linux/net/ipv6
Paolo Abeni 76c0ddd8c3 ip6_tunnel: be careful when accessing the inner header
the ip6 tunnel xmit ndo assumes that the processed skb always
contains an ip[v6] header, but syzbot has found a way to send
frames that fall short of this assumption, leading to the following splat:

BUG: KMSAN: uninit-value in ip6ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1307
[inline]
BUG: KMSAN: uninit-value in ip6_tnl_start_xmit+0x7d2/0x1ef0
net/ipv6/ip6_tunnel.c:1390
CPU: 0 PID: 4504 Comm: syz-executor558 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x185/0x1d0 lib/dump_stack.c:53
  kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
  __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
  ip6ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1307 [inline]
  ip6_tnl_start_xmit+0x7d2/0x1ef0 net/ipv6/ip6_tunnel.c:1390
  __netdev_start_xmit include/linux/netdevice.h:4066 [inline]
  netdev_start_xmit include/linux/netdevice.h:4075 [inline]
  xmit_one net/core/dev.c:3026 [inline]
  dev_hard_start_xmit+0x5f1/0xc70 net/core/dev.c:3042
  __dev_queue_xmit+0x27ee/0x3520 net/core/dev.c:3557
  dev_queue_xmit+0x4b/0x60 net/core/dev.c:3590
  packet_snd net/packet/af_packet.c:2944 [inline]
  packet_sendmsg+0x7c70/0x8a30 net/packet/af_packet.c:2969
  sock_sendmsg_nosec net/socket.c:630 [inline]
  sock_sendmsg net/socket.c:640 [inline]
  ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
  __sys_sendmmsg+0x42d/0x800 net/socket.c:2136
  SYSC_sendmmsg+0xc4/0x110 net/socket.c:2167
  SyS_sendmmsg+0x63/0x90 net/socket.c:2162
  do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x441819
RSP: 002b:00007ffe58ee8268 EFLAGS: 00000213 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441819
RDX: 0000000000000002 RSI: 0000000020000100 RDI: 0000000000000003
RBP: 00000000006cd018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000402510
R13: 00000000004025a0 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
  kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
  kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
  kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
  slab_post_alloc_hook mm/slab.h:445 [inline]
  slab_alloc_node mm/slub.c:2737 [inline]
  __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
  __kmalloc_reserve net/core/skbuff.c:138 [inline]
  __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
  alloc_skb include/linux/skbuff.h:984 [inline]
  alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
  sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
  packet_alloc_skb net/packet/af_packet.c:2803 [inline]
  packet_snd net/packet/af_packet.c:2894 [inline]
  packet_sendmsg+0x6454/0x8a30 net/packet/af_packet.c:2969
  sock_sendmsg_nosec net/socket.c:630 [inline]
  sock_sendmsg net/socket.c:640 [inline]
  ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
  __sys_sendmmsg+0x42d/0x800 net/socket.c:2136
  SYSC_sendmmsg+0xc4/0x110 net/socket.c:2167
  SyS_sendmmsg+0x63/0x90 net/socket.c:2162
  do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x3d/0xa2

This change addresses the issue adding the needed check before
accessing the inner header.

The ipv4 side of the issue is apparently there since the ipv4 over ipv6
initial support, and the ipv6 side predates git history.

Fixes: c4d3efafcc ("[IPV6] IP6TUNNEL: Add support to IPv4 over IPv6 tunnel.")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+3fde91d4d394747d6db4@syzkaller.appspotmail.com
Tested-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-19 21:24:28 -07:00
..
ila ila: remove blank lines at EOF 2018-07-24 14:10:42 -07:00
netfilter ip: frags: fix crash in ip_do_fragment() 2018-09-09 14:50:56 -07:00
addrconf_core.c net/ipv6: Add helper to return path MTU based on fib result 2018-05-22 10:51:09 +02:00
addrconf.c addrconf: reduce unnecessary atomic allocations 2018-08-22 21:42:07 -07:00
addrlabel.c net: Drop pernet_operations::async 2018-03-27 13:18:09 -04:00
af_inet6.c ipv6: fix cleanup ordering for pingv6 registration 2018-08-29 19:28:55 -07:00
ah6.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-11-15 11:56:19 -08:00
anycast.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-06-06 18:39:49 -07:00
calipso.c ipv6: make ipv6_renew_options() interrupt/kernel safe 2018-07-05 20:15:26 +09:00
datagram.c net: add helpers checking if socket can be bound to nonlocal address 2018-08-01 09:50:04 -07:00
esp6_offload.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2018-07-27 09:33:37 -07:00
esp6.c esp6: fix memleak on error path in esp6_input 2018-06-27 17:32:11 +02:00
exthdrs_core.c net: ipv6: Fix typo in ipv6_find_hdr() documentation 2018-05-07 23:50:27 -04:00
exthdrs_offload.c
exthdrs.c ipv6: make ipv6_renew_options() interrupt/kernel safe 2018-07-05 20:15:26 +09:00
fib6_notifier.c net: Add module reference to FIB notifiers 2017-09-01 20:33:42 -07:00
fib6_rules.c net/ipv6: Add fib6_lookup 2018-05-11 00:10:56 +02:00
fou6.c fou: make local function static 2017-05-21 13:42:36 -04:00
icmp.c ipv6: Add icmp_echo_ignore_all support for ICMPv6 2018-08-13 08:42:25 -07:00
inet6_connection_sock.c
inet6_hashtables.c bpf: Enable BPF_PROG_TYPE_SK_REUSEPORT bpf prog in reuseport selection 2018-08-11 01:58:46 +02:00
ip6_checksum.c udplite: fix partial checksum initialization 2018-02-16 15:57:42 -05:00
ip6_fib.c net/ipv6: Only update MTU metric if it set 2018-09-02 14:03:54 -07:00
ip6_flowlabel.c ipv6: fold sockcm_cookie into ipcm6_cookie 2018-07-07 10:58:49 +09:00
ip6_gre.c erspan: set erspan_ver to 1 by default when adding an erspan dev 2018-08-27 15:13:17 -07:00
ip6_icmp.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ip6_input.c net: ipv6: listify ipv6_rcv() and ip6_rcv_finish() 2018-07-06 11:19:07 +09:00
ip6_offload.c gso_segment: Reset skb->mac_len after modifying network header 2018-09-13 12:09:32 -07:00
ip6_offload.h
ip6_output.c ipv6: fix possible use-after-free in ip6_xmit() 2018-09-17 07:56:02 -07:00
ip6_tunnel.c ip6_tunnel: be careful when accessing the inner header 2018-09-19 21:24:28 -07:00
ip6_udp_tunnel.c
ip6_vti.c vti6: remove !skb->ignore_df check from vti6_xmit() 2018-08-29 17:51:44 -07:00
ip6mr.c rhashtable: split rhashtable.h 2018-06-22 13:43:27 +09:00
ipcomp6.c
ipv6_sockglue.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux 2018-07-20 21:17:12 -07:00
Kconfig net: remove blank lines at end of file 2018-07-24 14:10:43 -07:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mcast_snoop.c
mcast.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-07-24 19:21:58 -07:00
mip6.c
ndisc.c ipv6: make DAD fail with enhanced DAD when nonce length differs 2018-07-16 13:45:16 -07:00
netfilter.c netfilter: utils: move nf_ip6_checksum* from ipv6 to utils 2018-07-16 17:51:48 +02:00
output_core.c net: accept UFO datagrams from tuntap and packet 2017-11-24 01:37:35 +09:00
ping.c ipv6: fold sockcm_cookie into ipcm6_cookie 2018-07-07 10:58:49 +09:00
proc.c proc: introduce proc_create_net_single 2018-05-16 07:24:30 +02:00
protocol.c net: Add sysctl to toggle early demux for tcp and udp 2017-03-24 13:17:07 -07:00
raw.c ipv6: fold sockcm_cookie into ipcm6_cookie 2018-07-07 10:58:49 +09:00
reassembly.c ipv6: defrag: drop non-last frags smaller than min mtu 2018-08-05 17:21:14 -07:00
route.c ipv6: fix memory leak on dst->_metrics 2018-09-18 20:17:01 -07:00
seg6_hmac.c Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net 2018-07-03 10:29:26 +09:00
seg6_iptunnel.c ipv6: sr: fix useless rol32 call on hash 2018-07-18 15:10:47 -07:00
seg6_local.c bpf: add End.DT6 action to bpf_lwt_seg6_action helper 2018-07-31 09:22:48 +02:00
seg6.c rhashtable: split rhashtable.h 2018-06-22 13:43:27 +09:00
sit.c ip6_tunnel: remove magic mtu value 0xFFF8 2018-06-01 13:56:30 -04:00
syncookies.c net/ipv4: disable SMC TCP option with SYN Cookies 2018-03-25 20:53:54 -04:00
sysctl_net_ipv6.c ipv6: sr: Compute flowlabel for outer IPv6 header of seg6 encap mode 2018-04-25 13:02:15 -04:00
tcp_ipv6.c net/ipv6: Fix linklocal to global address with VRF 2018-07-21 19:31:46 -07:00
tcpv6_offload.c net: Convert GRO SKB handling to list_head. 2018-06-26 11:33:04 +09:00
tunnel6.c
udp_impl.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
udp_offload.c net: Convert GRO SKB handling to list_head. 2018-06-26 11:33:04 +09:00
udp.c udp6: add missing checks on edumux packet processing 2018-09-16 15:27:44 -07:00
udplite.c proc: introduce proc_create_net{,_data} 2018-05-16 07:24:30 +02:00
xfrm6_input.c xfrm: Reinject transport-mode packets through tasklet 2017-12-19 08:23:21 +01:00
xfrm6_mode_beet.c networking: make skb_pull & friends return void pointers 2017-06-16 11:48:39 -04:00
xfrm6_mode_ro.c ipv6: xfrm: use 64-bit timestamps 2018-07-11 15:26:35 +02:00
xfrm6_mode_transport.c ipv6: xfrm: Handle errors reported by xfrm6_find_1stfragopt() 2017-06-02 13:57:27 -04:00
xfrm6_mode_tunnel.c xfrm: Verify MAC header exists before overwriting eth_hdr(skb)->h_proto 2018-03-07 10:54:29 +01:00
xfrm6_output.c net: xfrm: use skb_gso_validate_network_len() to check gso sizes 2018-03-04 17:49:17 -05:00
xfrm6_policy.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-06-03 09:31:58 -04:00
xfrm6_protocol.c xfrm: input: constify xfrm_input_afinfo 2017-02-09 10:22:17 +01:00
xfrm6_state.c xfrm: remove VLA usage in __xfrm6_sort() 2018-04-26 07:51:48 +02:00
xfrm6_tunnel.c xfrm: Fix warning in xfrm6_tunnel_net_exit. 2018-04-16 07:50:09 +02:00