mwl8k: Fix use-after-free in mwl8k_fw_state_machine()

When the driver fails to request the firmware, it calls its error
handler. In the error handler, the driver detaches device from driver
first before releasing the firmware, which can cause a use-after-free bug.

Fix this by releasing firmware first.

The following log reveals it:

[    9.007301 ] BUG: KASAN: use-after-free in mwl8k_fw_state_machine+0x320/0xba0
[    9.010143 ] Workqueue: events request_firmware_work_func
[    9.010830 ] Call Trace:
[    9.010830 ]  dump_stack_lvl+0xa8/0xd1
[    9.010830 ]  print_address_description+0x87/0x3b0
[    9.010830 ]  kasan_report+0x172/0x1c0
[    9.010830 ]  ? mutex_unlock+0xd/0x10
[    9.010830 ]  ? mwl8k_fw_state_machine+0x320/0xba0
[    9.010830 ]  ? mwl8k_fw_state_machine+0x320/0xba0
[    9.010830 ]  __asan_report_load8_noabort+0x14/0x20
[    9.010830 ]  mwl8k_fw_state_machine+0x320/0xba0
[    9.010830 ]  ? mwl8k_load_firmware+0x5f0/0x5f0
[    9.010830 ]  request_firmware_work_func+0x172/0x250
[    9.010830 ]  ? read_lock_is_recursive+0x20/0x20
[    9.010830 ]  ? process_one_work+0x7a1/0x1100
[    9.010830 ]  ? request_firmware_nowait+0x460/0x460
[    9.010830 ]  ? __this_cpu_preempt_check+0x13/0x20
[    9.010830 ]  process_one_work+0x9bb/0x1100

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1634356979-6211-1-git-send-email-zheyuma97@gmail.com
This commit is contained in:
Zheyu Ma 2021-10-16 04:02:59 +00:00 committed by Kalle Valo
parent 515e7184bd
commit 257051a235

View File

@ -5800,8 +5800,8 @@ static void mwl8k_fw_state_machine(const struct firmware *fw, void *context)
fail:
priv->fw_state = FW_STATE_ERROR;
complete(&priv->firmware_loading_complete);
device_release_driver(&priv->pdev->dev);
mwl8k_release_firmware(priv);
device_release_driver(&priv->pdev->dev);
}
#define MAX_RESTART_ATTEMPTS 1