The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 251b7aea34ba3c4d4fdfa9447695642eb8b8b098 Mon Sep 17 00:00:00 2001

From: Eric Biggers ebiggers@google.com Date: Thu, 3 Jan 2019 20:16:13 -0800 Subject: [PATCH] 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: 91652be5d1b9 ("[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

diff --git a/crypto/pcbc.c b/crypto/pcbc.c index 8aa10144407c..1b182dfedc94 100644 --- a/crypto/pcbc.c +++ b/crypto/pcbc.c @@ -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; }