| 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-2024-39508: io_uring/io-wq: Use set_bit() and test_bit() at worker->flags |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| io_uring/io-wq: Use set_bit() and test_bit() at worker->flags |
| |
| Utilize set_bit() and test_bit() on worker->flags within io_uring/io-wq |
| to address potential data races. |
| |
| The structure io_worker->flags may be accessed through various data |
| paths, leading to concurrency issues. When KCSAN is enabled, it reveals |
| data races occurring in io_worker_handle_work and |
| io_wq_activate_free_worker functions. |
| |
| BUG: KCSAN: data-race in io_worker_handle_work / io_wq_activate_free_worker |
| write to 0xffff8885c4246404 of 4 bytes by task 49071 on cpu 28: |
| io_worker_handle_work (io_uring/io-wq.c:434 io_uring/io-wq.c:569) |
| io_wq_worker (io_uring/io-wq.c:?) |
| <snip> |
| |
| read to 0xffff8885c4246404 of 4 bytes by task 49024 on cpu 5: |
| io_wq_activate_free_worker (io_uring/io-wq.c:? io_uring/io-wq.c:285) |
| io_wq_enqueue (io_uring/io-wq.c:947) |
| io_queue_iowq (io_uring/io_uring.c:524) |
| io_req_task_submit (io_uring/io_uring.c:1511) |
| io_handle_tw_list (io_uring/io_uring.c:1198) |
| <snip> |
| |
| Line numbers against commit 18daea77cca6 ("Merge tag 'for-linus' of |
| git://git.kernel.org/pub/scm/virt/kvm/kvm"). |
| |
| These races involve writes and reads to the same memory location by |
| different tasks running on different CPUs. To mitigate this, refactor |
| the code to use atomic operations such as set_bit(), test_bit(), and |
| clear_bit() instead of basic "and" and "or" operations. This ensures |
| thread-safe manipulation of worker flags. |
| |
| Also, move `create_index` to avoid holes in the structure. |
| |
| The Linux kernel CVE team has assigned CVE-2024-39508 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.1 with commit 2b188cc1bb857a9d4701ae59aa7768b5124e262e and fixed in 6.6.35 with commit ab702c3483db9046bab9f40306f1a28b22dbbdc0 |
| Issue introduced in 5.1 with commit 2b188cc1bb857a9d4701ae59aa7768b5124e262e and fixed in 6.9.6 with commit 1cbb0affb15470a9621267fe0a8568007553a4bf |
| Issue introduced in 5.1 with commit 2b188cc1bb857a9d4701ae59aa7768b5124e262e and fixed in 6.10 with commit 8a565304927fbd28c9f028c492b5c1714002cbab |
| |
| 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-2024-39508 |
| 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: |
| io_uring/io-wq.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/ab702c3483db9046bab9f40306f1a28b22dbbdc0 |
| https://git.kernel.org/stable/c/1cbb0affb15470a9621267fe0a8568007553a4bf |
| https://git.kernel.org/stable/c/8a565304927fbd28c9f028c492b5c1714002cbab |
