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

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commit 251b7aea34 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: 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>
Signed-off-by: Maxim Zhukov <mussitantesmortem@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric Biggers 2019-01-03 20:16:13 -08:00 committed by Greg Kroah-Hartman
parent fc3a73f9a7
commit a329c157b9
1 changed files with 4 additions and 10 deletions
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14
crypto/pcbc.c
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@ -52,7 +52,7 @@ static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,
unsigned int nbytes = walk->nbytes; unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr; u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr; u8 *dst = walk->dst.virt.addr;
u8 *iv = walk->iv; u8 * const iv = walk->iv;
do { do {
crypto_xor(iv, src, bsize); 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); int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes; unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr; u8 *src = walk->src.virt.addr;
u8 *iv = walk->iv; u8 * const iv = walk->iv;
u8 tmpbuf[bsize]; u8 tmpbuf[bsize];
do { do {
@ -89,8 +89,6 @@ static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,
src += bsize; src += bsize;
} while ((nbytes -= bsize) >= bsize); } while ((nbytes -= bsize) >= bsize);
memcpy(walk->iv, iv, bsize);
return nbytes; return nbytes;
} }
@ -130,7 +128,7 @@ static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
unsigned int nbytes = walk->nbytes; unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr; u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr; u8 *dst = walk->dst.virt.addr;
u8 *iv = walk->iv; u8 * const iv = walk->iv;
do { do {
fn(crypto_cipher_tfm(tfm), dst, src); fn(crypto_cipher_tfm(tfm), dst, src);
@ -142,8 +140,6 @@ static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,
dst += bsize; dst += bsize;
} while ((nbytes -= bsize) >= bsize); } while ((nbytes -= bsize) >= bsize);
memcpy(walk->iv, iv, bsize);
return nbytes; return nbytes;
} }
@ -156,7 +152,7 @@ static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
int bsize = crypto_cipher_blocksize(tfm); int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes = walk->nbytes; unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr; u8 *src = walk->src.virt.addr;
u8 *iv = walk->iv; u8 * const iv = walk->iv;
u8 tmpbuf[bsize]; u8 tmpbuf[bsize];
do { do {
@ -169,8 +165,6 @@ static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,
src += bsize; src += bsize;
} while ((nbytes -= bsize) >= bsize); } while ((nbytes -= bsize) >= bsize);
memcpy(walk->iv, iv, bsize);
return nbytes; return nbytes;
} }