| 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-2025-21846: acct: perform last write from workqueue |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| acct: perform last write from workqueue |
| |
| In [1] it was reported that the acct(2) system call can be used to |
| trigger NULL deref in cases where it is set to write to a file that |
| triggers an internal lookup. This can e.g., happen when pointing acc(2) |
| to /sys/power/resume. At the point the where the write to this file |
| happens the calling task has already exited and called exit_fs(). A |
| lookup will thus trigger a NULL-deref when accessing current->fs. |
| |
| Reorganize the code so that the the final write happens from the |
| workqueue but with the caller's credentials. This preserves the |
| (strange) permission model and has almost no regression risk. |
| |
| This api should stop to exist though. |
| |
| The Linux kernel CVE team has assigned CVE-2025-21846 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 5.4.291 with commit 8acbf4a88c6a98c8ed00afd1a7d1abcca9b4735e |
| Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 5.10.235 with commit b03782ae707cc45e65242c7cddd8e28f1c22cde5 |
| Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 5.15.179 with commit 5d5b936cfa4b0d5670ca7420ef165a074bc008eb |
| Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.1.130 with commit 5ee8da9bea70dda492d61f075658939af33d8410 |
| Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.6.80 with commit 5c928e14a2ccd99462f2351ead627b58075bb736 |
| Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.12.17 with commit 5a59ced8ffc71973d42c82484a719c8f6ac8f7f7 |
| Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.13.5 with commit a8136afca090412a36429cb6c2543c714d9c0f84 |
| Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.14 with commit 56d5f3eba3f5de0efdd556de4ef381e109b973a9 |
| |
| 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-2025-21846 |
| 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: |
| kernel/acct.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/8acbf4a88c6a98c8ed00afd1a7d1abcca9b4735e |
| https://git.kernel.org/stable/c/b03782ae707cc45e65242c7cddd8e28f1c22cde5 |
| https://git.kernel.org/stable/c/5d5b936cfa4b0d5670ca7420ef165a074bc008eb |
| https://git.kernel.org/stable/c/5ee8da9bea70dda492d61f075658939af33d8410 |
| https://git.kernel.org/stable/c/5c928e14a2ccd99462f2351ead627b58075bb736 |
| https://git.kernel.org/stable/c/5a59ced8ffc71973d42c82484a719c8f6ac8f7f7 |
| https://git.kernel.org/stable/c/a8136afca090412a36429cb6c2543c714d9c0f84 |
| https://git.kernel.org/stable/c/56d5f3eba3f5de0efdd556de4ef381e109b973a9 |
