crypto: cfb - remove bogus memcpy() with src == dest
commit 6c2e322b3621dc8be72e5c86d4fdb587434ba625 upstream.
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: 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>
1 file changed