Bluetooth: MGMT: Protect mgmt_pending list with its own lock

Bluetooth: MGMT: Protect mgmt_pending list with its own lock

This uses a mutex to protect from concurrent access of mgmt_pending
list which can cause crashes like:

==================================================================
BUG: KASAN: slab-use-after-free in hci_sock_get_channel+0x60/0x68 net/bluetooth/hci_sock.c:91
Read of size 2 at addr ffff0000c48885b2 by task syz.4.334/7318

CPU: 0 UID: 0 PID: 7318 Comm: syz.4.334 Not tainted 6.15.0-rc7-syzkaller-g187899f4124a #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xa8/0x254 mm/kasan/report.c:408
 print_report+0x68/0x84 mm/kasan/report.c:521
 kasan_report+0xb0/0x110 mm/kasan/report.c:634
 __asan_report_load2_noabort+0x20/0x2c mm/kasan/report_generic.c:379
 hci_sock_get_channel+0x60/0x68 net/bluetooth/hci_sock.c:91
 mgmt_pending_find+0x7c/0x140 net/bluetooth/mgmt_util.c:223
 pending_find net/bluetooth/mgmt.c:947 [inline]
 remove_adv_monitor+0x44/0x1a4 net/bluetooth/mgmt.c:5445
 hci_mgmt_cmd+0x780/0xc00 net/bluetooth/hci_sock.c:1712
 hci_sock_sendmsg+0x544/0xbb0 net/bluetooth/hci_sock.c:1832
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg net/socket.c:727 [inline]
 sock_write_iter+0x25c/0x378 net/socket.c:1131
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x62c/0x97c fs/read_write.c:684
 ksys_write+0x120/0x210 fs/read_write.c:736
 __do_sys_write fs/read_write.c:747 [inline]
 __se_sys_write fs/read_write.c:744 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:744
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

Allocated by task 7037:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x2fc/0x4c8 mm/slub.c:4339
 kmalloc_noprof include/linux/slab.h:909 [inline]
 sk_prot_alloc+0xc4/0x1f0 net/core/sock.c:2198
 sk_alloc+0x44/0x3ac net/core/sock.c:2254
 bt_sock_alloc+0x4c/0x300 net/bluetooth/af_bluetooth.c:148
 hci_sock_create+0xa8/0x194 net/bluetooth/hci_sock.c:2202
 bt_sock_create+0x14c/0x24c net/bluetooth/af_bluetooth.c:132
 __sock_create+0x43c/0x91c net/socket.c:1541
 sock_create net/socket.c:1599 [inline]
 __sys_socket_create net/socket.c:1636 [inline]
 __sys_socket+0xd4/0x1c0 net/socket.c:1683
 __do_sys_socket net/socket.c:1697 [inline]
 __se_sys_socket net/socket.c:1695 [inline]
 __arm64_sys_socket+0x7c/0x94 net/socket.c:1695
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

Freed by task 6607:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x68/0x88 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2380 [inline]
 slab_free mm/slub.c:4642 [inline]
 kfree+0x17c/0x474 mm/slub.c:4841
 sk_prot_free net/core/sock.c:2237 [inline]
 __sk_destruct+0x4f4/0x760 net/core/sock.c:2332
 sk_destruct net/core/sock.c:2360 [inline]
 __sk_free+0x320/0x430 net/core/sock.c:2371
 sk_free+0x60/0xc8 net/core/sock.c:2382
 sock_put include/net/sock.h:1944 [inline]
 mgmt_pending_free+0x88/0x118 net/bluetooth/mgmt_util.c:290
 mgmt_pending_remove+0xec/0x104 net/bluetooth/mgmt_util.c:298
 mgmt_set_powered_complete+0x418/0x5cc net/bluetooth/mgmt.c:1355
 hci_cmd_sync_work+0x204/0x33c net/bluetooth/hci_sync.c:334
 process_one_work+0x7e8/0x156c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3400
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847

Fixes: a380b6cff1a2 ("Bluetooth: Add generic mgmt helper API")
Closes: https://syzkaller.appspot.com/bug?extid=0a7039d5d9986ff4ecec
Closes: https://syzkaller.appspot.com/bug?extid=cc0cc52e7f43dc9e6df1
Reported-by: syzbot+0a7039d5d9986ff4ecec@syzkaller.appspotmail.com
Tested-by: syzbot+0a7039d5d9986ff4ecec@syzkaller.appspotmail.com
Tested-by: syzbot+cc0cc52e7f43dc9e6df1@syzkaller.appspotmail.com
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>