CVE-2021-47241

ethtool: strset: fix message length calculation

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

In the Linux kernel, the following vulnerability has been resolved:

ethtool: strset: fix message length calculation

Outer nest for ETHTOOL_A_STRSET_STRINGSETS is not accounted for.
This may result in ETHTOOL_MSG_STRSET_GET producing a warning like:

calculated message payload length (684) not sufficient
WARNING: CPU: 0 PID: 30967 at net/ethtool/netlink.c:369 ethnl_default_doit+0x87a/0xa20

and a splat.

As usually with such warnings three conditions must be met for the warning
to trigger:
- there must be no skb size rounding up (e.g. reply_size of 684);
- string set must be per-device (so that the header gets populated);
- the device name must be at least 12 characters long.

all in all with current user space it looks like reading priv flags
is the only place this could potentially happen. Or with syzbot :)

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ethtool: strset: corrección del cálculo de la longitud del mensaje. No se tiene en cuenta el nido externo para ETHTOOL_A_STRSET_STRINGSETS. Esto puede provocar que ETHTOOL_MSG_STRSET_GET produzca una advertencia como: la longitud calculada de el payload del mensaje (684) no es suficiente ADVERTENCIA: CPU: 0 PID: 30967 en net/ethtool/netlink.c:369 ethnl_default_doit+0x87a/0xa20 y un símbolo. Como suele ocurrir con este tipo de advertencias, se deben cumplir tres condiciones para que se active la advertencia: - no debe haber ningún tamaño de skb redondeado hacia arriba (por ejemplo, tamaño_respuesta de 684); - el conjunto de cadenas debe ser por dispositivo (para que se complete el encabezado); - el nombre del dispositivo debe tener al menos 12 caracteres. Con todo, con el espacio de usuario actual, parece que leer indicadores privados es el único lugar donde esto podría suceder. O con syzbot :)

*Credits: N/A

CVSS Scores

CISAv3.1 7.5

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-04-10 CVE Reserved
2024-05-21 CVE Published
2024-05-22 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-266: Incorrect Privilege Assignment

CAPEC

References (4)

URL	Tag	Source
https://git.kernel.org/stable/c/71921690f9745fef60a2bad425f30adf8cdc9da0	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/fb3a948143688e14e2cfd2a2812877923d0e5e92	2021-06-23
https://git.kernel.org/stable/c/cfc7f0e70d649e6d2233fba0d9390b525677d971	2021-06-23
https://git.kernel.org/stable/c/e175aef902697826d344ce3a12189329848fe898	2021-06-14

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"				>= 5.6 < 5.10.46 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.6 < 5.10.46"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.6 < 5.12.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.6 < 5.12.13"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.6 < 5.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.6 < 5.13"		en		Affected