CVE-2024-35977 Affecting kernel-obs-build package, versions <6.4.0-150600.23.7.3
Threat Intelligence
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Test your applications- Snyk IDSNYK-SLES156-KERNELOBSBUILD-7718696
- published20 Aug 2024
- disclosed25 Jun 2024
Introduced: 25 Jun 2024
CVE-2024-35977 (opens in a new tab)How to fix?
Upgrade SLES:15.6 kernel-obs-build to version 6.4.0-150600.23.7.3 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-obs-build package and not the kernel-obs-build package as distributed by SLES.
See How to fix? for SLES:15.6 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
platform/chrome: cros_ec_uart: properly fix race condition
The cros_ec_uart_probe() function calls devm_serdev_device_open() before it calls serdev_device_set_client_ops(). This can trigger a NULL pointer dereference:
BUG: kernel NULL pointer dereference, address: 0000000000000000
...
Call Trace:
<TASK>
...
? ttyport_receive_buf
A simplified version of crashing code is as follows:
static inline size_t serdev_controller_receive_buf(struct serdev_controller *ctrl, const u8 *data, size_t count) { struct serdev_device *serdev = ctrl->serdev;if (!serdev || !serdev-&gt;ops-&gt;receive_buf) // CRASH! return 0; return serdev-&gt;ops-&gt;receive_buf(serdev, data, count);
}
It assumes that if SERPORT_ACTIVE is set and serdev exists, serdev->ops will also exist. This conflicts with the existing cros_ec_uart_probe() logic, as it first calls devm_serdev_device_open() (which sets SERPORT_ACTIVE), and only later sets serdev->ops via serdev_device_set_client_ops().
Commit 01f95d42b8f4 ("platform/chrome: cros_ec_uart: fix race condition") attempted to fix a similar race condition, but while doing so, made the window of error for this race condition to happen much wider.
Attempt to fix the race condition again, making sure we fully setup before calling devm_serdev_device_open().
References
- https://www.suse.com/security/cve/CVE-2024-35977.html
- https://bugzilla.suse.com/1224568
- https://git.kernel.org/stable/c/5e700b384ec13f5bcac9855cb28fcc674f1d3593
- https://git.kernel.org/stable/c/9e9bb74a93b7daa32313ccaefd0edc529d40daf8
- https://git.kernel.org/stable/c/cfd758041d8b79aa8c3f811b6bd6105379f2f702