[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>
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1 changed files with 5 additions and 1 deletions
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@ -124,6 +124,11 @@ static int crypto_xcbc_digest_update2(struct hash_desc *pdesc,
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unsigned int offset = sg[i].offset;
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unsigned int offset = sg[i].offset;
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unsigned int slen = sg[i].length;
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unsigned int slen = sg[i].length;
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if (unlikely(slen > nbytes))
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slen = nbytes;
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nbytes -= slen;
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while (slen > 0) {
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while (slen > 0) {
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unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
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unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
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char *p = crypto_kmap(pg, 0) + offset;
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char *p = crypto_kmap(pg, 0) + offset;
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@ -177,7 +182,6 @@ static int crypto_xcbc_digest_update2(struct hash_desc *pdesc,
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offset = 0;
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offset = 0;
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pg++;
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pg++;
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}
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}
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nbytes-=sg[i].length;
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i++;
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i++;
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} while (nbytes>0);
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} while (nbytes>0);
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