ntfs: bound $AttrDef table walk to the loaded table size

Summary

In the Linux kernel, the following vulnerability has been resolved: ntfs: bound $AttrDef table walk to the loaded table size ntfs_attr_find_in_attrdef() walks the in-memory $AttrDef table, but the loop condition bounds only the start of each entry, not the whole entry: for (ad = vol->attrdef; (u8 )ad - (u8 )vol->attrdef < vol->attrdef_size && ad->type; ++ad) struct attr_def is 160 bytes; the guard reads ad->type at offset 128 and the loop body reads further fields. vol->attrdef is kvzalloc(i_size), where i_size is the on-disk $AttrDef data size, checked in load_and_init_attrdef() only as 0 < i_size <= 0x7fffffff. A volume whose $AttrDef data size is smaller than one entry (e.g. 120 bytes) makes the read of ad->type run past the allocation. Creating a file reaches this through ntfs_attr_size_bounds_check() and reads out of bounds: BUG: KASAN: slab-out-of-bounds in ntfs_attr_find_in_attrdef+0x66/0xa0 Read of size 4 at addr ffff888005833280 by task init/1 ntfs_attr_find_in_attrdef ntfs_attr_size_bounds_check ntfs_attr_can_be_non_resident ntfs_attr_add Require the whole entry to lie within attrdef_size in the loop guard, and reject at mount a $AttrDef too small to hold one attr_def entry.

Timeline

1. Sep 25, 2026, 10:36 AM UTCCVE published
2. Oct 19, 2026, 9:14 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 1e9ea7e04472d4e5e12e58c881eaacfb3e49b669 · fixed in 3e2ae47b8ebc632c27e7843a4632d9a7c060885e; From 1e9ea7e04472d4e5e12e58c881eaacfb3e49b669 · fixed in c8504fc1245f5322af5fa5c325ab05f9cf792b87

• Linux Linux

  7.1

• KernelLinux

  From 7.1.0 · fixed in 7.2.7

References 2