gsd-2021-46928
Vulnerability from gsd
Modified
2024-02-26 06:03
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.
Aliases


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{
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2021-46928"
      ],
      "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": "GSD-2021-46928",
      "modified": "2024-02-26T06:03:52.513250Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
        "ASSIGNER": "cve@kernel.org",
        "ID": "CVE-2021-46928",
        "STATE": "PUBLIC"
      },
      "affects": {
        "vendor": {
          "vendor_data": [
            {
              "product": {
                "product_data": [
                  {
                    "product_name": "Linux",
                    "version": {
                      "version_data": [
                        {
                          "version_affected": "\u003c",
                          "version_name": "1da177e4c3f4",
                          "version_value": "d01e9ce1af61"
                        },
                        {
                          "version_value": "not down converted",
                          "x_cve_json_5_version_data": {
                            "defaultStatus": "affected",
                            "versions": [
                              {
                                "lessThanOrEqual": "5.10.*",
                                "status": "unaffected",
                                "version": "5.10.90",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "5.15.*",
                                "status": "unaffected",
                                "version": "5.15.13",
                                "versionType": "custom"
                              },
                              {
                                "lessThanOrEqual": "*",
                                "status": "unaffected",
                                "version": "5.16",
                                "versionType": "original_commit_for_fix"
                              }
                            ]
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                    }
                  }
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              },
              "vendor_name": "Linux"
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      },
      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
        "description_data": [
          {
            "lang": "eng",
            "value": "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."
          }
        ]
      },
      "generator": {
        "engine": "bippy-b01c2a820106"
      },
      "problemtype": {
        "problemtype_data": [
          {
            "description": [
              {
                "lang": "eng",
                "value": "n/a"
              }
            ]
          }
        ]
      },
      "references": {
        "reference_data": [
          {
            "name": "https://git.kernel.org/stable/c/d01e9ce1af6116f812491d3d3873d204f10ae0b8",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/d01e9ce1af6116f812491d3d3873d204f10ae0b8"
          },
          {
            "name": "https://git.kernel.org/stable/c/e96373f0a5f484bc1e193f9951dcb3adf24bf3f7",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/e96373f0a5f484bc1e193f9951dcb3adf24bf3f7"
          },
          {
            "name": "https://git.kernel.org/stable/c/484730e5862f6b872dca13840bed40fd7c60fa26",
            "refsource": "MISC",
            "url": "https://git.kernel.org/stable/c/484730e5862f6b872dca13840bed40fd7c60fa26"
          }
        ]
      }
    },
    "nvd.nist.gov": {
      "cve": {
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "61DD4F08-4AE9-4FE1-8E26-1BD1C74B6B2C",
                    "versionEndExcluding": "5.10.90",
                    "vulnerable": true
                  },
                  {
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                    "versionEndExcluding": "5.15.13",
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                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
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          }
        ],
        "descriptions": [
          {
            "lang": "en",
            "value": "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."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se resolvi\u00f3 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 instrucci\u00f3n debido a que faltan permisos de ejecuci\u00f3n en la regi\u00f3n de la memoria. En este caso, parece que la CPU ni siquiera obtuvo la instrucci\u00f3n de la memoria y, por lo tanto, no la almacen\u00f3 en el registro cr19 (IIR) antes de llamar al controlador de trampas. Entonces, el manejador de trampas encontrar\u00e1 alg\u00fan valor obsoleto aleatorio en cr19. Este parche simplemente sobrescribe el valor IIR obsoleto con un valor m\u00e1gico 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."
          }
        ],
        "id": "CVE-2021-46928",
        "lastModified": "2024-04-10T16:29:19.867",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 5.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 3.6,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2024-02-27T10:15:07.517",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
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            ],
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            "tags": [
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-755"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    }
  }
}


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