cbcvebase.
CVE-2022-48921
published 2024-08-22

CVE-2022-48921: 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…

PriorityP416medium4.7CVSS 3.1
AVLACHPRLUINSUCNINAH
EPSS
0.17%
6.4th percentile
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.

Affected

19 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.16.14-1 (bookworm)linux 5.16.14-1 (bookworm)
linuxlinux——
linuxlinux——
linuxlinux>= 3869eecf050416a1d19bac60926f6b5d64b0aa58 < e0bcd6b5779352aed88f2e538a82a39f1a7715bbe0bcd6b5779352aed88f2e538a82a39f1a7715bb
linuxlinux>= 4ef0c5c6b5ba1f38f0ea1cedad0cad722f00c14a < 589a954daab5e18399860b6c8ffaeaf79844eb20589a954daab5e18399860b6c8ffaeaf79844eb20
linuxlinux>= 4ef0c5c6b5ba1f38f0ea1cedad0cad722f00c14a < 13765de8148f71fa795e0a6607de37c49ea5915a13765de8148f71fa795e0a6607de37c49ea5915a
linuxlinux>= 5.10.80 < 5.10.1375.10.137
linuxlinux>= 5.14.19 < 5.155.15
linuxlinux>= 5.15.3 < 5.15.275.15.27
linuxlinux>= c85c6fadbef0a3eab41540ea628fa8fe8928c820 < 8f317cd888059c59e2fa924bf4b0957cfa53f78e8f317cd888059c59e2fa924bf4b0957cfa53f78e
linuxlinux_kernel——
linuxlinux_kernel>= 0 < 5.10.140-15.10.140-1
linuxlinux_kernel>= 0 < 5.16.14-15.16.14-1
linuxlinux_kernel>= 0 < 5.16.14-15.16.14-1
linuxlinux_kernel>= 0 < 5.16.14-15.16.14-1
linuxlinux_kernel>= 5.10.80 < 5.10.1375.10.137
linuxlinux_kernel>= 5.14.19 < 5.155.15
linuxlinux_kernel>= 5.15.3 < 5.15.275.15.27
linuxlinux_kernel>= 5.16 < 5.16.135.16.13

CVSS provenance

nvdv3.14.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
osv4.7MEDIUM
vendor_debian4.7MEDIUM
vendor_redhat4.7MEDIUM
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