// For flags

CVE-2023-52676

bpf: Guard stack limits against 32bit overflow

Severity Score

5.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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

bpf: Guard stack limits against 32bit overflow

This patch promotes the arithmetic around checking stack bounds to be
done in the 64-bit domain, instead of the current 32bit. The arithmetic
implies adding together a 64-bit register with a int offset. The
register was checked to be below 1<<29 when it was variable, but not
when it was fixed. The offset either comes from an instruction (in which
case it is 16 bit), from another register (in which case the caller
checked it to be below 1<<29 [1]), or from the size of an argument to a
kfunc (in which case it can be a u32 [2]). Between the register being
inconsistently checked to be below 1<<29, and the offset being up to an
u32, it appears that we were open to overflowing the `int`s which were
currently used for arithmetic.

[1] https://github.com/torvalds/linux/blob/815fb87b753055df2d9e50f6cd80eb10235fe3e9/kernel/bpf/verifier.c#L7494-L7498
[2] https://github.com/torvalds/linux/blob/815fb87b753055df2d9e50f6cd80eb10235fe3e9/kernel/bpf/verifier.c#L11904

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: Proteger los límites de la pila contra el desbordamiento de 32 bits. Este parche promueve que la aritmética en torno a la verificación de los límites de la pila se realice en el dominio de 64 bits, en lugar del actual de 32 bits. La aritmética implica sumar un registro de 64 bits con un desplazamiento int. Se comprobó que el registro estaba por debajo de 1&lt;&lt;29 cuando era variable, pero no cuando estaba arreglado. El desplazamiento proviene de una instrucción (en cuyo caso es de 16 bits), de otro registro (en cuyo caso la persona que llama comprobó que estaba por debajo de 1&lt;&lt;29 [1]) o del tamaño de un argumento para kfunc. (en cuyo caso puede ser un u32 [2]). Entre que el registro se verificaba de manera inconsistente para que estuviera por debajo de 1&lt;&lt;29 y el desplazamiento era de hasta u32, parece que estábamos abiertos a desbordar los "int" que se usaban actualmente para la aritmética. [1] https://github.com/torvalds/linux/blob/815fb87b753055df2d9e50f6cd80eb10235fe3e9/kernel/bpf/verifier.c#L7494-L7498 [2] https://github.com/torvalds/linux/blob/815fb87b753055df2d9e 50f6cd80eb10235fe3e9/núcleo /bpf/verifier.c#L11904

*Credits: N/A
CVSS Scores
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
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2024-03-07 CVE Reserved
  • 2024-05-17 CVE Published
  • 2024-05-18 EPSS Updated
  • 2024-11-04 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
CAPEC
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"
< 6.6.14
Search vendor "Linux" for product "Linux Kernel" and version " < 6.6.14"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
< 6.7.2
Search vendor "Linux" for product "Linux Kernel" and version " < 6.7.2"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
< 6.8
Search vendor "Linux" for product "Linux Kernel" and version " < 6.8"
en
Affected