fs/ntfs3: validate Dirty Page Table capacity in log_replay copy_lcns

Browse source

In the analysis pass of $LogFile journal replay, log_replay() copies
LCNs from each action log record into an existing Dirty Page Table
(DPT) entry without bounding the destination index. A crafted NTFS
image with DPT entry lcns_follow=1 and an action log record with
lcns_follow=2 produces a kernel slab out-of-bounds write at mount
time:

  BUG: KASAN: slab-out-of-bounds in log_replay+0x654c/0xdb60
  Write of size 8 at addr ffff8880095e1040 by task mount

Two attacker-controlled fields can drive j+i past the allocated
page_lcns[] array:

  1. dp->lcns_follow (capacity) can be smaller than lrh->lcns_follow.
  2. lrh->target_vcn may be smaller than dp->vcn, making the u64
     subtraction wrap to a huge size_t.

Validate target VCN delta and per-record LCN count against the
DPT entry capacity, bail via the existing out: cleanup label with
-EINVAL.

This mirrors the bounds-check pattern added in commit b2bc7c44ed
("fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot")
and commit 0ca0485e4b ("fs/ntfs3: validate rec->used in
journal-replay file record check").

Fixes: b46acd6a6a ("fs/ntfs3: Add NTFS journal")
Reported-by: Yunpeng Tian <shionthanatos@gmail.com>
Reported-by: Mingda Zhang <npczmd@qq.com>
Reported-by: Gongming Wang <gmwgg05@gmail.com>
Reported-by: Peiyuan Xu <paulbucket12@gmail.com>
Reported-by: Qinrun Dai <jupmouse@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Yunpeng Tian <shionthanatos@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

...

This commit is contained in:

Yunpeng Tian 2026-05-04 07:19:43 -07:00 • committed by Konstantin Komarov

parent 932fa0c149

commit 57382ec6ac

No known key found for this signature in database

GPG key ID: A9B0331F832407B6

1 changed files with 15 additions and 5 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

20

fs/ntfs3/fslog.c

View file