kernel/linux.git/fs/ntfs3, branch v6.18.21

fs/ntfs3: avoid calling run_get_entry() when run == NULL in ntfs_read_run_nb_ra()

2026-03-04T12:20:38+00:00

[ Upstream commit c5226b96c08a010ebef5fdf4c90572bcd89e4299 ] When ntfs_read_run_nb_ra() is invoked with run == NULL the code later assumes run is valid and may call run_get_entry(NULL, ...), and also uses clen/idx without initializing them. Smatch reported uninitialized variable warnings and this can lead to undefined behaviour. This patch fixes it. Reported-by: kernel test robot Reported-by: Dan Carpenter Closes: https://lore.kernel.org/r/202512230646.v5hrYXL0-lkp@intel.com/ Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

ntfs3: fix circular locking dependency in run_unpack_ex

2026-03-04T12:20:38+00:00

[ Upstream commit 08ce2fee1b869ecbfbd94e0eb2630e52203a2e03 ] 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 Signed-off-by: Sasha Levin

fs/ntfs3: drop preallocated clusters for sparse and compressed files

2026-03-04T12:20:37+00:00

[ Upstream commit 3a6aba7f3cf2b46816e08548c254d98de9c74eba ] Do not keep preallocated clusters for sparsed and compressed files. Preserving preallocation in these cases causes fsx failures when running with sparse files and preallocation enabled. Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

fs: ntfs3: fix infinite loop triggered by zero-sized ATTR_LIST

2026-03-04T12:20:37+00:00

[ Upstream commit 06909b2549d631a47fcda249d34be26f7ca1711d ] We found an infinite loop bug in the ntfs3 file system that can lead to a Denial-of-Service (DoS) condition. A malformed NTFS image can cause an infinite loop when an ATTR_LIST attribute indicates a zero data size while the driver allocates memory for it. When ntfs_load_attr_list() processes a resident ATTR_LIST with data_size set to zero, it still allocates memory because of al_aligned(0). This creates an inconsistent state where ni->attr_list.size is zero, but ni->attr_list.le is non-null. This causes ni_enum_attr_ex to incorrectly assume that no attribute list exists and enumerates only the primary MFT record. When it finds ATTR_LIST, the code reloads it and restarts the enumeration, repeating indefinitely. The mount operation never completes, hanging the kernel thread. This patch adds validation to ensure that data_size is non-zero before memory allocation. When a zero-sized ATTR_LIST is detected, the function returns -EINVAL, preventing a DoS vulnerability. Co-developed-by: Seunghun Han Signed-off-by: Seunghun Han Co-developed-by: Jihoon Kwon Signed-off-by: Jihoon Kwon Signed-off-by: Jaehun Gou Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

fs: ntfs3: fix infinite loop in attr_load_runs_range on inconsistent metadata

2026-03-04T12:20:37+00:00

[ Upstream commit 4b90f16e4bb5607fb35e7802eb67874038da4640 ] We found an infinite loop bug in the ntfs3 file system that can lead to a Denial-of-Service (DoS) condition. A malformed NTFS image can cause an infinite loop when an attribute header indicates an empty run list, while directory entries reference it as containing actual data. In NTFS, setting evcn=-1 with svcn=0 is a valid way to represent an empty run list, and run_unpack() correctly handles this by checking if evcn + 1 equals svcn and returning early without parsing any run data. However, this creates a problem when there is metadata inconsistency, where the attribute header claims to be empty (evcn=-1) but the caller expects to read actual data. When run_unpack() immediately returns success upon seeing this condition, it leaves the runs_tree uninitialized with run->runs as a NULL. The calling function attr_load_runs_range() assumes that a successful return means that the runs were loaded and sets clen to 0, expecting the next run_lookup_entry() call to succeed. Because runs_tree remains uninitialized, run_lookup_entry() continues to fail, and the loop increments vcn by zero (vcn += 0), leading to an infinite loop. This patch adds a retry counter to detect when run_lookup_entry() fails consecutively after attr_load_runs_vcn(). If the run is still not found on the second attempt, it indicates corrupted metadata and returns -EINVAL, preventing the Denial-of-Service (DoS) vulnerability. Co-developed-by: Seunghun Han Signed-off-by: Seunghun Han Co-developed-by: Jihoon Kwon Signed-off-by: Jihoon Kwon Signed-off-by: Jaehun Gou Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

fs: ntfs3: check return value of indx_find to avoid infinite loop

2026-03-04T12:20:37+00:00

[ Upstream commit 1732053c8a6b360e2d5afb1b34fe9779398b072c ] We found an infinite loop bug in the ntfs3 file system that can lead to a Denial-of-Service (DoS) condition. A malformed dentry in the ntfs3 filesystem can cause the kernel to hang during the lookup operations. By setting the HAS_SUB_NODE flag in an INDEX_ENTRY within a directory's INDEX_ALLOCATION block and manipulating the VCN pointer, an attacker can cause the indx_find() function to repeatedly read the same block, allocating 4 KB of memory each time. The kernel lacks VCN loop detection and depth limits, causing memory exhaustion and an OOM crash. This patch adds a return value check for fnd_push() to prevent a memory exhaustion vulnerability caused by infinite loops. When the index exceeds the size of the fnd->nodes array, fnd_push() returns -EINVAL. The indx_find() function checks this return value and stops processing, preventing further memory allocation. Co-developed-by: Seunghun Han Signed-off-by: Seunghun Han Co-developed-by: Jihoon Kwon Signed-off-by: Jihoon Kwon Signed-off-by: Jaehun Gou Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

ntfs: ->d_compare() must not block

2026-03-04T12:19:34+00:00

[ Upstream commit ca2a04e84af79596e5cd9cfe697d5122ec39c8ce ] ... so don't use __getname() there. Switch it (and ntfs_d_hash(), while we are at it) to kmalloc(PATH_MAX, GFP_NOWAIT). Yes, ntfs_d_hash() almost certainly can do with smaller allocations, but let ntfs folks deal with that - keep the allocation size as-is for now. Stop abusing names_cachep in ntfs, period - various uses of that thing in there have nothing to do with pathnames; just use k[mz]alloc() and be done with that. For now let's keep sizes as-in, but AFAICS none of the users actually want PATH_MAX. Signed-off-by: Al Viro Signed-off-by: Sasha Levin

fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot

2026-02-26T22:59:36+00:00

[ Upstream commit b2bc7c44ed1779fc9eaab9a186db0f0d01439622 ] In the 'DeleteIndexEntryRoot' case of the 'do_action' function, the entry size ('esize') is retrieved from the log record without adequate bounds checking. Specifically, the code calculates the end of the entry ('e2') using: e2 = Add2Ptr(e1, esize); It then calculates the size for memmove using 'PtrOffset(e2, ...)', which subtracts the end pointer from the buffer limit. If 'esize' is maliciously large, 'e2' exceeds the used buffer size. This results in a negative offset which, when cast to size_t for memmove, interprets as a massive unsigned integer, leading to a heap buffer overflow. This commit adds a check to ensure that the entry size ('esize') strictly fits within the remaining used space of the index header before performing memory operations. Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal") Signed-off-by: Jiasheng Jiang Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

fs/ntfs3: prevent infinite loops caused by the next valid being the same

2026-02-26T22:59:36+00:00

[ Upstream commit 27b75ca4e51e3e4554dc85dbf1a0246c66106fd3 ] When processing valid within the range [valid : pos), if valid cannot be retrieved correctly, for example, if the retrieved valid value is always the same, this can trigger a potential infinite loop, similar to the hung problem reported by syzbot [1]. Adding a check for the valid value within the loop body, and terminating the loop and returning -EINVAL if the value is the same as the current value, can prevent this. [1] INFO: task syz.4.21:6056 blocked for more than 143 seconds. Call Trace: rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:1027 [inline] ntfs_file_write_iter+0xe6/0x870 fs/ntfs3/file.c:1284 Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation") Reported-by: syzbot+bcf9e1868c1a0c7e04f1@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=bcf9e1868c1a0c7e04f1 Signed-off-by: Edward Adam Davis Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

fs/ntfs3: Initialize new folios before use

2026-02-26T22:59:36+00:00

[ Upstream commit f223ebffa185cc8da934333c5a31ff2d4f992dc9 ] KMSAN reports an uninitialized value in longest_match_std(), invoked from ntfs_compress_write(). When new folios are allocated without being marked uptodate and ni_read_frame() is skipped because the caller expects the frame to be completely overwritten, some reserved folios may remain only partially filled, leaving the rest memory uninitialized. Fixes: 584f60ba22f7 ("ntfs3: Convert ntfs_get_frame_pages() to use a folio") Tested-by: syzbot+08d8956768c96a2c52cf@syzkaller.appspotmail.com Reported-by: syzbot+08d8956768c96a2c52cf@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=08d8956768c96a2c52cf Signed-off-by: Bartlomiej Kubik Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin