drm/drm_file:修复 pid 引用计数竞争 (CVE-2024-39486)

admin 2024-07-09 08:08:33 Ali_nvd 来源:ZONE.CI 全球网 0 阅读模式
drm/drm_file:修复 pid 引用计数竞争 (CVE-2024-39486)

CVE编号

CVE-2024-39486

利用情况

暂无

补丁情况

N/A

披露时间

2024-07-06
漏洞描述
In the Linux kernel, the following vulnerability has been resolved: drm/drm_file: Fix pid refcounting race filp->pid is supposed to be a refcounted pointer; however, before this patch, drm_file_update_pid() only increments the refcount of a struct pid after storing a pointer to it in filp->pid and dropping the dev->filelist_mutex, making the following race possible: process A process B ========= ========= begin drm_file_update_pid mutex_lock(&dev->filelist_mutex) rcu_replace_pointer(filp->pid, <pid B>, 1) mutex_unlock(&dev->filelist_mutex) begin drm_file_update_pid mutex_lock(&dev->filelist_mutex) rcu_replace_pointer(filp->pid, <pid A>, 1) mutex_unlock(&dev->filelist_mutex) get_pid(<pid A>) synchronize_rcu() put_pid(<pid B>) *** pid B reaches refcount 0 and is freed here *** get_pid(<pid B>) *** UAF *** synchronize_rcu() put_pid(<pid A>) As far as I know, this race can only occur with CONFIG_PREEMPT_RCU=y because it requires RCU to detect a quiescent state in code that is not explicitly calling into the scheduler. This race leads to use-after-free of a "struct pid". It is probably somewhat hard to hit because process A has to pass through a synchronize_rcu() operation while process B is between mutex_unlock() and get_pid(). Fix it by ensuring that by the time a pointer to the current task's pid is stored in the file, an extra reference to the pid has been taken. This fix also removes the condition for synchronize_rcu(); I think that optimization is unnecessary complexity, since in that case we would usually have bailed out on the lockless check above.
解决建议
建议您更新当前系统或软件至最新版,完成漏洞的修复。
参考链接
https://git.kernel.org/stable/c/0acce2a5c619ef1abdee783d7fea5eac78ce4844
https://git.kernel.org/stable/c/16682588ead4a593cf1aebb33b36df4d1e9e4ffa
https://git.kernel.org/stable/c/4f2a129b33a2054e62273edd5a051c34c08d96e9
CVSS3评分 N/A
  • 攻击路径 N/A
  • 攻击复杂度 N/A
  • 权限要求 N/A
  • 影响范围 N/A
  • 用户交互 N/A
  • 可用性 N/A
  • 保密性 N/A
  • 完整性 N/A
N/A
CWE-ID 漏洞类型
- avd.aliyun.com
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