path: root/main/linux-grsec/0020-xfrm-check-bundle-policy-existance-before-dereferencing-it.patch
blob: 1a962e1610144dff1bc89ed296b30334aa32a986 (plain) (tree)

From patchwork Thu Jun 24 05:45:19 2010
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Subject: xfrm: check bundle policy existance before dereferencing it
Date: Wed, 23 Jun 2010 19:45:19 -0000
From: =?utf-8?b?VGltbyBUZXLDpHMgPHRpbW8udGVyYXNAaWtpLmZpPg==?=
X-Patchwork-Id: 56759
Message-Id: <1277358319-9868-1-git-send-email-timo.teras@iki.fi>
To: netdev@vger.kernel.org, "Justin P. Mattock" <justinmattock@gmail.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	"John W.Linville" <linville@tuxdriver.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Cc: =?UTF-8?q?Timo=20Ter=C3=A4s?= <timo.teras@iki.fi>

Fix the bundle validation code to not assume having a valid policy.
When we have multiple transformations for a xfrm policy, the bundle
instance will be a chain of bundles with only the first one having
the policy reference. When policy_genid is bumped it will expire the
first bundle in the chain which is equivalent of expiring the whole

Reported-bisected-and-tested-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>

net/xfrm/xfrm_policy.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 4bf27d9..af1c173 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2300,7 +2300,8 @@ int xfrm_bundle_ok(struct xfrm_policy *pol, struct xfrm_dst *first,
 			return 0;
 		if (xdst->xfrm_genid != dst->xfrm->genid)
 			return 0;
-		if (xdst->policy_genid != atomic_read(&xdst->pols[0]->genid))
+		if (xdst->num_pols > 0 &&
+		    xdst->policy_genid != atomic_read(&xdst->pols[0]->genid))
 			return 0;
 		if (strict && fl &&