fkie_cve-2022-48892
Vulnerability from fkie_nvd
Published
2024-08-21 07:15
Modified
2024-08-29 02:35
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: sched/core: Fix use-after-free bug in dup_user_cpus_ptr() Since commit 07ec77a1d4e8 ("sched: Allow task CPU affinity to be restricted on asymmetric systems"), the setting and clearing of user_cpus_ptr are done under pi_lock for arm64 architecture. However, dup_user_cpus_ptr() accesses user_cpus_ptr without any lock protection. Since sched_setaffinity() can be invoked from another process, the process being modified may be undergoing fork() at the same time. When racing with the clearing of user_cpus_ptr in __set_cpus_allowed_ptr_locked(), it can lead to user-after-free and possibly double-free in arm64 kernel. Commit 8f9ea86fdf99 ("sched: Always preserve the user requested cpumask") fixes this problem as user_cpus_ptr, once set, will never be cleared in a task's lifetime. However, this bug was re-introduced in commit 851a723e45d1 ("sched: Always clear user_cpus_ptr in do_set_cpus_allowed()") which allows the clearing of user_cpus_ptr in do_set_cpus_allowed(). This time, it will affect all arches. Fix this bug by always clearing the user_cpus_ptr of the newly cloned/forked task before the copying process starts and check the user_cpus_ptr state of the source task under pi_lock. Note to stable, this patch won't be applicable to stable releases. Just copy the new dup_user_cpus_ptr() function over.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7b5cc7fd1789ea5dbb942c9f8207b076d365badcPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/87ca4f9efbd7cc649ff43b87970888f2812945b8Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b22faa21b6230d5eccd233e1b7e0026a5002b287Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *


To clipboard 

{
   configurations: [
      {
         nodes: [
            {
               cpeMatch: [
                  {
                     criteria: "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                     matchCriteriaId: "AF60D859-5B7E-4CFA-9318-AFEFAB130E64",
                     versionEndExcluding: "5.15.89",
                     versionStartIncluding: "5.15",
                     vulnerable: true,
                  },
                  {
                     criteria: "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                     matchCriteriaId: "9275C81F-AE96-4CDB-AD20-7DBD36E5D909",
                     versionEndExcluding: "6.1.7",
                     versionStartIncluding: "5.16",
                     vulnerable: true,
                  },
               ],
               negate: false,
               operator: "OR",
            },
         ],
      },
   ],
   cveTags: [],
   descriptions: [
      {
         lang: "en",
         value: "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/core: Fix use-after-free bug in dup_user_cpus_ptr()\n\nSince commit 07ec77a1d4e8 (\"sched: Allow task CPU affinity to be\nrestricted on asymmetric systems\"), the setting and clearing of\nuser_cpus_ptr are done under pi_lock for arm64 architecture. However,\ndup_user_cpus_ptr() accesses user_cpus_ptr without any lock\nprotection. Since sched_setaffinity() can be invoked from another\nprocess, the process being modified may be undergoing fork() at\nthe same time.  When racing with the clearing of user_cpus_ptr in\n__set_cpus_allowed_ptr_locked(), it can lead to user-after-free and\npossibly double-free in arm64 kernel.\n\nCommit 8f9ea86fdf99 (\"sched: Always preserve the user requested\ncpumask\") fixes this problem as user_cpus_ptr, once set, will never\nbe cleared in a task's lifetime. However, this bug was re-introduced\nin commit 851a723e45d1 (\"sched: Always clear user_cpus_ptr in\ndo_set_cpus_allowed()\") which allows the clearing of user_cpus_ptr in\ndo_set_cpus_allowed(). This time, it will affect all arches.\n\nFix this bug by always clearing the user_cpus_ptr of the newly\ncloned/forked task before the copying process starts and check the\nuser_cpus_ptr state of the source task under pi_lock.\n\nNote to stable, this patch won't be applicable to stable releases.\nJust copy the new dup_user_cpus_ptr() function over.",
      },
      {
         lang: "es",
         value: "En el kernel de Linux, se resolvió la siguiente vulnerabilidad: sched/core: corrige el error de use-after-free en dup_user_cpus_ptr() Desde el commit 07ec77a1d4e8 (\"sched: permitir que la afinidad de la CPU de la tarea se restrinja en sistemas asimétricos\"), la configuración y La limpieza de user_cpus_ptr se realiza en pi_lock para la arquitectura arm64. Sin embargo, dup_user_cpus_ptr() accede a user_cpus_ptr sin ninguna protección de bloqueo. Dado que sched_setaffinity() puede invocarse desde otro proceso, el proceso que se está modificando puede estar pasando por fork() al mismo tiempo. Cuando se corre con la limpieza de user_cpus_ptr en __set_cpus_allowed_ptr_locked(), puede llevar a una liberación posterior del usuario y posiblemente a una liberación doble en el kernel arm64. El commit 8f9ea86fdf99 (\"programación: conservar siempre la máscara de CPU solicitada por el usuario\") soluciona este problema ya que user_cpus_ptr, una vez configurado, nunca se borrará durante la vida de una tarea. Sin embargo, este error se reintrodujo en el commit 851a723e45d1 (\"sched: borrar siempre user_cpus_ptr en do_set_cpus_allowed()\") que permite borrar user_cpus_ptr en do_set_cpus_allowed(). Esta vez afectará a todos los arcos. Corrija este error borrando siempre el user_cpus_ptr de la tarea recién clonada/bifurcada antes de que comience el proceso de copia y verifique el estado de user_cpus_ptr de la tarea fuente en pi_lock. Nota para las versiones estables: este parche no se aplicará a las versiones estables. Simplemente copie la nueva función dup_user_cpus_ptr().",
      },
   ],
   id: "CVE-2022-48892",
   lastModified: "2024-08-29T02:35:56.343",
   metrics: {
      cvssMetricV31: [
         {
            cvssData: {
               attackComplexity: "LOW",
               attackVector: "LOCAL",
               availabilityImpact: "HIGH",
               baseScore: 7.8,
               baseSeverity: "HIGH",
               confidentialityImpact: "HIGH",
               integrityImpact: "HIGH",
               privilegesRequired: "LOW",
               scope: "UNCHANGED",
               userInteraction: "NONE",
               vectorString: "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
               version: "3.1",
            },
            exploitabilityScore: 1.8,
            impactScore: 5.9,
            source: "nvd@nist.gov",
            type: "Primary",
         },
      ],
   },
   published: "2024-08-21T07:15:05.420",
   references: [
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
         ],
         url: "https://git.kernel.org/stable/c/7b5cc7fd1789ea5dbb942c9f8207b076d365badc",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
         ],
         url: "https://git.kernel.org/stable/c/87ca4f9efbd7cc649ff43b87970888f2812945b8",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
         ],
         url: "https://git.kernel.org/stable/c/b22faa21b6230d5eccd233e1b7e0026a5002b287",
      },
   ],
   sourceIdentifier: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
   vulnStatus: "Analyzed",
   weaknesses: [
      {
         description: [
            {
               lang: "en",
               value: "CWE-415",
            },
            {
               lang: "en",
               value: "CWE-416",
            },
         ],
         source: "nvd@nist.gov",
         type: "Primary",
      },
   ],
}


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