| 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-2024-46683: drm/xe: prevent UAF around preempt fence |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| drm/xe: prevent UAF around preempt fence |
| |
| The fence lock is part of the queue, therefore in the current design |
| anything locking the fence should then also hold a ref to the queue to |
| prevent the queue from being freed. |
| |
| However, currently it looks like we signal the fence and then drop the |
| queue ref, but if something is waiting on the fence, the waiter is |
| kicked to wake up at some later point, where upon waking up it first |
| grabs the lock before checking the fence state. But if we have already |
| dropped the queue ref, then the lock might already be freed as part of |
| the queue, leading to uaf. |
| |
| To prevent this, move the fence lock into the fence itself so we don't |
| run into lifetime issues. Alternative might be to have device level |
| lock, or only release the queue in the fence release callback, however |
| that might require pushing to another worker to avoid locking issues. |
| |
| References: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2454 |
| References: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2342 |
| References: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2020 |
| (cherry picked from commit 7116c35aacedc38be6d15bd21b2fc936eed0008b) |
| |
| The Linux kernel CVE team has assigned CVE-2024-46683 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.8 with commit dd08ebf6c3525a7ea2186e636df064ea47281987 and fixed in 6.10.8 with commit 10081b0b0ed201f53e24bd92deb2e0f3c3e713d4 |
| Issue introduced in 6.8 with commit dd08ebf6c3525a7ea2186e636df064ea47281987 and fixed in 6.11 with commit 730b72480e29f63fd644f5fa57c9d46109428953 |
| |
| 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-2024-46683 |
| 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: |
| drivers/gpu/drm/xe/xe_exec_queue.c |
| drivers/gpu/drm/xe/xe_exec_queue_types.h |
| drivers/gpu/drm/xe/xe_preempt_fence.c |
| drivers/gpu/drm/xe/xe_preempt_fence_types.h |
| |
| |
| 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/10081b0b0ed201f53e24bd92deb2e0f3c3e713d4 |
| https://git.kernel.org/stable/c/730b72480e29f63fd644f5fa57c9d46109428953 |
