Vulnerability-Lookup

GHSA-CJ4F-M7FJ-58GV

Vulnerability from github – Published: 2024-02-27 12:31 – Updated: 2024-04-10 18:30

Details

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.

Severity

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2021-46928"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-755"
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    "github_reviewed_at": null,
    "nvd_published_at": "2024-02-27T10:15:07Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nparisc: Clear stale IIR value on instruction access rights trap\n\nWhen a trap 7 (Instruction access rights) occurs, this means the CPU\ncouldn\u0027t execute an instruction due to missing execute permissions on\nthe memory region.  In this case it seems the CPU didn\u0027t even fetched\nthe instruction from memory and thus did not store it in the cr19 (IIR)\nregister before calling the trap handler. So, the trap handler will find\nsome random old stale value in cr19.\n\nThis patch simply overwrites the stale IIR value with a constant magic\n\"bad food\" value (0xbaadf00d), in the hope people don\u0027t start to try to\nunderstand the various random IIR values in trap 7 dumps.",
  "id": "GHSA-cj4f-m7fj-58gv",
  "modified": "2024-04-10T18:30:46Z",
  "published": "2024-02-27T12:31:10Z",
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CVE-2021-46928 (GCVE-0-2021-46928)

Vulnerability from cvelistv5 – Published: 2024-02-27 09:43 – Updated: 2026-05-11 13:44

Title

parisc: Clear stale IIR value on instruction access rights trap

Summary

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.

Severity

No CVSS data available.

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-02-27 15:39 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6996 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/d01e9ce1af6116f81…
https://git.kernel.org/stable/c/e96373f0a5f484bc1…
https://git.kernel.org/stable/c/484730e5862f6b872…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d01e9ce1af6116f812491d3d3873d204f10ae0b8 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < e96373f0a5f484bc1e193f9951dcb3adf24bf3f7 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 484730e5862f6b872dca13840bed40fd7c60fa26 (git)
Linux	Linux	Affected: 2.6.12 Unaffected: 0 , < 2.6.12 (semver) Unaffected: 5.10.90 , ≤ 5.10.* (semver) Unaffected: 5.15.13 , ≤ 5.15.* (semver) Unaffected: 5.16 , ≤ * (original_commit_for_fix)

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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