From: Eric Biggers ebiggers@google.com

The memcpy()s in the PCBC implementation use walk->iv as both the source and destination, which has undefined behavior. These memcpy()'s are actually unneeded, because walk->iv is already used to hold the previous plaintext block XOR'd with the previous ciphertext block. Thus, walk->iv is already updated to its final value.

So remove the broken and unnecessary memcpy()s.

Fixes: 91652be5d1b9 ("[CRYPTO] pcbc: Add Propagated CBC template") Cc: stable@vger.kernel.org # v2.6.21+ Cc: David Howells dhowells@redhat.com Signed-off-by: Eric Biggers ebiggers@google.com --- crypto/pcbc.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/crypto/pcbc.c b/crypto/pcbc.c index 8aa10144407c0..1b182dfedc948 100644 --- a/crypto/pcbc.c +++ b/crypto/pcbc.c @@ -51,7 +51,7 @@ static int crypto_pcbc_encrypt_segment(struct skcipher_request *req, unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; u8 *dst = walk->dst.virt.addr; - u8 *iv = walk->iv; + u8 * const iv = walk->iv;

do { crypto_xor(iv, src, bsize); @@ -72,7 +72,7 @@ static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req, int bsize = crypto_cipher_blocksize(tfm); unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; - u8 *iv = walk->iv; + u8 * const iv = walk->iv; u8 tmpbuf[MAX_CIPHER_BLOCKSIZE];

do { @@ -84,8 +84,6 @@ static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req, src += bsize; } while ((nbytes -= bsize) >= bsize);

- memcpy(walk->iv, iv, bsize); - return nbytes; }

@@ -121,7 +119,7 @@ static int crypto_pcbc_decrypt_segment(struct skcipher_request *req, unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; u8 *dst = walk->dst.virt.addr; - u8 *iv = walk->iv; + u8 * const iv = walk->iv;

do { crypto_cipher_decrypt_one(tfm, dst, src); @@ -132,8 +130,6 @@ static int crypto_pcbc_decrypt_segment(struct skcipher_request *req, dst += bsize; } while ((nbytes -= bsize) >= bsize);

- memcpy(walk->iv, iv, bsize); - return nbytes; }

@@ -144,7 +140,7 @@ static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req, int bsize = crypto_cipher_blocksize(tfm); unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; - u8 *iv = walk->iv; + u8 * const iv = walk->iv; u8 tmpbuf[MAX_CIPHER_BLOCKSIZE] __aligned(__alignof__(u32));

do { @@ -156,8 +152,6 @@ static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req, src += bsize; } while ((nbytes -= bsize) >= bsize);

- memcpy(walk->iv, iv, bsize); - return nbytes; }