diff options
| author | Claire Chang <tientzu@chromium.org> | 2020-11-10 11:49:08 +0300 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2020-11-12 11:18:06 +0300 |
| commit | 94e2bd0b259ed39a755fdded47e6734acf1ce464 (patch) | |
| tree | 0bc07fd2f2dd716949cec48e660a5ccf1e09c177 /net/rfkill | |
| parent | 52755b66ddcef2e897778fac5656df18817b59ab (diff) | |
| download | linux-94e2bd0b259ed39a755fdded47e6734acf1ce464.tar.xz | |
rfkill: Fix use-after-free in rfkill_resume()
If a device is getting removed or reprobed during resume, use-after-free
might happen. For example, h5_btrtl_resume() schedules a work queue for
device reprobing, which of course requires removal first.
If the removal happens in parallel with the device_resume() and wins the
race to acquire device_lock(), removal may remove the device from the PM
lists and all, but device_resume() is already running and will continue
when the lock can be acquired, thus calling rfkill_resume().
During this, if rfkill_set_block() is then called after the corresponding
*_unregister() and kfree() are called, there will be an use-after-free
in hci_rfkill_set_block():
BUG: KASAN: use-after-free in hci_rfkill_set_block+0x58/0xc0 [bluetooth]
...
Call trace:
dump_backtrace+0x0/0x154
show_stack+0x20/0x2c
dump_stack+0xbc/0x12c
print_address_description+0x88/0x4b0
__kasan_report+0x144/0x168
kasan_report+0x10/0x18
check_memory_region+0x19c/0x1ac
__kasan_check_write+0x18/0x24
hci_rfkill_set_block+0x58/0xc0 [bluetooth]
rfkill_set_block+0x9c/0x120
rfkill_resume+0x34/0x70
dpm_run_callback+0xf0/0x1f4
device_resume+0x210/0x22c
Fix this by checking rfkill->registered in rfkill_resume(). device_del()
in rfkill_unregister() requires device_lock() and the whole rfkill_resume()
is also protected by the same lock via device_resume(), we can make sure
either the rfkill->registered is false before rfkill_resume() starts or the
rfkill device won't be unregistered before rfkill_resume() returns.
As async_resume() holds a reference to the device, at this level there can
be no use-after-free; only in the user that doesn't expect this scenario.
Fixes: 8589086f4efd ("Bluetooth: hci_h5: Turn off RTL8723BS on suspend, reprobe on resume")
Signed-off-by: Claire Chang <tientzu@chromium.org>
Link: https://lore.kernel.org/r/20201110084908.219088-1-tientzu@chromium.org
[edit commit message for clarity and add more info provided later]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/rfkill')
| -rw-r--r-- | net/rfkill/core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/rfkill/core.c b/net/rfkill/core.c index 971c73c7d34c..97101c55763d 100644 --- a/net/rfkill/core.c +++ b/net/rfkill/core.c @@ -876,6 +876,9 @@ static int rfkill_resume(struct device *dev) rfkill->suspended = false; + if (!rfkill->registered) + return 0; + if (!rfkill->persistent) { cur = !!(rfkill->state & RFKILL_BLOCK_SW); rfkill_set_block(rfkill, cur); |