Bug 2019163 (CVE-2021-43057) - CVE-2021-43057 kernel: use-after-free in the SELinux handler for PTRACE_TRACEME
Summary: CVE-2021-43057 kernel: use-after-free in the SELinux handler for PTRACE_TRACEME
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2021-43057
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2008145 2019164 2020966 2021045
Blocks: 2019165
TreeView+ depends on / blocked
 
Reported: 2021-11-01 17:58 UTC by Guilherme de Almeida Suckevicz
Modified: 2022-05-17 11:45 UTC (History)
45 users (show)

Fixed In Version: kernel 5.15 rc3
Doc Type: If docs needed, set a value
Doc Text:
A use-after-free read flaw was found in selinux_ptrace_traceme in security/selinux/hooks.c in SELinux handler for PTRACE_TRACEME in the Linux kernel. In this flaw, an attempt to access the subjective credentials of another task may cause memory corruption by a user with local access and escalate privileges.
Clone Of:
Environment:
Last Closed: 2022-05-17 11:45:18 UTC
Embargoed:

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Description Guilherme de Almeida Suckevicz 2021-11-01 17:58:02 UTC 
An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges. This occurs because of an attempt to access the subjective credentials of another task.

Reference:
https://bugs.chromium.org/p/project-zero/issues/detail?id=2229

Upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a3727a8bac0a9e77c70820655fd8715523ba3db7
Comment 1 Guilherme de Almeida Suckevicz 2021-11-01 17:58:46 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2019164]
Comment 2 Justin M. Forbes 2021-11-02 20:51:22 UTC 
This was fixed for Fedora with the 5.14.8 stable kernel updates.
Comment 9 Product Security DevOps Team 2022-05-17 11:45:15 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-43057
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