• CVE-2021-47506

发布时间: 2024年6月4日

修改时间: 2025年4月13日

概要

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix use-after-free due to delegation race A delegation break could arrive as soon as we've called vfs_setlease. A delegation break runs a callback which immediately (in nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we then exit nfs4_set_delegation without hashing the delegation, it will be freed as soon as the callback is done with it, without ever being removed from del_recall_lru. Symptoms show up later as use-after-free or list corruption warnings, usually in the laundromat thread. I suspect aba2072f4523 "nfsd: grant read delegations to clients holding writes" made this bug easier to hit, but I looked as far back as v3.0 and it looks to me it already had the same problem. So I'm not sure where the bug was introduced; it may have been there from the beginning.

CVSS v3 指标

NVD openEuler
Confidentiality High None
Attack Vector Local Local
CVSS评分 7.8 5.5
Attack Complexity Low 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-2024-2566 In the Linux kernel, the following vulnerability has been resolved: nfsd: fix use-after-free due to delegation race A delegation break could arrive as soon as we've called vfs_setlease. A delegation break runs a callback which immediately (in nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we then exit nfs4_set_delegation without hashing the delegation, it will be freed as soon as the callback is done with it, without ever being removed from del_recall_lru. Symptoms show up later as use-after-free or list corruption warnings, usually in the laundromat thread. I suspect aba2072f4523 "nfsd: grant read delegations to clients holding writes" made this bug easier to hit, but I looked as far back as v3.0 and it looks to me it already had the same problem. So I'm not sure where the bug was introduced; it may have been there from the beginning. 2024年6月4日

影响产品

产品 状态
KY3.4-5 kernel Unaffected
KY3.5.2 kernel Unaffected
KY3.5.3 kernel Unaffected
V6 kernel Unaffected