Eric Dumazet 501a90c945 inet: protect against too small mtu values. ... syzbot was once again able to crash a host by setting a very small mtu on loopback device. Let's make inetdev_valid_mtu() available in include/net/ip.h, and use it in ip_setup_cork(), so that we protect both ip_append_page() and __ip_append_data() Also add a READ_ONCE() when the device mtu is read. Pairs this lockless read with one WRITE_ONCE() in __dev_set_mtu(), even if other code paths might write over this field. Add a big comment in include/linux/netdevice.h about dev->mtu needing READ_ONCE()/WRITE_ONCE() annotations. Hopefully we will add the missing ones in followup patches. [1] refcount_t: saturated; leaking memory. WARNING: CPU: 0 PID: 9464 at lib/refcount.c:22 refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 9464 Comm: syz-executor850 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x3e kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:174 [inline] fixup_bug arch/x86/kernel/traps.c:169 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x138/0x1f0 lib/refcount.c:22 Code: 06 31 ff 89 de e8 c8 f5 e6 fd 84 db 0f 85 6f ff ff ff e8 7b f4 e6 fd 48 c7 c7 e0 71 4f 88 c6 05 56 a6 a4 06 01 e8 c7 a8 b7 fd <0f> 0b e9 50 ff ff ff e8 5c f4 e6 fd 0f b6 1d 3d a6 a4 06 31 ff 89 RSP: 0018:ffff88809689f550 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815e4336 RDI: ffffed1012d13e9c RBP: ffff88809689f560 R08: ffff88809c50a3c0 R09: fffffbfff15d31b1 R10: fffffbfff15d31b0 R11: ffffffff8ae98d87 R12: 0000000000000001 R13: 0000000000040100 R14: ffff888099041104 R15: ffff888218d96e40 refcount_add include/linux/refcount.h:193 [inline] skb_set_owner_w+0x2b6/0x410 net/core/sock.c:1999 sock_wmalloc+0xf1/0x120 net/core/sock.c:2096 ip_append_page+0x7ef/0x1190 net/ipv4/ip_output.c:1383 udp_sendpage+0x1c7/0x480 net/ipv4/udp.c:1276 inet_sendpage+0xdb/0x150 net/ipv4/af_inet.c:821 kernel_sendpage+0x92/0xf0 net/socket.c:3794 sock_sendpage+0x8b/0xc0 net/socket.c:936 pipe_to_sendpage+0x2da/0x3c0 fs/splice.c:458 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x3ee/0x7c0 fs/splice.c:636 splice_from_pipe+0x108/0x170 fs/splice.c:671 generic_splice_sendpage+0x3c/0x50 fs/splice.c:842 do_splice_from fs/splice.c:861 [inline] direct_splice_actor+0x123/0x190 fs/splice.c:1035 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:990 do_splice_direct+0x1da/0x2a0 fs/splice.c:1078 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441409 Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffb64c4f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441409 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005 RBP: 0000000000073b8a R08: 0000000000000010 R09: 0000000000000010 R10: 0000000000010001 R11: 0000000000000246 R12: 0000000000402180 R13: 0000000000402210 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds.. Fixes: 1470ddf7f8 ("inet: Remove explicit write references to sk/inet in ip_append_data") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2019-12-07 11:55:11 -08:00
..
bpf_sk_storage.c	bpf: Switch bpf_map ref counter to atomic64_t so bpf_map_inc() never fails	2019-11-18 11:41:59 +01:00
datagram.c	net: add READ_ONCE() annotation in __skb_wait_for_more_packets()	2019-10-28 13:33:41 -07:00
datagram.h
dev_addr_lists.c	net: remove unnecessary variables and callback	2019-10-24 14:53:49 -07:00
dev_ioctl.c
dev.c	inet: protect against too small mtu values.	2019-12-07 11:55:11 -08:00
devlink.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2019-11-16 21:51:42 -08:00
drop_monitor.c
dst_cache.c
dst.c
ethtool.c	net: Zeroing the structure ethtool_wolinfo in ethtool_get_wol()	2019-10-26 11:20:10 -07:00
failover.c
fib_notifier.c	net: fib_notifier: propagate extack down to the notifier block callback	2019-10-04 11:10:56 -07:00
fib_rules.c	net: fib_notifier: propagate extack down to the notifier block callback	2019-10-04 11:10:56 -07:00
filter.c	net: skmsg: fix TLS 1.3 crash with full sk_msg	2019-11-28 22:40:29 -08:00
flow_dissector.c	net: dsa: fix flow dissection on Tx path	2019-12-06 20:20:17 -08:00
flow_offload.c	net: core: rename indirect block ingress cb function	2019-12-06 20:45:09 -08:00
gen_estimator.c	net_sched: gen_estimator: extend packet counter to 64bit	2019-11-06 21:51:36 -08:00
gen_stats.c	net_sched: add TCA_STATS_PKT64 attribute	2019-11-05 18:20:55 -08:00
gro_cells.c
hwbm.c
link_watch.c
lwt_bpf.c	net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup	2019-12-04 12:27:13 -08:00
lwtunnel.c
Makefile
neighbour.c	net: add annotations on hh->hh_len lockless accesses	2019-11-07 20:07:30 -08:00
net_namespace.c	netns: fix GFP flags in rtnl_net_notifyid()	2019-10-25 20:14:42 -07:00
net-procfs.c	net: procfs: use index hashlist instead of name hashlist	2019-10-01 14:47:19 -07:00
net-sysfs.c	net-sysfs: Call dev_hold always in netdev_queue_add_kobject	2019-12-06 20:37:28 -08:00
net-sysfs.h
net-traces.c
netclassid_cgroup.c
netevent.c
netpoll.c
netprio_cgroup.c	netprio: use css ID instead of cgroup ID	2019-11-12 08:18:03 -08:00
page_pool.c	net: page_pool: add the possibility to sync DMA memory for device	2019-11-20 12:34:28 -08:00
pktgen.c	pktgen: remove unnecessary assignment in pktgen_xmit()	2019-10-17 14:25:13 -04:00
ptp_classifier.c
request_sock.c	tcp: add rcu protection around tp->fastopen_rsk	2019-10-13 10:13:08 -07:00
rtnetlink.c	net/core: Populate VF index in struct ifla_vf_guid	2019-12-03 11:24:34 -08:00
scm.c	y2038: socket: remove timespec reference in timestamping	2019-11-15 14:38:29 +01:00
secure_seq.c
skbuff.c	net: Fixed updating of ethertype in skb_mpls_push()	2019-12-04 17:11:25 -08:00
skmsg.c	net: skmsg: fix TLS 1.3 crash with full sk_msg	2019-11-28 22:40:29 -08:00
sock_diag.c
sock_map.c
sock_reuseport.c	net/core: Replace rcu_swap_protected() with rcu_replace_pointer()	2019-10-30 08:45:26 -07:00
sock.c	Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2019-11-26 16:02:40 -08:00
stream.c
sysctl_net_core.c
timestamping.c
tso.c
utils.c
xdp.c	xdp: obtain the mem_id mutex before trying to remove an entry.	2019-12-04 16:35:18 -08:00