CVE-2026-90048fs/ntfs3: fix slab-out-of-bounds write in ni_create_attr_list()

Official description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: fix slab-out-of-bounds write in ni_create_attr_list() ni_create_attr_list() allocates a fixed buffer of al_aligned(record_size) (== record_size) bytes and then walks every attribute of the primary MFT record, writing one ATTR_LIST_ENTRY per attribute and advancing the cursor by le_size(name_len), with no check against the end of the buffer; the total size is only computed after the loop. A minimum-size resident attribute occupies SIZEOF_RESIDENT (0x18 = 24) bytes on disk, but an unnamed attribute expands to le_size(0) (0x20 = 32) bytes in the list. Because the number of attributes in a record is not bounded (mi_enum_attr() accepts arbitrarily many equal-type, nameless minimum-size attributes), a crafted record packed with such attributes produces a list larger than record_size and overflows the heap buffer. This is reachable from a crafted, loop-mounted NTFS image: opening the file and adding an attribute (e.g. via setxattr) drives ntfs_set_ea() -> ni_insert_resident() -> ni_insert_attr() -> ni_ins_attr_ext() -> ni_create_attr_list(). BUG: KASAN: slab-out-of-bounds in ni_create_attr_list+0xc48/0x1058 Write of size 4 at addr ffff000008984c00 by task setfattr/345 ni_create_attr_list+0xc48/0x1058 ni_ins_attr_ext+0x510/0x7c0 ni_insert_attr+0x3f8/0x70c ni_insert_resident+0xc8/0x3b0 ntfs_set_ea+0x66c/0xd28 ntfs_setxattr+0x4d8/0x5b0 __arm64_sys_setxattr+0xa4/0x124 Allocated by task 345: ni_create_attr_list+0x188/0x1058 The buggy address belongs to the cache kmalloc-1k of size 1024 (the write lands at object+1024). Size the buffer from the actual attributes instead of assuming a single record_size is always enough.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/3a38f3c71bcd9bd58d86489c364bd29a4c2c860e
• https://git.kernel.org/stable/c/7e9aee7e4d9767cc3e423b3beecb01c7ebb6bbcd
• https://git.kernel.org/stable/c/fa2215cf451414b0512cd6f7d37a057893811f4d
• https://git.kernel.org/stable/c/d07e281f2a7710502985d6f80b95ddac8f4e81d5
• https://git.kernel.org/stable/c/a84f3db72561c4d9281c5ff721ce46b9ffa7f30e
• https://git.kernel.org/stable/c/7c4841e2a62794a3bab7c1ff0540580f387e377f