There is a use-after-free error in cfg80211_shutdown_all_interfaces found by syzkaller:

BUG: KASAN: use-after-free in cfg80211_shutdown_all_interfaces+0x213/0x220 Read of size 8 at addr ffff888112a78d98 by task kworker/0:5/5326 CPU: 0 UID: 0 PID: 5326 Comm: kworker/0:5 Not tainted 6.19.0-rc2 #2 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: events cfg80211_rfkill_block_work Call Trace: <TASK> dump_stack_lvl+0x116/0x1f0 print_report+0xcd/0x630 kasan_report+0xe0/0x110 cfg80211_shutdown_all_interfaces+0x213/0x220 cfg80211_rfkill_block_work+0x1e/0x30 process_one_work+0x9cf/0x1b70 worker_thread+0x6c8/0xf10 kthread+0x3c5/0x780 ret_from_fork+0x56d/0x700 ret_from_fork_asm+0x1a/0x30 </TASK>

The problem arises due to the rfkill_block work is not cancelled when cfg80211 device is being freed. In order to fix the issue cancel the corresponding work before destroying rfkill in cfg80211_dev_free().

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 1f87f7d3a3b4 ("cfg80211: add rfkill support") Cc: stable@vger.kernel.org Signed-off-by: Daniil Dulov d.dulov@aladdin.ru --- net/wireless/core.c | 1 + 1 file changed, 1 insertion(+)

diff --git a/net/wireless/core.c b/net/wireless/core.c index 54a34d8d356e..e94f69205f50 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -1226,6 +1226,7 @@ void cfg80211_dev_free(struct cfg80211_registered_device *rdev) spin_unlock_irqrestore(&rdev->wiphy_work_lock, flags); cancel_work_sync(&rdev->wiphy_work);

+ cancel_work_sync(&rdev->rfkill_block); rfkill_destroy(rdev->wiphy.rfkill); list_for_each_entry_safe(reg, treg, &rdev->beacon_registrations, list) { list_del(&reg->list);