The memcpy() in crypto_cfb_decrypt_inplace() uses walk->iv as both the
source and destination, which has undefined behavior. It is unneeded
because walk->iv is already used to hold the previous ciphertext block;
thus, walk->iv is already updated to its final value. So, remove it.
Also, note that in-place decryption is the only case where the previous
ciphertext block is not directly available. Therefore, as a related
cleanup I also updated crypto_cfb_encrypt_segment() to directly use the
previous ciphertext block rather than save it into walk->iv. This makes
it consistent with in-place encryption and out-of-place decryption; now
only in-place decryption is different, because it has to be.
Fixes: a7d85e06ed ("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>
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: a7d85e06ed ("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>
In multiple functions, the algorithm fields are read after its reference
is dropped through crypto_mod_put. In this case, the algorithm memory
may be freed, resulting in use-after-free bugs. This patch delays the
put operation until the algorithm is never used.
Fixes: 79c65d179a ("crypto: cbc - Convert to skcipher")
Fixes: a7d85e06ed ("crypto: cfb - add support for Cipher FeedBack mode")
Fixes: 043a44001b ("crypto: pcbc - Convert to skcipher")
Cc: <stable@vger.kernel.org>
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
crypto_cfb_decrypt_segment() incorrectly XOR'ed generated keystream with
IV, rather than with data stream, resulting in incorrect decryption.
Test vectors will be added in the next patch.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
TPM security routines require encryption and decryption with AES in
CFB mode, so add it to the Linux Crypto schemes. CFB is basically a
one time pad where the pad is generated initially from the encrypted
IV and then subsequently from the encrypted previous block of
ciphertext. The pad is XOR'd into the plain text to get the final
ciphertext.
https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#CFB
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Eric Biggers