• CVE-2021-47281

发布时间: 2024年6月21日

修改时间: 2024年12月28日

概要

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix race of snd_seq_timer_open() The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses. It looks as if it's checking the already existing timer instance at the beginning, but it's not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily. This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently. For avoiding the race, add a proper check at the assignment of tmr->timeri again, and return -EBUSY if it's been already registered.

CVSS v3 指标

NVD openEuler
Confidentiality High None
Attack Vector Local Local
CVSS评分 7.0 5.5
Attack Complexity High Low
Privileges Required Low Low
Scope Unchanged Unchanged
Integrity High None
User Interaction None None
Availability High High

安全公告

公告名 概要 发布时间
KylinSec-SA-2024-4721 In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix race of snd_seq_timer_open() The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses. It looks as if it's checking the already existing timer instance at the beginning, but it's not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily. This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently. For avoiding the race, add a proper check at the assignment of tmr->timeri again, and return -EBUSY if it's been already registered. 2024年6月21日
KylinSec-SA-2024-4787 kernel security update 2024年6月21日

影响产品

产品 状态
KY3.4-5A kernel Fixed
KY3.5.2 kernel Unaffected
V6 kernel Unaffected