Windows reports automatic write-time updates with a resolution of roughly
15 milliseconds. If a file is written and closed within that interval, a
close response requesting full information can report the write time from
the open rather than the filesystem's finer-grained mtime update.
ksmbd currently converts the filesystem mtime directly in SMB2 CLOSE, so
even a sub-millisecond write is visible to the client. This makes
smb2.timestamp_resolution.resolution1 fail because the immediate write
changes LastWriteTime.
Save the write time returned by SMB2 CREATE in the file handle. When CLOSE
requests post-query attributes, coalesce a positive mtime change smaller
than 15 milliseconds to that saved value. Larger changes remain visible,
including the test's write after a 20 millisecond delay.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
ksmbd allocates both the volatile id (per-session file table) and the
persistent id (global file table) with idr_alloc_cyclic() starting at 0.
The first open after the module loads therefore gets volatile id 0 and
persistent id 0, and ksmbd returns an SMB2 FileId of {0, 0} in the create
response.
Clients treat an all-zero FileId as a null handle. smbtorture's
smb2_util_handle_empty() considers {0, 0} empty, so tests that guard the
close with it (e.g. smb2.oplock.statopen1, smb2.lease.statopen*) never
close that first handle. The leaked open keeps the inode's oplock count
non-zero, so a later batch oplock request on the same file is downgraded
to level II and the test fails.
Start the id allocation at 1 (KSMBD_START_FID) so no handle is ever
assigned a {0, 0} FileId, matching the behaviour of other SMB servers.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
smb2.create.blob sends an SMB2_CREATE_ALLOCATION_SIZE create context with
a 1MiB allocation size and expects the create response AllocationSize field
to match the requested size. smb2.create.open additionally compares the
AllocationSize returned in the CREATE response with the AllocationSize
returned by FILE_ALL_INFORMATION on the same handle.
ksmbd applies the allocation with fallocate(), but then fills both the
create response and handle-based information from stat.blocks << 9. On
filesystems such as ext4 this can include filesystem allocation rounding
and metadata effects, causing a response larger than the SMB2 allocation
size context and a disagreement between the two queries.
Remember the requested allocation size while processing the create context,
store the reported allocation size in struct ksmbd_file, and use it for
both the create response and handle-based allocation size responses. Update
the stored value when FILE_ALLOCATION_INFORMATION changes it, and fall back
to stat.blocks << 9 when no allocation size context was provided.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
smb2.streams.delete opens an alternate data stream without
FILE_SHARE_DELETE and then tries to delete the base file. Windows rejects
the base-file delete with STATUS_SHARING_VIOLATION while the stream handle
is open. ksmbd tracks stream opens on the same ksmbd_inode as the base
file, but the delete-on-close path only checked delete access on the base
handle before marking the inode delete-pending. As a result, deleting
the base file succeeded even though an open stream handle denied delete
sharing. Add a helper to detect open stream handles on the same inode that
do not allow FILE_SHARE_DELETE, and reject base-file delete pending and
DELETE opens with a sharing violation in that case.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Windows denies renaming a directory while a file below that directory is
still open. smb2.rename.rename_dir_openfile checks this by keeping a file
handle open under the directory and then attempting to rename the directory
handle. ksmbd did not check open children before calling vfs_rename(), so
the rename incorrectly succeeded.
For non-POSIX clients, scan the global open file table for active handles
whose dentries are below the directory being renamed. If any child is
open, fail the rename with -EACCES so the client receives
STATUS_ACCESS_DENIED.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
inode ctime is updated when a file is renamed. ksmbd returned that
ctime directly as SMB2 ChangeTime for handle-based query information.
This makes ChangeTime change after a rename through an already-open
handle, while Windows keeps the handle's ChangeTime stable for this
case.
Store the SMB ChangeTime in struct ksmbd_file when the handle is opened
and use that value for create, close, and handle-based query information
responses. If a client explicitly sets FILE_BASIC_INFORMATION
ChangeTime, update the stored value as well.
This fixes smbtorture smb2.rename.simple_modtime, which expects
ChangeTime and LastWriteTime to remain unchanged after renaming an
already-open file.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
The SMB2_CREATE_APP_INSTANCE_ID create context is used with durable v2
opens to identify another open from the same application instance. When
a new durable v2 open arrives with the same AppInstanceId as an existing
open, the server should close the previous open without sending an
oplock break notification.
ksmbd ignored this create context. A second durable v2 batch oplock open
with the same AppInstanceId therefore went through the normal competing
open path and sent an oplock break to the first opener. smbtorture
smb2.durable-v2-open.app-instance expects no oplock break and then
expects the old handle to be closed.
Parse and store AppInstanceId for durable v2 opens. Before creating the
new open, find an existing file with the same AppInstanceId and close it
through the normal close teardown path without issuing an oplock break.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
When a durable handle is preserved after a disconnect, its oplock state
can still block later opens. If another client opens the same file and
the preserved oplock or lease has to be broken, the old durable handle
must no longer be reconnectable after the break cannot be acknowledged.
ksmbd was treating a missing connection, or an oplock break timeout, as a
successful break only by downgrading the oplock state. The old durable
handle remained reconnectable, so a later durable reconnect for that
stale handle could succeed.
The open path can also see a detached durable handle before the break
notification helpers fully dispose of it. Invalidate such a preserved
durable handle directly when a competing open has to break its batch or
exclusive oplock, while leaving ordinary durable reconnects without a
competing open untouched.
If the old handle still reaches the reconnect path, reject it when the
same inode already has another active open. This matches the
smb2.durable-open.open2-lease/open2-oplock sequence where a later open
replaces the disconnected durable owner and the stale first handle must
not be reclaimed.
Also, reconnect lookup used only the persistent id. A new durable open
can get a persistent id that matches the stale reconnect request after
the old durable state is invalidated. Preserve the disconnected
handle's old volatile id and require durable reconnect contexts to match
it, so a stale reconnect cannot attach to a different durable open.
Windows allows the later open to proceed and rejects the old reconnect
with STATUS_OBJECT_NAME_NOT_FOUND. The smbtorture
smb2.durable-open.oplock test covers this case.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
A durable handle opened with FILE_DELETE_ON_CLOSE is preserved across a
disconnect so it can be reclaimed by a durable reconnect.
smb2.durable-open.delete_on_close2 disconnects such a handle and then
reconnects it, expecting the reconnect to succeed.
When the client does not reconnect but instead opens the same name with a
new delete-on-close create, the preserved handle keeps the file present
with delete-on-close set. ksmbd then rejects the new open with
STATUS_ACCESS_DENIED on the file_present + FILE_DELETE_ON_CLOSE +
OPEN_IF/OVERWRITE_IF path. smb2.durable-open.delete_on_close1 expects this
open to create a fresh, empty file instead, i.e. the disconnected handle's
delete-on-close must take effect first.
Add ksmbd_close_disconnected_durable_delete_on_close(), which closes
disconnected (conn == NULL) durable handles that keep a delete-on-close
file present. The final close promotes S_DEL_ON_CLS to S_DEL_PENDING and
unlinks the file, so a re-resolved path is absent and the new open creates
it fresh. Call it from smb2_open() before the delete-on-close conflict
check, only for the conflicting open shapes. A live (connected) handle
still keeps the file and blocks the open as before.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
SMB2_LOCK adds each granted byte-range lock to both the file lock list
and the lock list of the connection which handled the request. The
final close and durable handle paths, however, remove the connection
list entry while holding fp->conn->llist_lock.
With SMB3 multichannel, the connection handling the LOCK request can be
different from the connection which opened the file. The entry can
therefore be removed under a different spinlock from the one protecting
the list it belongs to. A concurrent traversal can then access freed
struct ksmbd_lock and struct file_lock objects.
Record the connection owning each lock's clist entry and hold a
reference to it while the entry is linked. Use that connection and its
llist_lock for unlock, rollback, close, and durable preserve. Durable
reconnect assigns the new connection as the owner when publishing the
locks again.
Fixes: f5a544e3ba ("ksmbd: add support for SMB3 multichannel")
Cc: stable@vger.kernel.org
Reported-by: Musaab Khan <musaab.khan@protonmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
smb2_query_dir() stores a pointer to its stack-allocated private data in
the ksmbd_file readdir_data. Concurrent QUERY_DIRECTORY requests using the
same file handle can overwrite this pointer while an iterate_dir() callback
is still using it, resulting in a stack use-after-free.
Add a per-file mutex and hold it while accessing the shared directory
enumeration state. The lock covers scan restart, dot entry state,
readdir_data setup and iteration, and response construction. This prevents
another request from replacing readdir_data.private before the current
request has finished using it and also serializes the shared file position.
Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-30527
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
__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>
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>
If the client sends SMB2_CREATE_POSIX_CONTEXT to ksmbd, allow the filename
to contain a colon (':'). This requires disabling the support for Alternate
Data Streams (ADS), which are denoted by a colon-separated suffix to the
filename on Windows. This should not be an issue, since this concept is not
known to POSIX anyway and the client has to explicitly request a POSIX
context to get this behavior.
Link: https://lore.kernel.org/all/f9401718e2be2ab22058b45a6817db912784ef61.camel@rx2.rx-server.de/
Signed-off-by: Philipp Kerling <pkerling@casix.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
The bug only appears when:
- windows 11 copies a file that has an alternate data stream
- streams_xattr is enabled on the share configuration.
Microsoft Edge adds a ZoneIdentifier data stream containing the URL
for files it downloads.
Another way to create a test file:
- open cmd.exe
- echo "hello from default data stream" > hello.txt
- echo "hello again from ads" > hello.txt:ads.txt
If you open the file using notepad, we'll see the first message.
If you run "notepad hello.txt:ads.txt" in cmd.exe, we should see
the second message.
dir /s /r should least all streams for the file.
The truncation happens because the windows 11 client sends
a SetInfo/EndOfFile message on the ADS, but it is instead applied
on the main file, because we don't check fp->stream.
When receiving set/get info file for a stream file, Change to process
requests using stream position and size.
Truncate is unnecessary for stream files, so we skip
set_file_allocation_info and set_end_of_file_info operations.
Reported-by: Marios Makassikis <mmakassikis@freebox.fr>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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>
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>
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>
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>
Don't immediately send directory lease break notification on smb2_write().
Instead, It postpones it until smb2_close().
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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>
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>
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>
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>
