CVE-2024-35879

In the Linux kernel, the following vulnerability has been resolved:

of: dynamic: Synchronize of_changeset_destroy() with the devlink removals

In the following sequence:

1. of_platform_depopulate()
2. of_overlay_remove()

During the step 1, devices are destroyed and devlinks are removed. During the step 2, OF nodes are destroyed but __of_changeset_entry_destroy() can raise warnings related to missing of_node_put(): ERROR: memory leak, expected refcount 1 instead of 2 …

Indeed, during the devlink removals performed at step 1, the removal itself releasing the device (and the attached of_node) is done by a job queued in a workqueue and so, it is done asynchronously with respect to function calls. When the warning is present, of_node_put() will be called but wrongly too late from the workqueue job.

In order to be sure that any ongoing devlink removals are done before the of_node destruction, synchronize the of_changeset_destroy() with the devlink removals.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/3127b2ee50c424a96eb3559fbb7b43cf0b111c7a
• https://git.kernel.org/stable/c/3ee2424107546d882e1ddd75333ca9c32879908c
• https://git.kernel.org/stable/c/7b6df050c45a1ea158fd50bc32a8e1447dd1e951
• https://git.kernel.org/stable/c/801c8b8ec5bfb3519566dff16a5ecd48302fca82
• https://git.kernel.org/stable/c/8917e7385346bd6584890ed362985c219fe6ae84
• https://git.kernel.org/stable/c/ae6d76e4f06c37a623e357e79d49b17411db6f5c
• https://git.kernel.org/stable/c/3127b2ee50c424a96eb3559fbb7b43cf0b111c7a
• https://git.kernel.org/stable/c/3ee2424107546d882e1ddd75333ca9c32879908c
• https://git.kernel.org/stable/c/7b6df050c45a1ea158fd50bc32a8e1447dd1e951
• https://git.kernel.org/stable/c/801c8b8ec5bfb3519566dff16a5ecd48302fca82
• https://git.kernel.org/stable/c/8917e7385346bd6584890ed362985c219fe6ae84
• https://git.kernel.org/stable/c/ae6d76e4f06c37a623e357e79d49b17411db6f5c
• https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html