CVE-2024-36891 Information

Description

In the Linux kernel the following vulnerability has been resolved:

maple_tree: fix mas_empty_area_rev() null pointer dereference

Currently the code calls mas_start() followed by mas_data_end() if the maple state is MA_START but mas_start() may return with the maple state node == NULL. This will lead to a null pointer dereference when checking information in the NULL node which is done in mas_data_end().

Avoid setting the offset if there is no node by waiting until after the maple state is checked for an empty or single entry state.

A user could trigger the events to cause a kernel oops by unmapping all vmas to produce an empty maple tree then mapping a vma that would cause the scenario described above.

Reference

https://git.kernel.org/stable/c/6c9c7c1e63b198a8b979ad963eb21410f10ccb00 https://git.kernel.org/stable/c/f3956791cf526540addd3295e4c1e0f0442486cc https://git.kernel.org/stable/c/955a923d2809803980ff574270f81510112be9cf