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authorClaire Chang <tientzu@chromium.org>2020-11-10 11:49:08 +0300
committerJohannes Berg <johannes.berg@intel.com>2020-11-12 11:18:06 +0300
commit94e2bd0b259ed39a755fdded47e6734acf1ce464 (patch)
tree0bc07fd2f2dd716949cec48e660a5ccf1e09c177 /net
parent52755b66ddcef2e897778fac5656df18817b59ab (diff)
downloadlinux-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')
-rw-r--r--net/rfkill/core.c3
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);