Eric Dumazet 12d94a8049 ipv6: fix NULL dereference in ip6_route_dev_notify() ... Based on a syzkaller report [1], I found that a per cpu allocation failure in snmp6_alloc_dev() would then lead to NULL dereference in ip6_route_dev_notify(). It seems this is a very old bug, thus no Fixes tag in this submission. Let's add in6_dev_put_clear() helper, as we will probably use it elsewhere (once available/present in net-next) [1] kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 17294 Comm: syz-executor6 Not tainted 4.13.0-rc2+ #10 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88019f456680 task.stack: ffff8801c6e58000 RIP: 0010:__read_once_size include/linux/compiler.h:250 [inline] RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:26 [inline] RIP: 0010:refcount_sub_and_test+0x7d/0x1b0 lib/refcount.c:178 RSP: 0018:ffff8801c6e5f1b0 EFLAGS: 00010202 RAX: 0000000000000037 RBX: dffffc0000000000 RCX: ffffc90005d25000 RDX: ffff8801c6e5f218 RSI: ffffffff82342bbf RDI: 0000000000000001 RBP: ffff8801c6e5f240 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10038dcbe37 R13: 0000000000000006 R14: 0000000000000001 R15: 00000000000001b8 FS: 00007f21e0429700(0000) GS:ffff8801dc100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001ddbc22000 CR3: 00000001d632b000 CR4: 00000000001426e0 DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: refcount_dec_and_test+0x1a/0x20 lib/refcount.c:211 in6_dev_put include/net/addrconf.h:335 [inline] ip6_route_dev_notify+0x1c9/0x4a0 net/ipv6/route.c:3732 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x51/0x90 net/core/dev.c:1678 call_netdevice_notifiers net/core/dev.c:1694 [inline] rollback_registered_many+0x91c/0xe80 net/core/dev.c:7107 rollback_registered+0x1be/0x3c0 net/core/dev.c:7149 register_netdevice+0xbcd/0xee0 net/core/dev.c:7587 register_netdev+0x1a/0x30 net/core/dev.c:7669 loopback_net_init+0x76/0x160 drivers/net/loopback.c:214 ops_init+0x10a/0x570 net/core/net_namespace.c:118 setup_net+0x313/0x710 net/core/net_namespace.c:294 copy_net_ns+0x27c/0x580 net/core/net_namespace.c:418 create_new_namespaces+0x425/0x880 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:206 SYSC_unshare kernel/fork.c:2347 [inline] SyS_unshare+0x653/0xfa0 kernel/fork.c:2297 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x4512c9 RSP: 002b:00007f21e0428c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 0000000000718150 RCX: 00000000004512c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000062020200 RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b973d R13: 00000000ffffffff R14: 000000002001d000 R15: 00000000000002dd Code: 50 2b 34 82 c7 00 f1 f1 f1 f1 c7 40 04 04 f2 f2 f2 c7 40 08 f3 f3 f3 f3 e8 a1 43 39 ff 4c 89 f8 48 8b 95 70 ff ff ff 48 c1 e8 03 <0f> b6 0c 18 4c 89 f8 83 e0 07 83 c0 03 38 c8 7c 08 84 c9 0f 85 RIP: __read_once_size include/linux/compiler.h:250 [inline] RSP: ffff8801c6e5f1b0 RIP: atomic_read arch/x86/include/asm/atomic.h:26 [inline] RSP: ffff8801c6e5f1b0 RIP: refcount_sub_and_test+0x7d/0x1b0 lib/refcount.c:178 RSP: ffff8801c6e5f1b0 ---[ end trace e441d046c6410d31 ]--- Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2017-08-15 17:06:34 -07:00
..
9p	9p: Implement show_options	2017-07-11 06:08:58 -04:00
bluetooth	Bluetooth: Set LE Default PHY preferences	2017-05-18 13:52:49 +02:00
caif
irda
iucv
netfilter	net: convert nf_bridge_info.use from atomic_t to refcount_t	2017-07-01 07:39:07 -07:00
netns	tcp: Namespaceify sysctl_tcp_timestamps	2017-06-08 10:53:29 -04:00
nfc
phonet
sctp	sctp: fix the check for _sctp_walk_params and _sctp_walk_errors	2017-07-27 00:03:12 -07:00
tc_act	net: sched: introduce helper to identify gact trap action	2017-06-06 12:45:23 -04:00
6lowpan.h
act_api.h	net: sched: add termination action to allow goto chain	2017-05-17 15:22:13 -04:00
addrconf.h	ipv6: fix NULL dereference in ip6_route_dev_notify()	2017-08-15 17:06:34 -07:00
af_ieee802154.h
af_rxrpc.h	rxrpc: Provide a cmsg to specify the amount of Tx data for a call	2017-06-07 17:15:46 +01:00
af_unix.h	Now that IPC and other changes have landed, enable manual markings for	2017-07-19 08:55:18 -07:00
af_vsock.h
ah.h
arp.h	net: convert neighbour.refcnt from atomic_t to refcount_t	2017-07-01 07:39:07 -07:00
atmclip.h
ax25.h	net, ax25: convert ax25_cb.refcount from atomic_t to refcount_t	2017-07-04 22:35:19 +01:00
ax88796.h
bond_3ad.h
bond_alb.h
bond_options.h	bonding: Prevent duplicate userspace notification	2017-05-27 18:51:41 -04:00
bonding.h	bonding: require speed/duplex only for 802.3ad, alb and tlb	2017-08-11 14:21:42 -07:00
busy_poll.h	net: fix compilation when busy poll is not enabled	2017-08-11 14:59:24 -07:00
calipso.h	net, calipso: convert calipso_doi.refcount from atomic_t to refcount_t	2017-07-04 22:35:16 +01:00
cfg80211-wext.h
cfg80211.h	nl80211: add authorized flag to ROAM event	2017-06-13 11:04:37 +02:00
cfg802154.h
checksum.h
cipso_ipv4.h	net, ipv4: convert cipso_v4_doi.refcount from atomic_t to refcount_t	2017-07-04 01:29:04 -07:00
cls_cgroup.h
codel_impl.h
codel_qdisc.h
codel.h
compat.h
datalink.h
dcbevent.h
dcbnl.h
devlink.h
dn_dev.h
dn_fib.h	net, decnet: convert dn_fib_info.fib_clntref from atomic_t to refcount_t	2017-07-04 22:35:15 +01:00
dn_neigh.h
dn_nsp.h
dn_route.h
dn.h
dsa.h	net: dsa: Associate slave network device with CPU port	2017-06-13 16:35:03 -04:00
dsfield.h
dst_cache.h
dst_metadata.h	net: store port/representator id in metadata_dst	2017-06-25 11:42:01 -04:00
dst_ops.h
dst.h	net: add debug atomic_inc_not_zero() in dst_hold()	2017-06-17 22:54:01 -04:00
esp.h
ethoc.h
fib_rules.h	net: convert fib_rule.refcnt from atomic_t to refcount_t	2017-07-01 07:39:09 -07:00
firewire.h
flow_dissector.h	net/flow_dissector: add support for dissection of misc ip header fields	2017-06-04 18:12:23 -04:00
flow.h
flowcache.h
fou.h
fq_impl.h
fq.h
garp.h
gen_stats.h
genetlink.h	genetlink: remove ops_list from genetlink header.	2017-06-05 10:54:55 -04:00
geneve.h
gre.h
gro_cells.h
gtp.h
gue.h
hwbm.h
icmp.h
ieee80211_radiotap.h
ieee802154_netdev.h
if_inet6.h	net, ipv6: convert ifacaddr6.aca_refcnt from atomic_t to refcount_t	2017-07-04 01:29:04 -07:00
ife.h
ila.h
inet_common.h
inet_connection_sock.h	tcp: ULP infrastructure	2017-06-15 12:12:40 -04:00
inet_ecn.h
inet_frag.h	Merge branch 'for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2017-07-06 08:59:41 -07:00
inet_hashtables.h	net: make sk_ehashfn() static	2017-07-03 03:29:14 -07:00
inet_sock.h
inet_timewait_sock.h
inet6_connection_sock.h
inet6_hashtables.h
inetpeer.h	net: convert inet_peer.refcnt from atomic_t to refcount_t	2017-07-01 07:39:07 -07:00
ip_fib.h	net, ipv4: convert fib_info.fib_clntref from atomic_t to refcount_t	2017-07-04 01:29:04 -07:00
ip_tunnels.h
ip_vs.h
ip.h
ip6_checksum.h
ip6_fib.h	net: remove DST_NOCACHE flag	2017-06-17 22:54:01 -04:00
ip6_route.h	net: ipv6: Compare lwstate in detecting duplicate nexthops	2017-07-06 10:48:01 +01:00
ip6_tunnel.h
ipcomp.h
ipconfig.h
ipv6.h	net, ipv6: convert ipv6_txoptions.refcnt from atomic_t to refcount_t	2017-07-04 01:29:03 -07:00
ipx.h	net, ipx: convert ipx_route.refcnt from atomic_t to refcount_t	2017-07-04 22:35:17 +01:00
iw_handler.h
kcm.h
l3mdev.h
lapb.h	net, lapb: convert lapb_cb.refcnt from atomic_t to refcount_t	2017-07-04 22:35:16 +01:00
lib80211.h
llc_c_ac.h
llc_c_ev.h
llc_c_st.h
llc_conn.h
llc_if.h
llc_pdu.h
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
llc.h	net, llc: convert llc_sap.refcnt from atomic_t to refcount_t	2017-07-04 22:35:15 +01:00
lwtunnel.h	net: add extack arg to lwtunnel build state	2017-05-30 11:55:32 -04:00
mac80211.h	mac80211: add api to start ba session timer expired flow	2017-08-09 09:49:42 +03:00
mac802154.h
mip6.h
mld.h
mpls_iptunnel.h
mpls.h
mrp.h
ncsi.h
ndisc.h	net: convert neighbour.refcnt from atomic_t to refcount_t	2017-07-01 07:39:07 -07:00
neighbour.h	Now that IPC and other changes have landed, enable manual markings for	2017-07-19 08:55:18 -07:00
net_namespace.h	Now that IPC and other changes have landed, enable manual markings for	2017-07-19 08:55:18 -07:00
net_ratelimit.h
netevent.h
netlabel.h	net: convert netlbl_lsm_cache.refcount from atomic_t to refcount_t	2017-07-01 07:39:09 -07:00
netlink.h	netlink: correctly document nla_put_u64_64bit()	2017-07-13 09:26:27 -07:00
netprio_cgroup.h
netrom.h	net, netrom: convert nr_node.refcount from atomic_t to refcount_t	2017-07-04 22:35:17 +01:00
nexthop.h
nl802154.h
p8022.h
ping.h
pkt_cls.h	sched: add helper for updating statistics on all actions	2017-05-31 17:58:13 -04:00
pkt_sched.h
pptp.h
protocol.h
psample.h
psnap.h
raw.h
rawv6.h
red.h
regulatory.h
request_sock.h	net: convert sock.sk_refcnt from atomic_t to refcount_t	2017-07-01 07:39:08 -07:00
rose.h
route.h	ipv4: call dst_hold_safe() properly	2017-06-17 22:54:00 -04:00
rtnetlink.h	net: add netlink_ext_ack argument to rtnl_link_ops.slave_validate	2017-06-26 23:13:22 -04:00
sch_generic.h	net, sched: convert Qdisc.refcnt from atomic_t to refcount_t	2017-07-04 22:35:16 +01:00
scm.h
secure_seq.h	tcp: Namespaceify sysctl_tcp_timestamps	2017-06-08 10:53:29 -04:00
seg6_hmac.h
seg6.h
slhc_vj.h
smc.h
snmp.h
sock_reuseport.h
sock.h	Now that IPC and other changes have landed, enable manual markings for	2017-07-19 08:55:18 -07:00
Space.h
stp.h
strparser.h
switchdev.h	net: switchdev: add SET_SWITCHDEV_OPS helper	2017-07-01 08:51:32 -07:00
tcp_states.h
tcp.h	tcp: introduce tcp_rto_delta_us() helper for xmit timer fix	2017-08-03 15:38:30 -07:00
timewait_sock.h
tls.h	tls: kernel TLS support	2017-06-15 12:12:40 -04:00
transp_v6.h
tso.h
udp_tunnel.h
udp.h	udp: fix linear skb reception with PEEK_OFF	2017-08-14 22:26:51 -07:00
udplite.h
vsock_addr.h
vxlan.h	net, vxlan: convert vxlan_sock.refcnt from atomic_t to refcount_t	2017-07-04 22:35:15 +01:00
wext.h	dev_ioctl: copy only the smaller struct iwreq for wext	2017-06-14 13:52:44 +02:00
wimax.h
x25.h	net, x25: convert x25_neigh.refcnt from atomic_t to refcount_t	2017-07-04 22:35:18 +01:00
x25device.h
xfrm.h	net, xfrm: convert sec_path.refcnt from atomic_t to refcount_t	2017-07-04 22:35:18 +01:00