5d407b071d
A kernel crash occurrs when defragmented packet is fragmented
in ip_do_fragment().
In defragment routine, skb_orphan() is called and
skb->ip_defrag_offset is set. but skb->sk and
skb->ip_defrag_offset are same union member. so that
frag->sk is not NULL.
Hence crash occurrs in skb->sk check routine in ip_do_fragment() when
defragmented packet is fragmented.
test commands:
%iptables -t nat -I POSTROUTING -j MASQUERADE
%hping3 192.168.4.2 -s 1000 -p 2000 -d 60000
splat looks like:
[ 261.069429] kernel BUG at net/ipv4/ip_output.c:636!
[ 261.075753] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 261.083854] CPU: 1 PID: 1349 Comm: hping3 Not tainted 4.19.0-rc2+ #3
[ 261.100977] RIP: 0010:ip_do_fragment+0x1613/0x2600
[ 261.106945] Code: e8 e2 38 e3 fe 4c 8b 44 24 18 48 8b 74 24 08 e9 92 f6 ff ff 80 3c 02 00 0f 85 da 07 00 00 48 8b b5 d0 00 00 00 e9 25 f6 ff ff <0f> 0b 0f 0b 44 8b 54 24 58 4c 8b 4c 24 18 4c 8b 5c 24 60 4c 8b 6c
[ 261.127015] RSP: 0018:ffff8801031cf2c0 EFLAGS: 00010202
[ 261.134156] RAX: 1ffff1002297537b RBX: ffffed0020639e6e RCX: 0000000000000004
[ 261.142156] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880114ba9bd8
[ 261.150157] RBP: ffff880114ba8a40 R08: ffffed0022975395 R09: ffffed0022975395
[ 261.158157] R10: 0000000000000001 R11: ffffed0022975394 R12: ffff880114ba9ca4
[ 261.166159] R13: 0000000000000010 R14: ffff880114ba9bc0 R15: dffffc0000000000
[ 261.174169] FS: 00007fbae2199700(0000) GS:ffff88011b400000(0000) knlGS:0000000000000000
[ 261.183012] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 261.189013] CR2: 00005579244fe000 CR3: 0000000119bf4000 CR4: 00000000001006e0
[ 261.198158] Call Trace:
[ 261.199018] ? dst_output+0x180/0x180
[ 261.205011] ? save_trace+0x300/0x300
[ 261.209018] ? ip_copy_metadata+0xb00/0xb00
[ 261.213034] ? sched_clock_local+0xd4/0x140
[ 261.218158] ? kill_l4proto+0x120/0x120 [nf_conntrack]
[ 261.223014] ? rt_cpu_seq_stop+0x10/0x10
[ 261.227014] ? find_held_lock+0x39/0x1c0
[ 261.233008] ip_finish_output+0x51d/0xb50
[ 261.237006] ? ip_fragment.constprop.56+0x220/0x220
[ 261.243011] ? nf_ct_l4proto_register_one+0x5b0/0x5b0 [nf_conntrack]
[ 261.250152] ? rcu_is_watching+0x77/0x120
[ 261.255010] ? nf_nat_ipv4_out+0x1e/0x2b0 [nf_nat_ipv4]
[ 261.261033] ? nf_hook_slow+0xb1/0x160
[ 261.265007] ip_output+0x1c7/0x710
[ 261.269005] ? ip_mc_output+0x13f0/0x13f0
[ 261.273002] ? __local_bh_enable_ip+0xe9/0x1b0
[ 261.278152] ? ip_fragment.constprop.56+0x220/0x220
[ 261.282996] ? nf_hook_slow+0xb1/0x160
[ 261.287007] raw_sendmsg+0x21f9/0x4420
[ 261.291008] ? dst_output+0x180/0x180
[ 261.297003] ? sched_clock_cpu+0x126/0x170
[ 261.301003] ? find_held_lock+0x39/0x1c0
[ 261.306155] ? stop_critical_timings+0x420/0x420
[ 261.311004] ? check_flags.part.36+0x450/0x450
[ 261.315005] ? _raw_spin_unlock_irq+0x29/0x40
[ 261.320995] ? _raw_spin_unlock_irq+0x29/0x40
[ 261.326142] ? cyc2ns_read_end+0x10/0x10
[ 261.330139] ? raw_bind+0x280/0x280
[ 261.334138] ? sched_clock_cpu+0x126/0x170
[ 261.338995] ? check_flags.part.36+0x450/0x450
[ 261.342991] ? __lock_acquire+0x4500/0x4500
[ 261.348994] ? inet_sendmsg+0x11c/0x500
[ 261.352989] ? dst_output+0x180/0x180
[ 261.357012] inet_sendmsg+0x11c/0x500
[ ... ]
v2:
- clear skb->sk at reassembly routine.(Eric Dumarzet)
Fixes:
|
||
---|---|---|
.. | ||
bpfilter | ||
netfilter | ||
af_inet.c | ||
ah4.c | ||
arp.c | ||
cipso_ipv4.c | ||
datagram.c | ||
devinet.c | ||
esp4_offload.c | ||
esp4.c | ||
fib_frontend.c | ||
fib_lookup.h | ||
fib_notifier.c | ||
fib_rules.c | ||
fib_semantics.c | ||
fib_trie.c | ||
fou.c | ||
gre_demux.c | ||
gre_offload.c | ||
icmp.c | ||
igmp.c | ||
inet_connection_sock.c | ||
inet_diag.c | ||
inet_fragment.c | ||
inet_hashtables.c | ||
inet_timewait_sock.c | ||
inetpeer.c | ||
ip_forward.c | ||
ip_fragment.c | ||
ip_gre.c | ||
ip_input.c | ||
ip_options.c | ||
ip_output.c | ||
ip_sockglue.c | ||
ip_tunnel_core.c | ||
ip_tunnel.c | ||
ip_vti.c | ||
ipcomp.c | ||
ipconfig.c | ||
ipip.c | ||
ipmr_base.c | ||
ipmr.c | ||
Kconfig | ||
Makefile | ||
metrics.c | ||
netfilter.c | ||
netlink.c | ||
ping.c | ||
proc.c | ||
protocol.c | ||
raw_diag.c | ||
raw.c | ||
route.c | ||
syncookies.c | ||
sysctl_net_ipv4.c | ||
tcp_bbr.c | ||
tcp_bic.c | ||
tcp_cdg.c | ||
tcp_cong.c | ||
tcp_cubic.c | ||
tcp_dctcp.c | ||
tcp_diag.c | ||
tcp_fastopen.c | ||
tcp_highspeed.c | ||
tcp_htcp.c | ||
tcp_hybla.c | ||
tcp_illinois.c | ||
tcp_input.c | ||
tcp_ipv4.c | ||
tcp_lp.c | ||
tcp_metrics.c | ||
tcp_minisocks.c | ||
tcp_nv.c | ||
tcp_offload.c | ||
tcp_output.c | ||
tcp_rate.c | ||
tcp_recovery.c | ||
tcp_scalable.c | ||
tcp_timer.c | ||
tcp_ulp.c | ||
tcp_vegas.c | ||
tcp_vegas.h | ||
tcp_veno.c | ||
tcp_westwood.c | ||
tcp_yeah.c | ||
tcp.c | ||
tunnel4.c | ||
udp_diag.c | ||
udp_impl.h | ||
udp_offload.c | ||
udp_tunnel.c | ||
udp.c | ||
udplite.c | ||
xfrm4_input.c | ||
xfrm4_mode_beet.c | ||
xfrm4_mode_transport.c | ||
xfrm4_mode_tunnel.c | ||
xfrm4_output.c | ||
xfrm4_policy.c | ||
xfrm4_protocol.c | ||
xfrm4_state.c | ||
xfrm4_tunnel.c |