From: Joy Latten Date: Thu, 6 Mar 2008 11:28:44 +0000 (+0800) Subject: [CRYPTO] xcbc: Fix crash with IPsec X-Git-Tag: v2.6.25-rc5~19^2 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f40a178e70030c4712fe63807c883f34c3645eb;p=linux-2.6 [CRYPTO] xcbc: Fix crash with IPsec When using aes-xcbc-mac for authentication in IPsec, the kernel crashes. It seems this algorithm doesn't account for the space IPsec may make in scatterlist for authtag. Thus when crypto_xcbc_digest_update2() gets called, nbytes may be less than sg[i].length. Since nbytes is an unsigned number, it wraps at the end of the loop allowing us to go back into loop and causing crash in memcpy. I used update function in digest.c to model this fix. Please let me know if it looks ok. Signed-off-by: Joy Latten Signed-off-by: Herbert Xu --- diff --git a/crypto/xcbc.c b/crypto/xcbc.c index 86727403e5..2feb0f239c 100644 --- a/crypto/xcbc.c +++ b/crypto/xcbc.c @@ -124,6 +124,11 @@ static int crypto_xcbc_digest_update2(struct hash_desc *pdesc, unsigned int offset = sg[i].offset; unsigned int slen = sg[i].length; + if (unlikely(slen > nbytes)) + slen = nbytes; + + nbytes -= slen; + while (slen > 0) { unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset); char *p = crypto_kmap(pg, 0) + offset; @@ -177,7 +182,6 @@ static int crypto_xcbc_digest_update2(struct hash_desc *pdesc, offset = 0; pg++; } - nbytes-=sg[i].length; i++; } while (nbytes>0);