linux/net
Paolo Abeni 10b8a3de60 ipv6: the entire IPv6 header chain must fit the first fragment
While building ipv6 datagram we currently allow arbitrary large
extheaders, even beyond pmtu size. The syzbot has found a way
to exploit the above to trigger the following splat:

kernel BUG at ./include/linux/skbuff.h:2073!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
    (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4230 Comm: syzkaller672661 Not tainted 4.16.0-rc2+ #326
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__skb_pull include/linux/skbuff.h:2073 [inline]
RIP: 0010:__ip6_make_skb+0x1ac8/0x2190 net/ipv6/ip6_output.c:1636
RSP: 0018:ffff8801bc18f0f0 EFLAGS: 00010293
RAX: ffff8801b17400c0 RBX: 0000000000000738 RCX: ffffffff84f01828
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8801b415ac18
RBP: ffff8801bc18f360 R08: ffff8801b4576844 R09: 0000000000000000
R10: ffff8801bc18f380 R11: ffffed00367aee4e R12: 00000000000000d6
R13: ffff8801b415a740 R14: dffffc0000000000 R15: ffff8801b45767c0
FS:  0000000001535880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002000b000 CR3: 00000001b4123001 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  ip6_finish_skb include/net/ipv6.h:969 [inline]
  udp_v6_push_pending_frames+0x269/0x3b0 net/ipv6/udp.c:1073
  udpv6_sendmsg+0x2a96/0x3400 net/ipv6/udp.c:1343
  inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
  sock_sendmsg_nosec net/socket.c:630 [inline]
  sock_sendmsg+0xca/0x110 net/socket.c:640
  ___sys_sendmsg+0x320/0x8b0 net/socket.c:2046
  __sys_sendmmsg+0x1ee/0x620 net/socket.c:2136
  SYSC_sendmmsg net/socket.c:2167 [inline]
  SyS_sendmmsg+0x35/0x60 net/socket.c:2162
  do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4404c9
RSP: 002b:00007ffdce35f948 EFLAGS: 00000217 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004404c9
RDX: 0000000000000003 RSI: 0000000020001f00 RDI: 0000000000000003
RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000020000080 R11: 0000000000000217 R12: 0000000000401df0
R13: 0000000000401e80 R14: 0000000000000000 R15: 0000000000000000
Code: ff e8 1d 5e b9 fc e9 15 e9 ff ff e8 13 5e b9 fc e9 44 e8 ff ff e8 29
5e b9 fc e9 c0 e6 ff ff e8 3f f3 80 fc 0f 0b e8 38 f3 80 fc <0f> 0b 49 8d
87 80 00 00 00 4d 8d 87 84 00 00 00 48 89 85 20 fe
RIP: __skb_pull include/linux/skbuff.h:2073 [inline] RSP: ffff8801bc18f0f0
RIP: __ip6_make_skb+0x1ac8/0x2190 net/ipv6/ip6_output.c:1636 RSP:
ffff8801bc18f0f0

As stated by RFC 7112 section 5:

   When a host fragments an IPv6 datagram, it MUST include the entire
   IPv6 Header Chain in the First Fragment.

So this patch addresses the issue dropping datagrams with excessive
extheader length. It also updates the error path to report to the
calling socket nonnegative pmtu values.

The issue apparently predates git history.

v1 -> v2: cleanup error path, as per Eric's suggestion

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+91e6f9932ff122fa4410@syzkaller.appspotmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-25 21:17:20 -04:00
..
6lowpan License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
9p virtio: bugfixes 2018-02-15 14:29:27 -08:00
802 treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
8021q vlan: Fix out of order vlan headers with reorder header off 2018-03-16 10:03:47 -04:00
appletalk net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
atm vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
ax25 net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
batman-adv batman-adv: Fix skbuff rcsum on packet reroute 2018-03-18 13:20:32 +01:00
bluetooth Bluetooth: Fix missing encryption refresh on Security Request 2018-03-01 19:55:56 +01:00
bpf bpf: fix null pointer deref in bpf_prog_test_run_xdp 2018-02-01 07:43:56 -08:00
bridge netfilter: bridge: ebt_among: add more missing match size checks 2018-03-11 21:24:49 +01:00
caif vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
can can: migrate documentation to restructured text 2018-01-26 10:46:44 +01:00
ceph libceph, ceph: avoid memory leak when specifying same option several times 2018-02-26 16:19:30 +01:00
core devlink: Remove redundant free on error path 2018-03-20 10:59:29 -04:00
dcb rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
dccp dccp: check sk for closed state in dccp_sendmsg() 2018-03-07 13:38:56 -05:00
decnet dn_getsockoptdecnet: move nf_{get/set}sockopt outside sock lock 2018-02-16 15:46:15 -05:00
dns_resolver afs: Support the AFS dynamic root 2018-02-06 14:43:37 +00:00
dsa net: dsa: Fix dsa_is_user_port() test inversion 2018-03-12 21:04:55 -04:00
ethernet
hsr net: hsr: Convert timers to use timer_setup() 2017-10-25 13:00:27 +09:00
ieee802154 ieee802154: 6lowpan: fix possible NULL deref in lowpan_device_event() 2018-03-09 11:19:26 -05:00
ife MAINTAINERS: Update Yotam's E-mail 2017-11-01 12:19:03 +09:00
ipv4 net/ipv4: disable SMC TCP option with SYN Cookies 2018-03-25 20:53:54 -04:00
ipv6 ipv6: the entire IPv6 header chain must fit the first fragment 2018-03-25 21:17:20 -04:00
iucv net/iucv: Free memory obtained by kzalloc 2018-03-16 11:42:12 -04:00
kcm kcm: lock lower socket in kcm_attach 2018-03-16 11:12:16 -04:00
key af_key: Fix memory leak in key_notify_policy. 2018-01-10 09:45:11 +01:00
l2tp l2tp: fix races with ipv4-mapped ipv6 addresses 2018-03-12 15:11:09 -04:00
l3mdev
lapb treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts 2017-11-21 16:35:54 -08:00
llc net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
mac80211 mac80211: add ieee80211_hw flag for QoS NDP support 2018-03-21 10:56:18 +01:00
mac802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
mpls net: rename skb_gso_validate_mtu -> skb_gso_validate_network_len 2018-03-04 17:49:17 -05:00
ncsi net/ncsi: Don't take any action on HNCDSC AEN 2017-12-18 14:50:11 -05:00
netfilter netfilter: nf_tables: do not hold reference on netdevice from preparation phase 2018-03-22 13:17:52 +01:00
netlabel net/netlabel: Add list_next_rcu() in rcu_dereference(). 2017-11-18 10:32:41 +09:00
netlink netlink: make sure nladdr has correct size in netlink_connect() 2018-03-25 21:14:51 -04:00
netrom net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
nfc NFC: llcp: Limit size of SDP URI 2018-02-16 15:16:05 -05:00
nsh openvswitch: enable NSH support 2017-11-08 16:12:33 +09:00
openvswitch openvswitch: meter: fix the incorrect calculation of max delta_t 2018-03-11 22:48:59 -04:00
packet vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
phonet vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
psample MAINTAINERS: Update Yotam's E-mail 2017-11-01 12:19:03 +09:00
qrtr qrtr: add MODULE_ALIAS macro to smd 2018-02-26 15:07:04 -05:00
rds rds: Incorrect reference counting in TCP socket creation 2018-03-02 09:40:27 -05:00
rfkill vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
rose net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
rxrpc rxrpc: Fix send in rxrpc_send_data_packet() 2018-02-22 15:37:47 -05:00
sched net/sched: fix idr leak in the error path of tcf_skbmod_init() 2018-03-21 18:12:37 -04:00
sctp net: use skb_is_gso_sctp() instead of open-coding 2018-03-09 11:41:47 -05:00
smc net/smc: simplify wait when closing listen socket 2018-03-15 09:49:13 -04:00
strparser strparser: Call sock_owned_by_user_nocheck 2017-12-28 14:28:22 -05:00
sunrpc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
switchdev net: bridge: Add/del switchdev object on host join/leave 2017-11-10 13:41:40 +09:00
tipc tipc: correct initial value for group congestion flag 2018-02-27 11:46:03 -05:00
tls tls: Use correct sk->sk_prot for IPV6 2018-02-27 14:41:48 -05:00
unix net: af_unix: fix typo in UNIX_SKB_FRAGS_SZ comment 2018-02-13 12:21:45 -05:00
vmw_vsock vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
wimax License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
wireless cfg80211: add missing dependency to CFG80211 suboptions 2018-02-27 10:54:12 +01:00
x25 treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts 2017-11-21 16:35:54 -08:00
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec 2018-03-13 10:38:07 -04:00
compat.c net: compat: assert the size of cmsg copied in is as expected 2017-09-20 15:36:18 -07:00
Kconfig Staging/IIO patches for 4.16-rc1 2018-02-01 09:51:57 -08:00
Makefile ipx: move Novell IPX protocol support into staging 2017-11-28 13:55:00 +01:00
socket.c sock_diag: request _diag module only when the family or proto has been registered 2018-03-12 11:03:42 -04:00
sysctl_net.c