Commit 251b7aea authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

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: 91652be5 ("[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>
parent b3e3e2db

crypto/pcbc.c

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

}

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