possible deadlock in ip_set_nfnl_put

11 views
Skip to first unread message

syzbot

unread,
Mar 1, 2020, 7:29:11 PM3/1/20
to syzkaller...@googlegroups.com
Hello,

syzbot found the following crash on:

HEAD commit: 78d697fc Linux 4.14.172
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16a35fd9e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=31ad682bcda9b93f
dashboard link: https://syzkaller.appspot.com/bug?extid=ea5c21ae1f10dd6e4d5f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ea5c21...@syzkaller.appspotmail.com

ip_tables: iptables: counters copy to user failed while replacing table
ptrace attach of "/root/syz-executor.1"[26732] was attempted by "/root/syz-executor.1"[26736]
======================================================
WARNING: possible circular locking dependency detected
4.14.172-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/26726 is trying to acquire lock:
(&table[i].mutex){+.+.}, at: [<ffffffff85306aeb>] ip_set_nfnl_put+0x11b/0x310 net/netfilter/ipset/ip_set_core.c:730

but task is already holding lock:
(&xt[i].mutex){+.+.}, at: [<ffffffff852bdb45>] xt_find_table_lock+0x35/0x3d0 net/netfilter/x_tables.c:1092

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&xt[i].mutex){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893
xt_find_revision+0x89/0x200 net/netfilter/x_tables.c:373
nfnl_compat_get+0x1f7/0x8a0 net/netfilter/nft_compat.c:678
nfnetlink_rcv_msg+0xa08/0xc00 net/netfilter/nfnetlink.c:214
netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2432
nfnetlink_rcv+0x1ab/0x1650 net/netfilter/nfnetlink.c:515
netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1312
netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1877
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xc5/0x100 net/socket.c:656
___sys_sendmsg+0x70a/0x840 net/socket.c:2062
__sys_sendmsg+0xa3/0x120 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x27/0x40 net/socket.c:2103
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7

-> #0 (&table[i].mutex){+.+.}:
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893
ip_set_nfnl_put+0x11b/0x310 net/netfilter/ipset/ip_set_core.c:730
set_target_v1_destroy+0xd7/0x150 net/netfilter/xt_set.c:392
cleanup_entry+0x169/0x220 net/ipv4/netfilter/ip_tables.c:666
__do_replace+0x38d/0x570 net/ipv4/netfilter/ip_tables.c:1086
do_replace net/ipv4/netfilter/ip_tables.c:1142 [inline]
do_ipt_set_ctl+0x255/0x39d net/ipv4/netfilter/ip_tables.c:1674
nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline]
ip_setsockopt+0x94/0xb0 net/ipv4/ip_sockglue.c:1240
raw_setsockopt+0xac/0xd0 net/ipv4/raw.c:855
SYSC_setsockopt net/socket.c:1865 [inline]
SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&xt[i].mutex);
lock(&table[i].mutex);
lock(&xt[i].mutex);
lock(&table[i].mutex);

*** DEADLOCK ***

1 lock held by syz-executor.4/26726:
#0: (&xt[i].mutex){+.+.}, at: [<ffffffff852bdb45>] xt_find_table_lock+0x35/0x3d0 net/netfilter/x_tables.c:1092

stack backtrace:
CPU: 0 PID: 26726 Comm: syz-executor.4 Not tainted 4.14.172-syzkaller #0
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+0x13e/0x194 lib/dump_stack.c:58
print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1258
check_prev_add kernel/locking/lockdep.c:1901 [inline]
check_prevs_add kernel/locking/lockdep.c:2018 [inline]
validate_chain kernel/locking/lockdep.c:2460 [inline]
__lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893
ip_set_nfnl_put+0x11b/0x310 net/netfilter/ipset/ip_set_core.c:730
set_target_v1_destroy+0xd7/0x150 net/netfilter/xt_set.c:392
cleanup_entry+0x169/0x220 net/ipv4/netfilter/ip_tables.c:666
__do_replace+0x38d/0x570 net/ipv4/netfilter/ip_tables.c:1086
do_replace net/ipv4/netfilter/ip_tables.c:1142 [inline]
do_ipt_set_ctl+0x255/0x39d net/ipv4/netfilter/ip_tables.c:1674
nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline]
ip_setsockopt+0x94/0xb0 net/ipv4/ip_sockglue.c:1240
raw_setsockopt+0xac/0xd0 net/ipv4/raw.c:855
SYSC_setsockopt net/socket.c:1865 [inline]
SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c479
RSP: 002b:00007f6adb4d2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f6adb4d36d4 RCX: 000000000045c479
RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000076bf20 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000020000240 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a34 R14: 00000000004cc9d4 R15: 000000000076bf2c
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table


---
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 syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

syzbot

unread,
Mar 10, 2020, 5:50:15 AM3/10/20
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following crash on:

HEAD commit: 78d697fc Linux 4.14.172
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11bf7655e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=3484a1ea90b8523a
dashboard link: https://syzkaller.appspot.com/bug?extid=ea5c21ae1f10dd6e4d5f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13a2c191e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=177e9e91e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ea5c21...@syzkaller.appspotmail.com

audit: type=1400 audit(1583833648.761:38): avc: denied { write } for pid=7358 comm="syz-executor168" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1
======================================================
WARNING: possible circular locking dependency detected
4.14.172-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor168/7360 is trying to acquire lock:
cleanup_entry+0x191/0x240 net/ipv6/netfilter/ip6_tables.c:684
__do_replace+0x38d/0x580 net/ipv6/netfilter/ip6_tables.c:1105
do_replace net/ipv6/netfilter/ip6_tables.c:1161 [inline]
do_ip6t_set_ctl+0x255/0x3a3 net/ipv6/netfilter/ip6_tables.c:1685
nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
ipv6_setsockopt net/ipv6/ipv6_sockglue.c:930 [inline]
ipv6_setsockopt+0xfd/0x130 net/ipv6/ipv6_sockglue.c:914
udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1459
SYSC_setsockopt net/socket.c:1865 [inline]
SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&xt[i].mutex);
lock(&table[i].mutex);
lock(&xt[i].mutex);
lock(&table[i].mutex);

*** DEADLOCK ***

1 lock held by syz-executor168/7360:
#0: (&xt[i].mutex){+.+.}, at: [<ffffffff852bdb45>] xt_find_table_lock+0x35/0x3d0 net/netfilter/x_tables.c:1092

stack backtrace:
CPU: 1 PID: 7360 Comm: syz-executor168 Not tainted 4.14.172-syzkaller #0
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+0x13e/0x194 lib/dump_stack.c:58
print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1258
check_prev_add kernel/locking/lockdep.c:1901 [inline]
check_prevs_add kernel/locking/lockdep.c:2018 [inline]
validate_chain kernel/locking/lockdep.c:2460 [inline]
__lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893
ip_set_nfnl_put+0x11b/0x310 net/netfilter/ipset/ip_set_core.c:730
set_target_v1_destroy+0xd7/0x150 net/netfilter/xt_set.c:392
cleanup_entry+0x191/0x240 net/ipv6/netfilter/ip6_tables.c:684
__do_replace+0x38d/0x580 net/ipv6/netfilter/ip6_tables.c:1105
do_replace net/ipv6/netfilter/ip6_tables.c:1161 [inline]
do_ip6t_set_ctl+0x255/0x3a3 net/ipv6/netfilter/ip6_tables.c:1685
nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
ipv6_setsockopt net/ipv6/ipv6_sockglue.c:930 [inline]
ipv6_setsockopt+0xfd/0x130 net/ipv6/ipv6_sockglue.c:914
udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1459
SYSC_setsockopt net/socket.c:1865 [inline]
SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441529
RSP: 002b:00007fff4c41f0d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441529
RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000005
RBP: 000000000000bc82 R08: 0000000000000001 R09: 00000000004002c8
R10: 0000000020001600 R11: 0000000000000246 R12: 0000000000402350
R13: 00000000004023e0 R14: 0000000000000000 R15: 0000000000000000
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
net_ratelimit: 730 callbacks suppressed
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
net_ratelimit: 849 callbacks suppressed
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table
ip6_tables: ip6tables: counters copy to user failed while replacing table

Reply all
Reply to author
Forward
0 new messages