CVE-2021-47479

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8712: fix use-after-free in rtl8712_dl_fw Syzbot reported use-after-free in rtl8712_dl_fw(). The problem was in race condition between r871xu_dev_remove() ->ndo_open() callback. It's easy to see from crash log, that driver accesses released firmware in ->ndo_open() callback. It may happen, since driver was releasing firmware _before_ unregistering netdev. Fix it by moving unregister_netdev() before cleaning up resources. Call Trace: ... rtl871x_open_fw drivers/staging/rtl8712/hal_init.c:83 [inline] rtl8712_dl_fw+0xd95/0xe10 drivers/staging/rtl8712/hal_init.c:170 rtl8712_hal_init drivers/staging/rtl8712/hal_init.c:330 [inline] rtl871x_hal_init+0xae/0x180 drivers/staging/rtl8712/hal_init.c:394 netdev_open+0xe6/0x6c0 drivers/staging/rtl8712/os_intfs.c:380 __dev_open+0x2bc/0x4d0 net/core/dev.c:1484 Freed by task 1306: ... release_firmware+0x1b/0x30 drivers/base/firmware_loader/main.c:1053 r871xu_dev_remove+0xcc/0x2c0 drivers/staging/rtl8712/usb_intf.c:599 usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458

• linux linux kernel (>= 3.2.6 < 3.3) • linux linux kernel (>= 3.3.1 < 5.10.79) • linux linux kernel (>= 5.11 < 5.14.18) • linux linux kernel (>= 5.15 < 5.15.2) • linux linux kernel 3.3