CVE-2021-47479

staging: rtl8712: fix use-after-free in rtl8712_dl_fw

Severity Score

6.4

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

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

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: staging: rtl8712: corrige el use-after-free en rtl8712_dl_fw Syzbot informó el use-after-free en rtl8712_dl_fw(). El problema estaba en la condición de ejecución entre la devolución de llamada r871xu_dev_remove() ->ndo_open(). Es fácil ver en el registro de fallos que el controlador accede al firmware lanzado en la devolución de llamada ->ndo_open(). Puede suceder, ya que el controlador estaba lanzando el firmware _antes_ de cancelar el registro de netdev. Solucionarlo moviendo unregister_netdev() antes de limpiar los recursos. Traza de llamada: ... RTL871X_OPEN_FW : 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 Liberado por tarea 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

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

*Credits: N/A

Attack Vector

Local

Attack Complexity

High

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Local

Attack Complexity

High

Authentication

Multiple

Confidentiality

Complete

Integrity

Complete

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-05-22 CVE Reserved
2024-05-22 CVE Published
2024-12-19 CVE Updated
2025-03-18 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (6)

URL	Tag	Source
https://git.kernel.org/stable/c/8c213fa59199f9673d66970d6940fa093186642f	Vuln. Introduced
https://git.kernel.org/stable/c/bc5d453eab4506cb52397db8830d1070904265a4	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/c430094541a80575259a94ff879063ef01473506	2021-11-12
https://git.kernel.org/stable/c/befd23bd3b17f1a3f9c943a8580b47444c7c63ed	2021-11-12
https://git.kernel.org/stable/c/a65c9afe9f2f55b7a7fb4a25ab654cd4139683a4	2021-11-12
https://git.kernel.org/stable/c/c052cc1a069c3e575619cf64ec427eb41176ca70	2021-10-20

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.3 < 5.10.79 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.3 < 5.10.79"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.3 < 5.14.18 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.3 < 5.14.18"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.3 < 5.15.2 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.3 < 5.15.2"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 3.3 < 5.16 Search vendor "Linux" for product "Linux Kernel" and version " >= 3.3 < 5.16"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				3.2.6 Search vendor "Linux" for product "Linux Kernel" and version "3.2.6"		en		Affected