5.5

CVE-2021-46928

parisc: Clear stale IIR value on instruction access rights trap

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version < 5.10.90
Linux ≫ Linux Kernel Version >= 5.11.0 < 5.15.13
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.23% 0.129
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-755 Improper Handling of Exceptional Conditions

The product does not handle or incorrectly handles an exceptional condition.

https://git.kernel.org/stable/c/484730e5862f6b872dca13840bed40fd7c60fa26
Patch
https://git.kernel.org/stable/c/d01e9ce1af6116f812491d3d3873d204f10ae0b8
Patch
https://git.kernel.org/stable/c/e96373f0a5f484bc1e193f9951dcb3adf24bf3f7
Patch