CVE-2022-49955 (GCVE-0-2022-49955)
Vulnerability from cvelistv5
Published
2025-06-18 11:00
Modified
2025-06-18 11:00
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: powerpc/rtas: Fix RTAS MSR[HV] handling for Cell The semi-recent changes to MSR handling when entering RTAS (firmware) cause crashes on IBM Cell machines. An example trace: kernel tried to execute user page (2fff01a8) - exploit attempt? (uid: 0) BUG: Unable to handle kernel instruction fetch Faulting instruction address: 0x2fff01a8 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=4 NUMA Cell Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 6.0.0-rc2-00433-gede0a8d3307a #207 NIP: 000000002fff01a8 LR: 0000000000032608 CTR: 0000000000000000 REGS: c0000000015236b0 TRAP: 0400 Tainted: G W (6.0.0-rc2-00433-gede0a8d3307a) MSR: 0000000008001002 <ME,RI> CR: 00000000 XER: 20000000 ... NIP 0x2fff01a8 LR 0x32608 Call Trace: 0xc00000000143c5f8 (unreliable) .rtas_call+0x224/0x320 .rtas_get_boot_time+0x70/0x150 .read_persistent_clock64+0x114/0x140 .read_persistent_wall_and_boot_offset+0x24/0x80 .timekeeping_init+0x40/0x29c .start_kernel+0x674/0x8f0 start_here_common+0x1c/0x50 Unlike PAPR platforms where RTAS is only used in guests, on the IBM Cell machines Linux runs with MSR[HV] set but also uses RTAS, provided by SLOF. Fix it by copying the MSR[HV] bit from the MSR value we've just read using mfmsr into the value used for RTAS. It seems like we could also fix it using an #ifdef CELL to set MSR[HV], but that doesn't work because it's possible to build a single kernel image that runs on both Cell native and pseries.
References
Impacted products
Vendor Product Version
Linux Linux Version: b6b1c3ce06ca438eb24e0f45bf0e63ecad0369f5
Version: b6b1c3ce06ca438eb24e0f45bf0e63ecad0369f5
Version: 5ca40fcf0da0ce2b5bc44e7d8b036535955f2e3d
Version: 5f4367448f6817c8a0e94dc9736ed84fa8eee4a3
Version: c9c41f0273826a13ac93124e66a4ff45df281ba0
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/kernel/rtas_entry.S"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8b08d4f97233d8e58fff2fd9d5f86397a49733c5",
              "status": "affected",
              "version": "b6b1c3ce06ca438eb24e0f45bf0e63ecad0369f5",
              "versionType": "git"
            },
            {
              "lessThan": "91926d8b7e71aaf5f84f0cf208fc5a8b7a761050",
              "status": "affected",
              "version": "b6b1c3ce06ca438eb24e0f45bf0e63ecad0369f5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5ca40fcf0da0ce2b5bc44e7d8b036535955f2e3d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5f4367448f6817c8a0e94dc9736ed84fa8eee4a3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c9c41f0273826a13ac93124e66a4ff45df281ba0",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/kernel/rtas_entry.S"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.19"
            },
            {
              "lessThan": "5.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.19.*",
              "status": "unaffected",
              "version": "5.19.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.19.8",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.0",
                  "versionStartIncluding": "5.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.15.46",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.17.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.18.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/rtas: Fix RTAS MSR[HV] handling for Cell\n\nThe semi-recent changes to MSR handling when entering RTAS (firmware)\ncause crashes on IBM Cell machines. An example trace:\n\n  kernel tried to execute user page (2fff01a8) - exploit attempt? (uid: 0)\n  BUG: Unable to handle kernel instruction fetch\n  Faulting instruction address: 0x2fff01a8\n  Oops: Kernel access of bad area, sig: 11 [#1]\n  BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=4 NUMA Cell\n  Modules linked in:\n  CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W          6.0.0-rc2-00433-gede0a8d3307a #207\n  NIP:  000000002fff01a8 LR: 0000000000032608 CTR: 0000000000000000\n  REGS: c0000000015236b0 TRAP: 0400   Tainted: G        W           (6.0.0-rc2-00433-gede0a8d3307a)\n  MSR:  0000000008001002 \u003cME,RI\u003e  CR: 00000000  XER: 20000000\n  ...\n  NIP 0x2fff01a8\n  LR  0x32608\n  Call Trace:\n    0xc00000000143c5f8 (unreliable)\n    .rtas_call+0x224/0x320\n    .rtas_get_boot_time+0x70/0x150\n    .read_persistent_clock64+0x114/0x140\n    .read_persistent_wall_and_boot_offset+0x24/0x80\n    .timekeeping_init+0x40/0x29c\n    .start_kernel+0x674/0x8f0\n    start_here_common+0x1c/0x50\n\nUnlike PAPR platforms where RTAS is only used in guests, on the IBM Cell\nmachines Linux runs with MSR[HV] set but also uses RTAS, provided by\nSLOF.\n\nFix it by copying the MSR[HV] bit from the MSR value we\u0027ve just read\nusing mfmsr into the value used for RTAS.\n\nIt seems like we could also fix it using an #ifdef CELL to set MSR[HV],\nbut that doesn\u0027t work because it\u0027s possible to build a single kernel\nimage that runs on both Cell native and pseries."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-06-18T11:00:17.617Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8b08d4f97233d8e58fff2fd9d5f86397a49733c5"
        },
        {
          "url": "https://git.kernel.org/stable/c/91926d8b7e71aaf5f84f0cf208fc5a8b7a761050"
        }
      ],
      "title": "powerpc/rtas: Fix RTAS MSR[HV] handling for Cell",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49955",
    "datePublished": "2025-06-18T11:00:17.617Z",
    "dateReserved": "2025-06-18T10:57:27.382Z",
    "dateUpdated": "2025-06-18T11:00:17.617Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2022-49955\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-06-18T11:15:22.630\",\"lastModified\":\"2025-06-18T13:46:52.973\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\npowerpc/rtas: Fix RTAS MSR[HV] handling for Cell\\n\\nThe semi-recent changes to MSR handling when entering RTAS (firmware)\\ncause crashes on IBM Cell machines. An example trace:\\n\\n  kernel tried to execute user page (2fff01a8) - exploit attempt? (uid: 0)\\n  BUG: Unable to handle kernel instruction fetch\\n  Faulting instruction address: 0x2fff01a8\\n  Oops: Kernel access of bad area, sig: 11 [#1]\\n  BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=4 NUMA Cell\\n  Modules linked in:\\n  CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W          6.0.0-rc2-00433-gede0a8d3307a #207\\n  NIP:  000000002fff01a8 LR: 0000000000032608 CTR: 0000000000000000\\n  REGS: c0000000015236b0 TRAP: 0400   Tainted: G        W           (6.0.0-rc2-00433-gede0a8d3307a)\\n  MSR:  0000000008001002 \u003cME,RI\u003e  CR: 00000000  XER: 20000000\\n  ...\\n  NIP 0x2fff01a8\\n  LR  0x32608\\n  Call Trace:\\n    0xc00000000143c5f8 (unreliable)\\n    .rtas_call+0x224/0x320\\n    .rtas_get_boot_time+0x70/0x150\\n    .read_persistent_clock64+0x114/0x140\\n    .read_persistent_wall_and_boot_offset+0x24/0x80\\n    .timekeeping_init+0x40/0x29c\\n    .start_kernel+0x674/0x8f0\\n    start_here_common+0x1c/0x50\\n\\nUnlike PAPR platforms where RTAS is only used in guests, on the IBM Cell\\nmachines Linux runs with MSR[HV] set but also uses RTAS, provided by\\nSLOF.\\n\\nFix it by copying the MSR[HV] bit from the MSR value we\u0027ve just read\\nusing mfmsr into the value used for RTAS.\\n\\nIt seems like we could also fix it using an #ifdef CELL to set MSR[HV],\\nbut that doesn\u0027t work because it\u0027s possible to build a single kernel\\nimage that runs on both Cell native and pseries.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: powerpc/rtas: Correcci\u00f3n del manejo de MSR[HV] de RTAS para Cell. Los cambios recientes en el manejo de MSR al ingresar RTAS (firmware) provocan bloqueos en las m\u00e1quinas IBM Cell. Ejemplo de rastreo: el kernel intent\u00f3 ejecutar la p\u00e1gina de usuario (2fff01a8): \u00bfintento de explotaci\u00f3n? (uid: 0) ERROR: No se puede controlar la obtenci\u00f3n de instrucciones del n\u00facleo Direcci\u00f3n de instrucci\u00f3n err\u00f3nea: 0x2fff01a8 Oops: Acceso del n\u00facleo al \u00e1rea defectuosa, firma: 11 [#1] BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=4 M\u00f3dulos de celda NUMA vinculados: CPU: 0 PID: 0 Comm: swapper/0 Contaminado: GW 6.0.0-rc2-00433-gede0a8d3307a #207 NIP: 000000002fff01a8 LR: 0000000000032608 CTR: 000000000000000 REGS: c0000000015236b0 TRAP: 0400 Contaminado: GW (6.0.0-rc2-00433-gede0a8d3307a) MSR: 0000000008001002  CR: 00000000 XER: 20000000 ... NIP 0x2fff01a8 LR 0x32608 Rastreo de llamadas: 0xc00000000143c5f8 (no confiable) .rtas_call+0x224/0x320 .rtas_get_boot_time+0x70/0x150 .read_persistent_clock64+0x114/0x140 .read_persistent_wall_and_boot_offset+0x24/0x80 .timekeeping_init+0x40/0x29c A diferencia de las plataformas PAPR, donde RTAS solo se usa en hu\u00e9spedes, en las m\u00e1quinas IBM Cell, Linux se ejecuta con MSR[HV] activado, pero tambi\u00e9n usa RTAS, proporcionado por SLOF. Para solucionarlo, copie el bit MSR[HV] del valor MSR que acabamos de leer con mfmsr al valor usado para RTAS. Parece que tambi\u00e9n podr\u00edamos solucionarlo usando un #ifdef CELL para activar MSR[HV], pero esto no funciona, ya que es posible crear una \u00fanica imagen de kernel que funcione tanto en Cell nativo como en pseries.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/8b08d4f97233d8e58fff2fd9d5f86397a49733c5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/91926d8b7e71aaf5f84f0cf208fc5a8b7a761050\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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