In the Linux kernel, the following vulnerability has been resolved:
net: hso: fix null-ptr-deref during tty device unregistration
Multiple ttys try to claim the same the minor number causing a double
unregistration of the same device. The first unregistration succeeds
but the next one results in a null-ptr-deref.
The get_free_serial_index() function returns an available minor number
but doesn't assign it immediately. The assignment is done by the caller
later. But before this assignment, calls to get_free_serial_index()
would return the same minor number.
Fix this by modifying get_free_serial_index to assign the minor number
immediately after one is found to be and rename it to obtain_minor()
to better reflect what it does. Similary, rename set_serial_by_index()
to release_minor() and modify it to free up the minor number of the
given hso_serial. Every obtain_minor() should have corresponding
release_minor() call.
CVE-2021-46904 - Medium Severity Vulnerability
Julia Cartwright's fork of linux-stable-rt.git
Library home page: https://git.kernel.org/pub/scm/linux/kernel/git/julia/linux-stable-rt.git
Found in HEAD commit: 63ac601c421ad3f087ec68a99300cc5058d1cc54
Found in base branch: master
In the Linux kernel, the following vulnerability has been resolved: net: hso: fix null-ptr-deref during tty device unregistration Multiple ttys try to claim the same the minor number causing a double unregistration of the same device. The first unregistration succeeds but the next one results in a null-ptr-deref. The get_free_serial_index() function returns an available minor number but doesn't assign it immediately. The assignment is done by the caller later. But before this assignment, calls to get_free_serial_index() would return the same minor number. Fix this by modifying get_free_serial_index to assign the minor number immediately after one is found to be and rename it to obtain_minor() to better reflect what it does. Similary, rename set_serial_by_index() to release_minor() and modify it to free up the minor number of the given hso_serial. Every obtain_minor() should have corresponding release_minor() call.
Publish Date: 2024-02-26
URL: CVE-2021-46904
Base Score Metrics: - Exploitability Metrics: - Attack Vector: Local - Attack Complexity: Low - Privileges Required: Low - User Interaction: None - Scope: Unchanged - Impact Metrics: - Confidentiality Impact: None - Integrity Impact: None - Availability Impact: High
For more information on CVSS3 Scores, click here.Type: Upgrade version
Origin: https://www.linuxkernelcves.com/cves/CVE-2021-46904
Release Date: 2024-02-26
Fix Resolution: v4.4.268,v4.9.268,v4.14.232,v4.19.187,v5.4.112,v5.10.30,v5.11.14
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