From: Alexey Dobriyan Subject: [PATCH] xfrm: fix xfrm_input/xfrm_tunnel_check oops Date: Thu, 2 Apr 2015 10:58:24 +0300 Message-ID: <20150402075824.GA2079@p183.telecom.by> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: mike@normi.net, netdev@vger.kernel.org, steffen.klassert@secunet.com, herbert@gondor.apana.org.au To: davem@davemloft.net Return-path: Received: from mail-wi0-f174.google.com ([209.85.212.174]:36886 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750771AbbDBH6Z (ORCPT ); Thu, 2 Apr 2015 03:58:25 -0400 Received: by wiaa2 with SMTP id a2so95241192wia.0 for ; Thu, 02 Apr 2015 00:58:24 -0700 (PDT) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: 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 --- Patch is in final testing, I'm sending it opportunistically. Mike, please chim in if this patch didn't help in the end! net/xfrm/xfrm_input.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/net/xfrm/xfrm_input.c +++ a/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;