Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 105/183] crypto: pcbc - remove bogus memcpy()s with src == dest | Date | Fri, 22 Mar 2019 12:15:33 +0100 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Eric Biggers <ebiggers@google.com>
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: 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> --- crypto/pcbc.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-)
--- a/crypto/pcbc.c +++ b/crypto/pcbc.c @@ -50,7 +50,7 @@ static int crypto_pcbc_encrypt_segment(s 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); @@ -71,7 +71,7 @@ static int crypto_pcbc_encrypt_inplace(s 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 { @@ -83,8 +83,6 @@ static int crypto_pcbc_encrypt_inplace(s src += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } @@ -120,7 +118,7 @@ static int crypto_pcbc_decrypt_segment(s 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); @@ -131,8 +129,6 @@ static int crypto_pcbc_decrypt_segment(s dst += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; } @@ -143,7 +139,7 @@ static int crypto_pcbc_decrypt_inplace(s 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] __aligned(__alignof__(u32)); do { @@ -155,8 +151,6 @@ static int crypto_pcbc_decrypt_inplace(s src += bsize; } while ((nbytes -= bsize) >= bsize); - memcpy(walk->iv, iv, bsize); - return nbytes; }
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