From 05c0283950485d3b5d1d35200b2e679f11ae081b Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 3 Jan 2019 20:16:13 -0800 Subject: crypto: pcbc - remove bogus memcpy()s with src == dest commit 251b7aea34ba3c4d4fdfa9447695642eb8b8b098 upstream. 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: # v2.6.21+ Cc: David Howells Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu Signed-off-by: Maxim Zhukov Signed-off-by: Greg Kroah-Hartman --- crypto/pcbc.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'crypto') diff --git a/crypto/pcbc.c b/crypto/pcbc.c index d9e45a958720..67009a532201 100644 --- a/crypto/pcbc.c +++ b/crypto/pcbc.c @@ -50,7 +50,7 @@ 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); @@ -71,7 +71,7 @@ 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[bsize]; do { @@ -83,8 +83,6 @@ static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req, src += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } @@ -120,7 +118,7 @@ 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); @@ -131,8 +129,6 @@ static int crypto_pcbc_decrypt_segment(struct skcipher_request *req, dst += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } @@ -143,7 +139,7 @@ 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[bsize] __aligned(__alignof__(u32)); do { @@ -155,8 +151,6 @@ static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req, src += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } -- cgit v1.2.3