| 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-2022-48931: configfs: fix a race in configfs_{,un}register_subsystem() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| configfs: fix a race in configfs_{,un}register_subsystem() |
| |
| When configfs_register_subsystem() or configfs_unregister_subsystem() |
| is executing link_group() or unlink_group(), |
| it is possible that two processes add or delete list concurrently. |
| Some unfortunate interleavings of them can cause kernel panic. |
| |
| One of cases is: |
| A --> B --> C --> D |
| A <-- B <-- C <-- D |
| |
| delete list_head *B | delete list_head *C |
| --------------------------------|----------------------------------- |
| configfs_unregister_subsystem | configfs_unregister_subsystem |
| unlink_group | unlink_group |
| unlink_obj | unlink_obj |
| list_del_init | list_del_init |
| __list_del_entry | __list_del_entry |
| __list_del | __list_del |
| // next == C | |
| next->prev = prev | |
| | next->prev = prev |
| prev->next = next | |
| | // prev == B |
| | prev->next = next |
| |
| Fix this by adding mutex when calling link_group() or unlink_group(), |
| but parent configfs_subsystem is NULL when config_item is root. |
| So I create a mutex configfs_subsystem_mutex. |
| |
| The Linux kernel CVE team has assigned CVE-2022-48931 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 2.6.16 with commit 7063fbf2261194f72ee75afca67b3b38b554b5fa and fixed in 4.9.304 with commit 40805099af11f68c5ca7dbcfacf455da8f99f622 |
| Issue introduced in 2.6.16 with commit 7063fbf2261194f72ee75afca67b3b38b554b5fa and fixed in 4.14.269 with commit d1654de19d42f513b6cfe955cc77e7f427e05a77 |
| Issue introduced in 2.6.16 with commit 7063fbf2261194f72ee75afca67b3b38b554b5fa and fixed in 4.19.232 with commit a37024f7757c25550accdebf49e497ad6ae239fe |
| Issue introduced in 2.6.16 with commit 7063fbf2261194f72ee75afca67b3b38b554b5fa and fixed in 5.4.182 with commit b7e2b91fcb5c78c414e33dc8d50642e307ca0c5a |
| Issue introduced in 2.6.16 with commit 7063fbf2261194f72ee75afca67b3b38b554b5fa and fixed in 5.10.103 with commit a7ab53d3c27dfe83bb594456b9f38a37796ec39b |
| Issue introduced in 2.6.16 with commit 7063fbf2261194f72ee75afca67b3b38b554b5fa and fixed in 5.15.26 with commit e7a66dd2687758718eddd79b542a95cf3aa488cc |
| Issue introduced in 2.6.16 with commit 7063fbf2261194f72ee75afca67b3b38b554b5fa and fixed in 5.16.12 with commit 3aadfd46858b1f64d4d6a0654b863e21aabff975 |
| Issue introduced in 2.6.16 with commit 7063fbf2261194f72ee75afca67b3b38b554b5fa and fixed in 5.17 with commit 84ec758fb2daa236026506868c8796b0500c047d |
| |
| 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-2022-48931 |
| 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/configfs/dir.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/40805099af11f68c5ca7dbcfacf455da8f99f622 |
| https://git.kernel.org/stable/c/d1654de19d42f513b6cfe955cc77e7f427e05a77 |
| https://git.kernel.org/stable/c/a37024f7757c25550accdebf49e497ad6ae239fe |
| https://git.kernel.org/stable/c/b7e2b91fcb5c78c414e33dc8d50642e307ca0c5a |
| https://git.kernel.org/stable/c/a7ab53d3c27dfe83bb594456b9f38a37796ec39b |
| https://git.kernel.org/stable/c/e7a66dd2687758718eddd79b542a95cf3aa488cc |
| https://git.kernel.org/stable/c/3aadfd46858b1f64d4d6a0654b863e21aabff975 |
| https://git.kernel.org/stable/c/84ec758fb2daa236026506868c8796b0500c047d |
