Azure Linux 3.0 セキュリティ更新カーネルCVE-2024-42245]

medium Nessus プラグイン ID 295904

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概要

リモートの Azure Linux ホストに 1 つ以上のセキュリティ更新プログラムがありません。

説明

リモートの Azure Linux 3.0 ホストにインストールされているカーネルのバージョンは、テスト済みのバージョンより前です。したがって、CVE-2024-42245 のアドバイザリに記載されている脆弱性の影響を受けます。

- Linux カーネルでは、以下の脆弱性が解決されています: Revert sched/fair: Make sure to try to detach at least one movable task This reverts commit b0defa7ae03ecf91b8bfd10ede430cff12fcbd06.
b0defa7ae03ec changed the load balancing logic to ignore env.max_loop if all tasks examined to that point were pinned. The goal of the patch was to make it more likely to be able to detach a task buried in a long list of pinned tasks. However, this has the unfortunate side effect of creating an O(n) iteration in detach_tasks(), as we now must fully iterate every task on a cpu if all or most are pinned. Since this load balance code is done with rq lock held, and often in softirq context, it is very easy to trigger hard lockups. We observed such hard lockups with a user who affined O(10k) threads to a single cpu. When I discussed this with Vincent he initially suggested that we keep the limit on the number of tasks to detach, but increase the number of tasks we can search. However, after some back and forth on the mailing list, he recommended we instead revert the original patch, as it seems likely no one was actually getting hit by the original issue. (CVE-2024-42245)

Nessus はこの問題をテストしておらず、代わりにアプリケーションが自己報告するバージョン番号にのみ依存していることに注意してください。