From: Steffen Klassert <steffen.klassert@secunet.com>
To: David Miller <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Steffen Klassert <steffen.klassert@secunet.com>,
<netdev@vger.kernel.org>
Subject: [PATCH 15/15] xfrm: fix a NULL-ptr deref in xfrm_local_error
Date: Fri, 29 May 2020 13:04:08 +0200 [thread overview]
Message-ID: <20200529110408.6349-16-steffen.klassert@secunet.com> (raw)
In-Reply-To: <20200529110408.6349-1-steffen.klassert@secunet.com>
From: Xin Long <lucien.xin@gmail.com>
This patch is to fix a crash:
[ ] kasan: GPF could be caused by NULL-ptr deref or user memory access
[ ] general protection fault: 0000 [#1] SMP KASAN PTI
[ ] RIP: 0010:ipv6_local_error+0xac/0x7a0
[ ] Call Trace:
[ ] xfrm6_local_error+0x1eb/0x300
[ ] xfrm_local_error+0x95/0x130
[ ] __xfrm6_output+0x65f/0xb50
[ ] xfrm6_output+0x106/0x46f
[ ] udp_tunnel6_xmit_skb+0x618/0xbf0 [ip6_udp_tunnel]
[ ] vxlan_xmit_one+0xbc6/0x2c60 [vxlan]
[ ] vxlan_xmit+0x6a0/0x4276 [vxlan]
[ ] dev_hard_start_xmit+0x165/0x820
[ ] __dev_queue_xmit+0x1ff0/0x2b90
[ ] ip_finish_output2+0xd3e/0x1480
[ ] ip_do_fragment+0x182d/0x2210
[ ] ip_output+0x1d0/0x510
[ ] ip_send_skb+0x37/0xa0
[ ] raw_sendmsg+0x1b4c/0x2b80
[ ] sock_sendmsg+0xc0/0x110
This occurred when sending a v4 skb over vxlan6 over ipsec, in which case
skb->protocol == htons(ETH_P_IPV6) while skb->sk->sk_family == AF_INET in
xfrm_local_error(). Then it will go to xfrm6_local_error() where it tries
to get ipv6 info from a ipv4 sk.
This issue was actually fixed by Commit 628e341f319f ("xfrm: make local
error reporting more robust"), but brought back by Commit 844d48746e4b
("xfrm: choose protocol family by skb protocol").
So to fix it, we should call xfrm6_local_error() only when skb->protocol
is htons(ETH_P_IPV6) and skb->sk->sk_family is AF_INET6.
Fixes: 844d48746e4b ("xfrm: choose protocol family by skb protocol")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
net/xfrm/xfrm_output.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 69c33cab8f49..69c4900db817 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -642,7 +642,8 @@ void xfrm_local_error(struct sk_buff *skb, int mtu)
if (skb->protocol == htons(ETH_P_IP))
proto = AF_INET;
- else if (skb->protocol == htons(ETH_P_IPV6))
+ else if (skb->protocol == htons(ETH_P_IPV6) &&
+ skb->sk->sk_family == AF_INET6)
proto = AF_INET6;
else
return;
--
2.17.1
next prev parent reply other threads:[~2020-05-29 11:10 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-29 11:03 pull request (net): ipsec 2020-05-29 Steffen Klassert
2020-05-29 11:03 ` [PATCH 01/15] xfrm: allow to accept packets with ipv6 NEXTHDR_HOP in xfrm_input Steffen Klassert
2020-05-29 11:03 ` [PATCH 02/15] xfrm: do pskb_pull properly in __xfrm_transport_prep Steffen Klassert
2020-05-29 11:03 ` [PATCH 03/15] esp6: get the right proto for transport mode in esp6_gso_encap Steffen Klassert
2020-05-29 11:03 ` [PATCH 04/15] xfrm: remove the xfrm_state_put call becofe going to out_reset Steffen Klassert
2020-05-29 11:03 ` [PATCH 05/15] xfrm: fix error in comment Steffen Klassert
2020-05-29 11:03 ` [PATCH 06/15] xfrm: espintcp: save and call old ->sk_destruct Steffen Klassert
2020-05-29 11:04 ` [PATCH 07/15] esp6: support ipv6 nexthdrs process for beet gso segment Steffen Klassert
2020-05-29 11:04 ` [PATCH 08/15] esp4: " Steffen Klassert
2020-05-29 11:04 ` [PATCH 09/15] xfrm: call xfrm_output_gso when inner_protocol is set in xfrm_output Steffen Klassert
2020-05-29 11:04 ` [PATCH 10/15] ip_vti: receive ipip packet by calling ip_tunnel_rcv Steffen Klassert
2020-05-29 11:04 ` [PATCH 11/15] xfrm interface: fix oops when deleting a x-netns interface Steffen Klassert
2020-05-29 11:04 ` [PATCH 12/15] esp6: calculate transport_header correctly when sel.family != AF_INET6 Steffen Klassert
2020-05-29 11:04 ` [PATCH 13/15] esp4: improve xfrm4_beet_gso_segment() to be more readable Steffen Klassert
2020-05-29 11:04 ` [PATCH 14/15] xfrm: fix a warning in xfrm_policy_insert_list Steffen Klassert
2020-05-29 11:04 ` Steffen Klassert [this message]
2020-05-29 20:06 ` pull request (net): ipsec 2020-05-29 David Miller
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