tree 0f7b5b7b5528cad419ffc19a3d29a82d61ae2935
parent 79960943fdc114fd4583c9ab164b5c89da7aa601
author Jason A. Donenfeld <Jason@zx2c4.com> 1449366697 +0100
committer Herbert Xu <herbert@gondor.apana.org.au> 1449663382 +0800

crypto: skcipher - Copy iv from desc even for 0-len walks

Some ciphers actually support encrypting zero length plaintexts. For
example, many AEAD modes support this. The resulting ciphertext for
those winds up being only the authentication tag, which is a result of
the key, the iv, the additional data, and the fact that the plaintext
had zero length. The blkcipher constructors won't copy the IV to the
right place, however, when using a zero length input, resulting in
some significant problems when ciphers call their initialization
routines, only to find that the ->iv parameter is uninitialized. One
such example of this would be using chacha20poly1305 with a zero length
input, which then calls chacha20, which calls the key setup routine,
which eventually OOPSes due to the uninitialized ->iv member.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>