CVE-2022-48892

Aug. 29, 2024, 2:35 a.m.

7.8
High

Description

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.

Product(s) Impacted

Vendor Product Versions
Linux
  • Linux Kernel
  • *

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-415
Double Free
The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
o linux linux_kernel / / / / / / / /
o linux linux_kernel / / / / / / / /

References

https://git.kernel.org/stable/c/7b5cc7fd1789ea5dbb942c9f8207b076d365badc
https://git.kernel.org/stable/c/87ca4f9efbd7cc649ff43b87970888f2812945b8
https://git.kernel.org/stable/c/b22faa21b6230d5eccd233e1b7e0026a5002b287

Tags

416baaa9-dc9f-4396-8d5f-8c081fb06d67
CWE-415
2024-08-21
CVE-2022-48892

CVSS Score

7.8 / 10

CVSS Data - 3.1

  • Attack Vector: LOCAL
  • Attack Complexity: LOW
  • Privileges Required: LOW
  • Scope: UNCHANGED
  • Confidentiality Impact: HIGH
  • Integrity Impact: HIGH
  • Availability Impact: HIGH

    • CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

    View Vector String

Timeline

Published: Aug. 21, 2024, 7:15 a.m.
Last Modified: Aug. 29, 2024, 2:35 a.m.

Status : Analyzed

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

416baaa9-dc9f-4396-8d5f-8c081fb06d67

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.