| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-49854: block, bfq: fix uaf for accessing waker_bfqq after splitting |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| block, bfq: fix uaf for accessing waker_bfqq after splitting |
| |
| After commit 42c306ed7233 ("block, bfq: don't break merge chain in |
| bfq_split_bfqq()"), if the current procress is the last holder of bfqq, |
| the bfqq can be freed after bfq_split_bfqq(). Hence recored the bfqq and |
| then access bfqq->waker_bfqq may trigger UAF. What's more, the waker_bfqq |
| may in the merge chain of bfqq, hence just recored waker_bfqq is still |
| not safe. |
| |
| Fix the problem by adding a helper bfq_waker_bfqq() to check if |
| bfqq->waker_bfqq is in the merge chain, and current procress is the only |
| holder. |
| |
| The Linux kernel CVE team has assigned CVE-2024-49854 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.19.323 with commit 9e813033594b141f61ff0ef0cfaaef292564b041 |
| Issue introduced in 5.4.285 with commit 3a5f45a4ad4e1fd36b0a998eef03d76a4f02a2a8 |
| Issue introduced in 5.10.227 with commit 3630a18846c7853aa326d3b42fd0a855af7b41bc |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-49854 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| block/bfq-iosched.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/63a07379fdb6c72450cb05294461c6016b8b7726 |
| https://git.kernel.org/stable/c/de0456460f2abf921e356ed2bd8da87a376680bd |
| https://git.kernel.org/stable/c/0780451f03bf518bc032a7c584de8f92e2d39d7f |
| https://git.kernel.org/stable/c/0b8bda0ff17156cd3f60944527c9d8c9f99f1583 |
| https://git.kernel.org/stable/c/cae58d19121a70329cf971359e2518c93fec04fe |
| https://git.kernel.org/stable/c/1ba0403ac6447f2d63914fb760c44a3b19c44eaf |
