netdev - [PATCH] xfrm: fix xfrm_input/xfrm_tunnel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 2 Apr 2015 10:58:24 +0300
From:	Alexey Dobriyan <adobriyan@...il.com>
To:	davem@...emloft.net
Cc:	mike@...mi.net, netdev@...r.kernel.org,
	steffen.klassert@...unet.com, herbert@...dor.apana.org.au
Subject: [PATCH] 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: [<ffffffff8150dca2>] xfrm_input+0x3c2/0x5a0
	...
[<ffffffff81500fc6>] ? xfrm4_esp_rcv+0x36/0x70
[<ffffffff814acc9a>] ? ip_local_deliver_finish+0x9a/0x200
[<ffffffff81471b83>] ? __netif_receive_skb_core+0x6f3/0x8f0
	...

RIP  [<ffffffff8150dca2>] xfrm_input+0x3c2/0x5a0
Kernel panic - not syncing: Fatal exception in interrupt

Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
---

	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;
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html