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crypto: pcbc - remove bogus memcpy()s with src == dest 

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: 91652be5d1 ("[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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers 2019-01-03 20:16:13 -08:00 committed by Herbert Xu
parent b3e3e2db7d
commit 251b7aea34
1 changed files with 4 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
crypto/pcbc.c
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@ -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;
}