Subject: KASAN: use-after-free Read in __nf_tables_abort

From: syzbot <[email-masked]>
Date: Mon, 20 Jan 2020 03:37:09 -0800

Hello,

syzbot found the following crash on:

HEAD commit:    def9d278 Linux 5.5-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16d4e966e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cf8e288883e40aba
dashboard link: https://syzkaller.appspot.com/bug?extid=29125d208b3dae9a7019
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12c78faee00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KASAN: use-after-free in __list_del_entry_valid+0xd2/0xf5 lib/list_debug.c:42
Read of size 8 at addr ffff888096085408 by task syz-executor.0/9949

CPU: 0 PID: 9949 Comm: syz-executor.0 Not tainted 5.5.0-rc7-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+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 __list_del_entry_valid+0xd2/0xf5 lib/list_debug.c:42
 __list_del_entry include/linux/list.h:131 [inline]
 list_del_rcu include/linux/rculist.h:148 [inline]
 __nf_tables_abort+0x1e53/0x2a50 net/netfilter/nf_tables_api.c:7258
 nf_tables_abort+0x17/0x30 net/netfilter/nf_tables_api.c:7373
 nfnetlink_rcv_batch+0xa5d/0x17a0 net/netfilter/nfnetlink.c:494
 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:543 [inline]
 nfnetlink_rcv+0x3e7/0x460 net/netfilter/nfnetlink.c:561
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:659
 ____sys_sendmsg+0x753/0x880 net/socket.c:2330
 ___sys_sendmsg+0x100/0x170 net/socket.c:2384
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b349
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:00007f29992c7c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f29992c86d4 RCX: 000000000045b349
RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000917 R14: 00000000004ca810 R15: 000000000075bf2c

Allocated by task 9949:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551
 kmalloc include/linux/slab.h:556 [inline]
 kzalloc include/linux/slab.h:670 [inline]
 nf_tables_newtable+0xa4d/0x1510 net/netfilter/nf_tables_api.c:981
 nfnetlink_rcv_batch+0xf42/0x17a0 net/netfilter/nfnetlink.c:433
 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:543 [inline]
 nfnetlink_rcv+0x3e7/0x460 net/netfilter/nfnetlink.c:561
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:659
 ____sys_sendmsg+0x753/0x880 net/socket.c:2330
 ___sys_sendmsg+0x100/0x170 net/socket.c:2384
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 2840:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3757
 nf_tables_table_destroy.isra.0+0xef/0x150 net/netfilter/nf_tables_api.c:1160
 nft_commit_release net/netfilter/nf_tables_api.c:6810 [inline]
 nf_tables_trans_destroy_work+0x406/0x7c0 net/netfilter/nf_tables_api.c:6860
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264
 worker_thread+0x98/0xe40 kernel/workqueue.c:2410
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff888096085400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
 512-byte region [ffff888096085400, ffff888096085600)
The buggy address belongs to the page:
page:ffffea0002582140 refcount:1 mapcount:0 mapping:ffff8880aa400a80 index:0x0
raw: 00fffe0000000200 ffffea0002402a88 ffffea000294a748 ffff8880aa400a80
raw: 0000000000000000 ffff888096085000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888096085300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888096085380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888096085400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888096085480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888096085500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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 [email-masked].

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