CVE-2024-42131

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

mm: avoid overflows in dirty throttling logic

The dirty throttling logic is interspersed with assumptions that dirty

limits in PAGE_SIZE units fit into 32-bit (so that various multiplications

fit into 64-bits). If limits end up being larger, we will hit overflows,

possible divisions by 0 etc. Fix these problems by never allowing so

large dirty limits as they have dubious practical value anyway. For

dirty_bytes / dirty_background_bytes interfaces we can just refuse to set

so large limits. For dirty_ratio / dirty_background_ratio it isn't so

simple as the dirty limit is computed from the amount of available memory

which can change due to memory hotplug etc. So when converting dirty

limits from ratios to numbers of pages, we just don't allow the result to

exceed UINT_MAX.

This is root-only triggerable problem which occurs when the operator

sets dirty limits to >16 TB.