diff options
| author | Steffen Klassert <steffen.klassert@secunet.com> | 2018-11-22 07:26:24 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-13 10:00:57 +0100 |
| commit | 4ddb80f4193cf344550458087977a500a2c3cd4c (patch) | |
| tree | 09e0d7094e2c2ce9dc42867f12bd9146594edcba /net/xfrm | |
| parent | ed04bb260d161cab36118537f888329712ad4abe (diff) | |
xfrm: Fix NULL pointer dereference in xfrm_input when skb_dst_force clears the dst_entry.
[ Upstream commit 0152eee6fc3b84298bb6a79961961734e8afa5b8 ]
Since commit 222d7dbd258d ("net: prevent dst uses after free")
skb_dst_force() might clear the dst_entry attached to the skb.
The xfrm code doesn'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 case the dst_entry was cleared. We also
move the skb_dst_force() to a codepath that is not used when
the transformation was offloaded, because in this case we
don't have a dst_entry attached to the skb.
The output and forwarding path was already fixed by
commit 9e1437937807 ("xfrm: Fix NULL pointer dereference when
skb_dst_force clears the dst_entry.")
Fixes: 222d7dbd258d ("net: prevent dst uses after free")
Reported-by: Jean-Philippe Menil <jpmenil@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/xfrm')
| -rw-r--r-- | net/xfrm/xfrm_input.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c index 8e75319dd9c0..06dec32503bd 100644 --- a/net/xfrm/xfrm_input.c +++ b/net/xfrm/xfrm_input.c @@ -341,6 +341,12 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) skb->sp->xvec[skb->sp->len++] = x; + skb_dst_force(skb); + if (!skb_dst(skb)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR); + goto drop; + } + lock: spin_lock(&x->lock); @@ -380,7 +386,6 @@ lock: XFRM_SKB_CB(skb)->seq.input.low = seq; XFRM_SKB_CB(skb)->seq.input.hi = seq_hi; - skb_dst_force(skb); dev_hold(skb->dev); if (crypto_done) |