CVE-2022-48846

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

block: release rq qos structures for queue without disk

blkcg_init_queue() may add rq qos structures to request queue, previously blk_cleanup_queue() calls rq_qos_exit() to release them, but commit 8e141f9eb803 (block: drain file system I/O on del_gendisk) moves rq_qos_exit() into del_gendisk(), so memory leak is caused because queues may not have disk, such as un-present scsi luns, nvme admin queue, …

Fixes the issue by adding rq_qos_exit() to blk_cleanup_queue() back.

BTW, v5.18 wont need this patch any more since we move blkcg_init_queue()/blkcg_exit_queue() into disk allocation/release handler, and patches have been in for-5.18/block.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.

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/60c2c8e2ef3a3ec79de8cbc80a06ca0c21df8c29
• https://git.kernel.org/stable/c/d4ad8736ac982111bb0be8306bf19c8207f6600e
• https://git.kernel.org/stable/c/daaca3522a8e67c46e39ef09c1d542e866f85f3b