KMSAN: uninit-value in ip6_parse

KMSAN: uninit-value in ip6_parse_tlv
Status: upstream: reported C repro on 2018/09/20 20:54
Reported-by: syzbot+f08ac29f2ac8aea19826@syzkaller.appspotmail.com
First crash: 375d, last: 1d03h

Sample crash report:

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
==================================================================
BUG: KMSAN: uninit-value in ip6_parse_tlv+0x8d5/0xcd0 net/ipv6/exthdrs.c:172
CPU: 1 PID: 4535 Comm: syz-executor786 Not tainted 4.17.0-rc3+ #88
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 ip6_parse_tlv+0x8d5/0xcd0 net/ipv6/exthdrs.c:172
 ipv6_destopt_rcv+0x50d/0xd90 net/ipv6/exthdrs.c:310
 ip6_input_finish+0xaac/0x2250 net/ipv6/ip6_input.c:284
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip6_input net/ipv6/ip6_input.c:327 [inline]
 ip6_mc_input+0xa67/0x1080 net/ipv6/ip6_input.c:404
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x46e/0x6e0 net/ipv6/ip6_input.c:71
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ipv6_rcv+0x1e16/0x2340 net/ipv6/ip6_input.c:208
 __netif_receive_skb_core+0x47df/0x4a90 net/core/dev.c:4592
 __netif_receive_skb net/core/dev.c:4657 [inline]
 process_backlog+0x62d/0xe20 net/core/dev.c:5337
 napi_poll net/core/dev.c:5735 [inline]
 net_rx_action+0x7c1/0x1a70 net/core/dev.c:5801
 __do_softirq+0x56d/0x93d kernel/softirq.c:285
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1046
 </IRQ>
 do_softirq+0xb6/0xf0 kernel/softirq.c:329
 netif_rx_ni net/core/dev.c:4219 [inline]
 dev_loopback_xmit+0x8b0/0x900 net/core/dev.c:3347
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip6_finish_output2+0x1e24/0x2110 net/ipv6/ip6_output.c:84
 ip6_finish_output+0xae9/0xba0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:277 [inline]
 ip6_output+0x597/0x6c0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:444 [inline]
 ip6_local_out+0x15e/0x1d0 net/ipv6/output_core.c:176
 ip6_send_skb net/ipv6/ip6_output.c:1702 [inline]
 ip6_push_pending_frames+0x218/0x4d0 net/ipv6/ip6_output.c:1722
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x4235/0x4fb0 net/ipv6/raw.c:935
 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 __sys_sendto+0x6c0/0x7e0 net/socket.c:1789
 __do_sys_sendto net/socket.c:1801 [inline]
 __se_sys_sendto net/socket.c:1797 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1797
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x43fe79
RSP: 002b:00007ffc475970d8 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fe79
RDX: 0000000000000000 RSI: 0000000020001ffe RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000020003000 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004017a0
R13: 0000000000401830 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan.c:321
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2753 [inline]
 __kmalloc_node_track_caller+0xb32/0x11b0 mm/slub.c:4395
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:988 [inline]
 alloc_skb_with_frags+0x1e6/0xb80 net/core/skbuff.c:5254
 sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2088
 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2105
 __ip6_append_data+0x33a2/0x4e40 net/ipv6/ip6_output.c:1427
 ip6_append_data+0x40e/0x6b0 net/ipv6/ip6_output.c:1596
 rawv6_sendmsg+0x2740/0x4fb0 net/ipv6/raw.c:928
 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 __sys_sendto+0x6c0/0x7e0 net/socket.c:1789
 __do_sys_sendto net/socket.c:1801 [inline]
 __se_sys_sendto net/socket.c:1797 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1797
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
==================================================================

All crashes (101):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kmsan-gce	2018/05/10 06:35	kmsan	74ee2200	12c7428a	.config	log	report	syz	C	davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/23 01:38	kmsan	199a02db	53199d6e	.config	log	report	syz	C	davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/02/06 04:05	kmsan	fa1981be	d672172c	.config	log	report	syz	C	davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2018/04/14 11:38	kmsan	35ff515e	7a67784c	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/23 18:14	kmsan	199a02db	53199d6e	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/23 18:12	kmsan	199a02db	53199d6e	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/23 15:59	kmsan	199a02db	53199d6e	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/22 11:20	kmsan	199a02db	0a77c33c	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/20 21:43	kmsan	199a02db	b0e8efcb	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/19 10:53	kmsan	199a02db	b0e8efcb	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/18 22:20	kmsan	199a02db	b0e8efcb	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/18 05:16	kmsan	199a02db	b0e8efcb	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/17 17:44	kmsan	199a02db	b0e8efcb	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/16 05:32	kmsan	199a02db	505ab413	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/13 22:59	kmsan	199a02db	c402d8f1	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/13 19:26	kmsan	199a02db	c402d8f1	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/13 14:23	kmsan	199a02db	c402d8f1	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/12 22:22	kmsan	199a02db	c402d8f1	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/12 11:37	kmsan	199a02db	8916f5e1	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/11 16:46	kmsan	199a02db	e955ac50	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/08 19:09	kmsan	c1f8455d	0dfb0452	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/06 12:23	kmsan	46200eb9	c34fde03	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/06 03:48	kmsan	46200eb9	fa763482	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/06 02:28	kmsan	46200eb9	fa763482	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/05 22:35	kmsan	46200eb9	fa763482	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/04 19:59	kmsan	46200eb9	6a475fff	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/02 14:39	kmsan	088c01ea	dfd3394d	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/01 21:11	kmsan	088c01ea	a9ca43d4	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/04/01 17:15	kmsan	088c01ea	a9ca43d4	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/03/30 17:44	kmsan	088c01ea	c35ee0ea	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/03/28 22:17	kmsan	35def5ce	14c58f8d	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/03/28 20:58	kmsan	35def5ce	14c58f8d	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/03/27 21:02	kmsan	3c26d882	4e668495	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/03/23 17:07	kmsan	c10a026b	a2cef203	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/03/23 02:51	kmsan	c10a026b	3361bde5	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/03/21 22:51	kmsan	c10a026b	dce6e62f	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/02/13 17:43	kmsan	fa1981be	0a49c954	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/01/27 11:01	kmsan	02f2d5ae	c73f090a	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/01/17 07:06	kmsan	02f2d5ae	c2faf9b2	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/01/03 19:16	kmsan	68006459	66fcd29b	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2019/01/03 13:45	kmsan	8ba10281	66fcd29b	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2018/12/25 23:32	kmsan	79fc24ff	8a41a0ad	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2018/12/16 21:37	kmsan	0a602458	def91db3	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2018/10/26 19:21	kmsan	4bb25354	a8292de9	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org
ci-upstream-kmsan-gce	2018/10/23 05:16	kmsan	4bb25354	ecb386fe	.config	log	report			davem@davemloft.net, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, yoshfuji@linux-ipv6.org