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* KASAN: use-after-free Read in tcindex_dump
@ 2020-03-10 22:25 syzbot
  2020-03-11  4:00 ` Cong Wang
  2020-03-16 19:47 ` Cong Wang
  0 siblings, 2 replies; 4+ messages in thread
From: syzbot @ 2020-03-10 22:25 UTC (permalink / raw)
  To: davem, jhs, jiri, kuba, linux-kernel, netdev, syzkaller-bugs,
	xiyou.wangcong

Hello,

syzbot found the following crash on:

HEAD commit:    c2003765 Merge tag 'io_uring-5.6-2020-03-07' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1275b731e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4527d1e2fb19fd5c
dashboard link: https://syzkaller.appspot.com/bug?extid=653090db2562495901dc
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1180ff29e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+653090db2562495901dc@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in tcindex_dump+0xb6e/0xc20 net/sched/cls_tcindex.c:637
Read of size 8 at addr ffff88807ebd0020 by task syz-executor.3/10006

CPU: 0 PID: 10006 Comm: syz-executor.3 Not tainted 5.6.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:374
 __kasan_report.cold+0x1a/0x32 mm/kasan/report.c:506
 kasan_report+0xe/0x20 mm/kasan/common.c:641
 tcindex_dump+0xb6e/0xc20 net/sched/cls_tcindex.c:637
 tcf_fill_node+0x572/0x930 net/sched/cls_api.c:1814
 tfilter_notify+0x139/0x2a0 net/sched/cls_api.c:1840
 tc_new_tfilter+0xab2/0x20b0 net/sched/cls_api.c:2107
 rtnetlink_rcv_msg+0x810/0xad0 net/core/rtnetlink.c:5427
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2343
 ___sys_sendmsg+0x100/0x170 net/socket.c:2397
 __sys_sendmsg+0xec/0x1b0 net/socket.c:2430
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c4a9
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb7e5f98c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb7e5f996d4 RCX: 000000000045c4a9
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000004
RBP: 000000000076bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009fa R14: 00000000004cc777 R15: 000000000076bfcc

Allocated by task 10000:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:488
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x161/0x7a0 mm/slab.c:3665
 kmalloc_array include/linux/slab.h:597 [inline]
 kcalloc include/linux/slab.h:608 [inline]
 tcindex_alloc_perfect_hash+0x5a/0x320 net/sched/cls_tcindex.c:281
 tcindex_set_parms+0x1568/0x1a00 net/sched/cls_tcindex.c:405
 tcindex_change+0x203/0x2e0 net/sched/cls_tcindex.c:518
 tc_new_tfilter+0xa59/0x20b0 net/sched/cls_api.c:2103
 rtnetlink_rcv_msg+0x810/0xad0 net/core/rtnetlink.c:5427
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2343
 ___sys_sendmsg+0x100/0x170 net/socket.c:2397
 __sys_sendmsg+0xec/0x1b0 net/socket.c:2430
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 262:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:476
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 tcindex_partial_destroy_work+0x2e/0x50 net/sched/cls_tcindex.c:264
 process_one_work+0x94b/0x1690 kernel/workqueue.c:2264
 worker_thread+0x96/0xe20 kernel/workqueue.c:2410
 kthread+0x357/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff88807ebd0000
 which belongs to the cache kmalloc-16k of size 16384
The buggy address is located 32 bytes inside of
 16384-byte region [ffff88807ebd0000, ffff88807ebd4000)
The buggy address belongs to the page:
page:ffffea0001faf400 refcount:1 mapcount:0 mapping:ffff8880aa002380 index:0x0 compound_mapcount: 0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea0001faf208 ffffea0001faf608 ffff8880aa002380
raw: 0000000000000000 ffff88807ebd0000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88807ebcff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88807ebcff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: KASAN: use-after-free Read in tcindex_dump
  2020-03-10 22:25 KASAN: use-after-free Read in tcindex_dump syzbot
@ 2020-03-11  4:00 ` Cong Wang
  2020-03-11  5:32   ` syzbot
  2020-03-16 19:47 ` Cong Wang
  1 sibling, 1 reply; 4+ messages in thread
From: Cong Wang @ 2020-03-11  4:00 UTC (permalink / raw)
  To: syzbot
  Cc: David Miller, Jamal Hadi Salim, Jiri Pirko, Jakub Kicinski, LKML,
	Linux Kernel Network Developers, syzkaller-bugs

#syz test: https://github.com/congwang/linux.git tcindex

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: KASAN: use-after-free Read in tcindex_dump
  2020-03-11  4:00 ` Cong Wang
@ 2020-03-11  5:32   ` syzbot
  0 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2020-03-11  5:32 UTC (permalink / raw)
  To: davem, jhs, jiri, kuba, linux-kernel, netdev, syzkaller-bugs,
	xiyou.wangcong

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger crash:

Reported-and-tested-by: syzbot+653090db2562495901dc@syzkaller.appspotmail.com

Tested on:

commit:         2c19e526 net_sched: hold rtnl lock for tcindex_partial_des..
git tree:       https://github.com/congwang/linux.git tcindex
kernel config:  https://syzkaller.appspot.com/x/.config?x=bcbe864577669742
dashboard link: https://syzkaller.appspot.com/bug?extid=653090db2562495901dc
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

Note: testing is done by a robot and is best-effort only.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: KASAN: use-after-free Read in tcindex_dump
  2020-03-10 22:25 KASAN: use-after-free Read in tcindex_dump syzbot
  2020-03-11  4:00 ` Cong Wang
@ 2020-03-16 19:47 ` Cong Wang
  1 sibling, 0 replies; 4+ messages in thread
From: Cong Wang @ 2020-03-16 19:47 UTC (permalink / raw)
  To: syzbot
  Cc: David Miller, Jamal Hadi Salim, Jiri Pirko, Jakub Kicinski, LKML,
	Linux Kernel Network Developers, syzkaller-bugs

#syz fix: net_sched: hold rtnl lock in tcindex_partial_destroy_work()

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-03-16 19:48 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-03-10 22:25 KASAN: use-after-free Read in tcindex_dump syzbot
2020-03-11  4:00 ` Cong Wang
2020-03-11  5:32   ` syzbot
2020-03-16 19:47 ` Cong Wang

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