Commit cd0ead4a authored by Eric Biggers's avatar Eric Biggers Committed by DidntRead
Browse files

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: <stable@vger.kernel.org> # v2.6.21+
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarMaxim Zhukov <mussitantesmortem@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b0b7e765

crypto/pcbc.c

+4 −10
Original line number Diff line number Diff line
@@ -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;

}