CVE-2021-47444

drm/edid: In connector_bad_edid() cap num_of_ext by num_blocks read

Severity Score

"-"

*CVSS v-

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:

drm/edid: In connector_bad_edid() cap num_of_ext by num_blocks read

In commit e11f5bd8228f ("drm: Add support for DP 1.4 Compliance edid
corruption test") the function connector_bad_edid() started assuming
that the memory for the EDID passed to it was big enough to hold
`edid[0x7e] + 1` blocks of data (1 extra for the base block). It
completely ignored the fact that the function was passed `num_blocks`
which indicated how much memory had been allocated for the EDID.

Let's fix this by adding a bounds check.

This is important for handling the case where there's an error in the
first block of the EDID. In that case we will call
connector_bad_edid() without having re-allocated memory based on
`edid[0x7e]`.

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: drm/edid: En conector_bad_edid() cap num_of_ext por num_blocks leído En commit e11f5bd8228f ("drm: Agregar soporte para prueba de corrupción edid de cumplimiento de DP 1.4") la función conector_bad_edid() comenzó a asumir que la memoria para el EDID que se le pasó era lo suficientemente grande como para contener bloques de datos `edid[0x7e] + 1` (1 adicional para el bloque base). Ignoró por completo el hecho de que a la función se le pasó `num_blocks`, que indicaba cuánta memoria se había asignado para el EDID. Arreglemos esto agregando una verificación de los límites. Esto es importante para manejar el caso en el que hay un error en el primer bloque del EDID. En ese caso llamaremos a Connector_bad_edid() sin haber reasignado memoria en base a `edid[0x7e]`.

*Credits: N/A

CVSS Scores

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

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

CWE

CAPEC

References (4)

URL	Tag	Source
https://git.kernel.org/stable/c/e11f5bd8228fc3760c221f940b9f6365dbf3e7ed	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/a7b45024f66f9ec769e8dbb1a51ae83cd05929c7	2021-10-20
https://git.kernel.org/stable/c/09f3946bb452918dbfb1982add56f9ffaae393dc	2021-10-20
https://git.kernel.org/stable/c/97794170b696856483f74b47bfb6049780d2d3a0	2021-10-15

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"				>= 5.7 < 5.10.75 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.7 < 5.10.75"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.7 < 5.14.14 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.7 < 5.14.14"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.7 < 5.15 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.7 < 5.15"		en		Affected