| 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-2024-50191: ext4: don't set SB_RDONLY after filesystem errors |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ext4: don't set SB_RDONLY after filesystem errors |
| |
| When the filesystem is mounted with errors=remount-ro, we were setting |
| SB_RDONLY flag to stop all filesystem modifications. We knew this misses |
| proper locking (sb->s_umount) and does not go through proper filesystem |
| remount procedure but it has been the way this worked since early ext2 |
| days and it was good enough for catastrophic situation damage |
| mitigation. Recently, syzbot has found a way (see link) to trigger |
| warnings in filesystem freezing because the code got confused by |
| SB_RDONLY changing under its hands. Since these days we set |
| EXT4_FLAGS_SHUTDOWN on the superblock which is enough to stop all |
| filesystem modifications, modifying SB_RDONLY shouldn't be needed. So |
| stop doing that. |
| |
| The Linux kernel CVE team has assigned CVE-2024-50191 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.15.168 with commit fbb177bc1d6487cd3e9b50ae0be2781b7297980d |
| Fixed in 6.1.113 with commit 4061e07f040a091f694f461b86a26cf95ae66439 |
| Fixed in 6.6.57 with commit 58c0648e4c773f5b54f0cb63bc8c7c6bf52719a9 |
| Fixed in 6.11.4 with commit ee77c388469116565e009eaa704a60bc78489e09 |
| Fixed in 6.12 with commit d3476f3dad4ad68ae5f6b008ea6591d1520da5d8 |
| |
| 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-2024-50191 |
| 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: |
| fs/ext4/super.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/fbb177bc1d6487cd3e9b50ae0be2781b7297980d |
| https://git.kernel.org/stable/c/4061e07f040a091f694f461b86a26cf95ae66439 |
| https://git.kernel.org/stable/c/58c0648e4c773f5b54f0cb63bc8c7c6bf52719a9 |
| https://git.kernel.org/stable/c/ee77c388469116565e009eaa704a60bc78489e09 |
| https://git.kernel.org/stable/c/d3476f3dad4ad68ae5f6b008ea6591d1520da5d8 |
