FKIE_CVE-2022-48921
Vulnerability from fkie_nvd - Published: 2024-08-22 02:15 - Updated: 2026-06-17 05:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
sched/fair: Fix fault in reweight_entity
Syzbot found a GPF in reweight_entity. This has been bisected to
commit 4ef0c5c6b5ba ("kernel/sched: Fix sched_fork() access an invalid
sched_task_group")
There is a race between sched_post_fork() and setpriority(PRIO_PGRP)
within a thread group that causes a null-ptr-deref in
reweight_entity() in CFS. The scenario is that the main process spawns
number of new threads, which then call setpriority(PRIO_PGRP, 0, -20),
wait, and exit. For each of the new threads the copy_process() gets
invoked, which adds the new task_struct and calls sched_post_fork()
for it.
In the above scenario there is a possibility that
setpriority(PRIO_PGRP) and set_one_prio() will be called for a thread
in the group that is just being created by copy_process(), and for
which the sched_post_fork() has not been executed yet. This will
trigger a null pointer dereference in reweight_entity(), as it will
try to access the run queue pointer, which hasn't been set.
Before the mentioned change the cfs_rq pointer for the task has been
set in sched_fork(), which is called much earlier in copy_process(),
before the new task is added to the thread_group. Now it is done in
the sched_post_fork(), which is called after that. To fix the issue
the remove the update_load param from the update_load param() function
and call reweight_task() only if the task flag doesn't have the
TASK_NEW flag set.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 5.17 | |
| linux | linux_kernel | 5.17 | |
| linux | linux_kernel | 5.17 |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/sched/core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "c85c6fadbef0a3eab41540ea628fa8fe8928c820",
"versionType": "git"
},
{
"lessThan": "e0bcd6b5779352aed88f2e538a82a39f1a7715bb",
"status": "affected",
"version": "3869eecf050416a1d19bac60926f6b5d64b0aa58",
"versionType": "git"
},
{
"lessThan": "589a954daab5e18399860b6c8ffaeaf79844eb20",
"status": "affected",
"version": "4ef0c5c6b5ba1f38f0ea1cedad0cad722f00c14a",
"versionType": "git"
},
{
"lessThan": "13765de8148f71fa795e0a6607de37c49ea5915a",
"status": "affected",
"version": "4ef0c5c6b5ba1f38f0ea1cedad0cad722f00c14a",
"versionType": "git"
},
{
"status": "affected",
"version": "25d40b828fb855ee62e1039c65a666c9afd60786",
"versionType": "git"
},
{
"lessThan": "5.10.137",
"status": "affected",
"version": "5.10.80",
"versionType": "semver"
},
{
"lessThan": "5.15.27",
"status": "affected",
"version": "5.15.3",
"versionType": "semver"
},
{
"lessThan": "5.15",
"status": "affected",
"version": "5.14.19",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/sched/core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.16"
},
{
"lessThan": "5.16",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.137",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.27",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.16.*",
"status": "unaffected",
"version": "5.16.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "5.17",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"configurations": [
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"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/fair: Fix fault in reweight_entity\n\nSyzbot found a GPF in reweight_entity. This has been bisected to\ncommit 4ef0c5c6b5ba (\"kernel/sched: Fix sched_fork() access an invalid\nsched_task_group\")\n\nThere\u00a0is a race between sched_post_fork() and setpriority(PRIO_PGRP)\nwithin a thread group that causes a null-ptr-deref\u00a0in\nreweight_entity() in CFS. The scenario is that the main process spawns\nnumber of new threads, which then call setpriority(PRIO_PGRP, 0, -20),\nwait, and exit. For each of the new threads the copy_process() gets\ninvoked, which adds the new task_struct and calls sched_post_fork()\nfor it.\n\nIn the above scenario there is a possibility that\nsetpriority(PRIO_PGRP) and set_one_prio() will be called for a thread\nin the group that is just being created by copy_process(), and for\nwhich the sched_post_fork() has not been executed yet. This will\ntrigger a null pointer dereference in reweight_entity(),\u00a0as it will\ntry to access the run queue pointer, which hasn\u0027t been set.\n\nBefore the mentioned change the cfs_rq pointer for the task has been\nset in sched_fork(), which is called much earlier in copy_process(),\nbefore the new task is added to the thread_group. Now it is done in\nthe sched_post_fork(), which is called after that. To fix the issue\nthe remove the update_load param from the update_load param() function\nand call reweight_task() only if the task flag doesn\u0027t have the\nTASK_NEW flag set."
},
{
"lang": "es",
"value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: sched/fair: Solucionar falla en reweight_entity Syzbot encontr\u00f3 un GPF en reweight_entity. Esto se ha dividido en dos para el commit 4ef0c5c6b5ba (\"kernel/sched: Fix sched_fork() accede a un sched_task_group no v\u00e1lido\") Hay una ejecuci\u00f3n entre sched_post_fork() y setpriority(PRIO_PGRP) dentro de un grupo de subprocesos que provoca un null-ptr-deref en reweight_entity () en el SFC. El escenario es que el proceso principal genera una cantidad de subprocesos nuevos, que luego llaman a setpriority(PRIO_PGRP, 0, -20), esperan y salen. Para cada uno de los nuevos subprocesos, se invoca copy_process(), lo que agrega la nueva task_struct y llama a sched_post_fork() para ello. En el escenario anterior existe la posibilidad de que se llame a setpriority(PRIO_PGRP) y set_one_prio() para un subproceso en el grupo que acaba de crear copy_process(), y para el cual sched_post_fork() a\u00fan no se ha ejecutado. Esto desencadenar\u00e1 una desreferencia del puntero nulo en reweight_entity(), ya que intentar\u00e1 acceder al puntero de la cola de ejecuci\u00f3n, que no se ha configurado. Antes del cambio mencionado, el puntero cfs_rq para la tarea se configur\u00f3 en sched_fork(), que se llama mucho antes en copy_process(), antes de que la nueva tarea se agregue al thread_group. Ahora se hace en sched_post_fork(), que se llama despu\u00e9s de eso. Para solucionar el problema, elimine el par\u00e1metro update_load de la funci\u00f3n update_load param() y llame a reweight_task() solo si el indicador de tarea no tiene establecido el indicador TASK_NEW."
}
],
"id": "CVE-2022-48921",
"lastModified": "2026-06-17T05:16:37.260",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 4.7,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.0,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2022-48921",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2024-09-10T15:33:28.558357Z",
"version": "2.0.3"
}
}
]
},
"published": "2024-08-22T02:15:08.197",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
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"url": "https://git.kernel.org/stable/c/13765de8148f71fa795e0a6607de37c49ea5915a"
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
"weaknesses": [
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"description": [
{
"lang": "en",
"value": "CWE-362"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Nomenclature
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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