Ubuntu: (CVE-2024-26806): linux-raspi-realtime vulnerability

Ubuntu: (CVE-2024-26806): linux-raspi-realtime vulnerability

Severity

4

CVSS

(AV:L/AC:M/Au:N/C:P/I:P/A:P)

Published

04/04/2024

Created

02/12/2025

Added

02/11/2025

Modified

02/11/2025

Description

In the Linux kernel, the following vulnerability has been resolved: spi: cadence-qspi: remove system-wide suspend helper calls from runtime PM hooks The ->runtime_suspend() and ->runtime_resume() callbacks are not expected to call spi_controller_suspend() and spi_controller_resume(). Remove calls to those in the cadence-qspi driver. Those helpers have two roles currently: - They stop/start the queue, including dealing with the kworker. - They toggle the SPI controller SPI_CONTROLLER_SUSPENDED flag. It requires acquiring ctlr->bus_lock_mutex. Step one is irrelevant because cadence-qspi is not queued. Step two however has two implications: - A deadlock occurs, because ->runtime_resume() is called in a context where the lock is already taken (in the ->exec_op() callback, where the usage count is incremented). - It would disallow all operations once the device is auto-suspended. Here is a brief call tree highlighting the mutex deadlock: spi_mem_exec_op() ... spi_mem_access_start() mutex_lock(&ctlr->bus_lock_mutex) cqspi_exec_mem_op() pm_runtime_resume_and_get() cqspi_resume() spi_controller_resume() mutex_lock(&ctlr->bus_lock_mutex) ... spi_mem_access_end() mutex_unlock(&ctlr->bus_lock_mutex) ...

Solution(s)

• ubuntu-upgrade-linux-raspi-realtime

References

• https://attackerkb.com/topics/cve-2024-26806
• CVE - 2024-26806
• https://git.kernel.org/stable/c/041562ebc4759c9932b59a06527f8753b86da365
• https://git.kernel.org/stable/c/959043afe53ae80633e810416cee6076da6e91c6
• https://www.cve.org/CVERecord?id=CVE-2024-26806