[syzbot] [bluetooth?] general protection fault in lock_sock_nested

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ae074e2b2fd4 sfc: check for zero length in EF10 RX prefix
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=17d9e78fa80000
kernel config: https://syzkaller.appspot.com/x/.config?x=634e05b4025da9da
dashboard link: https://syzkaller.appspot.com/bug?extid=d3ccfb78a0dc16ffebe3
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13075977a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1012d447a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/36dca89ab8e3/disk-ae074e2b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/935bb2b8e325/vmlinux-ae074e2b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5ab72169cc9/bzImage-ae074e2b.xz

The issue was bisected to:

commit 94d9ba9f9888b748d4abd2aa1547af56ae85f772
Author: Luiz Augusto von Dentz <luiz.vo...@intel.com>
Date: Wed Aug 9 23:49:33 2023 +0000

Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10a8c6bfa80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=12a8c6bfa80000
console output: https://syzkaller.appspot.com/x/log.txt?x=14a8c6bfa80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d3ccfb...@syzkaller.appspotmail.com
Fixes: 94d9ba9f9888 ("Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync")

general protection fault, probably for non-canonical address 0xdffffc0000000026: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000130-0x0000000000000137]
CPU: 0 PID: 918 Comm: kworker/0:2 Not tainted 6.5.0-syzkaller-04011-gae074e2b2fd4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: events l2cap_info_timeout
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5012
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 a1 14 23 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a a0 a9 3e 90 0f 84 96 0d 00
RSP: 0018:ffffc90004c8f8e8 EFLAGS: 00010002
RAX: ffff8880206d8000 RBX: 1ffff92000991f4d RCX: 0000000000000026
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000130
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000130 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0da069df50 CR3: 000000007a80d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5761 [inline]
lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726
lock_sock_nested+0x3a/0xf0 net/core/sock.c:3505
lock_sock include/net/sock.h:1722 [inline]
l2cap_sock_ready_cb+0x41/0x160 net/bluetooth/l2cap_sock.c:1630
l2cap_chan_ready net/bluetooth/l2cap_core.c:1365 [inline]
l2cap_conn_start+0x15c/0xa40 net/bluetooth/l2cap_core.c:1640
process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600
worker_thread+0x687/0x1110 kernel/workqueue.c:2751
kthread+0x33a/0x430 kernel/kthread.c:389
ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__lock_acquire+0x109/0x5de0 kernel/locking/lockdep.c:5012
Code: 45 85 c9 0f 84 cc 0e 00 00 44 8b 05 a1 14 23 0b 45 85 c0 0f 84 be 0d 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 d1 48 c1 e9 03 <80> 3c 11 00 0f 85 e8 40 00 00 49 81 3a a0 a9 3e 90 0f 84 96 0d 00
RSP: 0018:ffffc90004c8f8e8 EFLAGS: 00010002
RAX: ffff8880206d8000 RBX: 1ffff92000991f4d RCX: 0000000000000026
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000130
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000130 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0da069df50 CR3: 000000007a80d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 45 85 c9 test %r9d,%r9d
3: 0f 84 cc 0e 00 00 je 0xed5
9: 44 8b 05 a1 14 23 0b mov 0xb2314a1(%rip),%r8d # 0xb2314b1
10: 45 85 c0 test %r8d,%r8d
13: 0f 84 be 0d 00 00 je 0xdd7
19: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
20: fc ff df
23: 4c 89 d1 mov %r10,%rcx
26: 48 c1 e9 03 shr $0x3,%rcx
* 2a: 80 3c 11 00 cmpb $0x0,(%rcx,%rdx,1) <-- trapping instruction
2e: 0f 85 e8 40 00 00 jne 0x411c
34: 49 81 3a a0 a9 3e 90 cmpq $0xffffffff903ea9a0,(%r10)
3b: 0f .byte 0xf
3c: 84 .byte 0x84
3d: 96 xchg %eax,%esi
3e: 0d .byte 0xd


---
This report 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 issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Hillf Danton]

On Mon, 11 Sep 2023 00:52:56 -0700

> HEAD commit: ae074e2b2fd4 sfc: check for zero length in EF10 RX prefix
> git tree: net

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1012d447a80000

#syz test

--- x/net/bluetooth/l2cap_sock.c
+++ y/net/bluetooth/l2cap_sock.c
@@ -1227,14 +1227,17 @@ done:
*/
static void l2cap_sock_kill(struct sock *sk)
{
+ struct l2cap_chan *chan;
+
if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
return;

BT_DBG("sk %p state %s", sk, state_to_string(sk->sk_state));

+ chan = l2cap_pi(sk)->chan;
+ chan->data = NULL;
+ l2cap_chan_put(chan);
/* Kill poor orphan */
-
- l2cap_chan_put(l2cap_pi(sk)->chan);
sock_set_flag(sk, SOCK_DEAD);
sock_put(sk);
}
@@ -1627,6 +1630,8 @@ static void l2cap_sock_ready_cb(struct l
struct sock *sk = chan->data;
struct sock *parent;

+ if (!sk)
+ return;
lock_sock(sk);

parent = bt_sk(sk)->parent;
--

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+d3ccfb...@syzkaller.appspotmail.com

Tested on:

commit: 5a124b1f net: ethernet: mtk_eth_soc: fix pse_port conf..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=12440ca0680000
kernel config: https://syzkaller.appspot.com/x/.config?x=20110ebc6eac9d0a

dashboard link: https://syzkaller.appspot.com/bug?extid=d3ccfb78a0dc16ffebe3
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=128cdfec680000

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

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 181a42edddf51d5d9697ecdf365d72ebeab5afb0
Author: Ziyang Xuan <william.x...@huawei.com>
Date: Wed Oct 11 09:57:31 2023 +0000

Bluetooth: Make handle of hci_conn be unique

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15f7f6cee80000
start commit: ae074e2b2fd4 sfc: check for zero length in EF10 RX prefix
git tree: net

kernel config: https://syzkaller.appspot.com/x/.config?x=634e05b4025da9da
dashboard link: https://syzkaller.appspot.com/bug?extid=d3ccfb78a0dc16ffebe3

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13075977a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1012d447a80000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: Bluetooth: Make handle of hci_conn be unique