| Date | Fri, 21 Mar 2008 15:43:13 -0700 | From | Chris Wright <> | Subject | [patch 23/76] CRYPTO xcbc: Fix crash with IPsec |
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-stable review patch. If anyone has any objections, please let us know. ---------------------
From: Joy Latten <latten@austin.ibm.com>
[ Upstream commit: 2f40a178e70030c4712fe63807c883f34c3645eb ]
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> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- crypto/xcbc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/crypto/xcbc.c +++ b/crypto/xcbc.c @@ -124,6 +124,11 @@ static int crypto_xcbc_digest_update2(st 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(st offset = 0; pg++; } - nbytes-=sg[i].length; i++; } while (nbytes>0); --
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