CVE-2021-47231

can: mcba_usb: fix memory leak in mcba_usb

Severity Score

5.5

*CVSS v3.1

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:

can: mcba_usb: fix memory leak in mcba_usb

Syzbot reported memory leak in SocketCAN driver for Microchip CAN BUS
Analyzer Tool. The problem was in unfreed usb_coherent.

In mcba_usb_start() 20 coherent buffers are allocated and there is
nothing, that frees them:

1) In callback function the urb is resubmitted and that's all
2) In disconnect function urbs are simply killed, but URB_FREE_BUFFER
is not set (see mcba_usb_start) and this flag cannot be used with
coherent buffers.

Fail log:
| [ 1354.053291][ T8413] mcba_usb 1-1:0.0 can0: device disconnected
| [ 1367.059384][ T8420] kmemleak: 20 new suspected memory leaks (see /sys/kernel/debug/kmem)

So, all allocated buffers should be freed with usb_free_coherent()
explicitly

NOTE:
The same pattern for allocating and freeing coherent buffers
is used in drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: can: mcba_usb: repara la pérdida de memoria en mcba_usb. Syzbot informó una pérdida de memoria en el controlador SocketCAN para la herramienta Microchip CAN BUS Analyzer. El problema estaba en usb_coherent no liberado. En mcba_usb_start() se asignan 20 buffers coherentes y no hay nada que los libere: 1) En la función de devolución de llamada, la urb se vuelve a enviar y eso es todo 2) En la función de desconexión, las urbs simplemente se eliminan, pero URB_FREE_BUFFER no está configurado (ver mcba_usb_start) y Esta bandera no se puede utilizar con buffers coherentes. Registro de errores: | [ 1354.053291][ T8413] mcba_usb 1-1:0.0 can0: dispositivo desconectado | [ 1367.059384][ T8420] kmemleak: 20 nuevas pérdidas de memoria sospechosas (ver /sys/kernel/debug/kmem) Por lo tanto, todos los buffers asignados deben liberarse con usb_free_coherent() explícitamente NOTA: Se utiliza el mismo patrón para asignar y liberar buffers coherentes en controladores/net/can/usb/kvaser_usb/kvaser_usb_core.c

*Credits: N/A

CVSS Scores

CISAv3.1 5.5

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-04-10 CVE Reserved
2024-05-21 CVE Published
2024-05-22 EPSS Updated
2024-12-19 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (7)

URL	Tag	Source
https://git.kernel.org/stable/c/51f3baad7de943780ce0c17bd7975df567dd6e14	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/89df95ce32be204eef2e7d4b2f6fb552fb191a68	2021-06-30
https://git.kernel.org/stable/c/a115198caaab6d663bef75823a3c5f0802306d60	2021-06-30
https://git.kernel.org/stable/c/6f87c0e21ad20dd3d22108e33db1c552dfa352a0	2021-06-23
https://git.kernel.org/stable/c/6bd3d80d1f019cefa7011056c54b323f1d8b8e83	2021-06-23
https://git.kernel.org/stable/c/d0760a4ef85697bc756d06eae17ae27f3f055401	2021-06-23
https://git.kernel.org/stable/c/91c02557174be7f72e46ed7311e3bea1939840b0	2021-06-16

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"				>= 4.12 < 4.14.238 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.12 < 4.14.238"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.12 < 4.19.196 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.12 < 4.19.196"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.12 < 5.4.128 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.12 < 5.4.128"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.12 < 5.10.46 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.12 < 5.10.46"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.12 < 5.12.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.12 < 5.12.13"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 4.12 < 5.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.12 < 5.13"		en		Affected