linux-stable.git/net/netlink, branch v4.14.331 Linux kernel stable tree netlink: Add __sock_i_ino() for __netlink_diag_dump(). 2023-08-11T09:33:35+00:00 Kuniyuki Iwashima kuniyu@amazon.com 2023-06-26T16:43:13+00:00 62c204a35c702265c41d9e988a384d5b5bb770d5 [ Upstream commit 25a9c8a4431c364f97f75558cb346d2ad3f53fbb ] syzbot reported a warning in __local_bh_enable_ip(). [0] Commit 8d61f926d420 ("netlink: fix potential deadlock in netlink_set_err()") converted read_lock(&nl_table_lock) to read_lock_irqsave() in __netlink_diag_dump() to prevent a deadlock. However, __netlink_diag_dump() calls sock_i_ino() that uses read_lock_bh() and read_unlock_bh(). If CONFIG_TRACE_IRQFLAGS=y, read_unlock_bh() finally enables IRQ even though it should stay disabled until the following read_unlock_irqrestore(). Using read_lock() in sock_i_ino() would trigger a lockdep splat in another place that was fixed in commit f064af1e500a ("net: fix a lockdep splat"), so let's add __sock_i_ino() that would be safe to use under BH disabled. [0]: WARNING: CPU: 0 PID: 5012 at kernel/softirq.c:376 __local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376 Modules linked in: CPU: 0 PID: 5012 Comm: syz-executor487 Not tainted 6.4.0-rc7-syzkaller-00202-g6f68fc395f49 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 RIP: 0010:__local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376 Code: 45 bf 01 00 00 00 e8 91 5b 0a 00 e8 3c 15 3d 00 fb 65 8b 05 ec e9 b5 7e 85 c0 74 58 5b 5d c3 65 8b 05 b2 b6 b4 7e 85 c0 75 a2 <0f> 0b eb 9e e8 89 15 3d 00 eb 9f 48 89 ef e8 6f 49 18 00 eb a8 0f RSP: 0018:ffffc90003a1f3d0 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000201 RCX: 1ffffffff1cf5996 RDX: 0000000000000000 RSI: 0000000000000201 RDI: ffffffff8805c6f3 RBP: ffffffff8805c6f3 R08: 0000000000000001 R09: ffff8880152b03a3 R10: ffffed1002a56074 R11: 0000000000000005 R12: 00000000000073e4 R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000 FS: 0000555556726300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000045ad50 CR3: 000000007c646000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> sock_i_ino+0x83/0xa0 net/core/sock.c:2559 __netlink_diag_dump+0x45c/0x790 net/netlink/diag.c:171 netlink_diag_dump+0xd6/0x230 net/netlink/diag.c:207 netlink_dump+0x570/0xc50 net/netlink/af_netlink.c:2269 __netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2374 netlink_dump_start include/linux/netlink.h:329 [inline] netlink_diag_handler_dump+0x1ae/0x250 net/netlink/diag.c:238 __sock_diag_cmd net/core/sock_diag.c:238 [inline] sock_diag_rcv_msg+0x31e/0x440 net/core/sock_diag.c:269 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2547 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1914 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 ____sys_sendmsg+0x71c/0x900 net/socket.c:2503 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2557 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2586 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f5303aaabb9 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc7506e548 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5303aaabb9 RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000003 RBP: 00007f5303a6ed60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5303a6edf0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Fixes: 8d61f926d420 ("netlink: fix potential deadlock in netlink_set_err()") Reported-by: syzbot+5da61cf6a9bc1902d422@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=5da61cf6a9bc1902d422 Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20230626164313.52528-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 25a9c8a4431c364f97f75558cb346d2ad3f53fbb ]

syzbot reported a warning in __local_bh_enable_ip(). [0]

Commit 8d61f926d420 ("netlink: fix potential deadlock in
netlink_set_err()") converted read_lock(&nl_table_lock) to
read_lock_irqsave() in __netlink_diag_dump() to prevent a deadlock.

However, __netlink_diag_dump() calls sock_i_ino() that uses
read_lock_bh() and read_unlock_bh().  If CONFIG_TRACE_IRQFLAGS=y,
read_unlock_bh() finally enables IRQ even though it should stay
disabled until the following read_unlock_irqrestore().

Using read_lock() in sock_i_ino() would trigger a lockdep splat
in another place that was fixed in commit f064af1e500a ("net: fix
a lockdep splat"), so let's add __sock_i_ino() that would be safe
to use under BH disabled.

[0]:
WARNING: CPU: 0 PID: 5012 at kernel/softirq.c:376 __local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376
Modules linked in:
CPU: 0 PID: 5012 Comm: syz-executor487 Not tainted 6.4.0-rc7-syzkaller-00202-g6f68fc395f49 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
RIP: 0010:__local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376
Code: 45 bf 01 00 00 00 e8 91 5b 0a 00 e8 3c 15 3d 00 fb 65 8b 05 ec e9 b5 7e 85 c0 74 58 5b 5d c3 65 8b 05 b2 b6 b4 7e 85 c0 75 a2 <0f> 0b eb 9e e8 89 15 3d 00 eb 9f 48 89 ef e8 6f 49 18 00 eb a8 0f
RSP: 0018:ffffc90003a1f3d0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000201 RCX: 1ffffffff1cf5996
RDX: 0000000000000000 RSI: 0000000000000201 RDI: ffffffff8805c6f3
RBP: ffffffff8805c6f3 R08: 0000000000000001 R09: ffff8880152b03a3
R10: ffffed1002a56074 R11: 0000000000000005 R12: 00000000000073e4
R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000
FS:  0000555556726300(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045ad50 CR3: 000000007c646000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 sock_i_ino+0x83/0xa0 net/core/sock.c:2559
 __netlink_diag_dump+0x45c/0x790 net/netlink/diag.c:171
 netlink_diag_dump+0xd6/0x230 net/netlink/diag.c:207
 netlink_dump+0x570/0xc50 net/netlink/af_netlink.c:2269
 __netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2374
 netlink_dump_start include/linux/netlink.h:329 [inline]
 netlink_diag_handler_dump+0x1ae/0x250 net/netlink/diag.c:238
 __sock_diag_cmd net/core/sock_diag.c:238 [inline]
 sock_diag_rcv_msg+0x31e/0x440 net/core/sock_diag.c:269
 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2547
 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280
 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
 netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365
 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1914
 sock_sendmsg_nosec net/socket.c:724 [inline]
 sock_sendmsg+0xde/0x190 net/socket.c:747
 ____sys_sendmsg+0x71c/0x900 net/socket.c:2503
 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2557
 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2586
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f5303aaabb9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc7506e548 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5303aaabb9
RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 00007f5303a6ed60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5303a6edf0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Fixes: 8d61f926d420 ("netlink: fix potential deadlock in netlink_set_err()")
Reported-by: syzbot+5da61cf6a9bc1902d422@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=5da61cf6a9bc1902d422
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230626164313.52528-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netlink: fix potential deadlock in netlink_set_err() 2023-08-11T09:33:35+00:00 Eric Dumazet edumazet@google.com 2023-06-21T15:43:37+00:00 c09e8e3f7fd432984bf5422302b093d2371dfc48 [ Upstream commit 8d61f926d42045961e6b65191c09e3678d86a9cf ] syzbot reported a possible deadlock in netlink_set_err() [1] A similar issue was fixed in commit 1d482e666b8e ("netlink: disable IRQs for netlink_lock_table()") in netlink_lock_table() This patch adds IRQ safety to netlink_set_err() and __netlink_diag_dump() which were not covered by cited commit. [1] WARNING: possible irq lock inversion dependency detected 6.4.0-rc6-syzkaller-00240-g4e9f0ec38852 #0 Not tainted syz-executor.2/23011 just changed the state of lock: ffffffff8e1a7a58 (nl_table_lock){.+.?}-{2:2}, at: netlink_set_err+0x2e/0x3a0 net/netlink/af_netlink.c:1612 but this lock was taken by another, SOFTIRQ-safe lock in the past: (&local->queue_stop_reason_lock){..-.}-{2:2} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(nl_table_lock); local_irq_disable(); lock(&local->queue_stop_reason_lock); lock(nl_table_lock); <Interrupt> lock(&local->queue_stop_reason_lock); *** DEADLOCK *** Fixes: 1d482e666b8e ("netlink: disable IRQs for netlink_lock_table()") Reported-by: syzbot+a7d200a347f912723e5c@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=a7d200a347f912723e5c Link: https://lore.kernel.org/netdev/000000000000e38d1605fea5747e@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Johannes Berg <johannes.berg@intel.com> Link: https://lore.kernel.org/r/20230621154337.1668594-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8d61f926d42045961e6b65191c09e3678d86a9cf ]

syzbot reported a possible deadlock in netlink_set_err() [1]

A similar issue was fixed in commit 1d482e666b8e ("netlink: disable IRQs
for netlink_lock_table()") in netlink_lock_table()

This patch adds IRQ safety to netlink_set_err() and __netlink_diag_dump()
which were not covered by cited commit.

[1]

WARNING: possible irq lock inversion dependency detected
6.4.0-rc6-syzkaller-00240-g4e9f0ec38852 #0 Not tainted

syz-executor.2/23011 just changed the state of lock:
ffffffff8e1a7a58 (nl_table_lock){.+.?}-{2:2}, at: netlink_set_err+0x2e/0x3a0 net/netlink/af_netlink.c:1612
but this lock was taken by another, SOFTIRQ-safe lock in the past:
 (&local->queue_stop_reason_lock){..-.}-{2:2}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(nl_table_lock);
                               local_irq_disable();
                               lock(&local->queue_stop_reason_lock);
                               lock(nl_table_lock);
  <Interrupt>
    lock(&local->queue_stop_reason_lock);

 *** DEADLOCK ***

Fixes: 1d482e666b8e ("netlink: disable IRQs for netlink_lock_table()")
Reported-by: syzbot+a7d200a347f912723e5c@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=a7d200a347f912723e5c
Link: https://lore.kernel.org/netdev/000000000000e38d1605fea5747e@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20230621154337.1668594-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netlink: annotate accesses to nlk->cb_running 2023-05-30T11:38:34+00:00 Eric Dumazet edumazet@google.com 2023-05-09T16:56:34+00:00 e25e9d8a210ed78bdf0f364576dbee13aefadbf8 [ Upstream commit a939d14919b799e6fff8a9c80296ca229ba2f8a4 ] Both netlink_recvmsg() and netlink_native_seq_show() read nlk->cb_running locklessly. Use READ_ONCE() there. Add corresponding WRITE_ONCE() to netlink_dump() and __netlink_dump_start() syzbot reported: BUG: KCSAN: data-race in __netlink_dump_start / netlink_recvmsg write to 0xffff88813ea4db59 of 1 bytes by task 28219 on cpu 0: __netlink_dump_start+0x3af/0x4d0 net/netlink/af_netlink.c:2399 netlink_dump_start include/linux/netlink.h:308 [inline] rtnetlink_rcv_msg+0x70f/0x8c0 net/core/rtnetlink.c:6130 netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2577 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6192 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x56f/0x640 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x665/0x770 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg net/socket.c:747 [inline] sock_write_iter+0x1aa/0x230 net/socket.c:1138 call_write_iter include/linux/fs.h:1851 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x463/0x760 fs/read_write.c:584 ksys_write+0xeb/0x1a0 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x42/0x50 fs/read_write.c:646 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffff88813ea4db59 of 1 bytes by task 28222 on cpu 1: netlink_recvmsg+0x3b4/0x730 net/netlink/af_netlink.c:2022 sock_recvmsg_nosec+0x4c/0x80 net/socket.c:1017 ____sys_recvmsg+0x2db/0x310 net/socket.c:2718 ___sys_recvmsg net/socket.c:2762 [inline] do_recvmmsg+0x2e5/0x710 net/socket.c:2856 __sys_recvmmsg net/socket.c:2935 [inline] __do_sys_recvmmsg net/socket.c:2958 [inline] __se_sys_recvmmsg net/socket.c:2951 [inline] __x64_sys_recvmmsg+0xe2/0x160 net/socket.c:2951 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x00 -> 0x01 Fixes: 16b304f3404f ("netlink: Eliminate kmalloc in netlink dump operation.") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit a939d14919b799e6fff8a9c80296ca229ba2f8a4 ]

Both netlink_recvmsg() and netlink_native_seq_show() read
nlk->cb_running locklessly. Use READ_ONCE() there.

Add corresponding WRITE_ONCE() to netlink_dump() and
__netlink_dump_start()

syzbot reported:
BUG: KCSAN: data-race in __netlink_dump_start / netlink_recvmsg

write to 0xffff88813ea4db59 of 1 bytes by task 28219 on cpu 0:
__netlink_dump_start+0x3af/0x4d0 net/netlink/af_netlink.c:2399
netlink_dump_start include/linux/netlink.h:308 [inline]
rtnetlink_rcv_msg+0x70f/0x8c0 net/core/rtnetlink.c:6130
netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2577
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6192
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x56f/0x640 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x665/0x770 net/netlink/af_netlink.c:1942
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
sock_write_iter+0x1aa/0x230 net/socket.c:1138
call_write_iter include/linux/fs.h:1851 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x463/0x760 fs/read_write.c:584
ksys_write+0xeb/0x1a0 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__x64_sys_write+0x42/0x50 fs/read_write.c:646
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88813ea4db59 of 1 bytes by task 28222 on cpu 1:
netlink_recvmsg+0x3b4/0x730 net/netlink/af_netlink.c:2022
sock_recvmsg_nosec+0x4c/0x80 net/socket.c:1017
____sys_recvmsg+0x2db/0x310 net/socket.c:2718
___sys_recvmsg net/socket.c:2762 [inline]
do_recvmmsg+0x2e5/0x710 net/socket.c:2856
__sys_recvmmsg net/socket.c:2935 [inline]
__do_sys_recvmmsg net/socket.c:2958 [inline]
__se_sys_recvmmsg net/socket.c:2951 [inline]
__x64_sys_recvmmsg+0xe2/0x160 net/socket.c:2951
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00 -> 0x01

Fixes: 16b304f3404f ("netlink: Eliminate kmalloc in netlink dump operation.")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netlink: annotate data races around sk_state 2023-02-06T06:46:31+00:00 Eric Dumazet edumazet@google.com 2023-01-20T12:59:55+00:00 16e651dd1347aba05e7de499256efbcd923155ce [ Upstream commit 9b663b5cbb15b494ef132a3c937641c90646eb73 ] netlink_getsockbyportid() reads sk_state while a concurrent netlink_connect() can change its value. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 9b663b5cbb15b494ef132a3c937641c90646eb73 ]

netlink_getsockbyportid() reads sk_state while a concurrent
netlink_connect() can change its value.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netlink: annotate data races around dst_portid and dst_group 2023-02-06T06:46:31+00:00 Eric Dumazet edumazet@google.com 2023-01-20T12:59:54+00:00 be5850e7ba9962c71e5ce79229ce9f821f87977b [ Upstream commit 004db64d185a5f23dfb891d7701e23713b2420ee ] netlink_getname(), netlink_sendmsg() and netlink_getsockbyportid() can read nlk->dst_portid and nlk->dst_group while another thread is changing them. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 004db64d185a5f23dfb891d7701e23713b2420ee ]

netlink_getname(), netlink_sendmsg() and netlink_getsockbyportid()
can read nlk->dst_portid and nlk->dst_group while another
thread is changing them.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netlink: do not reset transport header in netlink_recvmsg() 2022-05-18T07:18:05+00:00 Eric Dumazet edumazet@google.com 2022-05-05T16:19:46+00:00 98a29c31dfb4e69e81cdeba431b215925728f84a [ Upstream commit d5076fe4049cadef1f040eda4aaa001bb5424225 ] netlink_recvmsg() does not need to change transport header. If transport header was needed, it should have been reset by the producer (netlink_dump()), not the consumer(s). The following trace probably happened when multiple threads were using MSG_PEEK. BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg write to 0xffff88811e9f15b2 of 2 bytes by task 32012 on cpu 1: skb_reset_transport_header include/linux/skbuff.h:2760 [inline] netlink_recvmsg+0x1de/0x790 net/netlink/af_netlink.c:1978 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] __sys_recvfrom+0x204/0x2c0 net/socket.c:2097 __do_sys_recvfrom net/socket.c:2115 [inline] __se_sys_recvfrom net/socket.c:2111 [inline] __x64_sys_recvfrom+0x74/0x90 net/socket.c:2111 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae write to 0xffff88811e9f15b2 of 2 bytes by task 32005 on cpu 0: skb_reset_transport_header include/linux/skbuff.h:2760 [inline] netlink_recvmsg+0x1de/0x790 net/netlink/af_netlink.c:1978 ____sys_recvmsg+0x162/0x2f0 ___sys_recvmsg net/socket.c:2674 [inline] __sys_recvmsg+0x209/0x3f0 net/socket.c:2704 __do_sys_recvmsg net/socket.c:2714 [inline] __se_sys_recvmsg net/socket.c:2711 [inline] __x64_sys_recvmsg+0x42/0x50 net/socket.c:2711 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0xffff -> 0x0000 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 32005 Comm: syz-executor.4 Not tainted 5.18.0-rc1-syzkaller-00328-ge1f700ebd6be-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Link: https://lore.kernel.org/r/20220505161946.2867638-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d5076fe4049cadef1f040eda4aaa001bb5424225 ]

netlink_recvmsg() does not need to change transport header.

If transport header was needed, it should have been reset
by the producer (netlink_dump()), not the consumer(s).

The following trace probably happened when multiple threads
were using MSG_PEEK.

BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg

write to 0xffff88811e9f15b2 of 2 bytes by task 32012 on cpu 1:
 skb_reset_transport_header include/linux/skbuff.h:2760 [inline]
 netlink_recvmsg+0x1de/0x790 net/netlink/af_netlink.c:1978
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 __sys_recvfrom+0x204/0x2c0 net/socket.c:2097
 __do_sys_recvfrom net/socket.c:2115 [inline]
 __se_sys_recvfrom net/socket.c:2111 [inline]
 __x64_sys_recvfrom+0x74/0x90 net/socket.c:2111
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff88811e9f15b2 of 2 bytes by task 32005 on cpu 0:
 skb_reset_transport_header include/linux/skbuff.h:2760 [inline]
 netlink_recvmsg+0x1de/0x790 net/netlink/af_netlink.c:1978
 ____sys_recvmsg+0x162/0x2f0
 ___sys_recvmsg net/socket.c:2674 [inline]
 __sys_recvmsg+0x209/0x3f0 net/socket.c:2704
 __do_sys_recvmsg net/socket.c:2714 [inline]
 __se_sys_recvmsg net/socket.c:2711 [inline]
 __x64_sys_recvmsg+0x42/0x50 net/socket.c:2711
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff -> 0x0000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 32005 Comm: syz-executor.4 Not tainted 5.18.0-rc1-syzkaller-00328-ge1f700ebd6be-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20220505161946.2867638-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netlink: reset network and mac headers in netlink_dump() 2022-04-27T11:15:29+00:00 Eric Dumazet edumazet@google.com 2022-04-15T18:14:42+00:00 57ba9f22de693034c5a78e0733854a823429291f [ Upstream commit 99c07327ae11e24886d552dddbe4537bfca2765d ] netlink_dump() is allocating an skb, reserves space in it but forgets to reset network header. This allows a BPF program, invoked later from sk_filter() to access uninitialized kernel memory from the reserved space. Theorically mac header reset could be omitted, because it is set to a special initial value. bpf_internal_load_pointer_neg_helper calls skb_mac_header() without checking skb_mac_header_was_set(). Relying on skb->len not being too big seems fragile. We also could add a sanity check in bpf_internal_load_pointer_neg_helper() to avoid surprises in the future. syzbot report was: BUG: KMSAN: uninit-value in ___bpf_prog_run+0xa22b/0xb420 kernel/bpf/core.c:1637 ___bpf_prog_run+0xa22b/0xb420 kernel/bpf/core.c:1637 __bpf_prog_run32+0x121/0x180 kernel/bpf/core.c:1796 bpf_dispatcher_nop_func include/linux/bpf.h:784 [inline] __bpf_prog_run include/linux/filter.h:626 [inline] bpf_prog_run include/linux/filter.h:633 [inline] __bpf_prog_run_save_cb+0x168/0x580 include/linux/filter.h:756 bpf_prog_run_save_cb include/linux/filter.h:770 [inline] sk_filter_trim_cap+0x3bc/0x8c0 net/core/filter.c:150 sk_filter include/linux/filter.h:905 [inline] netlink_dump+0xe0c/0x16c0 net/netlink/af_netlink.c:2276 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] sock_read_iter+0x5a9/0x630 net/socket.c:1039 do_iter_readv_writev+0xa7f/0xc70 do_iter_read+0x52c/0x14c0 fs/read_write.c:786 vfs_readv fs/read_write.c:906 [inline] do_readv+0x432/0x800 fs/read_write.c:943 __do_sys_readv fs/read_write.c:1034 [inline] __se_sys_readv fs/read_write.c:1031 [inline] __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x44/0xae Uninit was stored to memory at: ___bpf_prog_run+0x96c/0xb420 kernel/bpf/core.c:1558 __bpf_prog_run32+0x121/0x180 kernel/bpf/core.c:1796 bpf_dispatcher_nop_func include/linux/bpf.h:784 [inline] __bpf_prog_run include/linux/filter.h:626 [inline] bpf_prog_run include/linux/filter.h:633 [inline] __bpf_prog_run_save_cb+0x168/0x580 include/linux/filter.h:756 bpf_prog_run_save_cb include/linux/filter.h:770 [inline] sk_filter_trim_cap+0x3bc/0x8c0 net/core/filter.c:150 sk_filter include/linux/filter.h:905 [inline] netlink_dump+0xe0c/0x16c0 net/netlink/af_netlink.c:2276 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] sock_read_iter+0x5a9/0x630 net/socket.c:1039 do_iter_readv_writev+0xa7f/0xc70 do_iter_read+0x52c/0x14c0 fs/read_write.c:786 vfs_readv fs/read_write.c:906 [inline] do_readv+0x432/0x800 fs/read_write.c:943 __do_sys_readv fs/read_write.c:1034 [inline] __se_sys_readv fs/read_write.c:1031 [inline] __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x44/0xae Uninit was created at: slab_post_alloc_hook mm/slab.h:737 [inline] slab_alloc_node mm/slub.c:3244 [inline] __kmalloc_node_track_caller+0xde3/0x14f0 mm/slub.c:4972 kmalloc_reserve net/core/skbuff.c:354 [inline] __alloc_skb+0x545/0xf90 net/core/skbuff.c:426 alloc_skb include/linux/skbuff.h:1158 [inline] netlink_dump+0x30f/0x16c0 net/netlink/af_netlink.c:2242 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] sock_read_iter+0x5a9/0x630 net/socket.c:1039 do_iter_readv_writev+0xa7f/0xc70 do_iter_read+0x52c/0x14c0 fs/read_write.c:786 vfs_readv fs/read_write.c:906 [inline] do_readv+0x432/0x800 fs/read_write.c:943 __do_sys_readv fs/read_write.c:1034 [inline] __se_sys_readv fs/read_write.c:1031 [inline] __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x44/0xae CPU: 0 PID: 3470 Comm: syz-executor751 Not tainted 5.17.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: db65a3aaf29e ("netlink: Trim skb to alloc size to avoid MSG_TRUNC") Fixes: 9063e21fb026 ("netlink: autosize skb lengthes") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Link: https://lore.kernel.org/r/20220415181442.551228-1-eric.dumazet@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 99c07327ae11e24886d552dddbe4537bfca2765d ]

netlink_dump() is allocating an skb, reserves space in it
but forgets to reset network header.

This allows a BPF program, invoked later from sk_filter()
to access uninitialized kernel memory from the reserved
space.

Theorically mac header reset could be omitted, because
it is set to a special initial value.
bpf_internal_load_pointer_neg_helper calls skb_mac_header()
without checking skb_mac_header_was_set().
Relying on skb->len not being too big seems fragile.
We also could add a sanity check in bpf_internal_load_pointer_neg_helper()
to avoid surprises in the future.

syzbot report was:

BUG: KMSAN: uninit-value in ___bpf_prog_run+0xa22b/0xb420 kernel/bpf/core.c:1637
 ___bpf_prog_run+0xa22b/0xb420 kernel/bpf/core.c:1637
 __bpf_prog_run32+0x121/0x180 kernel/bpf/core.c:1796
 bpf_dispatcher_nop_func include/linux/bpf.h:784 [inline]
 __bpf_prog_run include/linux/filter.h:626 [inline]
 bpf_prog_run include/linux/filter.h:633 [inline]
 __bpf_prog_run_save_cb+0x168/0x580 include/linux/filter.h:756
 bpf_prog_run_save_cb include/linux/filter.h:770 [inline]
 sk_filter_trim_cap+0x3bc/0x8c0 net/core/filter.c:150
 sk_filter include/linux/filter.h:905 [inline]
 netlink_dump+0xe0c/0x16c0 net/netlink/af_netlink.c:2276
 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_read_iter+0x5a9/0x630 net/socket.c:1039
 do_iter_readv_writev+0xa7f/0xc70
 do_iter_read+0x52c/0x14c0 fs/read_write.c:786
 vfs_readv fs/read_write.c:906 [inline]
 do_readv+0x432/0x800 fs/read_write.c:943
 __do_sys_readv fs/read_write.c:1034 [inline]
 __se_sys_readv fs/read_write.c:1031 [inline]
 __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was stored to memory at:
 ___bpf_prog_run+0x96c/0xb420 kernel/bpf/core.c:1558
 __bpf_prog_run32+0x121/0x180 kernel/bpf/core.c:1796
 bpf_dispatcher_nop_func include/linux/bpf.h:784 [inline]
 __bpf_prog_run include/linux/filter.h:626 [inline]
 bpf_prog_run include/linux/filter.h:633 [inline]
 __bpf_prog_run_save_cb+0x168/0x580 include/linux/filter.h:756
 bpf_prog_run_save_cb include/linux/filter.h:770 [inline]
 sk_filter_trim_cap+0x3bc/0x8c0 net/core/filter.c:150
 sk_filter include/linux/filter.h:905 [inline]
 netlink_dump+0xe0c/0x16c0 net/netlink/af_netlink.c:2276
 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_read_iter+0x5a9/0x630 net/socket.c:1039
 do_iter_readv_writev+0xa7f/0xc70
 do_iter_read+0x52c/0x14c0 fs/read_write.c:786
 vfs_readv fs/read_write.c:906 [inline]
 do_readv+0x432/0x800 fs/read_write.c:943
 __do_sys_readv fs/read_write.c:1034 [inline]
 __se_sys_readv fs/read_write.c:1031 [inline]
 __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:737 [inline]
 slab_alloc_node mm/slub.c:3244 [inline]
 __kmalloc_node_track_caller+0xde3/0x14f0 mm/slub.c:4972
 kmalloc_reserve net/core/skbuff.c:354 [inline]
 __alloc_skb+0x545/0xf90 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1158 [inline]
 netlink_dump+0x30f/0x16c0 net/netlink/af_netlink.c:2242
 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_read_iter+0x5a9/0x630 net/socket.c:1039
 do_iter_readv_writev+0xa7f/0xc70
 do_iter_read+0x52c/0x14c0 fs/read_write.c:786
 vfs_readv fs/read_write.c:906 [inline]
 do_readv+0x432/0x800 fs/read_write.c:943
 __do_sys_readv fs/read_write.c:1034 [inline]
 __se_sys_readv fs/read_write.c:1031 [inline]
 __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x44/0xae

CPU: 0 PID: 3470 Comm: syz-executor751 Not tainted 5.17.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: db65a3aaf29e ("netlink: Trim skb to alloc size to avoid MSG_TRUNC")
Fixes: 9063e21fb026 ("netlink: autosize skb lengthes")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20220415181442.551228-1-eric.dumazet@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
af_netlink: Fix shift out of bounds in group mask calculation 2022-04-20T07:08:18+00:00 Petr Machata petrm@nvidia.com 2022-03-17T14:53:06+00:00 ac5883a8890a11c00b32a19949a25d4afeaa2f5a [ Upstream commit 0caf6d9922192dd1afa8dc2131abfb4df1443b9f ] When a netlink message is received, netlink_recvmsg() fills in the address of the sender. One of the fields is the 32-bit bitfield nl_groups, which carries the multicast group on which the message was received. The least significant bit corresponds to group 1, and therefore the highest group that the field can represent is 32. Above that, the UB sanitizer flags the out-of-bounds shift attempts. Which bits end up being set in such case is implementation defined, but it's either going to be a wrong non-zero value, or zero, which is at least not misleading. Make the latter choice deterministic by always setting to 0 for higher-numbered multicast groups. To get information about membership in groups >= 32, userspace is expected to use nl_pktinfo control messages[0], which are enabled by NETLINK_PKTINFO socket option. [0] https://lwn.net/Articles/147608/ The way to trigger this issue is e.g. through monitoring the BRVLAN group: # bridge monitor vlan & # ip link add name br type bridge Which produces the following citation: UBSAN: shift-out-of-bounds in net/netlink/af_netlink.c:162:19 shift exponent 32 is too large for 32-bit type 'int' Fixes: f7fa9b10edbb ("[NETLINK]: Support dynamic number of multicast groups per netlink family") Signed-off-by: Petr Machata <petrm@nvidia.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://lore.kernel.org/r/2bef6aabf201d1fc16cca139a744700cff9dcb04.1647527635.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 0caf6d9922192dd1afa8dc2131abfb4df1443b9f ]

When a netlink message is received, netlink_recvmsg() fills in the address
of the sender. One of the fields is the 32-bit bitfield nl_groups, which
carries the multicast group on which the message was received. The least
significant bit corresponds to group 1, and therefore the highest group
that the field can represent is 32. Above that, the UB sanitizer flags the
out-of-bounds shift attempts.

Which bits end up being set in such case is implementation defined, but
it's either going to be a wrong non-zero value, or zero, which is at least
not misleading. Make the latter choice deterministic by always setting to 0
for higher-numbered multicast groups.

To get information about membership in groups >= 32, userspace is expected
to use nl_pktinfo control messages[0], which are enabled by NETLINK_PKTINFO
socket option.
[0] https://lwn.net/Articles/147608/

The way to trigger this issue is e.g. through monitoring the BRVLAN group:

	# bridge monitor vlan &
	# ip link add name br type bridge

Which produces the following citation:

	UBSAN: shift-out-of-bounds in net/netlink/af_netlink.c:162:19
	shift exponent 32 is too large for 32-bit type 'int'

Fixes: f7fa9b10edbb ("[NETLINK]: Support dynamic number of multicast groups per netlink family")
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/2bef6aabf201d1fc16cca139a744700cff9dcb04.1647527635.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net: netlink: af_netlink: Prevent empty skb by adding a check on len. 2021-12-22T08:17:58+00:00 Harshit Mogalapalli harshit.m.mogalapalli@oracle.com 2021-11-29T17:53:27+00:00 54e785f7d5c197bc06dbb8053700df7e2a093ced [ Upstream commit f123cffdd8fe8ea6c7fded4b88516a42798797d0 ] Adding a check on len parameter to avoid empty skb. This prevents a division error in netem_enqueue function which is caused when skb->len=0 and skb->data_len=0 in the randomized corruption step as shown below. skb->data[prandom_u32() % skb_headlen(skb)] ^= 1<<(prandom_u32() % 8); Crash Report: [ 343.170349] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0 [ 343.216110] netem: version 1.3 [ 343.235841] divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI [ 343.236680] CPU: 3 PID: 4288 Comm: reproducer Not tainted 5.16.0-rc1+ [ 343.237569] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 [ 343.238707] RIP: 0010:netem_enqueue+0x1590/0x33c0 [sch_netem] [ 343.239499] Code: 89 85 58 ff ff ff e8 5f 5d e9 d3 48 8b b5 48 ff ff ff 8b 8d 50 ff ff ff 8b 85 58 ff ff ff 48 8b bd 70 ff ff ff 31 d2 2b 4f 74 <f7> f1 48 b8 00 00 00 00 00 fc ff df 49 01 d5 4c 89 e9 48 c1 e9 03 [ 343.241883] RSP: 0018:ffff88800bcd7368 EFLAGS: 00010246 [ 343.242589] RAX: 00000000ba7c0a9c RBX: 0000000000000001 RCX: 0000000000000000 [ 343.243542] RDX: 0000000000000000 RSI: ffff88800f8edb10 RDI: ffff88800f8eda40 [ 343.244474] RBP: ffff88800bcd7458 R08: 0000000000000000 R09: ffffffff94fb8445 [ 343.245403] R10: ffffffff94fb8336 R11: ffffffff94fb8445 R12: 0000000000000000 [ 343.246355] R13: ffff88800a5a7000 R14: ffff88800a5b5800 R15: 0000000000000020 [ 343.247291] FS: 00007fdde2bd7700(0000) GS:ffff888109780000(0000) knlGS:0000000000000000 [ 343.248350] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 343.249120] CR2: 00000000200000c0 CR3: 000000000ef4c000 CR4: 00000000000006e0 [ 343.250076] Call Trace: [ 343.250423] <TASK> [ 343.250713] ? memcpy+0x4d/0x60 [ 343.251162] ? netem_init+0xa0/0xa0 [sch_netem] [ 343.251795] ? __sanitizer_cov_trace_pc+0x21/0x60 [ 343.252443] netem_enqueue+0xe28/0x33c0 [sch_netem] [ 343.253102] ? stack_trace_save+0x87/0xb0 [ 343.253655] ? filter_irq_stacks+0xb0/0xb0 [ 343.254220] ? netem_init+0xa0/0xa0 [sch_netem] [ 343.254837] ? __kasan_check_write+0x14/0x20 [ 343.255418] ? _raw_spin_lock+0x88/0xd6 [ 343.255953] dev_qdisc_enqueue+0x50/0x180 [ 343.256508] __dev_queue_xmit+0x1a7e/0x3090 [ 343.257083] ? netdev_core_pick_tx+0x300/0x300 [ 343.257690] ? check_kcov_mode+0x10/0x40 [ 343.258219] ? _raw_spin_unlock_irqrestore+0x29/0x40 [ 343.258899] ? __kasan_init_slab_obj+0x24/0x30 [ 343.259529] ? setup_object.isra.71+0x23/0x90 [ 343.260121] ? new_slab+0x26e/0x4b0 [ 343.260609] ? kasan_poison+0x3a/0x50 [ 343.261118] ? kasan_unpoison+0x28/0x50 [ 343.261637] ? __kasan_slab_alloc+0x71/0x90 [ 343.262214] ? memcpy+0x4d/0x60 [ 343.262674] ? write_comp_data+0x2f/0x90 [ 343.263209] ? __kasan_check_write+0x14/0x20 [ 343.263802] ? __skb_clone+0x5d6/0x840 [ 343.264329] ? __sanitizer_cov_trace_pc+0x21/0x60 [ 343.264958] dev_queue_xmit+0x1c/0x20 [ 343.265470] netlink_deliver_tap+0x652/0x9c0 [ 343.266067] netlink_unicast+0x5a0/0x7f0 [ 343.266608] ? netlink_attachskb+0x860/0x860 [ 343.267183] ? __sanitizer_cov_trace_pc+0x21/0x60 [ 343.267820] ? write_comp_data+0x2f/0x90 [ 343.268367] netlink_sendmsg+0x922/0xe80 [ 343.268899] ? netlink_unicast+0x7f0/0x7f0 [ 343.269472] ? __sanitizer_cov_trace_pc+0x21/0x60 [ 343.270099] ? write_comp_data+0x2f/0x90 [ 343.270644] ? netlink_unicast+0x7f0/0x7f0 [ 343.271210] sock_sendmsg+0x155/0x190 [ 343.271721] ____sys_sendmsg+0x75f/0x8f0 [ 343.272262] ? kernel_sendmsg+0x60/0x60 [ 343.272788] ? write_comp_data+0x2f/0x90 [ 343.273332] ? write_comp_data+0x2f/0x90 [ 343.273869] ___sys_sendmsg+0x10f/0x190 [ 343.274405] ? sendmsg_copy_msghdr+0x80/0x80 [ 343.274984] ? slab_post_alloc_hook+0x70/0x230 [ 343.275597] ? futex_wait_setup+0x240/0x240 [ 343.276175] ? security_file_alloc+0x3e/0x170 [ 343.276779] ? write_comp_data+0x2f/0x90 [ 343.277313] ? __sanitizer_cov_trace_pc+0x21/0x60 [ 343.277969] ? write_comp_data+0x2f/0x90 [ 343.278515] ? __fget_files+0x1ad/0x260 [ 343.279048] ? __sanitizer_cov_trace_pc+0x21/0x60 [ 343.279685] ? write_comp_data+0x2f/0x90 [ 343.280234] ? __sanitizer_cov_trace_pc+0x21/0x60 [ 343.280874] ? sockfd_lookup_light+0xd1/0x190 [ 343.281481] __sys_sendmsg+0x118/0x200 [ 343.281998] ? __sys_sendmsg_sock+0x40/0x40 [ 343.282578] ? alloc_fd+0x229/0x5e0 [ 343.283070] ? write_comp_data+0x2f/0x90 [ 343.283610] ? write_comp_data+0x2f/0x90 [ 343.284135] ? __sanitizer_cov_trace_pc+0x21/0x60 [ 343.284776] ? ktime_get_coarse_real_ts64+0xb8/0xf0 [ 343.285450] __x64_sys_sendmsg+0x7d/0xc0 [ 343.285981] ? syscall_enter_from_user_mode+0x4d/0x70 [ 343.286664] do_syscall_64+0x3a/0x80 [ 343.287158] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 343.287850] RIP: 0033:0x7fdde24cf289 [ 343.288344] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 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 73 01 c3 48 8b 0d b7 db 2c 00 f7 d8 64 89 01 48 [ 343.290729] RSP: 002b:00007fdde2bd6d98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 343.291730] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdde24cf289 [ 343.292673] RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000004 [ 343.293618] RBP: 00007fdde2bd6e20 R08: 0000000100000001 R09: 0000000000000000 [ 343.294557] R10: 0000000100000001 R11: 0000000000000246 R12: 0000000000000000 [ 343.295493] R13: 0000000000021000 R14: 0000000000000000 R15: 00007fdde2bd7700 [ 343.296432] </TASK> [ 343.296735] Modules linked in: sch_netem ip6_vti ip_vti ip_gre ipip sit ip_tunnel geneve macsec macvtap tap ipvlan macvlan 8021q garp mrp hsr wireguard libchacha20poly1305 chacha_x86_64 poly1305_x86_64 ip6_udp_tunnel udp_tunnel libblake2s blake2s_x86_64 libblake2s_generic curve25519_x86_64 libcurve25519_generic libchacha xfrm_interface xfrm6_tunnel tunnel4 veth netdevsim psample batman_adv nlmon dummy team bonding tls vcan ip6_gre ip6_tunnel tunnel6 gre tun ip6t_rpfilter ipt_REJECT nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_security ip6table_raw iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_security iptable_raw ebtable_filter ebtables rfkill ip6table_filter ip6_tables iptable_filter ppdev bochs drm_vram_helper drm_ttm_helper ttm drm_kms_helper cec parport_pc drm joydev floppy parport sg syscopyarea sysfillrect sysimgblt i2c_piix4 qemu_fw_cfg fb_sys_fops pcspkr [ 343.297459] ip_tables xfs virtio_net net_failover failover sd_mod sr_mod cdrom t10_pi ata_generic pata_acpi ata_piix libata virtio_pci virtio_pci_legacy_dev serio_raw virtio_pci_modern_dev dm_mirror dm_region_hash dm_log dm_mod [ 343.311074] Dumping ftrace buffer: [ 343.311532] (ftrace buffer empty) [ 343.312040] ---[ end trace a2e3db5a6ae05099 ]--- [ 343.312691] RIP: 0010:netem_enqueue+0x1590/0x33c0 [sch_netem] [ 343.313481] Code: 89 85 58 ff ff ff e8 5f 5d e9 d3 48 8b b5 48 ff ff ff 8b 8d 50 ff ff ff 8b 85 58 ff ff ff 48 8b bd 70 ff ff ff 31 d2 2b 4f 74 <f7> f1 48 b8 00 00 00 00 00 fc ff df 49 01 d5 4c 89 e9 48 c1 e9 03 [ 343.315893] RSP: 0018:ffff88800bcd7368 EFLAGS: 00010246 [ 343.316622] RAX: 00000000ba7c0a9c RBX: 0000000000000001 RCX: 0000000000000000 [ 343.317585] RDX: 0000000000000000 RSI: ffff88800f8edb10 RDI: ffff88800f8eda40 [ 343.318549] RBP: ffff88800bcd7458 R08: 0000000000000000 R09: ffffffff94fb8445 [ 343.319503] R10: ffffffff94fb8336 R11: ffffffff94fb8445 R12: 0000000000000000 [ 343.320455] R13: ffff88800a5a7000 R14: ffff88800a5b5800 R15: 0000000000000020 [ 343.321414] FS: 00007fdde2bd7700(0000) GS:ffff888109780000(0000) knlGS:0000000000000000 [ 343.322489] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 343.323283] CR2: 00000000200000c0 CR3: 000000000ef4c000 CR4: 00000000000006e0 [ 343.324264] Kernel panic - not syncing: Fatal exception in interrupt [ 343.333717] Dumping ftrace buffer: [ 343.334175] (ftrace buffer empty) [ 343.334653] Kernel Offset: 0x13600000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 343.336027] Rebooting in 86400 seconds.. Reported-by: syzkaller <syzkaller@googlegroups.com> Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com> Link: https://lore.kernel.org/r/20211129175328.55339-1-harshit.m.mogalapalli@oracle.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f123cffdd8fe8ea6c7fded4b88516a42798797d0 ]

Adding a check on len parameter to avoid empty skb. This prevents a
division error in netem_enqueue function which is caused when skb->len=0
and skb->data_len=0 in the randomized corruption step as shown below.

skb->data[prandom_u32() % skb_headlen(skb)] ^= 1<<(prandom_u32() % 8);

Crash Report:
[  343.170349] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family
0 port 6081 - 0
[  343.216110] netem: version 1.3
[  343.235841] divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
[  343.236680] CPU: 3 PID: 4288 Comm: reproducer Not tainted 5.16.0-rc1+
[  343.237569] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.11.0-2.el7 04/01/2014
[  343.238707] RIP: 0010:netem_enqueue+0x1590/0x33c0 [sch_netem]
[  343.239499] Code: 89 85 58 ff ff ff e8 5f 5d e9 d3 48 8b b5 48 ff ff
ff 8b 8d 50 ff ff ff 8b 85 58 ff ff ff 48 8b bd 70 ff ff ff 31 d2 2b 4f
74 <f7> f1 48 b8 00 00 00 00 00 fc ff df 49 01 d5 4c 89 e9 48 c1 e9 03
[  343.241883] RSP: 0018:ffff88800bcd7368 EFLAGS: 00010246
[  343.242589] RAX: 00000000ba7c0a9c RBX: 0000000000000001 RCX:
0000000000000000
[  343.243542] RDX: 0000000000000000 RSI: ffff88800f8edb10 RDI:
ffff88800f8eda40
[  343.244474] RBP: ffff88800bcd7458 R08: 0000000000000000 R09:
ffffffff94fb8445
[  343.245403] R10: ffffffff94fb8336 R11: ffffffff94fb8445 R12:
0000000000000000
[  343.246355] R13: ffff88800a5a7000 R14: ffff88800a5b5800 R15:
0000000000000020
[  343.247291] FS:  00007fdde2bd7700(0000) GS:ffff888109780000(0000)
knlGS:0000000000000000
[  343.248350] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  343.249120] CR2: 00000000200000c0 CR3: 000000000ef4c000 CR4:
00000000000006e0
[  343.250076] Call Trace:
[  343.250423]  <TASK>
[  343.250713]  ? memcpy+0x4d/0x60
[  343.251162]  ? netem_init+0xa0/0xa0 [sch_netem]
[  343.251795]  ? __sanitizer_cov_trace_pc+0x21/0x60
[  343.252443]  netem_enqueue+0xe28/0x33c0 [sch_netem]
[  343.253102]  ? stack_trace_save+0x87/0xb0
[  343.253655]  ? filter_irq_stacks+0xb0/0xb0
[  343.254220]  ? netem_init+0xa0/0xa0 [sch_netem]
[  343.254837]  ? __kasan_check_write+0x14/0x20
[  343.255418]  ? _raw_spin_lock+0x88/0xd6
[  343.255953]  dev_qdisc_enqueue+0x50/0x180
[  343.256508]  __dev_queue_xmit+0x1a7e/0x3090
[  343.257083]  ? netdev_core_pick_tx+0x300/0x300
[  343.257690]  ? check_kcov_mode+0x10/0x40
[  343.258219]  ? _raw_spin_unlock_irqrestore+0x29/0x40
[  343.258899]  ? __kasan_init_slab_obj+0x24/0x30
[  343.259529]  ? setup_object.isra.71+0x23/0x90
[  343.260121]  ? new_slab+0x26e/0x4b0
[  343.260609]  ? kasan_poison+0x3a/0x50
[  343.261118]  ? kasan_unpoison+0x28/0x50
[  343.261637]  ? __kasan_slab_alloc+0x71/0x90
[  343.262214]  ? memcpy+0x4d/0x60
[  343.262674]  ? write_comp_data+0x2f/0x90
[  343.263209]  ? __kasan_check_write+0x14/0x20
[  343.263802]  ? __skb_clone+0x5d6/0x840
[  343.264329]  ? __sanitizer_cov_trace_pc+0x21/0x60
[  343.264958]  dev_queue_xmit+0x1c/0x20
[  343.265470]  netlink_deliver_tap+0x652/0x9c0
[  343.266067]  netlink_unicast+0x5a0/0x7f0
[  343.266608]  ? netlink_attachskb+0x860/0x860
[  343.267183]  ? __sanitizer_cov_trace_pc+0x21/0x60
[  343.267820]  ? write_comp_data+0x2f/0x90
[  343.268367]  netlink_sendmsg+0x922/0xe80
[  343.268899]  ? netlink_unicast+0x7f0/0x7f0
[  343.269472]  ? __sanitizer_cov_trace_pc+0x21/0x60
[  343.270099]  ? write_comp_data+0x2f/0x90
[  343.270644]  ? netlink_unicast+0x7f0/0x7f0
[  343.271210]  sock_sendmsg+0x155/0x190
[  343.271721]  ____sys_sendmsg+0x75f/0x8f0
[  343.272262]  ? kernel_sendmsg+0x60/0x60
[  343.272788]  ? write_comp_data+0x2f/0x90
[  343.273332]  ? write_comp_data+0x2f/0x90
[  343.273869]  ___sys_sendmsg+0x10f/0x190
[  343.274405]  ? sendmsg_copy_msghdr+0x80/0x80
[  343.274984]  ? slab_post_alloc_hook+0x70/0x230
[  343.275597]  ? futex_wait_setup+0x240/0x240
[  343.276175]  ? security_file_alloc+0x3e/0x170
[  343.276779]  ? write_comp_data+0x2f/0x90
[  343.277313]  ? __sanitizer_cov_trace_pc+0x21/0x60
[  343.277969]  ? write_comp_data+0x2f/0x90
[  343.278515]  ? __fget_files+0x1ad/0x260
[  343.279048]  ? __sanitizer_cov_trace_pc+0x21/0x60
[  343.279685]  ? write_comp_data+0x2f/0x90
[  343.280234]  ? __sanitizer_cov_trace_pc+0x21/0x60
[  343.280874]  ? sockfd_lookup_light+0xd1/0x190
[  343.281481]  __sys_sendmsg+0x118/0x200
[  343.281998]  ? __sys_sendmsg_sock+0x40/0x40
[  343.282578]  ? alloc_fd+0x229/0x5e0
[  343.283070]  ? write_comp_data+0x2f/0x90
[  343.283610]  ? write_comp_data+0x2f/0x90
[  343.284135]  ? __sanitizer_cov_trace_pc+0x21/0x60
[  343.284776]  ? ktime_get_coarse_real_ts64+0xb8/0xf0
[  343.285450]  __x64_sys_sendmsg+0x7d/0xc0
[  343.285981]  ? syscall_enter_from_user_mode+0x4d/0x70
[  343.286664]  do_syscall_64+0x3a/0x80
[  343.287158]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[  343.287850] RIP: 0033:0x7fdde24cf289
[  343.288344] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00
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 73 01 c3 48 8b 0d b7 db 2c 00 f7 d8 64 89 01 48
[  343.290729] RSP: 002b:00007fdde2bd6d98 EFLAGS: 00000246 ORIG_RAX:
000000000000002e
[  343.291730] RAX: ffffffffffffffda RBX: 0000000000000000 RCX:
00007fdde24cf289
[  343.292673] RDX: 0000000000000000 RSI: 00000000200000c0 RDI:
0000000000000004
[  343.293618] RBP: 00007fdde2bd6e20 R08: 0000000100000001 R09:
0000000000000000
[  343.294557] R10: 0000000100000001 R11: 0000000000000246 R12:
0000000000000000
[  343.295493] R13: 0000000000021000 R14: 0000000000000000 R15:
00007fdde2bd7700
[  343.296432]  </TASK>
[  343.296735] Modules linked in: sch_netem ip6_vti ip_vti ip_gre ipip
sit ip_tunnel geneve macsec macvtap tap ipvlan macvlan 8021q garp mrp
hsr wireguard libchacha20poly1305 chacha_x86_64 poly1305_x86_64
ip6_udp_tunnel udp_tunnel libblake2s blake2s_x86_64 libblake2s_generic
curve25519_x86_64 libcurve25519_generic libchacha xfrm_interface
xfrm6_tunnel tunnel4 veth netdevsim psample batman_adv nlmon dummy team
bonding tls vcan ip6_gre ip6_tunnel tunnel6 gre tun ip6t_rpfilter
ipt_REJECT nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set
ebtable_nat ebtable_broute ip6table_nat ip6table_mangle
ip6table_security ip6table_raw iptable_nat nf_nat nf_conntrack
nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_security
iptable_raw ebtable_filter ebtables rfkill ip6table_filter ip6_tables
iptable_filter ppdev bochs drm_vram_helper drm_ttm_helper ttm
drm_kms_helper cec parport_pc drm joydev floppy parport sg syscopyarea
sysfillrect sysimgblt i2c_piix4 qemu_fw_cfg fb_sys_fops pcspkr
[  343.297459]  ip_tables xfs virtio_net net_failover failover sd_mod
sr_mod cdrom t10_pi ata_generic pata_acpi ata_piix libata virtio_pci
virtio_pci_legacy_dev serio_raw virtio_pci_modern_dev dm_mirror
dm_region_hash dm_log dm_mod
[  343.311074] Dumping ftrace buffer:
[  343.311532]    (ftrace buffer empty)
[  343.312040] ---[ end trace a2e3db5a6ae05099 ]---
[  343.312691] RIP: 0010:netem_enqueue+0x1590/0x33c0 [sch_netem]
[  343.313481] Code: 89 85 58 ff ff ff e8 5f 5d e9 d3 48 8b b5 48 ff ff
ff 8b 8d 50 ff ff ff 8b 85 58 ff ff ff 48 8b bd 70 ff ff ff 31 d2 2b 4f
74 <f7> f1 48 b8 00 00 00 00 00 fc ff df 49 01 d5 4c 89 e9 48 c1 e9 03
[  343.315893] RSP: 0018:ffff88800bcd7368 EFLAGS: 00010246
[  343.316622] RAX: 00000000ba7c0a9c RBX: 0000000000000001 RCX:
0000000000000000
[  343.317585] RDX: 0000000000000000 RSI: ffff88800f8edb10 RDI:
ffff88800f8eda40
[  343.318549] RBP: ffff88800bcd7458 R08: 0000000000000000 R09:
ffffffff94fb8445
[  343.319503] R10: ffffffff94fb8336 R11: ffffffff94fb8445 R12:
0000000000000000
[  343.320455] R13: ffff88800a5a7000 R14: ffff88800a5b5800 R15:
0000000000000020
[  343.321414] FS:  00007fdde2bd7700(0000) GS:ffff888109780000(0000)
knlGS:0000000000000000
[  343.322489] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  343.323283] CR2: 00000000200000c0 CR3: 000000000ef4c000 CR4:
00000000000006e0
[  343.324264] Kernel panic - not syncing: Fatal exception in interrupt
[  343.333717] Dumping ftrace buffer:
[  343.334175]    (ftrace buffer empty)
[  343.334653] Kernel Offset: 0x13600000 from 0xffffffff81000000
(relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[  343.336027] Rebooting in 86400 seconds..

Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Link: https://lore.kernel.org/r/20211129175328.55339-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netlink: annotate data races around nlk->bound 2021-10-17T08:08:33+00:00 Eric Dumazet edumazet@google.com 2021-10-04T21:24:15+00:00 cb2047932a9c88ddbf1c8b764e74d0d860f3e359 [ Upstream commit 7707a4d01a648e4c655101a469c956cb11273655 ] While existing code is correct, KCSAN is reporting a data-race in netlink_insert / netlink_sendmsg [1] It is correct to read nlk->bound without a lock, as netlink_autobind() will acquire all needed locks. [1] BUG: KCSAN: data-race in netlink_insert / netlink_sendmsg write to 0xffff8881031c8b30 of 1 bytes by task 18752 on cpu 0: netlink_insert+0x5cc/0x7f0 net/netlink/af_netlink.c:597 netlink_autobind+0xa9/0x150 net/netlink/af_netlink.c:842 netlink_sendmsg+0x479/0x7c0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:703 [inline] sock_sendmsg net/socket.c:723 [inline] ____sys_sendmsg+0x360/0x4d0 net/socket.c:2392 ___sys_sendmsg net/socket.c:2446 [inline] __sys_sendmsg+0x1ed/0x270 net/socket.c:2475 __do_sys_sendmsg net/socket.c:2484 [inline] __se_sys_sendmsg net/socket.c:2482 [inline] __x64_sys_sendmsg+0x42/0x50 net/socket.c:2482 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff8881031c8b30 of 1 bytes by task 18751 on cpu 1: netlink_sendmsg+0x270/0x7c0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:703 [inline] sock_sendmsg net/socket.c:723 [inline] __sys_sendto+0x2a8/0x370 net/socket.c:2019 __do_sys_sendto net/socket.c:2031 [inline] __se_sys_sendto net/socket.c:2027 [inline] __x64_sys_sendto+0x74/0x90 net/socket.c:2027 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x00 -> 0x01 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 18751 Comm: syz-executor.0 Not tainted 5.14.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: da314c9923fe ("netlink: Replace rhash_portid with bound") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7707a4d01a648e4c655101a469c956cb11273655 ]

While existing code is correct, KCSAN is reporting
a data-race in netlink_insert / netlink_sendmsg [1]

It is correct to read nlk->bound without a lock, as netlink_autobind()
will acquire all needed locks.

[1]
BUG: KCSAN: data-race in netlink_insert / netlink_sendmsg

write to 0xffff8881031c8b30 of 1 bytes by task 18752 on cpu 0:
 netlink_insert+0x5cc/0x7f0 net/netlink/af_netlink.c:597
 netlink_autobind+0xa9/0x150 net/netlink/af_netlink.c:842
 netlink_sendmsg+0x479/0x7c0 net/netlink/af_netlink.c:1892
 sock_sendmsg_nosec net/socket.c:703 [inline]
 sock_sendmsg net/socket.c:723 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2392
 ___sys_sendmsg net/socket.c:2446 [inline]
 __sys_sendmsg+0x1ed/0x270 net/socket.c:2475
 __do_sys_sendmsg net/socket.c:2484 [inline]
 __se_sys_sendmsg net/socket.c:2482 [inline]
 __x64_sys_sendmsg+0x42/0x50 net/socket.c:2482
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881031c8b30 of 1 bytes by task 18751 on cpu 1:
 netlink_sendmsg+0x270/0x7c0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:703 [inline]
 sock_sendmsg net/socket.c:723 [inline]
 __sys_sendto+0x2a8/0x370 net/socket.c:2019
 __do_sys_sendto net/socket.c:2031 [inline]
 __se_sys_sendto net/socket.c:2027 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:2027
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18751 Comm: syz-executor.0 Not tainted 5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: da314c9923fe ("netlink: Replace rhash_portid with bound")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>