linux-stable.git/fs, branch v6.12.90

btrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak

2026-05-17T15:14:35+00:00

[ Upstream commit 973e57c726c1f8e77259d1c8e519519f1e9aea77 ]

btrfs_ioctl_space_info() has a TOCTOU race between two passes over the
block group RAID type lists. The first pass counts entries to determine
the allocation size, then the second pass fills the buffer. The
groups_sem rwlock is released between passes, allowing concurrent block
group removal to reduce the entry count.

When the second pass fills fewer entries than the first pass counted,
copy_to_user() copies the full alloc_size bytes including trailing
uninitialized kmalloc bytes to userspace.

Fix by copying only total_spaces entries (the actually-filled count from
the second pass) instead of alloc_size bytes, and switch to kzalloc so
any future copy size mismatch cannot leak heap data.

Fixes: 7fde62bffb57 ("Btrfs: buffer results in the space_info ioctl")
CC: stable@vger.kernel.org # 3.0
Signed-off-by: Yochai Eisenrich 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
[ adapted upstream's `return -EFAULT;` to stable's `ret = -EFAULT;` fall-through to existing `out:` cleanup label ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

btrfs: fix double free in create_space_info_sub_group() error path

2026-05-17T15:14:34+00:00

[ Upstream commit a7449edf96143f192606ec8647e3167e1ecbd728 ]

When kobject_init_and_add() fails, the call chain is:

create_space_info_sub_group()
-> btrfs_sysfs_add_space_info_type()
-> kobject_init_and_add()
-> failure
-> kobject_put(&sub_group->kobj)
-> space_info_release()
-> kfree(sub_group)

Then control returns to create_space_info_sub_group(), where:

btrfs_sysfs_add_space_info_type() returns error
-> kfree(sub_group)

Thus, sub_group is freed twice.

Keep parent->sub_group[index] = NULL for the failure path, but after
btrfs_sysfs_add_space_info_type() has called kobject_put(), let the
kobject release callback handle the cleanup.

Fixes: f92ee31e031c ("btrfs: introduce btrfs_space_info sub-group")
CC: stable@vger.kernel.org # 6.18+
Reviewed-by: Qu Wenruo 
Signed-off-by: Guangshuo Li 
Signed-off-by: David Sterba 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

btrfs: remove fs_info argument from btrfs_sysfs_add_space_info_type()

2026-05-17T15:14:34+00:00

[ Upstream commit 771af6ff72e0ed0eb8bf97e5ae4fa5094e0c5d1d ]

We don't need it since we can grab fs_info from the given space_info.
So remove the fs_info argument.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba 
Stable-dep-of: a7449edf9614 ("btrfs: fix double free in create_space_info_sub_group() error path")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

tracefs: Fix default permissions not being applied on initial mount

2026-05-17T15:14:34+00:00

[ Upstream commit e8368d1f4bedbb0cce4cfe33a1d2664bb0fd4f27 ]

Commit e4d32142d1de ("tracing: Fix tracefs mount options") moved the
option application from tracefs_fill_super() to tracefs_reconfigure()
called from tracefs_get_tree(). This fixed mount options being ignored
on user-space mounts when the superblock already exists, but introduced
a regression for the initial kernel-internal mount.

On the first mount (via simple_pin_fs during init), sget_fc() transfers
fc->s_fs_info to sb->s_fs_info and sets fc->s_fs_info to NULL. When
tracefs_get_tree() then calls tracefs_reconfigure(), it sees a NULL
fc->s_fs_info and returns early without applying any options. The root
inode keeps mode 0755 from simple_fill_super() instead of the intended
TRACEFS_DEFAULT_MODE (0700).

Furthermore, even on subsequent user-space mounts without an explicit
mode= option, tracefs_apply_options(sb, true) gates the mode behind
fsi->opts & BIT(Opt_mode), which is unset for the defaults. So the
mode is never corrected unless the user explicitly passes mode=0700.

Restore the tracefs_apply_options(sb, false) call in tracefs_fill_super()
to apply default permissions on initial superblock creation, matching
what debugfs does in debugfs_fill_super().

Cc: stable@vger.kernel.org
Fixes: e4d32142d1de ("tracing: Fix tracefs mount options")
Link: https://patch.msgid.link/20260404134747.98867-1-devnexen@gmail.com
Signed-off-by: David Carlier 
Signed-off-by: Steven Rostedt (Google) 
[ kept 6.12's `sb->s_d_op = &tracefs_dentry_operations;` instead of upstream's `set_default_d_op()` ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ksmbd: validate inherited ACE SID length

2026-05-14T13:29:29+00:00

commit 996454bc0da84d5a1dedb1a7861823087e01a7ae upstream.

smb_inherit_dacl() walks the parent directory DACL loaded from the
security descriptor xattr. It verifies that each ACE contains the fixed
SID header before using it, but does not verify that the variable-length
SID described by sid.num_subauth is fully contained in the ACE.

A malformed inheritable ACE can advertise more subauthorities than are
present in the ACE. compare_sids() may then read past the ACE.
smb_set_ace() also clamps the copied destination SID, but used the
unchecked source SID count to compute the inherited ACE size. That could
advance the temporary inherited ACE buffer pointer and nt_size accounting
past the allocated buffer.

Fix this by validating the parent ACE SID count and SID length before
using the SID during inheritance. Compute the inherited ACE size from the
copied SID so the size matches the bounded destination SID. Reject the
inherited DACL if size accumulation would overflow smb_acl.size or the
security descriptor allocation size.

Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Signed-off-by: Shota Zaizen 
Acked-by: Namjae Jeon 
Signed-off-by: Steve French 
Signed-off-by: Greg Kroah-Hartman

erofs: fix unsigned underflow in z_erofs_lz4_handle_overlap()

2026-05-14T13:29:29+00:00

[ Upstream commit 21e161de2dc660b1bb70ef5b156ab8e6e1cca3ab ]

Some crafted images can have illegal (!partial_decoding &&
m_llen < m_plen) extents, and the LZ4 inplace decompression path
can be wrongly hit, but it cannot handle (outpages < inpages)
properly: "outpages - inpages" wraps to a large value and
the subsequent rq->out[] access reads past the decompressed_pages
array.

However, such crafted cases can correctly result in a corruption
report in the normal LZ4 non-inplace path.

Let's add an additional check to fix this for backporting.

Reproducible image (base64-encoded gzipped blob):

H4sIAJGR12kCA+3SPUoDQRgG4MkmkkZk8QRbRFIIi9hbpEjrHQI5ghfwCN5BLCzTGtLbBI+g
dilSJo1CnIm7GEXFxhT6PDDwfrs73/ywIQD/1ePD4r7Ou6ETsrq4mu7XcWfj++Pb58nJU/9i
PNtbjhan04/9GtX4qVYc814WDqt6FaX5s+ZwXXeq52lndT6IuVvlblytLMvh4Gzwaf90nsvz
2DF/21+20T/ldgp5s1jXRaN4t/8izsy/OUB6e/Qa79r+JwAAAAAAAL52vQVuGQAAAP6+my1w
ywAAAAAAAADwu14ATsEYtgBQAAA=

$ mount -t erofs -o cache_strategy=disabled foo.erofs /mnt
$ dd if=/mnt/data of=/dev/null bs=4096 count=1

Fixes: 598162d05080 ("erofs: support decompress big pcluster for lz4 backend")
Reported-by: Yuhao Jiang 
Cc: stable@vger.kernel.org
Signed-off-by: Junrui Luo 
Reviewed-by: Gao Xiang 
Signed-off-by: Gao Xiang 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

erofs: tidy up z_erofs_lz4_handle_overlap()

2026-05-14T13:29:28+00:00

[ Upstream commit 9ae77198d4815c63fc8ebacc659c71d150d1e51b ]

 - Add some useful comments to explain inplace I/Os and decompression;

 - Rearrange the code to get rid of one unnecessary goto.

Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang 
Stable-dep-of: 21e161de2dc6 ("erofs: fix unsigned underflow in z_erofs_lz4_handle_overlap()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

erofs: move {in,out}pages into struct z_erofs_decompress_req

2026-05-14T13:29:28+00:00

[ Upstream commit 0243cc257ffa6d8cb210a3070b687fb510f113c7 ]

It seems that all compressors need those two values, so just move
them into the common structure.

`struct z_erofs_lz4_decompress_ctx` can be dropped too.

Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang 
Link: https://lore.kernel.org/r/20250305124007.1810731-1-hsiangkao@linux.alibaba.com
Stable-dep-of: 21e161de2dc6 ("erofs: fix unsigned underflow in z_erofs_lz4_handle_overlap()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

hfsplus: fix held lock freed on hfsplus_fill_super()

2026-05-14T13:29:28+00:00

[ Upstream commit 90c500e4fd83fa33c09bc7ee23b6d9cc487ac733 ]

hfsplus_fill_super() calls hfs_find_init() to initialize a search
structure, which acquires tree->tree_lock. If the subsequent call to
hfsplus_cat_build_key() fails, the function jumps to the out_put_root
error label without releasing the lock. The later cleanup path then
frees the tree data structure with the lock still held, triggering a
held lock freed warning.

Fix this by adding the missing hfs_find_exit(&fd) call before jumping
to the out_put_root error label. This ensures that tree->tree_lock is
properly released on the error path.

The bug was originally detected on v6.13-rc1 using an experimental
static analysis tool we are developing, and we have verified that the
issue persists in the latest mainline kernel. The tool is specifically
designed to detect memory management issues. It is currently under active
development and not yet publicly available.

We confirmed the bug by runtime testing under QEMU with x86_64 defconfig,
lockdep enabled, and CONFIG_HFSPLUS_FS=y. To trigger the error path, we
used GDB to dynamically shrink the max_unistr_len parameter to 1 before
hfsplus_asc2uni() is called. This forces hfsplus_asc2uni() to naturally
return -ENAMETOOLONG, which propagates to hfsplus_cat_build_key() and
exercises the faulty error path. The following warning was observed
during mount:

	=========================
	WARNING: held lock freed!
	7.0.0-rc3-00016-gb4f0dd314b39 #4 Not tainted
	-------------------------
	mount/174 is freeing memory ffff888103f92000-ffff888103f92fff, with a lock still held there!
	ffff888103f920b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x154/0x1e0
	2 locks held by mount/174:
	#0: ffff888103f960e0 (&type->s_umount_key#42/1){+.+.}-{4:4}, at: alloc_super.constprop.0+0x167/0xa40
	#1: ffff888103f920b0 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x154/0x1e0

	stack backtrace:
	CPU: 2 UID: 0 PID: 174 Comm: mount Not tainted 7.0.0-rc3-00016-gb4f0dd314b39 #4 PREEMPT(lazy)
	Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
	Call Trace:
	
	dump_stack_lvl+0x82/0xd0
	debug_check_no_locks_freed+0x13a/0x180
	kfree+0x16b/0x510
	? hfsplus_fill_super+0xcb4/0x18a0
	hfsplus_fill_super+0xcb4/0x18a0
	? __pfx_hfsplus_fill_super+0x10/0x10
	? srso_return_thunk+0x5/0x5f
	? bdev_open+0x65f/0xc30
	? srso_return_thunk+0x5/0x5f
	? pointer+0x4ce/0xbf0
	? trace_contention_end+0x11c/0x150
	? __pfx_pointer+0x10/0x10
	? srso_return_thunk+0x5/0x5f
	? bdev_open+0x79b/0xc30
	? srso_return_thunk+0x5/0x5f
	? srso_return_thunk+0x5/0x5f
	? vsnprintf+0x6da/0x1270
	? srso_return_thunk+0x5/0x5f
	? __mutex_unlock_slowpath+0x157/0x740
	? __pfx_vsnprintf+0x10/0x10
	? srso_return_thunk+0x5/0x5f
	? srso_return_thunk+0x5/0x5f
	? mark_held_locks+0x49/0x80
	? srso_return_thunk+0x5/0x5f
	? srso_return_thunk+0x5/0x5f
	? irqentry_exit+0x17b/0x5e0
	? trace_irq_disable.constprop.0+0x116/0x150
	? __pfx_hfsplus_fill_super+0x10/0x10
	? __pfx_hfsplus_fill_super+0x10/0x10
	get_tree_bdev_flags+0x302/0x580
	? __pfx_get_tree_bdev_flags+0x10/0x10
	? vfs_parse_fs_qstr+0x129/0x1a0
	? __pfx_vfs_parse_fs_qstr+0x3/0x10
	vfs_get_tree+0x89/0x320
	fc_mount+0x10/0x1d0
	path_mount+0x5c5/0x21c0
	? __pfx_path_mount+0x10/0x10
	? trace_irq_enable.constprop.0+0x116/0x150
	? trace_irq_enable.constprop.0+0x116/0x150
	? srso_return_thunk+0x5/0x5f
	? srso_return_thunk+0x5/0x5f
	? kmem_cache_free+0x307/0x540
	? user_path_at+0x51/0x60
	? __x64_sys_mount+0x212/0x280
	? srso_return_thunk+0x5/0x5f
	__x64_sys_mount+0x212/0x280
	? __pfx___x64_sys_mount+0x10/0x10
	? srso_return_thunk+0x5/0x5f
	? trace_irq_enable.constprop.0+0x116/0x150
	? srso_return_thunk+0x5/0x5f
	do_syscall_64+0x111/0x680
	entry_SYSCALL_64_after_hwframe+0x77/0x7f
	RIP: 0033:0x7ffacad55eae
	Code: 48 8b 0d 85 1f 0f 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 8
	RSP: 002b:00007fff1ab55718 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
	RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ffacad55eae
	RDX: 000055740c64e5b0 RSI: 000055740c64e630 RDI: 000055740c651ab0
	RBP: 000055740c64e380 R08: 0000000000000000 R09: 0000000000000001
	R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
	R13: 000055740c64e5b0 R14: 000055740c651ab0 R15: 000055740c64e380
	

After applying this patch, the warning no longer appears.

Fixes: 89ac9b4d3d1a ("hfsplus: fix longname handling")
CC: stable@vger.kernel.org
Signed-off-by: Zilin Guan 
Reviewed-by: Viacheslav Dubeyko 
Tested-by: Viacheslav Dubeyko 
Signed-off-by: Viacheslav Dubeyko 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

hfsplus: fix uninit-value by validating catalog record size

2026-05-14T13:29:28+00:00

[ Upstream commit b6b592275aeff184aa82fcf6abccd833fb71b393 ]

Syzbot reported a KMSAN uninit-value issue in hfsplus_strcasecmp(). The
root cause is that hfs_brec_read() doesn't validate that the on-disk
record size matches the expected size for the record type being read.

When mounting a corrupted filesystem, hfs_brec_read() may read less data
than expected. For example, when reading a catalog thread record, the
debug output showed:

  HFSPLUS_BREC_READ: rec_len=520, fd->entrylength=26
  HFSPLUS_BREC_READ: WARNING - entrylength (26) < rec_len (520) - PARTIAL READ!

hfs_brec_read() only validates that entrylength is not greater than the
buffer size, but doesn't check if it's less than expected. It successfully
reads 26 bytes into a 520-byte structure and returns success, leaving 494
bytes uninitialized.

This uninitialized data in tmp.thread.nodeName then gets copied by
hfsplus_cat_build_key_uni() and used by hfsplus_strcasecmp(), triggering
the KMSAN warning when the uninitialized bytes are used as array indices
in case_fold().

Fix by introducing hfsplus_brec_read_cat() wrapper that:
1. Calls hfs_brec_read() to read the data
2. Validates the record size based on the type field:
   - Fixed size for folder and file records
   - Variable size for thread records (depends on string length)
3. Returns -EIO if size doesn't match expected

For thread records, check against HFSPLUS_MIN_THREAD_SZ before reading
nodeName.length to avoid reading uninitialized data at call sites that
don't zero-initialize the entry structure.

Also initialize the tmp variable in hfsplus_find_cat() as defensive
programming to ensure no uninitialized data even if validation is
bypassed.

Reported-by: syzbot+d80abb5b890d39261e72@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d80abb5b890d39261e72
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Tested-by: syzbot+d80abb5b890d39261e72@syzkaller.appspotmail.com
Reviewed-by: Viacheslav Dubeyko 
Tested-by: Viacheslav Dubeyko 
Suggested-by: Charalampos Mitrodimas 
Link: https://lore.kernel.org/all/20260120051114.1281285-1-kartikey406@gmail.com/ [v1]
Link: https://lore.kernel.org/all/20260121063109.1830263-1-kartikey406@gmail.com/ [v2]
Link: https://lore.kernel.org/all/20260212014233.2422046-1-kartikey406@gmail.com/ [v3]
Link: https://lore.kernel.org/all/20260214002100.436125-1-kartikey406@gmail.com/T/ [v4]
Link: https://lore.kernel.org/all/20260221061626.15853-1-kartikey406@gmail.com/T/ [v5]
Signed-off-by: Deepanshu Kartikey 
Signed-off-by: Viacheslav Dubeyko 
Link: https://lore.kernel.org/r/20260307010302.41547-1-kartikey406@gmail.com
Signed-off-by: Viacheslav Dubeyko 
Stable-dep-of: 90c500e4fd83 ("hfsplus: fix held lock freed on hfsplus_fill_super()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman