btrfs：qgroup：修复子卷操作中的 qgroup prealloc rsv 泄漏 (CVE-2024-35956)
CVE编号
CVE-2024-35956利用情况
暂无补丁情况
N/A披露时间
2024-05-20漏洞描述
In the Linux kernel, the following vulnerability has been resolved: btrfs: qgroup: fix qgroup prealloc rsv leak in subvolume operations Create subvolume, create snapshot and delete subvolume all use btrfs_subvolume_reserve_metadata() to reserve metadata for the changes done to the parent subvolume's fs tree, which cannot be mediated in the normal way via start_transaction. When quota groups (squota or qgroups) are enabled, this reserves qgroup metadata of type PREALLOC. Once the operation is associated to a transaction, we convert PREALLOC to PERTRANS, which gets cleared in bulk at the end of the transaction. However, the error paths of these three operations were not implementing this lifecycle correctly. They unconditionally converted the PREALLOC to PERTRANS in a generic cleanup step regardless of errors or whether the operation was fully associated to a transaction or not. This resulted in error paths occasionally converting this rsv to PERTRANS without calling record_root_in_trans successfully, which meant that unless that root got recorded in the transaction by some other thread, the end of the transaction would not free that root's PERTRANS, leaking it. Ultimately, this resulted in hitting a WARN in CONFIG_BTRFS_DEBUG builds at unmount for the leaked reservation. The fix is to ensure that every qgroup PREALLOC reservation observes the following properties: 1. any failure before record_root_in_trans is called successfully results in freeing the PREALLOC reservation. 2. after record_root_in_trans, we convert to PERTRANS, and now the transaction owns freeing the reservation. This patch enforces those properties on the three operations. Without it, generic/269 with squotas enabled at mkfs time would fail in ~5-10 runs on my system. With this patch, it ran successfully 1000 times in a row.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。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 | |||||
- 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
| CWE-ID | 漏洞类型 |
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