| 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-2025-21695: platform/x86: dell-uart-backlight: fix serdev race |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| platform/x86: dell-uart-backlight: fix serdev race |
| |
| The dell_uart_bl_serdev_probe() function calls devm_serdev_device_open() |
| before setting the client ops via serdev_device_set_client_ops(). This |
| ordering can trigger a NULL pointer dereference in the serdev controller's |
| receive_buf handler, as it assumes serdev->ops is valid when |
| SERPORT_ACTIVE is set. |
| |
| This is similar to the issue fixed in commit 5e700b384ec1 |
| ("platform/chrome: cros_ec_uart: properly fix race condition") where |
| devm_serdev_device_open() was called before fully initializing the |
| device. |
| |
| Fix the race by ensuring client ops are set before enabling the port via |
| devm_serdev_device_open(). |
| |
| Note, serdev_device_set_baudrate() and serdev_device_set_flow_control() |
| calls should be after the devm_serdev_device_open() call. |
| |
| The Linux kernel CVE team has assigned CVE-2025-21695 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.10 with commit 484bae9e4d6acb5eec39e1ea47f9aa43f11b154d and fixed in 6.12.11 with commit d3a24d923333f75aaece9acb051d676edc0afb75 |
| Issue introduced in 6.10 with commit 484bae9e4d6acb5eec39e1ea47f9aa43f11b154d and fixed in 6.13 with commit 1b2128aa2d45ab20b22548dcf4b48906298ca7fd |
| |
| 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-2025-21695 |
| 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/platform/x86/dell/dell-uart-backlight.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/d3a24d923333f75aaece9acb051d676edc0afb75 |
| https://git.kernel.org/stable/c/1b2128aa2d45ab20b22548dcf4b48906298ca7fd |
