humetlb、userfaultfd：修复了 userfaultfd 错误上的保留恢复 (CVE-2021-47214)

CVE编号

CVE-2021-47214

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: hugetlb, userfaultfd: fix reservation restore on userfaultfd error Currently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we bail out using "goto out_release_unlock;" in the cases where idx >= size, or !huge_pte_none(), the code will detect that new_pagecache_page == false, and so call restore_reserve_on_error(). In this case I see restore_reserve_on_error() delete the reservation, and the following call to remove_inode_hugepages() will increment h->resv_hugepages causing a 100% reproducible leak. We should treat the is_continue case similar to adding a page into the pagecache and set new_pagecache_page to true, to indicate that there is no reservation to restore on the error path, and we need not call restore_reserve_on_error(). Rename new_pagecache_page to page_in_pagecache to make that clear.

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/b5069d44e2fbc4a9093d005b3ef0949add3dd27e
https://git.kernel.org/stable/c/cc30042df6fcc82ea18acf0dace831503e60a0b7

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_11	linux	*		Up to (excluding) 5.10.209-2
	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