This is a note to let you know that I've just added the patch titled
xfrm: Fix null pointer dereference when decoding sessions
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xfrm-fix-null-pointer-dereference-when-decoding-sessions.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Dec 5 16:16:39 PST 2013
From: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Date: Wed, 30 Oct 2013 11:16:28 +0100
Subject: xfrm: Fix null pointer dereference when decoding sessions
From: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
[ Upstream commit 84502b5ef9849a9694673b15c31bd3ac693010ae ]
On some codepaths the skb does not have a dst entry
when xfrm_decode_session() is called. So check for
a valid skb_dst() before dereferencing the device
interface index. We use 0 as the device index if
there is no valid skb_dst(), or at reverse decoding
we use skb_iif as device interface index.
Bug was introduced with git commit bafd4bd4dc
("xfrm: Decode sessions with output interface.").
Reported-by: Meelis Roos <mroos@xxxxxxxx>
Tested-by: Meelis Roos <mroos@xxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/xfrm4_policy.c | 6 +++++-
net/ipv6/xfrm6_policy.c | 6 +++++-
2 files changed, 10 insertions(+), 2 deletions(-)
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -104,10 +104,14 @@ _decode_session4(struct sk_buff *skb, st
const struct iphdr *iph = ip_hdr(skb);
u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
struct flowi4 *fl4 = &fl->u.ip4;
+ int oif = 0;
+
+ if (skb_dst(skb))
+ oif = skb_dst(skb)->dev->ifindex;
memset(fl4, 0, sizeof(struct flowi4));
fl4->flowi4_mark = skb->mark;
- fl4->flowi4_oif = skb_dst(skb)->dev->ifindex;
+ fl4->flowi4_oif = reverse ? skb->skb_iif : oif;
if (!ip_is_fragment(iph)) {
switch (iph->protocol) {
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -135,10 +135,14 @@ _decode_session6(struct sk_buff *skb, st
struct ipv6_opt_hdr *exthdr;
const unsigned char *nh = skb_network_header(skb);
u8 nexthdr = nh[IP6CB(skb)->nhoff];
+ int oif = 0;
+
+ if (skb_dst(skb))
+ oif = skb_dst(skb)->dev->ifindex;
memset(fl6, 0, sizeof(struct flowi6));
fl6->flowi6_mark = skb->mark;
- fl6->flowi6_oif = skb_dst(skb)->dev->ifindex;
+ fl6->flowi6_oif = reverse ? skb->skb_iif : oif;
fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
Patches currently in stable-queue which might be from steffen.klassert@xxxxxxxxxxx are
queue-3.12/xfrm-fix-null-pointer-dereference-when-decoding-sessions.patch
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