drm/prime：使用 drm_gem_ttm_mmap 修复 mmap 中释放后的使用 (CVE-2021-47200)

CVE编号

CVE-2021-47200

利用情况

暂无

补丁情况

N/A

披露时间

2024-04-11

漏洞描述

In the Linux kernel, the following vulnerability has been resolved: drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap drm_gem_ttm_mmap() drops a reference to the gem object on success. If the gem object's refcount == 1 on entry to drm_gem_prime_mmap(), that drop will free the gem object, and the subsequent drm_gem_object_get() will be a UAF. Fix by grabbing a reference before calling the mmap helper. This issue was forseen when the reference dropping was adding in commit 9786b65bc61ac ("drm/ttm: fix mmap refcounting"): "For that to work properly the drm_gem_object_get() call in drm_gem_ttm_mmap() must be moved so it happens before calling obj->funcs->mmap(), otherwise the gem refcount would go down to zero."

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/4f8e469a2384dfa4047145b0093126462cbb6dc0
https://git.kernel.org/stable/c/8244a3bc27b3efd057da154b8d7e414670d5044f

受影响软件情况

#	类型	厂商	产品	版本	影响面
1
	运行在以下环境
	系统	debian_10	linux	*		Up to (excluding) 4.19.304-1
	运行在以下环境
	系统	debian_12	linux	*		Up to (excluding) 5.15.5-1

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

Exp相关链接

- avd.aliyun.com