CVE-2021-46928
parisc: Clear stale IIR value on instruction access rights trap
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
parisc: Clear stale IIR value on instruction access rights trap
When a trap 7 (Instruction access rights) occurs, this means the CPU
couldn't execute an instruction due to missing execute permissions on
the memory region. In this case it seems the CPU didn't even fetched
the instruction from memory and thus did not store it in the cr19 (IIR)
register before calling the trap handler. So, the trap handler will find
some random old stale value in cr19.
This patch simply overwrites the stale IIR value with a constant magic
"bad food" value (0xbaadf00d), in the hope people don't start to try to
understand the various random IIR values in trap 7 dumps.
En el kernel de Linux, se resolvió la siguiente vulnerabilidad: parisc: borra el valor IIR obsoleto en la trampa de derechos de acceso a instrucciones Cuando ocurre una trampa 7 (derechos de acceso a instrucciones), esto significa que la CPU no pudo ejecutar una instrucción debido a que faltan permisos de ejecución en la región de la memoria. En este caso, parece que la CPU ni siquiera obtuvo la instrucción de la memoria y, por lo tanto, no la almacenó en el registro cr19 (IIR) antes de llamar al controlador de trampas. Entonces, el manejador de trampas encontrará algún valor obsoleto aleatorio en cr19. Este parche simplemente sobrescribe el valor IIR obsoleto con un valor mágico constante de "mala comida" (0xbaadf00d), con la esperanza de que la gente no empiece a intentar comprender los diversos valores IIR aleatorios en los volcados de la trampa 7.
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-02-25 CVE Reserved
- 2024-02-27 CVE Published
- 2024-04-21 EPSS Updated
- 2024-12-19 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
- CWE-755: Improper Handling of Exceptional Conditions
CAPEC
References (3)
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Affected Vendors, Products, and Versions
Vendor | Product | Version | Other | Status | ||||||
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Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | < 5.10.90 Search vendor "Linux" for product "Linux Kernel" and version " < 5.10.90" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | < 5.15.13 Search vendor "Linux" for product "Linux Kernel" and version " < 5.15.13" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | < 5.16 Search vendor "Linux" for product "Linux Kernel" and version " < 5.16" | en |
Affected
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