Pull vfs fixes from Christian Brauner: - Fix error handling in ovl_cache_get() - Tighten access checks for exited tasks in pidfd_getfd() - Fix selftests leak in __wait_for_test() - Limit FUSE_NOTIFY_RETRIEVE to uptodate folios - Reject fuse_notify() pagecache ops on directories - Clear JOBCTL_PENDING_MASK for caller in zap_other_threads() - Fix failure to unlock in nfsd4_create_file() - Fix pointer arithmetic in qnx6 directory iteration - Fix UAF due to unlocked ->mnt_ns read in may_decode_fh() - Avoid potential null folio->mapping deref during iomap error reporting * tag 'vfs-7.1-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: iomap: avoid potential null folio->mapping deref during error reporting fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh() fs/qnx6: fix pointer arithmetic in directory iteration VFS: fix possible failure to unlock in nfsd4_create_file() signal: clear JOBCTL_PENDING_MASK for caller in zap_other_threads() fuse: reject fuse_notify() pagecache ops on directories fuse: limit FUSE_NOTIFY_RETRIEVE to uptodate folios selftests: harness: fix pidfd leak in __wait_for_test pidfd: refuse access to tasks that have started exiting harder ovl: keep err zero after successful ovl_cache_get()
Pull NFS client fix from Trond Myklebust: - Fix a use after free in nfs_write_completion * tag 'nfs-for-7.1-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: NFS: write_completion: dereference loop-local req, not hdr->req
Pull xfs fixes from Carlos Maiolino: "A collection of fixes mostly for the RT device, including a small refactor that has no functional change" * tag 'xfs-fixes-7.1-rc7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: Remove mention of PageWriteback xfs: abort mount if xfs_fs_reserve_ag_blocks fails xfs: factor rtgroup geom write pointer reporting into a helper xfs: drop the RTG reference later in xfs_ioc_rtgroup_geometry xfs: fix rtgroup cleanup in CoW fork repair xfs: fix error returns in CoW fork repair xfs: fix overlapping extents returned for pNFS LAYOUTGET xfs: fix use of uninitialized imap in xfs_fs_map_blocks error path xfs: handle racing deletions in xfs_zone_gc_iter_irec
Pull erofs fixes from Gao Xiang: - Fix a UAF of sbi->sync_decompress when compressed I/Os race with unmount - Fix a regression introduced this development cycle that incorrectly rejects multiple-algorithm images * tag 'erofs-for-7.1-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs: erofs: fix EFSCORRUPTED on multi-algorithm images in z_erofs_map_sanity_check() erofs: fix use-after-free on sbi->sync_decompress
When a buffered read fails, iomap_finish_folio_read() reports the error
with fserror_report_io(folio->mapping->host, ...). This is called after
ifs->read_bytes_pending has been decremented by the bytes attempted to
be read.
For a folio split across multiple read completions, the folio is only
guaranteed to stay locked while read_bytes_pending > 0. Once
iomap_finish_folio_read() decrements read_bytes_pending, another
in-flight read can complete and end the read on the folio, which unlocks
it. This allows truncate logic to run and detach the folio (set
folio->mapping to NULL). The error reporting path then can dereference a
NULL folio->mapping. As reported by Sam Sun, this is the race that can
occur:
CPU0: failed completion CPU1: final completion CPU2: truncate
----------------------- ---------------------- --------------
read_bytes_pending -= len
finished = false
/* preempted before
fserror_report_io() */
read_bytes_pending -= len
finished = true
folio_end_read()
truncate clears
folio->mapping
fserror_report_io(
folio->mapping->host, ...)
^ NULL deref
Fix this by reporting the error first before decrementing
ifs->read_bytes_pending.
Fixes: a9d573ee88af ("iomap: report file I/O errors to the VFS")
Cc: stable@vger.kernel.org
Reported-by: Sam Sun <samsun1006219@gmail.com>
Closes: https://lore.kernel.org/linux-fsdevel/CAEkJfYPhWdd59RKmuNLJg-bkypHz7xiOwaWyNVu3A8CUqQCnvg@mail.gmail.com/
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://patch.msgid.link/20260604011858.2297561-1-joannelkoong@gmail.com
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
may_decode_fh() accesses mount::mnt_ns without holding any locks; that
means the mount can concurrently be unmounted, and the mnt_namespace can
concurrently be freed after an RCU grace period.
This race can happens as follows, assuming that the mount point was
created by open_tree(..., OPEN_TREE_CLONE):
thread 1 thread 2 RCU
__do_sys_open_by_handle_at
do_handle_open
handle_to_path
may_decode_fh
is_mounted
[mount::mnt_ns access]
[mount::mnt_ns access]
__do_sys_close
fput_close_sync
__fput
dissolve_on_fput
umount_tree
class_namespace_excl_destructor
namespace_unlock
free_mnt_ns
mnt_ns_tree_remove
call_rcu(mnt_ns_release_rcu)
mnt_ns_release_rcu
mnt_ns_release
kfree
[mnt_namespace::user_ns access] **UAF**
Fix it by taking rcu_read_lock() around the mount::mnt_ns access, like
in __prepend_path().
Additionally, document the semantics of mount::mnt_ns, and use WRITE_ONCE()
for writers that can race with lockless readers.
This bug is unreachable unless one of the following is set:
- CONFIG_PREEMPTION
- CONFIG_RCU_STRICT_GRACE_PERIOD
because it requires an RCU grace period to happen during a syscall without
an explicit preemption.
This doesn't seem to have interesting security impact; worst-case, it could
leak the result of an integer comparison to userspace (from the level
check in cap_capable()), cause an endless loop, or crash the kernel by
dereferencing an invalid address.
Fixes: 620c266f3949 ("fhandle: relax open_by_handle_at() permission checks")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://patch.msgid.link/20260603-vfs-fhandle-uaf-fix-v2-1-d05db76a5084@google.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
5d3869a41f36 ("NFS: fix writeback in presence of errors") introduced
a dereference of hdr->req->wb_lock_context in nfs_write_completion's
per-request loop. hdr->req is set once at nfs_pgheader_init() time
and is not refcount-protected for the lifetime of the loop; when hdr
aggregates requests from multiple page groups (common under heavy
NFSv3 writeback), a parallel COMMIT on hdr->req's group can drop the
last reference and free it while the outer loop is still iterating
requests from other groups. KASAN catches this as an 8-byte read at
offset +24 of a freed nfs_page slab object (wb_lock_context).
All requests in a given pgio share the same open_context, so reading
the loop-local req's wb_lock_context yields the same value and is
safe -- req is still on hdr->pages and holds its writeback kref
through the commit branch.
Caught with kasan:
BUG: KASAN: slab-use-after-free in nfs_write_completion+0x8f8/0xa50 [nfs]
Read of size 8 at addr ffff888118af2058 by task kworker/u16:16/122062
CPU: 2 UID: 0 PID: 122062 Comm: kworker/u16:16 Kdump: loaded Not tainted 7.1.0-rc4+ #ge05a759574b2 PREEMPT
Workqueue: nfsiod rpc_async_release
Call Trace:
<TASK>
dump_stack_lvl+0xaf/0x100
? nfs_write_completion+0x8f8/0xa50 [nfs]
print_report+0x157/0x4a1
? __virt_addr_valid+0x1fb/0x400
? nfs_write_completion+0x8f8/0xa50 [nfs]
kasan_report+0xc2/0x190
? nfs_write_completion+0x8f8/0xa50 [nfs]
nfs_write_completion+0x8f8/0xa50 [nfs]
? nfs_commit_release_pages+0xbd0/0xbd0 [nfs]
? lock_acquire+0x182/0x2e0
? process_one_work+0x937/0x1890
? nfs_pgio_header_alloc+0xd0/0xd0 [nfs]
rpc_free_task+0xee/0x160
rpc_async_release+0x5d/0xb0
process_one_work+0x9b0/0x1890
? pwq_dec_nr_in_flight+0xed0/0xed0
? rpc_final_put_task+0x140/0x140
worker_thread+0x75a/0x10a0
? process_one_work+0x1890/0x1890
? kthread+0x1af/0x4d0
? process_one_work+0x1890/0x1890
kthread+0x3d3/0x4d0
? kthread_affine_node+0x2c0/0x2c0
ret_from_fork+0x669/0xa50
? native_tss_update_io_bitmap+0x660/0x660
? __switch_to+0x9dd/0x1310
? kthread_affine_node+0x2c0/0x2c0
ret_from_fork_asm+0x11/0x20
</TASK>
Allocated by task 121997 on cpu 3 at 31643.290294s:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x13/0x60
__kasan_slab_alloc+0x62/0x70
kmem_cache_alloc_noprof+0x1ab/0x4e0
nfs_page_create+0x152/0x460 [nfs]
nfs_page_create_from_folio+0x7e/0x210 [nfs]
nfs_update_folio+0x7a9/0x32a0 [nfs]
nfs_write_end+0x290/0xc60 [nfs]
generic_perform_write+0x4ce/0x990
nfs_file_write+0x6b3/0xce0 [nfs]
vfs_write+0x63c/0xfa0
ksys_write+0x122/0x240
do_syscall_64+0xc3/0x13f0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Freed by task 122046 on cpu 0 at 31647.037964s:
kasan_save_stack+0x1e/0x40
kasan_save_track+0x13/0x60
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x3b/0x60
kmem_cache_free+0x11b/0x5a0
nfs_page_group_destroy+0x13a/0x210 [nfs]
nfs_unlock_and_release_request+0x64/0x90 [nfs]
nfs_commit_release_pages+0x339/0xbd0 [nfs]
nfs_commit_release+0x51/0xb0 [nfs]
rpc_free_task+0xee/0x160
rpc_async_release+0x5d/0xb0
process_one_work+0x9b0/0x1890
worker_thread+0x75a/0x10a0
kthread+0x3d3/0x4d0
ret_from_fork+0x669/0xa50
ret_from_fork_asm+0x11/0x20
The buggy address belongs to the object at ffff888118af2040\x0a which belongs to the cache nfs_page of size 96
The buggy address is located 24 bytes inside of\x0a freed 96-byte region [ffff888118af2040, ffff888118af20a0)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x118af2
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4000000000000040(head|zone=2)
page_type: f5(slab)
raw: 4000000000000040 ffff88818cf2c4c0 ffffea000e61b990 ffffea0004e7d110
raw: 0000000000000000 0000000800190019 00000000f5000000 0000000000000000
head: 4000000000000040 ffff88818cf2c4c0 ffffea000e61b990 ffffea0004e7d110
head: 0000000000000000 0000000800190019 00000000f5000000 0000000000000000
head: 4000000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 121997, tgid 121997 (rsync), ts 31643290274577, free_ts 31642154777182
post_alloc_hook+0xd1/0x100
get_page_from_freelist+0xbad/0x2910
__alloc_frozen_pages_noprof+0x1c6/0x4a0
allocate_slab+0x330/0x620
___slab_alloc+0xe9/0x930
kmem_cache_alloc_noprof+0x35b/0x4e0
nfs_page_create+0x152/0x460 [nfs]
nfs_page_create_from_folio+0x7e/0x210 [nfs]
nfs_update_folio+0x7a9/0x32a0 [nfs]
nfs_write_end+0x290/0xc60 [nfs]
generic_perform_write+0x4ce/0x990
nfs_file_write+0x6b3/0xce0 [nfs]
vfs_write+0x63c/0xfa0
ksys_write+0x122/0x240
do_syscall_64+0xc3/0x13f0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
page last free pid 122202 tgid 122202 stack trace:
__free_frozen_pages+0x6da/0xf30
qlist_free_all+0x53/0x130
kasan_quarantine_reduce+0x198/0x1f0
__kasan_slab_alloc+0x46/0x70
kmem_cache_alloc_noprof+0x1ab/0x4e0
__alloc_object+0x2f/0x230
__create_object+0x22/0x80
kmem_cache_alloc_node_noprof+0x416/0x4d0
__alloc_skb+0x146/0x6e0
tcp_stream_alloc_skb+0x35/0x660
tcp_sendmsg_locked+0x1746/0x4260
tcp_sendmsg+0x2f/0x40
inet_sendmsg+0x9e/0xe0
__sock_sendmsg+0xd9/0x180
sock_sendmsg+0x122/0x200
xprt_sock_sendmsg+0x4ff/0x9a0
Memory state around the buggy address:
ffff888118af1f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
ffff888118af1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888118af2000: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
^
ffff888118af2080: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
ffff888118af2100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Reviewed-by Jeff Layton <jlayton@kernel.org>
Fixes: 5d3869a41f36 ("NFS: fix writeback in presence of errors")
Cc: Olga Kornievskaia <okorniev@redhat.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: linux-nfs@vger.kernel.org
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Commit a5242d37c83a ("erofs: error out obviously illegal extents in
advance") changed the per-extent algorithm presence check from "is the
bit set" to "is the only bit set":
- !(sbi->available_compr_algs & (1 << map->m_algorithmformat))
+ (sbi->available_compr_algs ^ BIT(map->m_algorithmformat))
`available_compr_algs` is a bitmap of every compression algorithm
available in the image (z_erofs_parse_cfgs() iterates it with
for_each_set_bit()), so an image that enables more than one algorithm
has multiple bits set. XOR is zero only when the bitmap is exactly
BIT(map->m_algorithmformat); for any image with two or more algorithms
the test is non-zero for every extent and the read fails with
-EFSCORRUPTED ("inconsistent algorithmtype %u").
Reproducer (mkfs.erofs from erofs-utils 1.7.1):
$ mkdir src
$ yes A | head -c 100K > src/a
$ head -c 64K /dev/zero > src/b
$ mkfs.erofs -zlz4:deflate multi.erofs src
$ mount -t erofs -o loop multi.erofs /mnt
$ cat /mnt/a >/dev/null
cat: /mnt/a: Structure needs cleaning
$ dmesg | tail
erofs (device loop0): inconsistent algorithmtype 0 for nid 46
erofs (device loop0): read error -117 @ 0 of nid 46
The erofs on-disk format (Z_EROFS_COMPRESSION_MAX = 4 with LZ4, LZMA,
DEFLATE, ZSTD) and the kernel parser explicitly support
multi-algorithm images, and erofs-utils 1.7.1 generates them via the
"-z X:Y" syntax.
Restore the original per-bit presence check.
Fixes: a5242d37c83a ("erofs: error out obviously illegal extents in advance")
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
A deferred byte-range lock (an SMB2_LOCK that blocks) registers an async work on
conn->async_requests via setup_async_work(), with cancel_fn =
smb2_remove_blocked_lock and cancel_argv[0] pointing at the struct file_lock.
When the request is cancelled, the worker frees the file_lock with
locks_free_lock() and takes the cancelled early-exit, which "goto out"s and never
reaches release_async_work() -- the only site that unlinks the work from
conn->async_requests and clears cancel_fn/cancel_argv. The work therefore stays
matchable on async_requests with a live cancel_fn pointing at the freed file_lock,
until connection teardown finally runs release_async_work().
smb2_cancel() fires cancel_fn unconditionally with no state guard, so a second
SMB2_CANCEL for the same AsyncId, arriving in that window, re-runs
smb2_remove_blocked_lock() on the freed file_lock -- a slab use-after-free:
BUG: KASAN: slab-use-after-free in __locks_delete_block
__locks_delete_block
locks_delete_block
ksmbd_vfs_posix_lock_unblock
smb2_remove_blocked_lock
smb2_cancel <- 2nd SMB2_CANCEL fires cancel_fn
handle_ksmbd_work
Allocated by ...: locks_alloc_lock <- smb2_lock
Freed by ...: locks_free_lock <- smb2_lock (cancelled branch)
... cache file_lock_cache of size 192
Reproduced on mainline with KASAN by an authenticated SMB client.
Skip a work whose state is already KSMBD_WORK_CANCELLED so its cancel callback
cannot be fired a second time.
Cc: stable@vger.kernel.org
Signed-off-by: Gil Portnoy <dddhkts1@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Two concurrent same-user DHnC reconnects can both observe fp->conn == NULL
before either sets it. ksmbd_reopen_durable_fd() checks fp->conn to guard
against a handle already being reconnected, but the check and the binding
assignment are not atomic: both threads pass the guard, both call
ksmbd_conn_get() on the same fp, and both eventually reach
kfree(fp->owner.name) -- a double-free of the owner.name slab object.
The double-bound ksmbd_file also causes a write-UAF on the 344-byte
ksmbd_file_cache object when a concurrent smb2_close() spins on fp->f_lock
after the object has been freed by the losing reconnect path.
KASAN on 7.1-rc5 (48-thread concurrent reconnect, 3000 cycles):
BUG: KASAN: double-free in ksmbd_reopen_durable_fd+0x268/0x308
BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xac/0x150
Write of size 4 at offset 24 into freed ksmbd_file_cache object
Five double-bind windows observed; 63 total KASAN reports triggered.
Fix: validate and claim fp->conn under write_lock(&global_ft.lock) so the
check-and-claim is atomic. ksmbd_lookup_durable_fd() already treats
fp->conn != NULL as "in use" and skips such an fp; setting fp->conn before
dropping the lock closes the race. ksmbd_conn_get() is a non-sleeping
refcount increment, safe under the rwlock. The rollback path on __open_id()
failure also clears fp->conn/tcon under the lock so concurrent readers see
a consistent state.
Fixes: b1f1e80620de ("ksmbd: centralize ksmbd_conn final release to plug transport leak")
Assisted-by: Henry (Claude):claude-opus-4
Signed-off-by: Gil Portnoy <dddhkts1@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>