cbcvebase.
CVE-2022-48892
published 2024-08-21

CVE-2022-48892: 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…

PriorityP339high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.25%
16.4th percentile
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.

Affected

10 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.7-1 (bookworm)linux 6.1.7-1 (bookworm)
linuxlinux
linuxlinux>= 07ec77a1d4e82526e1588979fff2f024f8e96df2 < b22faa21b6230d5eccd233e1b7e0026a5002b287b22faa21b6230d5eccd233e1b7e0026a5002b287
linuxlinux>= 07ec77a1d4e82526e1588979fff2f024f8e96df2 < 7b5cc7fd1789ea5dbb942c9f8207b076d365badc7b5cc7fd1789ea5dbb942c9f8207b076d365badc
linuxlinux>= 07ec77a1d4e82526e1588979fff2f024f8e96df2 < 87ca4f9efbd7cc649ff43b87970888f2812945b887ca4f9efbd7cc649ff43b87970888f2812945b8
linuxlinux_kernel>= 0 < 6.1.7-16.1.7-1
linuxlinux_kernel>= 0 < 6.1.7-16.1.7-1
linuxlinux_kernel>= 0 < 6.1.7-16.1.7-1
linuxlinux_kernel>= 5.15 < 5.15.895.15.89
linuxlinux_kernel>= 5.16 < 6.1.76.1.7

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8HIGH
vendor_redhat7.8HIGH
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