CVE-2024-36891

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> maple_tree: fix mas_empty_area_rev() null pointer dereference<br /> <br /> Currently the code calls mas_start() followed by mas_data_end() if the<br /> maple state is MA_START, but mas_start() may return with the maple state<br /> node == NULL. This will lead to a null pointer dereference when checking<br /> information in the NULL node, which is done in mas_data_end().<br /> <br /> Avoid setting the offset if there is no node by waiting until after the<br /> maple state is checked for an empty or single entry state.<br /> <br /> A user could trigger the events to cause a kernel oops by unmapping all<br /> vmas to produce an empty maple tree, then mapping a vma that would cause<br /> the scenario described above.