Messages in this thread | | | From | Cong Wang <> | Date | Mon, 30 Oct 2017 11:41:50 -0700 | Subject | Re: KASAN: use-after-free Read in sit_tunnel_xmit |
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On Mon, Oct 30, 2017 at 8:34 AM, syzbot <bot+1aa412fe58f4059538c0204a0f096524e6dce60b@syzkaller.appspotmail.com> wrote: > Hello, > > syzkaller hit the following crash on > 4dc12ffeaeac939097a3f55c881d3dc3523dff0c > git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > > > > > skbuff: bad partial csum: csum=53081/14726 len=2273 > ================================================================== > BUG: KASAN: use-after-free in ipv6_get_dsfield include/net/dsfield.h:23 > [inline] > BUG: KASAN: use-after-free in ipip6_tunnel_xmit net/ipv6/sit.c:968 [inline] > BUG: KASAN: use-after-free in sit_tunnel_xmit+0x2a41/0x3130 > net/ipv6/sit.c:1016 > Read of size 2 at addr ffff8801c64afd00 by task syz-executor3/16942 > > CPU: 0 PID: 16942 Comm: syz-executor3 Not tainted 4.14.0-rc5+ #97 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:16 [inline] > dump_stack+0x194/0x257 lib/dump_stack.c:52 > print_address_description+0x73/0x250 mm/kasan/report.c:252 > kasan_report_error mm/kasan/report.c:351 [inline] > kasan_report+0x25b/0x340 mm/kasan/report.c:409 > __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:428 > ipv6_get_dsfield include/net/dsfield.h:23 [inline] > ipip6_tunnel_xmit net/ipv6/sit.c:968 [inline] > sit_tunnel_xmit+0x2a41/0x3130 net/ipv6/sit.c:1016 > __netdev_start_xmit include/linux/netdevice.h:4022 [inline] > netdev_start_xmit include/linux/netdevice.h:4031 [inline] > xmit_one net/core/dev.c:3008 [inline] > dev_hard_start_xmit+0x248/0xac0 net/core/dev.c:3024 > __dev_queue_xmit+0x17d2/0x2070 net/core/dev.c:3505 > dev_queue_xmit+0x17/0x20 net/core/dev.c:3538 > neigh_direct_output+0x15/0x20 net/core/neighbour.c:1390 > neigh_output include/net/neighbour.h:481 [inline] > ip6_finish_output2+0xad1/0x22a0 net/ipv6/ip6_output.c:120 > ip6_fragment+0x25ae/0x3420 net/ipv6/ip6_output.c:723 > ip6_finish_output+0x319/0x920 net/ipv6/ip6_output.c:144 > NF_HOOK_COND include/linux/netfilter.h:238 [inline] > ip6_output+0x1f4/0x850 net/ipv6/ip6_output.c:163 > dst_output include/net/dst.h:459 [inline] > ip6_local_out+0x95/0x160 net/ipv6/output_core.c:176 > ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1658 > ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1678 > rawv6_push_pending_frames net/ipv6/raw.c:616 [inline] > rawv6_sendmsg+0x2eb9/0x3e40 net/ipv6/raw.c:935 > inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 > sock_sendmsg_nosec net/socket.c:633 [inline] > sock_sendmsg+0xca/0x110 net/socket.c:643 > SYSC_sendto+0x352/0x5a0 net/socket.c:1750 > SyS_sendto+0x40/0x50 net/socket.c:1718 > entry_SYSCALL_64_fastpath+0x1f/0xbe > RIP: 0033:0x452869 > RSP: 002b:00007fe3c12e5be8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c > RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452869 > RDX: 00000000000007f1 RSI: 000000002013b7ff RDI: 0000000000000014 > RBP: 0000000000000161 R08: 00000000204e8fe4 R09: 000000000000001c > R10: 0000000001000000 R11: 0000000000000212 R12: 00000000006f01b8 > R13: 00000000ffffffff R14: 00007fe3c12e66d4 R15: 0000000000000017 > > Allocated by task 16924: > save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 > save_stack+0x43/0xd0 mm/kasan/kasan.c:447 > set_track mm/kasan/kasan.c:459 [inline] > kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 > __do_kmalloc_node mm/slab.c:3689 [inline] > __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3703 > __kmalloc_reserve.isra.40+0x41/0xd0 net/core/skbuff.c:138 > __alloc_skb+0x13b/0x780 net/core/skbuff.c:206 > alloc_skb include/linux/skbuff.h:985 [inline] > sock_wmalloc+0x140/0x1d0 net/core/sock.c:1932 > __ip6_append_data.isra.43+0x2681/0x3340 net/ipv6/ip6_output.c:1397 > ip6_append_data+0x189/0x290 net/ipv6/ip6_output.c:1552 > rawv6_sendmsg+0x1dd9/0x3e40 net/ipv6/raw.c:928 > inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 > sock_sendmsg_nosec net/socket.c:633 [inline] > sock_sendmsg+0xca/0x110 net/socket.c:643 > SYSC_sendto+0x352/0x5a0 net/socket.c:1750 > SyS_sendto+0x40/0x50 net/socket.c:1718 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > Freed by task 16942: > save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 > save_stack+0x43/0xd0 mm/kasan/kasan.c:447 > set_track mm/kasan/kasan.c:459 [inline] > kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 > __cache_free mm/slab.c:3503 [inline] > kfree+0xca/0x250 mm/slab.c:3820 > skb_free_head+0x74/0xb0 net/core/skbuff.c:554 > pskb_expand_head+0x36b/0x1210 net/core/skbuff.c:1494 > __pskb_pull_tail+0x14a/0x17c0 net/core/skbuff.c:1877 > pskb_may_pull include/linux/skbuff.h:2102 [inline] > _decode_session6+0x8a4/0x1100 net/ipv6/xfrm6_policy.c:148
Looks like we should indicate error by returning some int for afinfo->decode_session().
> __xfrm_decode_session+0x63/0x100 net/xfrm/xfrm_policy.c:2343 > xfrm_decode_session_reverse include/net/xfrm.h:1181 [inline] > icmpv6_route_lookup+0x343/0x640 net/ipv6/icmp.c:372 > icmp6_send+0x1569/0x25b0 net/ipv6/icmp.c:551 > icmpv6_send+0x142/0x280 net/ipv6/ip6_icmp.c:42 > ip6_link_failure+0x94/0x580 net/ipv6/route.c:1997 > dst_link_failure include/net/dst.h:442 [inline] > ipip6_tunnel_xmit net/ipv6/sit.c:940 [inline] > sit_tunnel_xmit+0x244f/0x3130 net/ipv6/sit.c:1016 > __netdev_start_xmit include/linux/netdevice.h:4022 [inline] > netdev_start_xmit include/linux/netdevice.h:4031 [inline] > xmit_one net/core/dev.c:3008 [inline] > dev_hard_start_xmit+0x248/0xac0 net/core/dev.c:3024 > __dev_queue_xmit+0x17d2/0x2070 net/core/dev.c:3505 > dev_queue_xmit+0x17/0x20 net/core/dev.c:3538 > neigh_direct_output+0x15/0x20 net/core/neighbour.c:1390 > neigh_output include/net/neighbour.h:481 [inline] > ip6_finish_output2+0xad1/0x22a0 net/ipv6/ip6_output.c:120 > ip6_fragment+0x25ae/0x3420 net/ipv6/ip6_output.c:723 > ip6_finish_output+0x319/0x920 net/ipv6/ip6_output.c:144 > NF_HOOK_COND include/linux/netfilter.h:238 [inline] > ip6_output+0x1f4/0x850 net/ipv6/ip6_output.c:163 > dst_output include/net/dst.h:459 [inline] > ip6_local_out+0x95/0x160 net/ipv6/output_core.c:176 > ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1658 > ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1678 > rawv6_push_pending_frames net/ipv6/raw.c:616 [inline] > rawv6_sendmsg+0x2eb9/0x3e40 net/ipv6/raw.c:935 > inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 > sock_sendmsg_nosec net/socket.c:633 [inline] > sock_sendmsg+0xca/0x110 net/socket.c:643 > SYSC_sendto+0x352/0x5a0 net/socket.c:1750 > SyS_sendto+0x40/0x50 net/socket.c:1718 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > The buggy address belongs to the object at ffff8801c64afc80 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 128 bytes inside of > 512-byte region [ffff8801c64afc80, ffff8801c64afe80) > The buggy address belongs to the page: > page:ffffea0007192bc0 count:1 mapcount:0 mapping:ffff8801c64af000 index:0x0 > flags: 0x200000000000100(slab) > raw: 0200000000000100 ffff8801c64af000 0000000000000000 0000000100000006 > raw: ffffea00072d04e0 ffffea0007083fe0 ffff8801dac00940 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801c64afc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801c64afc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> >> ffff8801c64afd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ^ > ffff8801c64afd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801c64afe00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This bug is generated by a dumb bot. It may contain errors. > See https://goo.gl/tpsmEJ for details. > Direct all questions to syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. > Once a fix for this bug is committed, please reply to this email with: > #syz fix: exact-commit-title > To mark this as a duplicate of another syzbot report, please reply with: > #syz dup: exact-subject-of-another-report > If it's a one-off invalid bug report, please reply with: > #syz invalid > Note: if the crash happens again, it will cause creation of a new bug > report.
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