kernel/linux.git/fs/ntfs3/run.c, branch linux-7.1.y

ntfs3: fix integer overflow in run_unpack() volume boundary check

2026-04-07T16:43:39+00:00

The volume boundary check `lcn + len > sbi->used.bitmap.nbits` uses raw addition which can wrap around for large lcn and len values, bypassing the validation. Use check_add_overflow() as is already done for the adjacent prev_lcn + dlcn and vcn64 + len checks added by commit 3ac37e100385 ("ntfs3: Fix integer overflow in run_unpack()"). Found by fuzzing with a source-patched harness (LibAFL + QEMU). Fixes: 82cae269cfa95 ("fs/ntfs3: Add initialization of super block") Cc: stable@vger.kernel.org Signed-off-by: Tobias Gaertner Signed-off-by: Konstantin Komarov

ntfs3: add buffer boundary checks to run_unpack()

2026-04-07T16:43:38+00:00

run_unpack() checks `run_buf < run_last` at the top of the while loop but then reads size_size and offset_size bytes via run_unpack_s64() without verifying they fit within the remaining buffer. A crafted NTFS image with truncated run data in an MFT attribute triggers an OOB heap read of up to 15 bytes when the filesystem is mounted. Add boundary checks before each run_unpack_s64() call to ensure the declared field size does not exceed the remaining buffer. Found by fuzzing with a source-patched harness (LibAFL + QEMU). Fixes: 82cae269cfa95 ("fs/ntfs3: Add initialization of super block") Cc: stable@vger.kernel.org Signed-off-by: Tobias Gaertner Signed-off-by: Konstantin Komarov

fs/ntfs3: add delayed-allocation (delalloc) support

2026-02-16T16:23:51+00:00

This patch implements delayed allocation (delalloc) in ntfs3 driver. It introduces an in-memory delayed-runlist (run_da) and the helpers to track, reserve and later convert those delayed reservations into real clusters at writeback time. The change keeps on-disk formats untouched and focuses on pagecache integration, correctness and safe interaction with fallocate, truncate, and dio/iomap paths. Key points: - add run_da (delay-allocated run tree) and bookkeeping for delayed clusters. - mark ranges as delalloc (DELALLOC_LCN) instead of immediately allocating. Actual allocation performed later (writeback / attr_set_size_ex / explicit flush paths). - direct i/o / iomap paths updated to avoid dio collisions with delalloc: dio falls back or forces allocation of delayed blocks before proceeding. - punch/collapse/truncate/fallocate check and cancel delay-alloc reservations. Sparse/compressed files handled specially. - free-space checks updated (ntfs_check_free_space) to account for reserved delalloc clusters and MFT record budgeting. - delayed allocations are committed on last writer (file release) and on explicit allocation flush paths. Tested-by: syzbot@syzkaller.appspotmail.com Reported-by: syzbot+2bd8e813c7f767aa9bb1@syzkaller.appspotmail.com Signed-off-by: Konstantin Komarov

ntfs3: fix circular locking dependency in run_unpack_ex

2026-01-15T04:57:48+00:00

Syzbot reported a circular locking dependency between wnd->rw_lock (sbi->used.bitmap) and ni->file.run_lock. The deadlock scenario: 1. ntfs_extend_mft() takes ni->file.run_lock then wnd->rw_lock. 2. run_unpack_ex() takes wnd->rw_lock then tries to acquire ni->file.run_lock inside ntfs_refresh_zone(). This creates an AB-BA deadlock. Fix this by using down_read_trylock() instead of down_read() when acquiring run_lock in run_unpack_ex(). If the lock is contended, skip ntfs_refresh_zone() - the MFT zone will be refreshed on the next MFT operation. This breaks the circular dependency since we never block waiting for run_lock while holding wnd->rw_lock. Reported-by: syzbot+d27edf9f96ae85939222@syzkaller.appspotmail.com Tested-by: syzbot+d27edf9f96ae85939222@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d27edf9f96ae85939222 Signed-off-by: Szymon Wilczek Signed-off-by: Konstantin Komarov

fs/ntfs3: correct attr_collapse_range when file is too fragmented

2025-11-17T08:08:49+00:00

Fix incorrect VCN adjustments in attr_collapse_range() that caused filesystem errors or corruption on very fragmented NTFS files when performing collapse-range operations. Signed-off-by: Konstantin Komarov

fs/ntfs3: fix mount failure for sparse runs in run_unpack()

2025-10-17T10:08:43+00:00

Some NTFS volumes failed to mount because sparse data runs were not handled correctly during runlist unpacking. The code performed arithmetic on the special SPARSE_LCN64 marker, leading to invalid LCN values and mount errors. Add an explicit check for the case described above, marking the run as sparse without applying arithmetic. Fixes: 736fc7bf5f68 ("fs: ntfs3: Fix integer overflow in run_unpack()") Cc: stable@vger.kernel.org Signed-off-by: Konstantin Komarov

fs: ntfs3: Fix integer overflow in run_unpack()

2025-09-10T09:01:39+00:00

The MFT record relative to the file being opened contains its runlist, an array containing information about the file's location on the physical disk. Analysis of all Call Stack paths showed that the values of the runlist array, from which LCNs are calculated, are not validated before run_unpack function. The run_unpack function decodes the compressed runlist data format from MFT attributes (for example, $DATA), converting them into a runs_tree structure, which describes the mapping of virtual clusters (VCN) to logical clusters (LCN). The NTFS3 subsystem also has a shortcut for deleting files from MFT records - in this case, the RUN_DEALLOCATE command is sent to the run_unpack input, and the function logic provides that all data transferred to the runlist about file or directory is deleted without creating a runs_tree structure. Substituting the runlist in the $DATA attribute of the MFT record for an arbitrary file can lead either to access to arbitrary data on the disk bypassing access checks to them (since the inode access check occurs above) or to destruction of arbitrary data on the disk. Add overflow check for addition operation. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation") Signed-off-by: Vitaly Grigoryev Signed-off-by: Konstantin Komarov

fs/ntfs3: Accumulated refactoring changes

2024-11-01T08:19:53+00:00

Changes made to improve readability and debuggability. Signed-off-by: Konstantin Komarov

fs/ntfs3: Fix case when unmarked clusters intersect with zone

2024-11-01T08:19:50+00:00

Reported-by: syzbot+7f3761b790fa41d0f3d5@syzkaller.appspotmail.com Signed-off-by: Konstantin Komarov

fs/ntfs3: Make checks in run_unpack more clear

2024-09-03T13:58:43+00:00

Signed-off-by: Konstantin Komarov