Re: [syzbot] Re: [PATCH v1] Bluetooth: MGMT: Fix slab-use-after-free Read in set_powered_sync

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Subject: Re: [PATCH v1] Bluetooth: MGMT: Fix slab-use-after-free Read in set_powered_sync
Author: luiz.dentz@gmail.com

#syz test

On Fri, Nov 15, 2024 at 10:59 AM Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
>
> This fixes the following crash:
>
> ==================================================================
> BUG: KASAN: slab-use-after-free in set_powered_sync+0x3a/0xc0 net/bluetooth/mgmt.c:1353
> Read of size 8 at addr ffff888029b4dd18 by task kworker/u9:0/54
>
> CPU: 1 UID: 0 PID: 54 Comm: kworker/u9:0 Not tainted 6.11.0-rc6-syzkaller-01155-gf723224742fc #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
> Workqueue: hci0 hci_cmd_sync_work
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:93 [inline]
>  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
>  print_address_description mm/kasan/report.c:377 [inline]
>  print_report+0x169/0x550 mm/kasan/report.c:488
> q kasan_report+0x143/0x180 mm/kasan/report.c:601
>  set_powered_sync+0x3a/0xc0 net/bluetooth/mgmt.c:1353
>  hci_cmd_sync_work+0x22b/0x400 net/bluetooth/hci_sync.c:328
>  process_one_work kernel/workqueue.c:3231 [inline]
>  process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
>  worker_thread+0x86d/0xd10 kernel/workqueue.c:3389
>  kthread+0x2f0/0x390 kernel/kthread.c:389
>  ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>  </TASK>
>
> Allocated by task 5247:
>  kasan_save_stack mm/kasan/common.c:47 [inline]
>  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>  poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
>  __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
>  kasan_kmalloc include/linux/kasan.h:211 [inline]
>  __kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4193
>  kmalloc_noprof include/linux/slab.h:681 [inline]
>  kzalloc_noprof include/linux/slab.h:807 [inline]
>  mgmt_pending_new+0x65/0x250 net/bluetooth/mgmt_util.c:269
>  mgmt_pending_add+0x36/0x120 net/bluetooth/mgmt_util.c:296
>  set_powered+0x3cd/0x5e0 net/bluetooth/mgmt.c:1394
>  hci_mgmt_cmd+0xc47/0x11d0 net/bluetooth/hci_sock.c:1712
>  hci_sock_sendmsg+0x7b8/0x11c0 net/bluetooth/hci_sock.c:1832
>  sock_sendmsg_nosec net/socket.c:730 [inline]
>  __sock_sendmsg+0x221/0x270 net/socket.c:745
>  sock_write_iter+0x2dd/0x400 net/socket.c:1160
>  new_sync_write fs/read_write.c:497 [inline]
>  vfs_write+0xa72/0xc90 fs/read_write.c:590
>  ksys_write+0x1a0/0x2c0 fs/read_write.c:643
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Freed by task 5246:
>  kasan_save_stack mm/kasan/common.c:47 [inline]
>  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>  kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
>  poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
>  __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
>  kasan_slab_free include/linux/kasan.h:184 [inline]
>  slab_free_hook mm/slub.c:2256 [inline]
>  slab_free mm/slub.c:4477 [inline]
>  kfree+0x149/0x360 mm/slub.c:4598
>  settings_rsp+0x2bc/0x390 net/bluetooth/mgmt.c:1443
>  mgmt_pending_foreach+0xd1/0x130 net/bluetooth/mgmt_util.c:259
>  __mgmt_power_off+0x112/0x420 net/bluetooth/mgmt.c:9455
>  hci_dev_close_sync+0x665/0x11a0 net/bluetooth/hci_sync.c:5191
>  hci_dev_do_close net/bluetooth/hci_core.c:483 [inline]
>  hci_dev_close+0x112/0x210 net/bluetooth/hci_core.c:508
>  sock_do_ioctl+0x158/0x460 net/socket.c:1222
>  sock_ioctl+0x629/0x8e0 net/socket.c:1341
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:907 [inline]
>  __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83gv
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Reported-by: syzbot+03d6270b6425df1605bf@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=03d6270b6425df1605bf
> Fixes: 275f3f648702 ("Bluetooth: Fix not checking MGMT cmd pending queue")
> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> ---
>  net/bluetooth/mgmt.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> index 1f6d083682b8..6a26c1ea0d04 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -1441,6 +1441,10 @@ static void settings_rsp(struct mgmt_pending_cmd *cmd, void *data)
>                 sock_hold(match->sk);
>         }
>
> +       /* dequeue cmd_sync entries using cmd as data as that is about to be
> +        * removed/freed.
> +        */
> +       hci_cmd_sync_dequeue(match->hdev, NULL, cmd, NULL);
>         mgmt_pending_free(cmd);
>  }
>
> --
> 2.47.0
>


-- 
Luiz Augusto von Dentz