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authorJoy Latten <latten@austin.ibm.com>2008-03-06 19:28:44 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2008-03-06 19:28:44 +0800
commit2f40a178e70030c4712fe63807c883f34c3645eb (patch)
tree8b84e1c7a18df7c134d32cbe587cd6d88c9e942e
parent6212f2c7f70c591efb0d9f3d50ad29112392fee2 (diff)
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[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 <latten@austin.ibm.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/xcbc.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/crypto/xcbc.c b/crypto/xcbc.c
index 86727403e5ab..2feb0f239c38 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);