Taehee Yoo 5d407b071d ip: frags: fix crash in ip_do_fragment() ... 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: fa0f527358 ("ip: use rb trees for IP frag queue.") Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Taehee Yoo <ap420073@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2018-09-09 14:50:56 -07:00
..
ip6_tables.c	netfilter: x_tables: set module owner for icmp(6) matches	2018-07-05 11:45:11 +02:00
ip6t_ah.c
ip6t_eui64.c
ip6t_frag.c
ip6t_hbh.c
ip6t_ipv6header.c
ip6t_MASQUERADE.c	netfilter: add NAT support for shifted portmap ranges	2018-04-24 10:29:12 +02:00
ip6t_mh.c
ip6t_NPT.c
ip6t_REJECT.c
ip6t_rpfilter.c	netfilter: ip6t_rpfilter: set F_IFACE for linklocal addresses	2018-08-16 19:36:58 +02:00
ip6t_rt.c
ip6t_srh.c	netfilter: ip6t_srh: extend SRH matching for previous, next and last SID	2018-05-06 23:33:03 +02:00
ip6t_SYNPROXY.c
ip6table_filter.c
ip6table_mangle.c
ip6table_nat.c	netfilter: nf_nat: add nat type hooks to nat core	2018-05-23 09:14:06 +02:00
ip6table_raw.c
ip6table_security.c
Kconfig	netfilter: conntrack: remove l3proto abstraction	2018-07-17 15:27:49 +02:00
Makefile	netfilter: conntrack: remove l3proto abstraction	2018-07-17 15:27:49 +02:00
nf_conntrack_reasm.c	ip: frags: fix crash in ip_do_fragment()	2018-09-09 14:50:56 -07:00
nf_defrag_ipv6_hooks.c	ipv6: remove dependency of nf_defrag_ipv6 on ipv6 module	2018-07-18 11:26:53 +02:00
nf_dup_ipv6.c
nf_flow_table_ipv6.c	netfilter: nf_flow_table: move init code to nf_flow_table_core.c	2018-04-24 10:28:45 +02:00
nf_log_ipv6.c	netfilter: check if the socket netns is correct.	2018-06-28 22:21:32 +09:00
nf_nat_l3proto_ipv6.c	netfilter: nf_nat: add nat type hooks to nat core	2018-05-23 09:14:06 +02:00
nf_nat_masquerade_ipv6.c	netfilter: nat: merge ipv4/ipv6 masquerade code into main nat module	2018-05-29 00:25:36 +02:00
nf_nat_proto_icmpv6.c	netfilter: add NAT support for shifted portmap ranges	2018-04-24 10:29:12 +02:00
nf_reject_ipv6.c
nf_socket_ipv6.c
nf_tproxy_ipv6.c	netfilter: nf_tproxy: fix possible non-linear access to transport header	2018-07-06 14:32:44 +02:00
nft_chain_nat_ipv6.c	netfilter: nf_nat: add nat type hooks to nat core	2018-05-23 09:14:06 +02:00
nft_chain_route_ipv6.c	netfilter: nf_tables: nft_register_chain_type() returns void	2018-03-30 11:29:18 +02:00
nft_dup_ipv6.c
nft_fib_ipv6.c
nft_masq_ipv6.c	netfilter: add NAT support for shifted portmap ranges	2018-04-24 10:29:12 +02:00
nft_redir_ipv6.c	netfilter: add NAT support for shifted portmap ranges	2018-04-24 10:29:12 +02:00
nft_reject_ipv6.c