From: Ping-Ke Shih pkshih@realtek.com
commit 4dfde294b9792dcf8615b55c58f093d544f472f0 upstream.
request_firmware_nowait() which schedules another work is used to load firmware when USB is probing. If USB is unplugged before running the firmware work, it goes disconnect ops, and then causes use-after-free. Though we wait for completion of firmware work before freeing the hw, firmware callback rises completion too early. So I move it to the last step.
usb 5-1: Direct firmware load for rtlwifi/rtl8192cufw.bin failed with error -2 rtlwifi: Loading alternative firmware rtlwifi/rtl8192cufw.bin rtlwifi: Selected firmware is not available ================================================================== BUG: KASAN: use-after-free in rtl_fw_do_work.cold+0x68/0x6a drivers/net/wireless/realtek/rtlwifi/core.c:93 Write of size 4 at addr ffff8881454cff50 by task kworker/0:6/7379
CPU: 0 PID: 7379 Comm: kworker/0:6 Not tainted 5.10.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events request_firmware_work_func Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 rtl_fw_do_work.cold+0x68/0x6a drivers/net/wireless/realtek/rtlwifi/core.c:93 request_firmware_work_func+0x12c/0x230 drivers/base/firmware_loader/main.c:1079 process_one_work+0x933/0x1520 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x38c/0x460 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
The buggy address belongs to the page: page:00000000f54435b3 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1454cf flags: 0x200000000000000() raw: 0200000000000000 0000000000000000 ffffea00051533c8 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff8881454cfe00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881454cfe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8881454cff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^ ffff8881454cff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881454d0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
Reported-by: syzbot+65be4277f3c489293939@syzkaller.appspotmail.com Signed-off-by: Ping-Ke Shih pkshih@realtek.com Signed-off-by: Kalle Valo kvalo@codeaurora.org Link: https://lore.kernel.org/r/20201214053106.7748-1-pkshih@realtek.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/net/wireless/realtek/rtlwifi/core.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/net/wireless/realtek/rtlwifi/core.c +++ b/drivers/net/wireless/realtek/rtlwifi/core.c @@ -78,7 +78,6 @@ static void rtl_fw_do_work(const struct
rtl_dbg(rtlpriv, COMP_ERR, DBG_LOUD, "Firmware callback routine entered!\n"); - complete(&rtlpriv->firmware_loading_complete); if (!firmware) { if (rtlpriv->cfg->alt_fw_name) { err = request_firmware(&firmware, @@ -91,13 +90,13 @@ static void rtl_fw_do_work(const struct } pr_err("Selected firmware is not available\n"); rtlpriv->max_fw_size = 0; - return; + goto exit; } found_alt: if (firmware->size > rtlpriv->max_fw_size) { pr_err("Firmware is too big!\n"); release_firmware(firmware); - return; + goto exit; } if (!is_wow) { memcpy(rtlpriv->rtlhal.pfirmware, firmware->data, @@ -109,6 +108,9 @@ found_alt: rtlpriv->rtlhal.wowlan_fwsize = firmware->size; } release_firmware(firmware); + +exit: + complete(&rtlpriv->firmware_loading_complete); }
void rtl_fw_cb(const struct firmware *firmware, void *context)