kernel/linux.git/fs/ntfs3, branch v5.15.211

ntfs3: reject direct userspace writes to reserved $LX* xattrs

2026-07-04T11:39:39+00:00

commit 5b08dccecf825cbf905f348bc6ccb497507e28e2 upstream. NTFS3 uses $LXUID, $LXGID, $LXMOD and $LXDEV as internal WSL permission metadata and reloads them into i_uid, i_gid and i_mode from ntfs_get_wsl_perm(). Because the empty-prefix xattr handler also lets file owners call setxattr() on these names directly, an unprivileged writer on a writable ntfs3 mount can plant root ownership and S_ISUID on their own file and gain euid 0 after inode reload. Reject direct userspace writes to the reserved $LX* names. Internal ntfs3 metadata updates are unchanged because ntfs_save_wsl_perm() writes them via ntfs_set_ea() directly. Signed-off-by: Zhen Yan [almaz.alexandrovich@paragon-software.com: added an additional check for non privileged users] Signed-off-by: Konstantin Komarov Signed-off-by: Greg Kroah-Hartman

fs/ntfs3: Return error for inconsistent extended attributes

2026-06-19T11:33:34+00:00

[ Upstream commit c9db0ff04649aa0b45f497183c957fe260f229f6 ] ntfs_read_ea is called when we want to read extended attributes. There are some sanity checks for the validity of the EAs. However, it fails to return a proper error code for the inconsistent attributes, which might lead to unpredicted memory accesses after return. [ 138.916927] BUG: KASAN: use-after-free in ntfs_set_ea+0x453/0xbf0 [ 138.923876] Write of size 4 at addr ffff88800205cfac by task poc/199 [ 138.931132] [ 138.933016] CPU: 0 PID: 199 Comm: poc Not tainted 6.2.0-rc1+ #4 [ 138.938070] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 [ 138.947327] Call Trace: [ 138.949557] [ 138.951539] dump_stack_lvl+0x4d/0x67 [ 138.956834] print_report+0x16f/0x4a6 [ 138.960798] ? ntfs_set_ea+0x453/0xbf0 [ 138.964437] ? kasan_complete_mode_report_info+0x7d/0x200 [ 138.969793] ? ntfs_set_ea+0x453/0xbf0 [ 138.973523] kasan_report+0xb8/0x140 [ 138.976740] ? ntfs_set_ea+0x453/0xbf0 [ 138.980578] __asan_store4+0x76/0xa0 [ 138.984669] ntfs_set_ea+0x453/0xbf0 [ 138.988115] ? __pfx_ntfs_set_ea+0x10/0x10 [ 138.993390] ? kernel_text_address+0xd3/0xe0 [ 138.998270] ? __kernel_text_address+0x16/0x50 [ 139.002121] ? unwind_get_return_address+0x3e/0x60 [ 139.005659] ? __pfx_stack_trace_consume_entry+0x10/0x10 [ 139.010177] ? arch_stack_walk+0xa2/0x100 [ 139.013657] ? filter_irq_stacks+0x27/0x80 [ 139.017018] ntfs_setxattr+0x405/0x440 [ 139.022151] ? __pfx_ntfs_setxattr+0x10/0x10 [ 139.026569] ? kvmalloc_node+0x2d/0x120 [ 139.030329] ? kasan_save_stack+0x41/0x60 [ 139.033883] ? kasan_save_stack+0x2a/0x60 [ 139.037338] ? kasan_set_track+0x29/0x40 [ 139.040163] ? kasan_save_alloc_info+0x1f/0x30 [ 139.043588] ? __kasan_kmalloc+0x8b/0xa0 [ 139.047255] ? __kmalloc_node+0x68/0x150 [ 139.051264] ? kvmalloc_node+0x2d/0x120 [ 139.055301] ? vmemdup_user+0x2b/0xa0 [ 139.058584] __vfs_setxattr+0x121/0x170 [ 139.062617] ? __pfx___vfs_setxattr+0x10/0x10 [ 139.066282] __vfs_setxattr_noperm+0x97/0x300 [ 139.070061] __vfs_setxattr_locked+0x145/0x170 [ 139.073580] vfs_setxattr+0x137/0x2a0 [ 139.076641] ? __pfx_vfs_setxattr+0x10/0x10 [ 139.080223] ? __kasan_check_write+0x18/0x20 [ 139.084234] do_setxattr+0xce/0x150 [ 139.087768] setxattr+0x126/0x140 [ 139.091250] ? __pfx_setxattr+0x10/0x10 [ 139.094948] ? __virt_addr_valid+0xcb/0x140 [ 139.097838] ? __call_rcu_common.constprop.0+0x1c7/0x330 [ 139.102688] ? debug_smp_processor_id+0x1b/0x30 [ 139.105985] ? kasan_quarantine_put+0x5b/0x190 [ 139.109980] ? putname+0x84/0xa0 [ 139.113886] ? __kasan_slab_free+0x11e/0x1b0 [ 139.117961] ? putname+0x84/0xa0 [ 139.121316] ? preempt_count_sub+0x1c/0xd0 [ 139.124427] ? __mnt_want_write+0xae/0x100 [ 139.127836] ? mnt_want_write+0x8f/0x150 [ 139.130954] path_setxattr+0x164/0x180 [ 139.133998] ? __pfx_path_setxattr+0x10/0x10 [ 139.137853] ? __pfx_ksys_pwrite64+0x10/0x10 [ 139.141299] ? debug_smp_processor_id+0x1b/0x30 [ 139.145714] ? fpregs_assert_state_consistent+0x6b/0x80 [ 139.150796] __x64_sys_setxattr+0x71/0x90 [ 139.155407] do_syscall_64+0x3f/0x90 [ 139.159035] entry_SYSCALL_64_after_hwframe+0x72/0xdc [ 139.163843] RIP: 0033:0x7f108cae4469 [ 139.166481] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 088 [ 139.183764] RSP: 002b:00007fff87588388 EFLAGS: 00000286 ORIG_RAX: 00000000000000bc [ 139.190657] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f108cae4469 [ 139.196586] RDX: 00007fff875883b0 RSI: 00007fff875883d1 RDI: 00007fff875883b6 [ 139.201716] RBP: 00007fff8758c530 R08: 0000000000000001 R09: 00007fff8758c618 [ 139.207940] R10: 0000000000000006 R11: 0000000000000286 R12: 00000000004004c0 [ 139.214007] R13: 00007fff8758c610 R14: 0000000000000000 R15: 0000000000000000 Signed-off-by: Edward Lo Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

fs/ntfs3: terminate the cached volume label after UTF-8 conversion

2026-06-01T15:35:36+00:00

[ Upstream commit a6cd43fe9b083fa23fe1595666d5738856cb261a ] ntfs_fill_super() loads the on-disk volume label with utf16s_to_utf8s() and stores the result in sbi->volume.label. The converted label is later exposed through ntfs3_label_show() using %s, but utf16s_to_utf8s() only returns the number of bytes written and does not add a trailing NUL. If the converted label fills the entire fixed buffer, ntfs3_label_show() can read past the end of sbi->volume.label while looking for a terminator. Terminate the cached label explicitly after a successful conversion and clamp the exact-full case to the last byte of the buffer. Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block") Signed-off-by: Pengpeng Hou Signed-off-by: Konstantin Komarov Signed-off-by: Sasha Levin

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

2026-06-01T15:35:18+00:00

commit 984a415f019536ea2d24de9010744e5302a9a948 upstream. 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 Signed-off-by: Greg Kroah-Hartman

ntfs3: add buffer boundary checks to run_unpack()

2026-06-01T15:35:18+00:00

commit b62567bca47408e6739dee75f02a2113548af875 upstream. 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 Signed-off-by: Greg Kroah-Hartman

fs/ntfs3: validate rec->used in journal-replay file record check

2026-06-01T15:35:12+00:00

commit 0ca0485e4b2e837ebb6cbd4f2451aba665a03e4b upstream. check_file_record() validates rec->total against the record size but never validates rec->used. The do_action() journal-replay handlers read rec->used from disk and use it to compute memmove lengths: DeleteAttribute: memmove(attr, ..., used - asize - roff) CreateAttribute: memmove(..., attr, used - roff) change_attr_size: memmove(..., used - PtrOffset(rec, next)) When rec->used is smaller than the offset of a validated attribute, or larger than the record size, these subtractions can underflow allowing us to copy huge amounts of memory in to a 4kb buffer, generally considered a bad idea overall. This requires a corrupted filesystem, which isn't a threat model the kernel really needs to worry about, but checking for such an obvious out-of-bounds value is good to keep things robust, especially on journal replay Fix this up by bounding rec->used correctly. This is much like commit b2bc7c44ed17 ("fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot") which checked different values in this same switch statement. Cc: Konstantin Komarov Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal") Cc: stable Assisted-by: gregkh_clanker_t1000 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Konstantin Komarov Signed-off-by: Greg Kroah-Hartman

fs/ntfs3: Add more attributes checks in mi_enum_attr()

2026-06-01T15:35:11+00:00

[ Upstream commit 013ff63b649475f0ee134e2c8d0c8e65284ede50 ] Signed-off-by: Konstantin Komarov [ Overflow check deleted to keep context consistent. ] Signed-off-by: Robert Garcia Signed-off-by: Greg Kroah-Hartman

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

2026-03-04T12:20:18+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

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

2026-03-04T12:20:18+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

2026-03-04T12:20:18+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