In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: reject restart table growth beyond U16_MAX entries
During $LogFile replay, log_replay() indexes the transaction table by the
transact_id taken from the log record header. check_log_rec() only
verifies that transact_id is non-zero and properly aligned, not its
magnitude, so a crafted image can request an arbitrarily large index.
alloc_rsttbl_from_idx() grows the table to cover that index via
extend_rsttbl(), which passes the new entry count to init_rsttbl():
<pre>
rt = init_rsttbl(esize, used + add);
</pre>
used + add is computed as u32 but init_rsttbl() takes a u16, and the
count is stored in struct RESTART_TABLE as a __le16. When used + add
exceeds U16_MAX it is truncated, init_rsttbl() allocates a table far
smaller than the index requires, and alloc_rsttbl_from_idx() then
dereferences and writes at the original, untruncated offset -- an
out-of-bounds access past the allocation, reachable by mounting a
crafted NTFS image.
BUG: KASAN: use-after-free in alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)
Read of size 4 at addr ffff8880327ffff8 by task exploit
alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)
log_replay (fs/ntfs3/fslog.c:4562)
ntfs_loadlog_and_replay (fs/ntfs3/fsntfs.c:324)
ntfs_fill_super (fs/ntfs3/super.c:1393)
get_tree_bdev_flags
vfs_get_tree
path_mount
__x64_sys_mount
A restart table is limited to U16_MAX entries by its __le16 count, so a
larger growth request is invalid input. Reject it in extend_rsttbl();
all callers already handle a NULL return.
CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 8.4
AV:L - The bug is reached only while mounting a local NTFS block or loop device: path_mount → ntfs_fill_super → ntfs_loadlog_and_replay → log_replay → alloc_rsttbl_from_idx. ksmbd/nfsd never parse $LogFile; journal replay runs at fill_super, not while serving exported files.
AC:L - The attacker fully controls on-disk $LogFile LFS_RECORD_HDR.transact_id. check_log_rec() only requires it non-zero and TRANSACTION_ENTRY-aligned, so a crafted index with used+add > U16_MAX truncates init_rsttbl() and hits the OOB access deterministically on mount with no race.
PR:N - No account or privilege on the victim is required: a crafted NTFS volume on USB/removable media, a disk image, or shared storage is sufficient for udisks2/systemd automount or an administrator mount to run $LogFile replay as root.
UI:N - Desktop, kiosk, automotive, and shared-workstation automounters mount attacker-supplied NTFS media and run log_replay() inside ntfs_fill_super() without the user opening files or confirming a dialog; attaching the crafted volume is sufficient to trigger the overflow.
S:U - Heap out-of-bounds access and use-after-free occur in the host kernel during ntfs3 journal replay in the mounting process; impact stays within one kernel security authority and is not a VM escape or IOMMU/DMA bypass.
C:H - After the truncated allocation, alloc_rsttbl_from_idx() reads a restart-table word at the original untruncated transact_id offset (KASAN use-after-free). That attacker-chosen heap index plus UAF of the freed old table enable arbitrary kernel memory disclosure.
I:H - extend_rsttbl() memcpy's the old table into a truncated kmalloc buffer, then alloc_rsttbl_from_idx() memset's and writes RESTART_ENTRY_ALLOCATED at the untruncated offset, producing an OOB/UAF heap write that can corrupt adjacent slab objects for control-flow hijacking.
A:H - KASAN reported use-after-free in alloc_rsttbl_from_idx() on mount of a crafted NTFS image; the out-of-bounds heap access during log replay can oops or panic the kernel and is repeatable on every mount of the malicious volume.
| Attack Vector |
Local |
Scope |
Unchanged |
| Attack Complexity |
Low |
Confidentiality Impact |
High |
| Privileges Required |
None |
Integrity Impact |
High |
| User Interaction |
None |
Availability Impact |
High |
AV:L - The bug is reached only while mounting a local NTFS block or loop device: path_mount → ntfs_fill_super → ntfs_loadlog_and_replay → log_replay → alloc_rsttbl_from_idx. ksmbd/nfsd never parse $LogFile; journal replay runs at fill_super, not while serving exported files.
AC:L - The attacker fully controls on-disk $LogFile LFS_RECORD_HDR.transact_id. check_log_rec() only requires it non-zero and TRANSACTION_ENTRY-aligned, so a crafted index with used+add > U16_MAX truncates init_rsttbl() and hits the OOB access deterministically on mount with no race.
PR:N - No account or privilege on the victim is required: a crafted NTFS volume on USB/removable media, a disk image, or shared storage is sufficient for udisks2/systemd automount or an administrator mount to run $LogFile replay as root.
UI:N - Desktop, kiosk, automotive, and shared-workstation automounters mount attacker-supplied NTFS media and run log_replay() inside ntfs_fill_super() without the user opening files or confirming a dialog; attaching the crafted volume is sufficient to trigger the overflow.
S:U - Heap out-of-bounds access and use-after-free occur in the host kernel during ntfs3 journal replay in the mounting process; impact stays within one kernel security authority and is not a VM escape or IOMMU/DMA bypass.
C:H - After the truncated allocation, alloc_rsttbl_from_idx() reads a restart-table word at the original untruncated transact_id offset (KASAN use-after-free). That attacker-chosen heap index plus UAF of the freed old table enable arbitrary kernel memory disclosure.
I:H - extend_rsttbl() memcpy's the old table into a truncated kmalloc buffer, then alloc_rsttbl_from_idx() memset's and writes RESTART_ENTRY_ALLOCATED at the untruncated offset, producing an OOB/UAF heap write that can corrupt adjacent slab objects for control-flow hijacking.
A:H - KASAN reported use-after-free in alloc_rsttbl_from_idx() on mount of a crafted NTFS image; the out-of-bounds heap access during log replay can oops or panic the kernel and is repeatable on every mount of the malicious volume.
CVSS 3.1