KASAN: use-after-free Read in pfifo_fast_enqueue

Status: fixed on 2018/03/23 18:14
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+ed43b6903ab968b16f54@syzkaller.appspotmail.com
Fix commit: cce6294cc2ea net: sched: fix uses after free
First crash: 3125d, last: 3059d
▶ ▼ Discussions (4)
Title Replies (including bot) Last reply
[PATCH v2 net] net: sched: fix uses after free 4 (4) 2018/03/17 21:04
[PATCH net] net: sched: fix uses after free 2 (2) 2018/03/15 01:54
Re: KASAN: use-after-free Read in pfifo_fast_enqueue 2 (2) 2018/03/15 00:47
KASAN: use-after-free Read in pfifo_fast_enqueue 0 (1) 2018/01/16 18:29

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in qdisc_pkt_len include/net/sch_generic.h:610 [inline]
BUG: KASAN: use-after-free in qdisc_qstats_cpu_backlog_inc include/net/sch_generic.h:712 [inline]
BUG: KASAN: use-after-free in pfifo_fast_enqueue+0x4bc/0x5e0 net/sched/sch_generic.c:639
Read of size 4 at addr ffff8801cc554728 by task syzkaller887270/9305

CPU: 1 PID: 9305 Comm: syzkaller887270 Not tainted 4.16.0-rc5+ #353
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23c/0x360 mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 qdisc_pkt_len include/net/sch_generic.h:610 [inline]
 qdisc_qstats_cpu_backlog_inc include/net/sch_generic.h:712 [inline]
 pfifo_fast_enqueue+0x4bc/0x5e0 net/sched/sch_generic.c:639
 __dev_xmit_skb net/core/dev.c:3216 [inline]
 __dev_queue_xmit+0xd50/0x2f30 net/core/dev.c:3517
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3582
 neigh_hh_output include/net/neighbour.h:472 [inline]
 neigh_output include/net/neighbour.h:480 [inline]
 ip6_finish_output2+0x1492/0x23a0 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x69b/0xaf0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:277 [inline]
 ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:443 [inline]
 ip6_local_out+0x95/0x160 net/ipv6/output_core.c:176
 ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1677
 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1697
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x2f96/0x40c0 net/ipv6/raw.c:935
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x320/0x8b0 net/socket.c:2046
 __sys_sendmmsg+0x1ee/0x620 net/socket.c:2136
 SYSC_sendmmsg net/socket.c:2167 [inline]
 SyS_sendmmsg+0x35/0x60 net/socket.c:2162
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x447bb9
RSP: 002b:00007fab24d5ad58 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000006e3a1c RCX: 0000000000447bb9
RDX: 0000000000000249 RSI: 0000000020001300 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000020000000 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e3a18
R13: 00007ffc3eda88df R14: 00007fab24d5b9c0 R15: 0000000000000009

Allocated by task 9305:
 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:552
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc_node+0x144/0x760 mm/slab.c:3631
 __alloc_skb+0xf1/0x780 net/core/skbuff.c:193
 alloc_skb include/linux/skbuff.h:983 [inline]
 sock_wmalloc+0x140/0x1d0 net/core/sock.c:1937
 __ip6_append_data.isra.43+0x26b9/0x3390 net/ipv6/ip6_output.c:1416
 ip6_append_data+0x189/0x290 net/ipv6/ip6_output.c:1571
 rawv6_sendmsg+0x1e09/0x40c0 net/ipv6/raw.c:928
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x320/0x8b0 net/socket.c:2046
 __sys_sendmmsg+0x1ee/0x620 net/socket.c:2136
 SYSC_sendmmsg net/socket.c:2167 [inline]
 SyS_sendmmsg+0x35/0x60 net/socket.c:2162
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 9336:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3485 [inline]
 kmem_cache_free+0x83/0x2a0 mm/slab.c:3743
 kfree_skbmem+0x1a1/0x1d0 net/core/skbuff.c:582
 __kfree_skb net/core/skbuff.c:642 [inline]
 kfree_skb+0x165/0x4c0 net/core/skbuff.c:659
 ip_tunnel_xmit+0x710/0x3550 net/ipv4/ip_tunnel.c:795
 __gre_xmit+0x546/0x8b0 net/ipv4/ip_gre.c:449
 erspan_xmit+0x779/0x22a0 net/ipv4/ip_gre.c:728
 __netdev_start_xmit include/linux/netdevice.h:4066 [inline]
 netdev_start_xmit include/linux/netdevice.h:4075 [inline]
 xmit_one net/core/dev.c:3026 [inline]
 dev_hard_start_xmit+0x24e/0xac0 net/core/dev.c:3042
 sch_direct_xmit+0x40d/0x1140 net/sched/sch_generic.c:327
 qdisc_restart net/sched/sch_generic.c:393 [inline]
 __qdisc_run+0x57d/0x19c0 net/sched/sch_generic.c:401
 __dev_xmit_skb net/core/dev.c:3217 [inline]
 __dev_queue_xmit+0xd5e/0x2f30 net/core/dev.c:3517
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3582
 neigh_hh_output include/net/neighbour.h:472 [inline]
 neigh_output include/net/neighbour.h:480 [inline]
 ip6_finish_output2+0x1492/0x23a0 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x69b/0xaf0 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:277 [inline]
 ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:443 [inline]
 ip6_local_out+0x95/0x160 net/ipv6/output_core.c:176
 ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1677
 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1697
 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline]
 rawv6_sendmsg+0x2f96/0x40c0 net/ipv6/raw.c:935
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x320/0x8b0 net/socket.c:2046
 __sys_sendmmsg+0x1ee/0x620 net/socket.c:2136
 SYSC_sendmmsg net/socket.c:2167 [inline]
 SyS_sendmmsg+0x35/0x60 net/socket.c:2162
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff8801cc554700
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 40 bytes inside of
 232-byte region [ffff8801cc554700, ffff8801cc5547e8)
The buggy address belongs to the page:
page:ffffea0007315500 count:1 mapcount:0 mapping:ffff8801cc5540c0 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801cc5540c0 0000000000000000 000000010000000c
raw: ffffea0006cf5ca0 ffffea0006c74f60 ffff8801d9bec680 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cc554600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cc554680: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
>ffff8801cc554700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff8801cc554780: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
 ffff8801cc554800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/03/15 00:03 upstream 3032f8c504d2 08dacaa0 .config console log report syz C ci-upstream-kasan-gce
2018/03/14 23:29 net-next-old a870a02cc963 08dacaa0 .config console log report syz C ci-upstream-net-kasan-gce
2018/03/14 23:59 upstream 3032f8c504d2 08dacaa0 .config console log report syz ci-upstream-kasan-gce-386
2018/03/22 00:44 net-next-old 454bfe97837a 95c88d7a .config console log report ci-upstream-net-kasan-gce
2018/03/21 19:42 net-next-old 454bfe97837a f63eeee9 .config console log report ci-upstream-net-kasan-gce
2018/03/21 09:23 net-next-old 0466080c751e 113a43ff .config console log report ci-upstream-net-kasan-gce
2018/03/20 14:23 net-next-old c314c7ba4038 72c33b66 .config console log report ci-upstream-net-kasan-gce
2018/03/20 04:10 net-next-old c314c7ba4038 7e7d7ed2 .config console log report ci-upstream-net-kasan-gce
2018/03/18 15:02 net-next-old 76f38f1f3cf8 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/18 08:03 net-next-old d7cb44496a9b 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/17 23:43 net-next-old d7cb44496a9b 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/16 20:52 net-next-old 0aee4c259849 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/15 23:24 net-next-old 80d9f3a0fdb8 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/15 07:29 net-next-old c292566a7779 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/14 22:14 net-next-old a870a02cc963 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/14 06:10 net-next-old be9fc0971a5c 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/13 22:13 net-next-old 9ba32046fc2d 08dacaa0 .config console log report ci-upstream-net-kasan-gce
2018/03/06 11:39 net-next-old ef3f6c256f0b aef0b792 .config console log report ci-upstream-net-kasan-gce
2018/03/05 06:40 net-next-old efab163bbc19 2c6f473e .config console log report ci-upstream-net-kasan-gce
2018/01/15 01:23 mmots ce3c209f6733 66d492a6 .config console log report ci-upstream-mmots-kasan-gce
* Struck through repros no longer work on HEAD.