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| author | Steffen Klassert <steffen.klassert@secunet.com> | 2018-09-11 10:31:15 +0200 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2018-09-11 11:28:25 +0200 |
| commit | 9e1437937807b0122e8da1ca8765be2adca9aee6 (patch) | |
| tree | 9da838ab391fbc47b379d00dab98aefe0888639e | |
| parent | 782710e333a526780d65918d669cb96646983ba2 (diff) | |
| download | talos-obmc-linux-9e1437937807b0122e8da1ca8765be2adca9aee6.tar.gz talos-obmc-linux-9e1437937807b0122e8da1ca8765be2adca9aee6.zip | |
xfrm: Fix NULL pointer dereference when skb_dst_force clears the dst_entry.
Since commit 222d7dbd258d ("net: prevent dst uses after free")
skb_dst_force() might clear the dst_entry attached to the skb.
The xfrm code don't expect this to happen, so we crash with
a NULL pointer dereference in this case. Fix it by checking
skb_dst(skb) for NULL after skb_dst_force() and drop the packet
in cast the dst_entry was cleared.
Fixes: 222d7dbd258d ("net: prevent dst uses after free")
Reported-by: Tobias Hommel <netdev-list@genoetigt.de>
Reported-by: Kristian Evensen <kristian.evensen@gmail.com>
Reported-by: Wolfgang Walter <linux@stwm.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
| -rw-r--r-- | net/xfrm/xfrm_output.c | 4 | ||||
| -rw-r--r-- | net/xfrm/xfrm_policy.c | 4 |
2 files changed, 8 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c index 89b178a78dc7..36d15a38ce5e 100644 --- a/net/xfrm/xfrm_output.c +++ b/net/xfrm/xfrm_output.c @@ -101,6 +101,10 @@ static int xfrm_output_one(struct sk_buff *skb, int err) spin_unlock_bh(&x->lock); skb_dst_force(skb); + if (!skb_dst(skb)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); + goto error_nolock; + } if (xfrm_offload(skb)) { x->type_offload->encap(x, skb); diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 7c5e8978aeaa..626e0f4d1749 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -2548,6 +2548,10 @@ int __xfrm_route_forward(struct sk_buff *skb, unsigned short family) } skb_dst_force(skb); + if (!skb_dst(skb)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMFWDHDRERROR); + return 0; + } dst = xfrm_lookup(net, skb_dst(skb), &fl, NULL, XFRM_LOOKUP_QUEUE); if (IS_ERR(dst)) { |
