Problem Description:

A particular case of memory sharing is mishandled in the virtual memory system. It is possible and legal to establish a relationship where multiple descendant processes share a mapping which shadows memory of an ancestor process. In this scenario, when one process modifies memory through such a mapping, the copy-on-write logic fails to invalidate other mappings of the source page. These stale mappings may remain even after the mapped pages have been reused for another purpose.

Impact:

An unprivileged local user process can maintain a mapping of a page after it is freed, allowing that process to read private data belonging to other processes or the kernel.

ge 12.2 lt 12.2_6

ge 11.4 lt 11.4_9