From: Alexey Dobriyan Date: Thu, 2 Apr 2015 07:58:24 +0000 (+0300) Subject: xfrm: fix xfrm_input/xfrm_tunnel_check oops X-Git-Tag: v4.1-rc1~128^2~2^2~2^2~1 X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-linux.git;a=commitdiff_plain;h=68c11e98ef6748ddb63865799b12fc45abb3755d xfrm: fix xfrm_input/xfrm_tunnel_check oops https://bugzilla.kernel.org/show_bug.cgi?id=95211 Commit 70be6c91c86596ad2b60c73587880b47df170a41 ("xfrm: Add xfrm_tunnel_skb_cb to the skb common buffer") added check which dereferences ->outer_mode too early but larval SAs don't have this pointer set (yet). So check for tunnel stuff later. Mike Noordermeer reported this bug and patiently applied all the debugging. Technically this is remote-oops-in-interrupt-context type of thing. BUG: unable to handle kernel NULL pointer dereference at 0000000000000034 IP: [] xfrm_input+0x3c2/0x5a0 ... [] ? xfrm4_esp_rcv+0x36/0x70 [] ? ip_local_deliver_finish+0x9a/0x200 [] ? __netif_receive_skb_core+0x6f3/0x8f0 ... RIP [] xfrm_input+0x3c2/0x5a0 Kernel panic - not syncing: Fatal exception in interrupt Signed-off-by: Alexey Dobriyan Signed-off-by: Steffen Klassert --- diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c index 85d1d4764612..526c4feb3b50 100644 --- a/net/xfrm/xfrm_input.c +++ b/net/xfrm/xfrm_input.c @@ -238,11 +238,6 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) skb->sp->xvec[skb->sp->len++] = x; - if (xfrm_tunnel_check(skb, x, family)) { - XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR); - goto drop; - } - spin_lock(&x->lock); if (unlikely(x->km.state == XFRM_STATE_ACQ)) { XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR); @@ -271,6 +266,11 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) spin_unlock(&x->lock); + if (xfrm_tunnel_check(skb, x, family)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR); + goto drop; + } + seq_hi = htonl(xfrm_replay_seqhi(x, seq)); XFRM_SKB_CB(skb)->seq.input.low = seq;