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CVE-2021-47505— Linux kernel 安全漏洞

一分钟漏洞结论

影响对象
Linux Linux
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel 存在安全漏洞，该漏洞源于 aio 模块由于缺少 POLLFREE 处理而导致的释放后重用问题。

CVSS 7.8 · High EPSS 0.25% · P16

影响版本矩阵 12

厂商产品 版本范围状态
Linux Linux 2c14fa838cbefc23cf1c73ca167ed85b274b2913< 321fba81ec034f88aea4898993c1bf15605c023f affected
2c14fa838cbefc23cf1c73ca167ed85b274b2913< 4105e6a128e8a98455dfc9e6dbb2ab0c33c4497f affected
2c14fa838cbefc23cf1c73ca167ed85b274b2913< 47ffefd88abfffe8a040bcc1dd0554d4ea6f7689 affected
2c14fa838cbefc23cf1c73ca167ed85b274b2913< 60d311f9e6381d779d7d53371f87285698ecee24 affected
2c14fa838cbefc23cf1c73ca167ed85b274b2913< 50252e4b5e989ce64555c7aef7516bdefc2fea72 affected
4.18 affected
< 4.18 unaffected
4.19.221≤ 4.19.* unaffected
… +4 条更多
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一、 漏洞 CVE-2021-47505 基础信息

漏洞信息
对漏洞内容有疑问？看看神龙的深度分析是否有帮助！
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Vulnerability Title
aio: fix use-after-free due to missing POLLFREE handling
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: aio: fix use-after-free due to missing POLLFREE handling signalfd_poll() and binder_poll() are special in that they use a waitqueue whose lifetime is the current task, rather than the struct file as is normally the case. This is okay for blocking polls, since a blocking poll occurs within one task; however, non-blocking polls require another solution. This solution is for the queue to be cleared before it is freed, by sending a POLLFREE notification to all waiters. Unfortunately, only eventpoll handles POLLFREE. A second type of non-blocking poll, aio poll, was added in kernel v4.18, and it doesn't handle POLLFREE. This allows a use-after-free to occur if a signalfd or binder fd is polled with aio poll, and the waitqueue gets freed. Fix this by making aio poll handle POLLFREE. A patch by Ramji Jiyani <ramjiyani@google.com> (https://lore.kernel.org/r/20211027011834.2497484-1-ramjiyani@google.com) tried to do this by making aio_poll_wake() always complete the request inline if POLLFREE is seen. However, that solution had two bugs. First, it introduced a deadlock, as it unconditionally locked the aio context while holding the waitqueue lock, which inverts the normal locking order. Second, it didn't consider that POLLFREE notifications are missed while the request has been temporarily de-queued. The second problem was solved by my previous patch. This patch then properly fixes the use-after-free by handling POLLFREE in a deadlock-free way. It does this by taking advantage of the fact that freeing of the waitqueue is RCU-delayed, similar to what eventpoll does.
来源: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel 存在安全漏洞，该漏洞源于 aio 模块由于缺少 POLLFREE 处理而导致的释放后重用问题。
来源: 中国国家信息安全漏洞库 CNNVD
CVSS Information
N/A
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Type
N/A
来源: 中国国家信息安全漏洞库 CNNVD

受影响产品

厂商 产品 影响版本 CPE 订阅
Linux Linux 2c14fa838cbefc23cf1c73ca167ed85b274b2913 ~ 321fba81ec034f88aea4898993c1bf15605c023f -
Linux Linux 4.18 -

二、漏洞 CVE-2021-47505 的公开POC

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三、漏洞 CVE-2021-47505 的情报信息

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CVE-2021-47505 其他参考 (5)

同批安全公告 · Linux · 2024-05-24 · 共 72 条

CVE-2021-47544 9.8 CRITICAL Linux kernel 安全漏洞
CVE-2021-47536 9.8 CRITICAL Linux kernel 安全漏洞
CVE-2021-47506 9.8 CRITICAL Linux kernel 安全漏洞
CVE-2021-47520 8.8 HIGH Linux kernel 安全漏洞
CVE-2021-47535 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47533 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47500 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47552 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47551 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47555 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47541 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47561 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47517 7.8 HIGH Linux kernel 安全漏洞
CVE-2023-52880 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47512 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47502 7.8 HIGH Linux kernel 安全漏洞
CVE-2021-47515 7.5 HIGH Linux kernel 安全漏洞
CVE-2021-47559 7.5 HIGH Linux kernel 安全漏洞
CVE-2021-47549 Linux kernel 安全漏洞
CVE-2021-47569 Linux kernel 安全漏洞

显示前 20 条，共 72 条。 查看全部 &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47505

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