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| author |   Xin Long <lucien.xin@gmail.com> | 2020-05-26 17:41:46 +0800 |
|---|---|---|
| committer |   Steffen Klassert <steffen.klassert@secunet.com> | 2020-05-29 12:10:22 +0200 |
| commit | f6a23d85d078c2ffde79c66ca81d0a1dde451649 (patch) | |
| tree | 932011271e0b03f674b1911cd8d281585b4b628f /net | |
| parent | xfrm: fix a warning in xfrm_policy_insert_list (diff) | |
| download | wireguard-linux-f6a23d85d078c2ffde79c66ca81d0a1dde451649.tar.xz wireguard-linux-f6a23d85d078c2ffde79c66ca81d0a1dde451649.zip | |
xfrm: fix a NULL-ptr deref in xfrm_local_error
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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/xfrm/xfrm_output.c | 3 |
1 files changed, 2 insertions, 1 deletions
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; |