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.
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 9.8
AV:N - ntfs3 registers export_operations, so ksmbd/nfsd VFS write and setxattr on an exported NTFS volume reach ni_create_attr_list() via ntfs_set_size/attr_set_size_ex and ntfs_setxattr→ni_insert_resident→ni_ins_attr_ext; NAS/router SMB sharing of USB NTFS is a reasonable high-impact path.
AC:L - The attacker fully controls a primary MFT record packed with unnamed SIZEOF_RESIDENT attributes, so the ATTR_LIST_ENTRY walk overflows the fixed kzalloc(record_size) buffer on the first attribute insert or allocation extend; no race or attacker-uncontrollable layout is required.
PR:N - Triggering needs only write or setxattr permission on the crafted file, including guest/anonymous SMB or a permissive NFS export; no local account, init-namespace root, or CAP_SYS_ADMIN is required on the trigger path.
UI:N - Once the crafted NTFS volume is mounted and exported, or automounted from removable/shared storage, the attacker triggers the overflow with an ordinary write, truncate, or setxattr; no extra victim clicks, prompts, or confirmation are required.
S:U - The slab out-of-bounds write corrupts kernel heap in the same host OS security authority as ntfs3; it can enable privilege escalation but does not cross a VM, IOMMU, or sandbox boundary.
C:H - The overflow writes attacker-controlled ATTR_LIST_ENTRY fields (type, name, id) past the kmalloc-1k object into adjacent slab, a heap-corruption primitive that can be leveraged for kernel memory disclosure.
I:H - The unbounded ATTR_LIST_ENTRY walk is a slab out-of-bounds write of attacker-influenced attribute metadata into adjacent heap objects, enabling arbitrary kernel writes and potential control-flow hijack.
A:H - KASAN reports a slab-out-of-bounds write in ni_create_attr_list(); overflowing the kmalloc object corrupts adjacent heap and causes a kernel oops, panic, or hang.
| Attack Vector |
Network |
Scope |
Unchanged |
| Attack Complexity |
Low |
Confidentiality Impact |
High |
| Privileges Required |
None |
Integrity Impact |
High |
| User Interaction |
None |
Availability Impact |
High |
AV:N - ntfs3 registers export_operations, so ksmbd/nfsd VFS write and setxattr on an exported NTFS volume reach ni_create_attr_list() via ntfs_set_size/attr_set_size_ex and ntfs_setxattr→ni_insert_resident→ni_ins_attr_ext; NAS/router SMB sharing of USB NTFS is a reasonable high-impact path.
AC:L - The attacker fully controls a primary MFT record packed with unnamed SIZEOF_RESIDENT attributes, so the ATTR_LIST_ENTRY walk overflows the fixed kzalloc(record_size) buffer on the first attribute insert or allocation extend; no race or attacker-uncontrollable layout is required.
PR:N - Triggering needs only write or setxattr permission on the crafted file, including guest/anonymous SMB or a permissive NFS export; no local account, init-namespace root, or CAP_SYS_ADMIN is required on the trigger path.
UI:N - Once the crafted NTFS volume is mounted and exported, or automounted from removable/shared storage, the attacker triggers the overflow with an ordinary write, truncate, or setxattr; no extra victim clicks, prompts, or confirmation are required.
S:U - The slab out-of-bounds write corrupts kernel heap in the same host OS security authority as ntfs3; it can enable privilege escalation but does not cross a VM, IOMMU, or sandbox boundary.
C:H - The overflow writes attacker-controlled ATTR_LIST_ENTRY fields (type, name, id) past the kmalloc-1k object into adjacent slab, a heap-corruption primitive that can be leveraged for kernel memory disclosure.
I:H - The unbounded ATTR_LIST_ENTRY walk is a slab out-of-bounds write of attacker-influenced attribute metadata into adjacent heap objects, enabling arbitrary kernel writes and potential control-flow hijack.
A:H - KASAN reports a slab-out-of-bounds write in ni_create_attr_list(); overflowing the kmalloc object corrupts adjacent heap and causes a kernel oops, panic, or hang.
CVSS 3.1