50 lines
1.8 KiB
Diff
50 lines
1.8 KiB
Diff
From c9c8995fc83b476fdf3fc0c4b498feef2949ec75 Mon Sep 17 00:00:00 2001
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Message-Id: <c9c8995fc83b476fdf3fc0c4b498feef2949ec75.1516188238.git.jan.steffens@gmail.com>
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In-Reply-To: <4e54373158caa50df5402fdd3db1794c5394026b.1516188238.git.jan.steffens@gmail.com>
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References: <4e54373158caa50df5402fdd3db1794c5394026b.1516188238.git.jan.steffens@gmail.com>
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From: Steffen Klassert <steffen.klassert@secunet.com>
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Date: Fri, 22 Dec 2017 10:44:57 +0100
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Subject: [PATCH 3/4] xfrm: Fix stack-out-of-bounds read on socket policy
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lookup.
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When we do tunnel or beet mode, we pass saddr and daddr from the
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template to xfrm_state_find(), this is ok. On transport mode,
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we pass the addresses from the flowi, assuming that the IP
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addresses (and address family) don't change during transformation.
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This assumption is wrong in the IPv4 mapped IPv6 case, packet
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is IPv4 and template is IPv6.
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Fix this by catching address family missmatches of the policy
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and the flow already before we do the lookup.
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Reported-by: syzbot <syzkaller@googlegroups.com>
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Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
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---
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net/xfrm/xfrm_policy.c | 8 +++++++-
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1 file changed, 7 insertions(+), 1 deletion(-)
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diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
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index 6bc16bb61b55..50c5f46b5cca 100644
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--- a/net/xfrm/xfrm_policy.c
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+++ b/net/xfrm/xfrm_policy.c
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@@ -1169,9 +1169,15 @@ static struct xfrm_policy *xfrm_sk_policy_lookup(const struct sock *sk, int dir,
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again:
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pol = rcu_dereference(sk->sk_policy[dir]);
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if (pol != NULL) {
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- bool match = xfrm_selector_match(&pol->selector, fl, family);
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+ bool match;
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int err = 0;
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+ if (pol->family != family) {
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+ pol = NULL;
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+ goto out;
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+ }
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+
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+ match = xfrm_selector_match(&pol->selector, fl, family);
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if (match) {
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if ((sk->sk_mark & pol->mark.m) != pol->mark.v) {
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pol = NULL;
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--
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2.15.1
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