| 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-2021-47163: tipc: wait and exit until all work queues are done |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| tipc: wait and exit until all work queues are done |
| |
| On some host, a crash could be triggered simply by repeating these |
| commands several times: |
| |
| # modprobe tipc |
| # tipc bearer enable media udp name UDP1 localip 127.0.0.1 |
| # rmmod tipc |
| |
| [] BUG: unable to handle kernel paging request at ffffffffc096bb00 |
| [] Workqueue: events 0xffffffffc096bb00 |
| [] Call Trace: |
| [] ? process_one_work+0x1a7/0x360 |
| [] ? worker_thread+0x30/0x390 |
| [] ? create_worker+0x1a0/0x1a0 |
| [] ? kthread+0x116/0x130 |
| [] ? kthread_flush_work_fn+0x10/0x10 |
| [] ? ret_from_fork+0x35/0x40 |
| |
| When removing the TIPC module, the UDP tunnel sock will be delayed to |
| release in a work queue as sock_release() can't be done in rtnl_lock(). |
| If the work queue is schedule to run after the TIPC module is removed, |
| kernel will crash as the work queue function cleanup_beareri() code no |
| longer exists when trying to invoke it. |
| |
| To fix it, this patch introduce a member wq_count in tipc_net to track |
| the numbers of work queues in schedule, and wait and exit until all |
| work queues are done in tipc_exit_net(). |
| |
| The Linux kernel CVE team has assigned CVE-2021-47163 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.1 with commit d0f91938bede204a343473792529e0db7d599836 and fixed in 5.4.124 with commit d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa |
| Issue introduced in 4.1 with commit d0f91938bede204a343473792529e0db7d599836 and fixed in 5.10.42 with commit 5195ec5e365a2a9331bfeb585b613a6e94f98dba |
| Issue introduced in 4.1 with commit d0f91938bede204a343473792529e0db7d599836 and fixed in 5.12.9 with commit b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d |
| Issue introduced in 4.1 with commit d0f91938bede204a343473792529e0db7d599836 and fixed in 5.13 with commit 04c26faa51d1e2fe71cf13c45791f5174c37f986 |
| |
| 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-2021-47163 |
| 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: |
| net/tipc/core.c |
| net/tipc/core.h |
| net/tipc/udp_media.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/d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa |
| https://git.kernel.org/stable/c/5195ec5e365a2a9331bfeb585b613a6e94f98dba |
| https://git.kernel.org/stable/c/b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d |
| https://git.kernel.org/stable/c/04c26faa51d1e2fe71cf13c45791f5174c37f986 |
