Linux Kernel up to 6.6.15/6.7.3/6.8-rc2 pds_core queue_work null pointer dereference

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 6.6.15/6.7.3/6.8-rc2. Impacted is the function queue_work of the component pds_core. The manipulation leads to null pointer dereference. This vulnerability is uniquely identified as CVE-2024-26623. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.15/6.7.3/6.8-rc2 (Operating System). It has been rated as critical. This issue affects the function queue_work of the component pds_core. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: pds_core: Prevent race issues involving the adminq There are multiple paths that can result in using the pdsc's adminq. [1] pdsc_adminq_isr and the resulting work from queue_work(), i.e. pdsc_work_thread()->pdsc_process_adminq() [2] pdsc_adminq_post() When the device goes through reset via PCIe reset and/or a fw_down/fw_up cycle due to bad PCIe state or bad device state the adminq is destroyed and recreated. A NULL pointer dereference can happen if [1] or [2] happens after the adminq is already destroyed. In order to fix this, add some further state checks and implement reference counting for adminq uses. Reference counting was used because multiple threads can attempt to access the adminq at the same time via [1] or [2]. Additionally, multiple clients (i.e. pds-vfio-pci) can be using [2] at the same time. The adminq_refcnt is initialized to 1 when the adminq has been allocated and is ready to use. Users/clients of the adminq (i.e. [1] and [2]) will increment the refcnt when they are using the adminq. When the driver goes into a fw_down cycle it will set the PDSC_S_FW_DEAD bit and then wait for the adminq_refcnt to hit 1. Setting the PDSC_S_FW_DEAD before waiting will prevent any further adminq_refcnt increments. Waiting for the adminq_refcnt to hit 1 allows for any current users of the adminq to finish before the driver frees the adminq. Once the adminq_refcnt hits 1 the driver clears the refcnt to signify that the adminq is deleted and cannot be used. On the fw_up cycle the driver will once again initialize the adminq_refcnt to 1 allowing the adminq to be used again.

The weakness was disclosed 03/06/2024. It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2024-26623 since 02/19/2024. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 209512 (Oracle Linux 8 / 9 : Unbreakable Enterprise kernel (ELSA-2024-12796)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.16, 6.7.4 or 6.8-rc3 eliminates this vulnerability. Applying the patch 22cd6046eb21/5939feb63ea1/7e82a8745b95 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (209512). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5
• 6.6.6
• 6.6.7
• 6.6.8
• 6.6.9
• 6.6.10
• 6.6.11
• 6.6.12
• 6.6.13
• 6.6.14
• 6.6.15
• 6.7.0
• 6.7.1
• 6.7.2
• 6.7.3
• 6.8-rc1
• 6.8-rc2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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