Commit Graph

27 Commits

Author SHA1 Message Date
ChenXiaoSong
4ec9c8e023 smb/server: promote S_DEL_ON_CLS to S_DEL_PENDING when close
Reproducer:

  1. server: systemctl start ksmbd
  2. client: mount -t cifs //${server_ip}/export /mnt
  3. client: C program: openat(AT_FDCWD, "/mnt", O_RDWR | O_TMPFILE, 0600)

Do not treat `FILE_DELETE_ON_CLOSE_LE` as delete pending while files
remain open.

This patch fixes xfstests generic/004.

Cc: stable@vger.kernel.org
Link: https://chenxiaosong.com/en/smb-xfstests-generic-004.html
Co-developed-by: Huiwen He <hehuiwen@kylinos.cn>
Signed-off-by: Huiwen He <hehuiwen@kylinos.cn>
Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Tested-by: Steve French <stfrench@microsoft.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-05-21 18:20:24 -05:00
Jeremy Laratro
904901561e ksmbd: fix null pointer dereference in proc_show_files()
When a SMB2 client opens a file with a durable v2 handle and then issues
SMB2 SESSION_LOGOFF, session_fd_check() clears fp->tcon = NULL on the
reconnectable file pointer but leaves the fp registered in global_ft.idr
until the durable scavenger fires (up to fp->durable_timeout seconds
later).

During that window any read of /proc/fs/ksmbd/files (mode 0400) panics
the kernel because proc_show_files() walks global_ft.idr and
unconditionally dereferences fp->tcon->id with no NULL guard.

Reproducer requires only a successful SMB2 SESSION_SETUP and a share
configured with 'durable handles = yes'. KASAN report on mainline
70390501d194:

  general protection fault, probably for non-canonical address
  0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  RIP: 0010:proc_show_files+0x118/0x740
  Call Trace:
   proc_show_files+0x118/0x740
   seq_read_iter+0x4ef/0xe10
   proc_reg_read_iter+0x1b7/0x280
   ...

Guard the dereference. A durable-disconnected fp legitimately has no
tcon; report its tree id as 0 rather than oopsing.

Fixes: b38f99c121 ("ksmbd: add procfs interface for runtime monitoring and statistics")
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Laratro <research@aradex.io>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-05-13 16:35:23 -05:00
DaeMyung Kang
bf736184d0 ksmbd: close durable scavenger races against m_fp_list lookups
ksmbd_durable_scavenger() has two related races against any walker
that iterates f_ci->m_fp_list, including ksmbd_lookup_fd_inode()
(used by ksmbd_vfs_rename) and the share-mode checks in
fs/smb/server/smb_common.c.

(1) fp->node list-head reuse.  Durable-preserved handles can remain
linked on f_ci->m_fp_list after session teardown so share-mode checks
still see them while the handle is reconnectable.  The scavenger
collected expired handles by adding fp->node to a local
scavenger_list after removing them from the global durable idr.
Because fp->node is the same list_head used by m_fp_list,
list_add(&fp->node, &scavenger_list) overwrites the m_fp_list links
and corrupts both lists.  CONFIG_DEBUG_LIST can report this on the
share-mode walk path.

(2) Refcount race against m_fp_list walkers.  The scavenger qualifies
an expired durable handle with atomic_read(&fp->refcount) > 1 and
fp->conn under global_ft.lock, removes fp from global_ft, then drops
global_ft.lock before unlinking fp from m_fp_list and freeing it.
During that gap fp is still linked on m_fp_list with f_state ==
FP_INITED.  ksmbd_lookup_fd_inode() under m_lock read calls
ksmbd_fp_get() (atomic_inc_not_zero on refcount that is still 1) and
takes a live reference; the scavenger then unlinks and frees fp
while the holder owns a reference, leading to UAF on the holder's
subsequent ksmbd_fd_put() and on any field reads performed by a
concurrent share-mode walker that iterates m_fp_list without taking
ksmbd_fp_get() (smb_check_perm_dleases-like paths).

Fix both:

  * Stop reusing fp->node as a scavenger-private list node.  Remove
    one expired handle from global_ft under global_ft.lock, take an
    explicit transient reference, drop the lock, unlink fp->node
    from m_fp_list under f_ci->m_lock, then drop both the durable
    lifetime and transient references with atomic_sub_and_test(2,
    &fp->refcount).  If the scavenger is the last putter the close
    runs there; otherwise an in-flight holder that already raced
    through the m_fp_list lookup owns the final close via its
    ksmbd_fd_put() path.  The one-at-a-time disposal can rescan the
    durable idr when multiple handles expire in the same pass, but
    durable scavenging is a background expiration path and the final
    full scan recomputes min_timeout before the next wait.

  * Clear fp->persistent_id inside __ksmbd_remove_durable_fd() right
    after idr_remove(), so a delayed final close from a holder that
    snatched fp does not re-issue idr_remove() on a persistent id
    that idr_alloc_cyclic() in ksmbd_open_durable_fd() may have
    already handed out to a brand-new durable handle.

  * Bypass the per-conn open_files_count decrement in
    __put_fd_final() when fp is detached from any session table
    (fp->conn cleared by session_fd_check() at durable preserve --
    paired with the volatile_id clear at unpublish, so checking
    fp->conn alone is sufficient).  The walker that owns the final
    close runs from an unrelated work->conn whose
    stats.open_files_count never tracked this durable fp; without
    this guard the holder would underflow that unrelated counter.

The two races are folded into one patch because patch (1) alone
cleans up the corrupted list but leaves a deterministic UAF window
for m_fp_list walkers that the transient-reference and
persistent_id discipline in (2) close; bisecting onto an
intermediate state would land on a UAF that pre-patch chaos merely
made less reproducible.

Validation:
  * CONFIG_DEBUG_LIST coverage for the list_head reuse path.
  * KASAN-enabled direct SMB2 durable-handle coverage that exercised
    ksmbd_durable_scavenger() and non-NULL ksmbd_lookup_fd_inode()
    returns while durable handles expired under concurrent rename
    lookups, with no KASAN, UAF, list-corruption, ODEBUG, or WARNING
    reports.
  * checkpatch --strict
  * make -j$(nproc) M=fs/smb/server

Fixes: d484d621d4 ("ksmbd: add durable scavenger timer")
Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-05-01 21:49:35 -05:00
DaeMyung Kang
a42896bebf ksmbd: harden file lifetime during session teardown
__close_file_table_ids() is the per-session teardown that closes every
fp belonging to a session (or to one tree connect on that session) by
walking the session's volatile-id idr.  The current loop has three
related problems on busy or racing workloads:

  * Sleeping under ft->lock.  The session-teardown skip callback,
    session_fd_check(), already sleeps in ksmbd_vfs_copy_durable_owner()
    -> kstrdup(GFP_KERNEL) and down_write(&fp->f_ci->m_lock) (a
    rw_semaphore).  Running the callback inside write_lock(&ft->lock)
    trips CONFIG_DEBUG_ATOMIC_SLEEP / CONFIG_PROVE_LOCKING on a
    durable-fd workload.

  * Refcount accounting blind to f_state.  The unconditional
    atomic_dec_and_test(&fp->refcount) does not distinguish
    FP_INITED (idr-owned reference still intact) from FP_CLOSED (an
    earlier ksmbd_close_fd() already consumed the idr-owned reference
    while leaving fp in the idr because a holder kept refcount
    non-zero).  When the latter races with teardown the same path
    over-decrements into a holder reference and ksmbd_fd_put() later
    UAFs that holder.

  * FP_NEW window.  Between __open_id() publishing fp into the
    session idr and ksmbd_update_fstate(..., FP_INITED) committing the
    transition at the end of smb2_open(), an fp is in FP_NEW and an
    intervening teardown that takes a transient reference and
    unpublishes the volatile id leaves the original idr-owned
    reference orphaned -- the opener is unaware that fp has been
    unpublished, returns success to the client, and the fp leaks at
    refcount = 1.

Refactor __close_file_table_ids() to take a transient reference on fp
and unpublish fp from the session idr *under ft->lock* before calling
skip() outside the lock.  A transient ref protects lifetime but not
concurrent field mutation, so the idr_remove() is what keeps
__ksmbd_lookup_fd() through this session's idr from granting a new
ksmbd_fp_get() reference to an fp whose fp->conn / fp->tcon /
fp->volatile_id / op->conn / lock_list links are about to be rewritten
by session_fd_check().  Durable reconnect is unaffected because it
reaches fp through the global durable table (ksmbd_lookup_durable_fd
-> global_ft).

Decide n_to_drop together with any FP_INITED -> FP_CLOSED transition
under ft->lock so teardown and ksmbd_close_fd() never both consume the
idr-owned reference.  See ksmbd_mark_fp_closed() for the per-state
accounting.  For the FP_NEW path to be safe, the opener has to learn
that fp was unpublished: ksmbd_update_fstate() now returns -ENOENT
when an FP_NEW -> FP_INITED transition finds f_state already advanced
or the volatile id cleared (both committed by teardown under
ft->lock); smb2_open() propagates that as STATUS_OBJECT_NAME_INVALID
and drops the original reference via ksmbd_fd_put().

The list removal cannot be left for a deferred final putter because
fp->volatile_id has already been cleared and __ksmbd_remove_fd() will
intentionally skip both idr_remove() and list_del_init().  Move the
m_fp_list unlink in __ksmbd_remove_fd() above the volatile-id check so
that an FP_NEW fp that happened to be added to m_fp_list (smb2_open()
adds fp->node before ksmbd_update_fstate() runs) is still cleaned up
on the deferred putter path; list_del_init() on an empty node is a
no-op and remains safe for fps that were never added.

Add a defensive guard in session_fd_check() that refuses non-FP_INITED
fps so that even if a teardown reaches an FP_NEW fp it falls into the
close branch (where the n_to_drop = 1 accounting keeps the opener's
reference alive) instead of the durable-preserve branch (which mutates
fp->conn / fp->tcon).

Validation on a debug kernel additionally built with CONFIG_DEBUG_LIST
and CONFIG_DEBUG_OBJECTS_WORK used a same-session two-tcon workload
(open/write storm on one tcon, 50 tree disconnects on the other) and
reported no list-corruption, work_struct ODEBUG, sleep-in-atomic,
lockdep or kmemleak reports.  Reverting only the
__close_file_table_ids() hunk while keeping a forced-is_reconnectable()
harness produced the expected sleep-in-atomic at vfs_cache.c:1095,
confirming the ft->lock-out-of-sleepable-skip discipline.

KASAN-enabled direct SMB2 coverage with durable handles enabled
exercised ksmbd_close_tree_conn_fds(), ksmbd_close_session_fds(),
the FP_NEW failure path, tree_conn_fd_check(), and a non-zero
session_fd_check() durable-preserve return.  This produced no KASAN,
DEBUG_LIST, ODEBUG, or WARNING reports.

Fixes: f441584858 ("cifsd: add file operations")
Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-05-01 21:49:35 -05:00
DaeMyung Kang
b1f1e80620 ksmbd: centralize ksmbd_conn final release to plug transport leak
ksmbd_conn_free() is one of four sites that can observe the last
refcount drop of a struct ksmbd_conn.  The other three

    fs/smb/server/connection.c    ksmbd_conn_r_count_dec()
    fs/smb/server/oplock.c        __free_opinfo()
    fs/smb/server/vfs_cache.c     session_fd_check()

end the conn with a bare kfree(), skipping
ida_destroy(&conn->async_ida) and
conn->transport->ops->free_transport(conn->transport).  Whenever one
of them is the last putter, the embedded async_ida and the entire
transport struct leak -- for TCP, that is also the struct socket and
the kvec iov.

__free_opinfo() being a final putter is not theoretical.  opinfo_put()
queues the callback via call_rcu(&opinfo->rcu, free_opinfo_rcu), so
ksmbd_server_terminate_conn() can deposit N opinfo releases in RCU and
have ksmbd_conn_free() run in the handler thread before any of them
fire.  ksmbd_conn_free() then observes refcnt > 0 and short-circuits;
the last RCU-delivered __free_opinfo() falls onto its bare kfree(conn)
branch and the transport is lost.

A/B validation in a QEMU/virtme guest, mounting //127.0.0.1/testshare:
each iteration holds 8 files open via sleep processes, force-closes
TCP with "ss -K sport = :445", kills the holders, lazy-umounts;
repeated 10 times, then ksmbd shutdown and kmemleak scan.

    state         conn_alloc  conn_free  tcp_free  opi_rcu  kmemleak
    ----------    ----------  ---------  --------  -------  --------
    pre-patch         20          20        10       160        7
    with patch        20          20        20       160        0

Pre-patch conn_free=20 with tcp_free=10 directly demonstrates the
bare-kfree paths skipping transport cleanup; kmemleak backtraces point
into struct tcp_transport / iov.  With this patch tcp_free matches
conn_free at 20/20 and kmemleak is clean.

Move the per-struct final release into __ksmbd_conn_release_work() and
route the three bare-kfree final-put sites through a new
ksmbd_conn_put().  Those sites now pair ida_destroy() and
free_transport() with kfree(conn) regardless of which holder happens
to release the last reference.  stop_sessions() only triggers the
transport shutdown and does not itself drop the last conn reference,
so it is unaffected.

The centralized release reaches sock_release() -> tcp_close() ->
lock_sock_nested() (might_sleep) from every final putter, including
__free_opinfo() invoked from an RCU softirq callback, which trips
CONFIG_DEBUG_ATOMIC_SLEEP.  Defer the release to a dedicated
ksmbd_conn_wq workqueue so ksmbd_conn_put() is safe from any
non-sleeping context.

Make ksmbd_file own a strong connection reference while fp->conn is
non-NULL so durable-preserve and final-close paths cannot dereference
a stale connection.  ksmbd_open_fd() and ksmbd_reopen_durable_fd()
take the reference via ksmbd_conn_get() (the latter also reorders the
fp->conn / fp->tcon assignments before __open_id() so the published fp
is never observed with fp->conn == NULL); session_fd_check() and
__ksmbd_close_fd() drop it via ksmbd_conn_put().  With that invariant,
session_fd_check() can take a local conn pointer once and use it
across the m_op_list and lock_list iterations even though op->conn
puts may otherwise drop the last reference.

At module exit the workqueue is flushed and destroyed after
rcu_barrier(), so any release queued by a trailing RCU callback is
drained before the inode hash and module text go away.

Fixes: ee426bfb9d ("ksmbd: add refcnt to ksmbd_conn struct")
Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-05-01 21:49:35 -05:00
Namjae Jeon
49110a8ce6 ksmbd: validate owner of durable handle on reconnect
Currently, ksmbd does not verify if the user attempting to reconnect
to a durable handle is the same user who originally opened the file.
This allows any authenticated user to hijack an orphaned durable handle
by predicting or brute-forcing the persistent ID.

According to MS-SMB2, the server MUST verify that the SecurityContext
of the reconnect request matches the SecurityContext associated with
the existing open.
Add a durable_owner structure to ksmbd_file to store the original opener's
UID, GID, and account name. and catpure the owner information when a file
handle becomes orphaned. and implementing ksmbd_vfs_compare_durable_owner()
to validate the identity of the requester during SMB2_CREATE (DHnC).

Fixes: c8efcc7861 ("ksmbd: add support for durable handles v1/v2")
Reported-by: Davide Ornaghi <d.ornaghi97@gmail.com>
Reported-by: Navaneeth K <knavaneeth786@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-04-12 18:07:54 -05:00
Namjae Jeon
235e32320a ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger
When a durable file handle survives session disconnect (TCP close without
SMB2_LOGOFF), session_fd_check() sets fp->conn = NULL to preserve the
handle for later reconnection. However, it did not clean up the byte-range
locks on fp->lock_list.

Later, when the durable scavenger thread times out and calls
__ksmbd_close_fd(NULL, fp), the lock cleanup loop did:

    spin_lock(&fp->conn->llist_lock);

This caused a slab use-after-free because fp->conn was NULL and the
original connection object had already been freed by
ksmbd_tcp_disconnect().

The root cause is asymmetric cleanup: lock entries (smb_lock->clist) were
left dangling on the freed conn->lock_list while fp->conn was nulled out.

To fix this issue properly, we need to handle the lifetime of
smb_lock->clist across three paths:
 - Safely skip clist deletion when list is empty and fp->conn is NULL.
 - Remove the lock from the old connection's lock_list in
   session_fd_check()
 - Re-add the lock to the new connection's lock_list in
   ksmbd_reopen_durable_fd().

Fixes: c8efcc7861 ("ksmbd: add support for durable handles v1/v2")
Co-developed-by: munan Huang <munanevil@gmail.com>
Signed-off-by: munan Huang <munanevil@gmail.com>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-04-12 18:07:54 -05:00
Ali Khaledi
40955015fa ksmbd: fix use-after-free in proc_show_files due to early rcu_read_unlock
The opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is
dereferenced after rcu_read_unlock(), creating a use-after-free
window. A concurrent opinfo_put() can free the opinfo between the
unlock and the subsequent access to opinfo->is_lease,
opinfo->o_lease->state, and opinfo->level.

Fix this by deferring rcu_read_unlock() until after all opinfo
field accesses are complete. The values needed (const_names, count,
level) are copied into local variables under the RCU read lock,
and the potentially-sleeping seq_printf calls happen after the
lock is released.

Found by AI-assisted code review (Claude Opus 4.6, Anthropic)
in collaboration with Ali Khaledi.

Cc: stable@vger.kernel.org
Fixes: b38f99c121 ("ksmbd: add procfs interface for runtime monitoring and statistics")
Signed-off-by: Ali Khaledi <ali.khaledi1989@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-03-08 21:28:39 -05:00
Kees Cook
69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Bahubali B Gumaji
b38f99c121 ksmbd: add procfs interface for runtime monitoring and statistics
This patch introduces a /proc filesystem interface to ksmbd, providing
visibility into the internal state of the SMB server. This allows
administrators and developers to monitor active connections, user
sessions, and opened files in real-time without relying on external
tools or heavy debugging.

Key changes include:
 - Connection Monitoring (/proc/fs/ksmbd/clients): Displays a list of
   active network connections, including client IP addresses, SMB dialects,
   credits, and last active timestamps.

 - Session Management (/proc/fs/ksmbd/sessions/): Adds a global sessions
   file to list all authenticated users and their session IDs.

 - Creates individual session entries (e.g., /proc/fs/ksmbd/sessions/<id>)
   detailing capabilities (DFS, Multi-channel, etc.), signing/encryption
   algorithms, and connected tree shares.

 - File Tracking (/proc/fs/ksmbd/files): Shows all currently opened files
   across the server, including tree IDs, process IDs (PID), access modes
   (daccess/saccess), and oplock/lease states.

 - Statistics & Counters: Implements internal counters for global server
   metrics, such as the number of tree connections, total sessions, and
   processed read/write bytes.

Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Bahubali B Gumaji <bahubali.bg@samsung.com>
Signed-off-by: Sang-Soo Lee  <constant.lee@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2026-02-08 20:25:16 -06:00
Qianchang Zhao
991f8a79db ksmbd: vfs: fix race on m_flags in vfs_cache
ksmbd maintains delete-on-close and pending-delete state in
ksmbd_inode->m_flags. In vfs_cache.c this field is accessed under
inconsistent locking: some paths read and modify m_flags under
ci->m_lock while others do so without taking the lock at all.

Examples:

 - ksmbd_query_inode_status() and __ksmbd_inode_close() use
   ci->m_lock when checking or updating m_flags.
 - ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),
   ksmbd_clear_inode_pending_delete() and ksmbd_fd_set_delete_on_close()
   used to read and modify m_flags without ci->m_lock.

This creates a potential data race on m_flags when multiple threads
open, close and delete the same file concurrently. In the worst case
delete-on-close and pending-delete bits can be lost or observed in an
inconsistent state, leading to confusing delete semantics (files that
stay on disk after delete-on-close, or files that disappear while still
in use).

Fix it by:

 - Making ksmbd_query_inode_status() look at m_flags under ci->m_lock
   after dropping inode_hash_lock.
 - Adding ci->m_lock protection to all helpers that read or modify
   m_flags (ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(),
   ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close()).
 - Keeping the existing ci->m_lock protection in __ksmbd_inode_close(),
   and moving the actual unlink/xattr removal outside the lock.

This unifies the locking around m_flags and removes the data race while
preserving the existing delete-on-close behaviour.

Reported-by: Qianchang Zhao <pioooooooooip@gmail.com>
Reported-by: Zhitong Liu <liuzhitong1993@gmail.com>
Signed-off-by: Qianchang Zhao <pioooooooooip@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-11-30 21:11:45 -06:00
Sean Heelan
36991c1ccd ksmbd: Fix UAF in __close_file_table_ids
A use-after-free is possible if one thread destroys the file
via __ksmbd_close_fd while another thread holds a reference to
it. The existing checks on fp->refcount are not sufficient to
prevent this.

The fix takes ft->lock around the section which removes the
file from the file table. This prevents two threads acquiring the
same file pointer via __close_file_table_ids, as well as the other
functions which retrieve a file from the IDR and which already use
this same lock.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Heelan <seanheelan@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-05-06 08:37:02 -05:00
Namjae Jeon
1df0d4c616 ksmbd: fix WARNING "do not call blocking ops when !TASK_RUNNING"
wait_event_timeout() will set the state of the current
task to TASK_UNINTERRUPTIBLE, before doing the condition check. This
means that ksmbd_durable_scavenger_alive() will try to acquire the mutex
while already in a sleeping state. The scheduler warns us by giving
the following warning:

do not call blocking ops when !TASK_RUNNING; state=2 set at
 [<0000000061515a6f>] prepare_to_wait_event+0x9f/0x6c0
WARNING: CPU: 2 PID: 4147 at kernel/sched/core.c:10099 __might_sleep+0x12f/0x160

mutex lock is not needed in ksmbd_durable_scavenger_alive().

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-04-14 22:21:26 -05:00
Namjae Jeon
0066f623bc ksmbd: use __GFP_RETRY_MAYFAIL
Prefer to report ENOMEM rather than incur the oom for allocations in
ksmbd. __GFP_NORETRY could not achieve that, It would fail the allocations
just too easily. __GFP_RETRY_MAYFAIL will keep retrying the allocation
until there is no more progress and fail the allocation instead go OOM
and let the caller to deal with it.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-11-25 18:58:02 -06:00
Namjae Jeon
ee426bfb9d ksmbd: add refcnt to ksmbd_conn struct
When sending an oplock break request, opinfo->conn is used,
But freed ->conn can be used on multichannel.
This patch add a reference count to the ksmbd_conn struct
so that it can be freed when it is no longer used.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-09-14 00:03:15 -05:00
Namjae Jeon
d484d621d4 ksmbd: add durable scavenger timer
Launch ksmbd-durable-scavenger kernel thread to scan durable fps that
have not been reclaimed by a client within the configured time.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-07-14 21:45:40 -05:00
Namjae Jeon
520da3c488 ksmbd: avoid reclaiming expired durable opens by the client
The expired durable opens should not be reclaimed by client.
This patch add ->durable_scavenger_timeout to fp and check it in
ksmbd_lookup_durable_fd().

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-07-14 18:00:35 -05:00
Namjae Jeon
2bfc4214c6 ksmbd: fix missing use of get_write in in smb2_set_ea()
Fix an issue where get_write is not used in smb2_set_ea().

Fixes: 6fc0a265e1 ("ksmbd: fix potential circular locking issue in smb2_set_ea()")
Cc: stable@vger.kernel.org
Reported-by: Wang Zhaolong <wangzhaolong1@huawei.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-06-11 23:43:09 -05:00
Namjae Jeon
d1c189c6cb ksmbd: use rwsem instead of rwlock for lease break
lease break wait for lease break acknowledgment.
rwsem is more suitable than unlock while traversing the list for parent
lease break in ->m_op_list.

Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-05-04 23:53:36 -05:00
Namjae Jeon
c8efcc7861 ksmbd: add support for durable handles v1/v2
Durable file handles allow reopening a file preserved on a short
network outage and transparent client reconnection within a timeout.
i.e. Durable handles aren't necessarily cleaned up when the opening
process terminates.

This patch add support for durable handle version 1 and 2.

To prove durable handles work on ksmbd, I have tested this patch with
the following smbtorture tests:

smb2.durable-open.open-oplock
smb2.durable-open.open-lease
smb2.durable-open.reopen1
smb2.durable-open.reopen1a
smb2.durable-open.reopen1a-lease
smb2.durable-open.reopen2
smb2.durable-open.reopen2a
smb2.durable-open.reopen2-lease
smb2.durable-open.reopen2-lease-v2
smb2.durable-open.reopen3
smb2.durable-open.reopen4
smb2.durable-open.delete_on_close2
smb2.durable-open.file-position
smb2.durable-open.lease
smb2.durable-open.alloc-size
smb2.durable-open.read-only
smb2.durable-v2-open.create-blob
smb2.durable-v2-open.open-oplock
smb2.durable-v2-open.open-lease
smb2.durable-v2-open.reopen1
smb2.durable-v2-open.reopen1a
smb2.durable-v2-open.reopen1a-lease
smb2.durable-v2-open.reopen2
smb2.durable-v2-open.reopen2b

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-12 00:36:39 -05:00
Namjae Jeon
d47d9886ae ksmbd: send v2 lease break notification for directory
If client send different parent key, different client guid, or there is
no parent lease key flags in create context v2 lease, ksmbd send lease
break to client.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-12-08 10:11:33 -06:00
Namjae Jeon
4274a9dc6a ksmbd: separately allocate ci per dentry
xfstests generic/002 test fail when enabling smb2 leases feature.
This test create hard link file, but removeal failed.
ci has a file open count to count file open through the smb client,
but in the case of hard link files, The allocation of ci per inode
cause incorrectly open count for file deletion. This patch allocate
ci per dentry to counts open counts for hard link.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-11-23 20:50:45 -06:00
Namjae Jeon
414849040f ksmbd: fix Null pointer dereferences in ksmbd_update_fstate()
Coverity Scan report the following one. This report is a false alarm.
Because fp is never NULL when rc is zero. This patch add null check for fp
in ksmbd_update_fstate to make alarm silence.

*** CID 1568583:  Null pointer dereferences  (FORWARD_NULL)
/fs/smb/server/smb2pdu.c: 3408 in smb2_open()
3402                    path_put(&path);
3403                    path_put(&parent_path);
3404            }
3405            ksmbd_revert_fsids(work);
3406     err_out1:
3407            if (!rc) {
>>>     CID 1568583:  Null pointer dereferences  (FORWARD_NULL)
>>>     Passing null pointer "fp" to "ksmbd_update_fstate", which dereferences it.
3408                    ksmbd_update_fstate(&work->sess->file_table, fp, FP_INITED);
3409                    rc = ksmbd_iov_pin_rsp(work, (void *)rsp, iov_len);
3410            }
3411            if (rc) {
3412                    if (rc == -EINVAL)
3413                            rsp->hdr.Status = STATUS_INVALID_PARAMETER;

Fixes: e2b76ab8b5 ("ksmbd: add support for read compound")
Reported-by: Coverity Scan <scan-admin@coverity.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-10-12 22:44:09 -05:00
Namjae Jeon
f43328357d ksmbd: not allow to open file if delelete on close bit is set
Cthon test fail with the following error.

check for proper open/unlink operation
nfsjunk files before unlink:
  -rwxr-xr-x 1 root root 0  9월 25 11:03 ./nfs2y8Jm9
./nfs2y8Jm9 open; unlink ret = 0
nfsjunk files after unlink:
  -rwxr-xr-x 1 root root 0  9월 25 11:03 ./nfs2y8Jm9
data compare ok
nfsjunk files after close:
  ls: cannot access './nfs2y8Jm9': No such file or directory
special tests failed

Cthon expect to second unlink failure when file is already unlinked.
ksmbd can not allow to open file if flags of ksmbd inode is set with
S_DEL_ON_CLS flags.

Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-10-12 22:43:52 -05:00
Namjae Jeon
5a7ee91d11 ksmbd: fix race condition with fp
fp can used in each command. If smb2_close command is coming at the
same time, UAF issue can happen by race condition.

                           Time
                            +
Thread A                    | Thread B1 B2 .... B5
smb2_open                   | smb2_close
                            |
 __open_id                  |
   insert fp to file_table  |
                            |
                            |   atomic_dec_and_test(&fp->refcount)
                            |   if fp->refcount == 0, free fp by kfree.
 // UAF!                    |
 use fp                     |
                            +
This patch add f_state not to use freed fp is used and not to free fp in
use.

Reported-by: luosili <rootlab@huawei.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-10-04 20:21:48 -05:00
Namjae Jeon
40b268d384 ksmbd: add mnt_want_write to ksmbd vfs functions
ksmbd is doing write access using vfs helpers. There are the cases that
mnt_want_write() is not called in vfs helper. This patch add missing
mnt_want_write() to ksmbd vfs functions.

Cc: stable@vger.kernel.org
Cc: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-06-16 21:04:19 -05:00
Steve French
38c8a9a520 smb: move client and server files to common directory fs/smb
Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:

   fs/cifs --> fs/smb/client
   fs/ksmbd --> fs/smb/server
   fs/smbfs_common --> fs/smb/common

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2023-05-24 16:29:21 -05:00