Threats Tagged 'cve-2025-68794'

A critical vulnerability in the Linux kernel's iomap subsystem involves incorrect handling of read ranges for non-block-aligned positions. The function iomap_adjust_read_range() incorrectly assumes block alignment, leading to underflow in length calculations and returning invalid read positions. This flaw can cause incorrect data reads and potentially compromise confidentiality, integrity, and availability of the system. The issue was identified through syzbot testing and affects the erofs filesystem. A fix has been implemented to correctly account for block offsets when calculating bytes to skip for uptodate blocks.

In the Linux kernel, the following vulnerability has been resolved: iomap: adjust read range correctly for non-block-aligned positions iomap_adjust_read_range() assumes that the position and length passed in are block-aligned. This is not always the case however, as shown in the syzbot generated case for erofs. This causes too many bytes to be skipped for uptodate blocks, which results in returning the incorrect position and length to read in. If all the blocks are uptodate, this underflows length and returns a position beyond the folio. Fix the calculation to also take into account the block offset when calculating how many bytes can be skipped for uptodate blocks.