In the Linux kernel, the following vulnerability has been resolved: ntfs: fix off-by-one page overflow in ntfs_decompress() The per-token range check in ntfs_decompress() uses if (cb >= cb_sb_end || dp_addr > dp_sb_end) break; so …

Overview

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

ntfs: fix off-by-one page overflow in ntfs_decompress()

The per-token range check in ntfs_decompress() uses

if (cb >= cb_sb_end || dp_addr > dp_sb_end)
	break;

so dp_addr == dp_sb_end falls through to the symbol copy *dp_addr++ = *cb++, writing one byte past the destination page. Since NTFS_SB_SIZE == PAGE_SIZE the destination is a single page, so the byte lands in the adjacent page, and *dest_ofs is left one past the sub-block end (the later *dest_ofs &= ~PAGE_MASK then yields 1, not 0, so the page is never finalized and later sub-blocks keep writing further past it). A corrupted compressed $DATA attribute thus produces a bounded run of out-of-bounds writes when the file is read.

Break as soon as dp_addr reaches dp_sb_end; a full sub-block still completes, as its final copy advances dp_addr to exactly dp_sb_end.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.