501a90c945
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:
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||
|---|---|---|
| .. | ||
| 9p | ||
| bluetooth | ||
| caif | ||
| iucv | ||
| netfilter | ||
| netns | ||
| nfc | ||
| phonet | ||
| sctp | ||
| tc_act | ||
| 6lowpan.h | ||
| Space.h | ||
| act_api.h | ||
| addrconf.h | ||
| af_ieee802154.h | ||
| af_rxrpc.h | ||
| af_unix.h | ||
| af_vsock.h | ||
| ah.h | ||
| arp.h | ||
| atmclip.h | ||
| ax25.h | ||
| ax88796.h | ||
| bond_3ad.h | ||
| bond_alb.h | ||
| bond_options.h | ||
| bonding.h | ||
| bpf_sk_storage.h | ||
| busy_poll.h | ||
| calipso.h | ||
| cfg80211-wext.h | ||
| cfg80211.h | ||
| cfg802154.h | ||
| checksum.h | ||
| cipso_ipv4.h | ||
| cls_cgroup.h | ||
| codel.h | ||
| codel_impl.h | ||
| codel_qdisc.h | ||
| compat.h | ||
| datalink.h | ||
| dcbevent.h | ||
| dcbnl.h | ||
| devlink.h | ||
| dn.h | ||
| dn_dev.h | ||
| dn_fib.h | ||
| dn_neigh.h | ||
| dn_nsp.h | ||
| dn_route.h | ||
| drop_monitor.h | ||
| dsa.h | ||
| dsfield.h | ||
| dst.h | ||
| dst_cache.h | ||
| dst_metadata.h | ||
| dst_ops.h | ||
| erspan.h | ||
| esp.h | ||
| ethoc.h | ||
| failover.h | ||
| fib_notifier.h | ||
| fib_rules.h | ||
| firewire.h | ||
| flow.h | ||
| flow_dissector.h | ||
| flow_offload.h | ||
| fou.h | ||
| fq.h | ||
| fq_impl.h | ||
| garp.h | ||
| gen_stats.h | ||
| genetlink.h | ||
| geneve.h | ||
| gre.h | ||
| gro_cells.h | ||
| gtp.h | ||
| gue.h | ||
| hwbm.h | ||
| icmp.h | ||
| ieee80211_radiotap.h | ||
| ieee802154_netdev.h | ||
| if_inet6.h | ||
| ife.h | ||
| ila.h | ||
| inet6_connection_sock.h | ||
| inet6_hashtables.h | ||
| inet_common.h | ||
| inet_connection_sock.h | ||
| inet_ecn.h | ||
| inet_frag.h | ||
| inet_hashtables.h | ||
| inet_sock.h | ||
| inet_timewait_sock.h | ||
| inetpeer.h | ||
| ip.h | ||
| ip6_checksum.h | ||
| ip6_fib.h | ||
| ip6_route.h | ||
| ip6_tunnel.h | ||
| ip_fib.h | ||
| ip_tunnels.h | ||
| ip_vs.h | ||
| ipcomp.h | ||
| ipconfig.h | ||
| ipv6.h | ||
| ipv6_frag.h | ||
| ipv6_stubs.h | ||
| ipx.h | ||
| iw_handler.h | ||
| kcm.h | ||
| l3mdev.h | ||
| lag.h | ||
| lapb.h | ||
| lib80211.h | ||
| llc.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 | ||
| lwtunnel.h | ||
| mac80211.h | ||
| mac802154.h | ||
| mip6.h | ||
| mld.h | ||
| mpls.h | ||
| mpls_iptunnel.h | ||
| mrp.h | ||
| ncsi.h | ||
| ndisc.h | ||
| neighbour.h | ||
| net_failover.h | ||
| net_namespace.h | ||
| net_ratelimit.h | ||
| netevent.h | ||
| netlabel.h | ||
| netlink.h | ||
| netprio_cgroup.h | ||
| netrom.h | ||
| nexthop.h | ||
| nl802154.h | ||
| nsh.h | ||
| p8022.h | ||
| page_pool.h | ||
| ping.h | ||
| pkt_cls.h | ||
| pkt_sched.h | ||
| pptp.h | ||
| protocol.h | ||
| psample.h | ||
| psnap.h | ||
| raw.h | ||
| rawv6.h | ||
| red.h | ||
| regulatory.h | ||
| request_sock.h | ||
| rose.h | ||
| route.h | ||
| rsi_91x.h | ||
| rtnetlink.h | ||
| rtnh.h | ||
| sch_generic.h | ||
| scm.h | ||
| secure_seq.h | ||
| seg6.h | ||
| seg6_hmac.h | ||
| seg6_local.h | ||
| slhc_vj.h | ||
| smc.h | ||
| snmp.h | ||
| sock.h | ||
| sock_reuseport.h | ||
| stp.h | ||
| strparser.h | ||
| switchdev.h | ||
| tcp.h | ||
| tcp_states.h | ||
| timewait_sock.h | ||
| tipc.h | ||
| tls.h | ||
| tls_toe.h | ||
| transp_v6.h | ||
| tso.h | ||
| tun_proto.h | ||
| udp.h | ||
| udp_tunnel.h | ||
| udplite.h | ||
| vsock_addr.h | ||
| vxlan.h | ||
| wext.h | ||
| wimax.h | ||
| x25.h | ||
| x25device.h | ||
| xdp.h | ||
| xdp_priv.h | ||
| xdp_sock.h | ||
| xfrm.h | ||