - err = crypto_blkcipher_encrypt_iv(&lcldesc, dst, src, bsize); + if (tot_blocks <= 1) { + err = crypto_blkcipher_encrypt_iv(&lcldesc, dst, src, nbytes); } else if (nbytes <= bsize * 2) { err = cts_cbc_encrypt(ctx, desc, dst, src, 0, nbytes); } else { @@ -232,8 +232,8 @@ static int crypto_cts_decrypt(struct blkcipher_desc *desc, lcldesc.info = desc->info; lcldesc.flags = desc->flags; - if (tot_blocks == 1) { - err = crypto_blkcipher_decrypt_iv(&lcldesc, dst, src, bsize); + if (tot_blocks <= 1) { + err = crypto_blkcipher_decrypt_iv(&lcldesc, dst, src, nbytes); } else if (nbytes <= bsize * 2) { err = cts_cbc_decrypt(ctx, desc, dst, src, 0, nbytes); } else { |