From 9bde9df79f24895e0b1be03b9f76a7ad8fa1cbba 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/pcbc.c') diff --git a/crypto/pcbc.c b/crypto/pcbc.c index f654965f0933..de81f716cf26 100644 --- a/crypto/pcbc.c +++ b/crypto/pcbc.c @@ -52,7 +52,7 @@ static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc, 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); @@ -76,7 +76,7 @@ static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc, 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 { @@ -89,8 +89,6 @@ static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc, src += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } @@ -130,7 +128,7 @@ static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc, 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 { fn(crypto_cipher_tfm(tfm), dst, src); @@ -142,8 +140,6 @@ static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc, dst += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } @@ -156,7 +152,7 @@ static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc, 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 { @@ -169,8 +165,6 @@ static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc, src += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } -- cgit v1.2.3