fkie_cve-2022-48892
Vulnerability from fkie_nvd
Published
2024-08-21 07:15
Modified
2024-08-29 02:35
Severity ?
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
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * |
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"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\u0027s 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\u0027t be applicable to stable releases.\nJust copy the new dup_user_cpus_ptr() function over."
},
{
"lang": "es",
"value": "En el kernel de Linux, se resolvi\u00f3 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 asim\u00e9tricos\"), la configuraci\u00f3n 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 protecci\u00f3n de bloqueo. Dado que sched_setaffinity() puede invocarse desde otro proceso, el proceso que se est\u00e1 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 liberaci\u00f3n posterior del usuario y posiblemente a una liberaci\u00f3n doble en el kernel arm64. El commit 8f9ea86fdf99 (\"programaci\u00f3n: conservar siempre la m\u00e1scara de CPU solicitada por el usuario\") soluciona este problema ya que user_cpus_ptr, una vez configurado, nunca se borrar\u00e1 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 afectar\u00e1 a todos los arcos. Corrija este error borrando siempre el user_cpus_ptr de la tarea reci\u00e9n 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 aplicar\u00e1 a las versiones estables. Simplemente copie la nueva funci\u00f3n 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"
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},
"published": "2024-08-21T07:15:05.420",
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"url": "https://git.kernel.org/stable/c/7b5cc7fd1789ea5dbb942c9f8207b076d365badc"
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
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"value": "CWE-415"
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"value": "CWE-416"
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],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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