netdev - Re: [PATCH ipsec] xfrm: call xfrm_output_gso when inner_protocol is set in xfrm

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-prev] [day] [month] [year] [list]

Message-ID: <20200422092625.GX13121@gauss3.secunet.de>
Date:   Wed, 22 Apr 2020 11:26:25 +0200
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     Xin Long <lucien.xin@...il.com>
CC:     <netdev@...r.kernel.org>, Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Sabrina Dubroca <sd@...asysnail.net>
Subject: Re: [PATCH ipsec] xfrm: call xfrm_output_gso when inner_protocol is
 set in xfrm_output

On Mon, Apr 20, 2020 at 09:51:09PM +0800, Xin Long wrote:
> An use-after-free crash can be triggered when sending big packets over
> vxlan over esp with esp offload enabled:
> 
>   [] BUG: KASAN: use-after-free in ipv6_gso_pull_exthdrs.part.8+0x32c/0x4e0
>   [] Call Trace:
>   []  dump_stack+0x75/0xa0
>   []  kasan_report+0x37/0x50
>   []  ipv6_gso_pull_exthdrs.part.8+0x32c/0x4e0
>   []  ipv6_gso_segment+0x2c8/0x13c0
>   []  skb_mac_gso_segment+0x1cb/0x420
>   []  skb_udp_tunnel_segment+0x6b5/0x1c90
>   []  inet_gso_segment+0x440/0x1380
>   []  skb_mac_gso_segment+0x1cb/0x420
>   []  esp4_gso_segment+0xae8/0x1709 [esp4_offload]
>   []  inet_gso_segment+0x440/0x1380
>   []  skb_mac_gso_segment+0x1cb/0x420
>   []  __skb_gso_segment+0x2d7/0x5f0
>   []  validate_xmit_skb+0x527/0xb10
>   []  __dev_queue_xmit+0x10f8/0x2320 <---
>   []  ip_finish_output2+0xa2e/0x1b50
>   []  ip_output+0x1a8/0x2f0
>   []  xfrm_output_resume+0x110e/0x15f0
>   []  __xfrm4_output+0xe1/0x1b0
>   []  xfrm4_output+0xa0/0x200
>   []  iptunnel_xmit+0x5a7/0x920
>   []  vxlan_xmit_one+0x1658/0x37a0 [vxlan]
>   []  vxlan_xmit+0x5e4/0x3ec8 [vxlan]
>   []  dev_hard_start_xmit+0x125/0x540
>   []  __dev_queue_xmit+0x17bd/0x2320  <---
>   []  ip6_finish_output2+0xb20/0x1b80
>   []  ip6_output+0x1b3/0x390
>   []  ip6_xmit+0xb82/0x17e0
>   []  inet6_csk_xmit+0x225/0x3d0
>   []  __tcp_transmit_skb+0x1763/0x3520
>   []  tcp_write_xmit+0xd64/0x5fe0
>   []  __tcp_push_pending_frames+0x8c/0x320
>   []  tcp_sendmsg_locked+0x2245/0x3500
>   []  tcp_sendmsg+0x27/0x40
> 
> As on the tx path of vxlan over esp, skb->inner_network_header would be
> set on vxlan_xmit() and xfrm4_tunnel_encap_add(), and the later one can
> overwrite the former one. It causes skb_udp_tunnel_segment() to use a
> wrong skb->inner_network_header, then the issue occurs.
> 
> This patch is to fix it by calling xfrm_output_gso() instead when the
> inner_protocol is set, in which gso_segment of inner_protocol will be
> done first.
> 
> While at it, also improve some code around.
> 
> Fixes: 7862b4058b9f ("esp: Add gso handlers for esp4 and esp6")
> Reported-by: Xiumei Mu <xmu@...hat.com>
> Signed-off-by: Xin Long <lucien.xin@...il.com>

Applied, thanks a lot Xin!