CVE-2021-47317
powerpc/bpf: Fix detecting BPF atomic instructions
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
powerpc/bpf: Fix detecting BPF atomic instructions
Commit 91c960b0056672 ("bpf: Rename BPF_XADD and prepare to encode other
atomics in .imm") converted BPF_XADD to BPF_ATOMIC and added a way to
distinguish instructions based on the immediate field. Existing JIT
implementations were updated to check for the immediate field and to
reject programs utilizing anything more than BPF_ADD (such as BPF_FETCH)
in the immediate field.
However, the check added to powerpc64 JIT did not look at the correct
BPF instruction. Due to this, such programs would be accepted and
incorrectly JIT'ed resulting in soft lockups, as seen with the atomic
bounds test. Fix this by looking at the correct immediate value.
En el kernel de Linux, se resolvió la siguiente vulnerabilidad: powerpc/bpf: Corrección de la detección de instrucciones atómicas BPF. La confirmación 91c960b0056672 ("bpf: Renombrar BPF_XADD y prepararse para codificar otros átomos en .imm") convirtió BPF_XADD a BPF_ATOMIC y agregó una forma de distinguir instrucciones basadas en el campo inmediato. Las implementaciones JIT existentes se actualizaron para verificar el campo inmediato y rechazar programas que utilicen algo más que BPF_ADD (como BPF_FETCH) en el campo inmediato. Sin embargo, la verificación agregada a powerpc64 JIT no analizó la instrucción BPF correcta. Debido a esto, dichos programas serían aceptados y sometidos a JIT incorrectamente, lo que provocaría bloqueos suaves, como se ve con la prueba de límites atómicos. Solucione este problema observando el valor inmediato correcto.
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-05-21 CVE Reserved
- 2024-05-21 CVE Published
- 2024-05-22 EPSS Updated
- 2024-09-11 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (4)
| URL | Tag | Source |
|---|---|---|
| https://git.kernel.org/stable/c/91c960b0056672e74627776655c926388350fa30 | Vuln. Introduced |
| URL | Date | SRC |
|---|
| URL | Date | SRC |
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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" | >= 5.12 < 5.12.19 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.12.19" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.12 < 5.13.4 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.13.4" | en |
Affected
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| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.12 < 5.14 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.12 < 5.14" | en |
Affected
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