Commit 2f40a178 authored Mar 06, 2008 by Joy Latten Committed by Herbert Xu Mar 06, 2008

[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>

parent 6212f2c7

crypto/xcbc.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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);

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