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| author | Joy Latten <latten@austin.ibm.com> | 2008-03-06 19:28:44 +0800 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2008-03-06 19:28:44 +0800 |
| commit | 2f40a178e70030c4712fe63807c883f34c3645eb (patch) | |
| tree | 8b84e1c7a18df7c134d32cbe587cd6d88c9e942e /crypto/xcbc.c | |
| parent | 6212f2c7f70c591efb0d9f3d50ad29112392fee2 (diff) | |
| download | lwn-2f40a178e70030c4712fe63807c883f34c3645eb.tar.gz lwn-2f40a178e70030c4712fe63807c883f34c3645eb.zip | |
[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>
Diffstat (limited to 'crypto/xcbc.c')
| -rw-r--r-- | crypto/xcbc.c | 6 |
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); |