3.16.70-rc1 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: David Howells dhowells@redhat.com Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- crypto/pcbc.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-)
--- a/crypto/pcbc.c +++ b/crypto/pcbc.c @@ -52,7 +52,7 @@ 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); @@ -76,7 +76,7 @@ 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 { @@ -89,8 +89,6 @@ static int crypto_pcbc_encrypt_inplace(s src += bsize; } while ((nbytes -= bsize) >= bsize);
- memcpy(walk->iv, iv, bsize); - return nbytes; }
@@ -130,7 +128,7 @@ 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 { fn(crypto_cipher_tfm(tfm), dst, src); @@ -142,8 +140,6 @@ static int crypto_pcbc_decrypt_segment(s dst += bsize; } while ((nbytes -= bsize) >= bsize);
- memcpy(walk->iv, iv, bsize); - return nbytes; }
@@ -156,7 +152,7 @@ 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];
do { @@ -169,8 +165,6 @@ static int crypto_pcbc_decrypt_inplace(s src += bsize; } while ((nbytes -= bsize) >= bsize);
- memcpy(walk->iv, iv, bsize); - return nbytes; }