| 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-2024-36966: erofs: reliably distinguish block based and fscache mode |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| erofs: reliably distinguish block based and fscache mode |
| |
| When erofs_kill_sb() is called in block dev based mode, s_bdev may not |
| have been initialised yet, and if CONFIG_EROFS_FS_ONDEMAND is enabled, |
| it will be mistaken for fscache mode, and then attempt to free an anon_dev |
| that has never been allocated, triggering the following warning: |
| |
| ============================================ |
| ida_free called for id=0 which is not allocated. |
| WARNING: CPU: 14 PID: 926 at lib/idr.c:525 ida_free+0x134/0x140 |
| Modules linked in: |
| CPU: 14 PID: 926 Comm: mount Not tainted 6.9.0-rc3-dirty #630 |
| RIP: 0010:ida_free+0x134/0x140 |
| Call Trace: |
| <TASK> |
| erofs_kill_sb+0x81/0x90 |
| deactivate_locked_super+0x35/0x80 |
| get_tree_bdev+0x136/0x1e0 |
| vfs_get_tree+0x2c/0xf0 |
| do_new_mount+0x190/0x2f0 |
| [...] |
| ============================================ |
| |
| Now when erofs_kill_sb() is called, erofs_sb_info must have been |
| initialised, so use sbi->fsid to distinguish between the two modes. |
| |
| The Linux kernel CVE team has assigned CVE-2024-36966 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.6 with commit aca740cecbe57b12bd9c1fc632092af5ebacda0c and fixed in 6.6.32 with commit f9b877a7ee312ec8ce17598a7ef85cb820d7c371 |
| Issue introduced in 6.6 with commit aca740cecbe57b12bd9c1fc632092af5ebacda0c and fixed in 6.8.11 with commit dcdd49701e429c55b3644fd70fc58d85745f8cfe |
| Issue introduced in 6.6 with commit aca740cecbe57b12bd9c1fc632092af5ebacda0c and fixed in 6.9 with commit 7af2ae1b1531feab5d38ec9c8f472dc6cceb4606 |
| |
| 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-2024-36966 |
| 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/erofs/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/f9b877a7ee312ec8ce17598a7ef85cb820d7c371 |
| https://git.kernel.org/stable/c/dcdd49701e429c55b3644fd70fc58d85745f8cfe |
| https://git.kernel.org/stable/c/7af2ae1b1531feab5d38ec9c8f472dc6cceb4606 |
