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ksmbd_tree_conn_connect() publishes a new tree connection in
sess->tree_conns with a single reference and returns its pointer to
smb2_tree_connect(). The handler continues to initialize the object and
build the response after publication. A concurrent session logoff can
erase the connection and drop that reference, freeing the object while
the handler still uses it.
BUG: KASAN: slab-use-after-free in smb2_tree_connect+0xe3d/0xf90
smb2_tree_connect (fs/smb/server/smb2pdu.c:2872)
handle_ksmbd_work
process_one_work
worker_thread
kthread
After xa_store() succeeds, take a second reference before releasing
tree_conns_lock. The original reference belongs to the xarray entry and
the second belongs to the creating smb2_tree_connect() handler.
Keep the references balanced in every path:
- On normal exit or an error after publication, smb2_tree_connect()
drops its creator reference. Error cleanup also calls
ksmbd_tree_conn_disconnect(), which drops the xarray reference only if
it removes the exact entry.
- SMB2 TREE_DISCONNECT uses the same helper to remove the entry and drop
its xarray reference. The request's existing lookup reference remains
owned by the request and is released by the existing cleanup.
- Session LOGOFF removes each entry and drops its xarray reference. If
it wins the race, later cleanup sees that the entry is gone and does
not drop that reference again.
To enforce this ownership, claim the disconnected state and erase the
exact entry atomically under tree_conns_lock. This guarantees one drop
for the xarray reference and one drop by each in-flight user, regardless
of which teardown path wins. If logoff removes the entry before
initialization completes, fail the connect instead of marking the
detached object TREE_CONNECTED.
Fixes: 33b235a6e6eb ("ksmbd: fix race condition between tree conn lookup and disconnect")
Reported-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Cc: AutonomousCodeSecurity@microsoft.com
Cc: stable@vger.kernel.org
Signed-off-by: Cen Zhang (Microsoft Security FORGE Labs) <cenzhang@linux.microsoft.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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Validate IPC share configuration payload sizes before consuming
variable-length fields. Bound veto list parsing and account for
the separator byte when deriving the path length.
Fixes: a677ebd8ca2f ("ksmbd: validate payload size in ipc response")
Reported-by: Kanishka De Silva <kpskanna1915@gmail.com>
Reported-by: Farhad Alemi <farhad.alemi@berkeley.edu>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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SMB3 multichannel allows requests for one session to run on multiple
connections. Wait for all channels bound to a session before freeing
shared session objects.
A deferred byte-range lock remains counted as a running request and only
wakes when its file closes. Wake blocked locks during the drain without
unpublishing or modifying their file objects. Synchronous CANCEL requests
must invoke their cancellation callback to wake pending operations, while
CHANGE_NOTIFY completion remains specific to the asynchronous path.
Serialize session teardown with channel registration and previous-session
cleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and
connection teardown invoke cancellation callbacks only once.
Fixes: 76e98a158b20 ("ksmbd: fix race condition between destroy_previous_session() and smb2 operations()")
Reported-by: Cheryl Babcock <cheryl@renat.io>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/smb
Pull smb server updates from Namjae Jeon:
"This contains server updates focused on SMB2 command sequencing, SMB3
request replay and encryption, Apple Time Machine interoperability,
protocol-compatibility fixes validated with smbtorture, security
hardening, SMB Direct transport support, connection reliability, and
other correctness improvements.
New features:
- Implement the SMB2 command sequence window
Enforce the credit-based MessageId range for each connection,
rejecting out-of-window, duplicate, and wrapped sequence numbers.
This prevents invalid requests and same-channel replays from being
processed
- Add SMB3 request replay support
SMB3 clients may resend requests with SMB2_FLAGS_REPLAY_OPERATION
after a channel disconnect when the original response was lost.
Track the required channel and open state to safely handle durable
CREATE replays and make oplock, lease, and lock replays idempotent,
avoiding duplicate state changes and improving multichannel
reconnect reliability
- Add opt-in Apple Time Machine support
Implement the AAPL negotiation and related Finder, stream,
COPYCHUNK, sparse-file, CHANGE_NOTIFY, and RPC compatibility
required for Time Machine shares, allowing macOS backupd to use
ksmbd for backups
- Add per-share SMB3 encryption support
Allow individual shares to require SMB3 encryption by advertising
SMB2_SHAREFLAG_ENCRYPT_DATA in TREE_CONNECT responses and rejecting
unencrypted tree connects and plaintext requests for protected
shares
- Add SMB Direct RDMA encryption support
Extend SMB Direct to support SMB3 encrypted payloads over RDMA,
with transform negotiation and encryption/decryption for RDMA
READ/WRITE
Other changes:
- Parse and retain AppInstanceVersion contexts, enforce version
ordering, close older active handles for newer takeovers, and
reject invalid or unversioned opens according to the SMB2 semantics
- Accept durable reconnect requests that omit VolatileFileId when the
persistent ID and reconnect context identify the handle, while
continuing to reject explicit volatile-ID mismatches
- Fix SMB2/SMB3 protocol validation and security issues, including
request offsets, file and object IDs, IPC responses, output buffer
sizes, SMB3.1.1 binding validation, signing-required handling,
durable handles, ACLs, maximal access, and security information
- Fix heap out-of-bounds accesses, use-after-free bugs, memory leaks,
invalid pointer dereferences, and sensitive-data lifetime issues in
authentication, Kerberos, preauthentication, sessions, connections,
and module teardown
- Correct alternate-data-stream and named-stream handling, COPYCHUNK
behavior, sparse-file and compression attributes, allocated-range
queries, file trimming, duplicate extents, DOS attributes,
snapshots, normalized names, and partial information responses
- Fix locking, lease, oplock, durable reconnect, async request, and
CHANGE_NOTIFY races, including deferred-lock rollback, parent
directory lease notifications, and connection teardown lifetime
bugs
- Fix SMB3 encryption handling for compressed requests, expired
encrypted sessions, interim responses, bound multichannel
connections, and decryption failures
- Fix SMB3 multichannel session lookup and session state transitions
so changes are scoped to the correct bound connections and cannot
revive connections that are already shutting down
- Fix DACL access checks so ACE walks are bounded by the declared
DACL size, preventing data beyond the DACL boundary from being
interpreted during access validation
- Fix session accounting and lifetime issues, including session
counter updates during publication and removal, session leaks on
registration failure, and procfs creation diagnostics
- Improve TCP connection reliability by enabling TCP keepalive for
accepted connections and preserving TCP timers for kernel sockets,
preventing silent peers from holding connections indefinitely
- Fix smbdirect RDMA cleanup ordering for completion queues, QPs,
child sockets, and listener locking
- Improve async response framing, multi-iovec signing, RPC pipe
status handling, and ksmbd procfs monitoring for server, share,
connection, session, and open-file state
- Remove the obsolete DES crypto header and Kconfig dependency now
that NTLMv1 support has been removed
- Update the ksmbd repository URL in MAINTAINERS and add an
additional KSMBD reviewer"
* tag 'ksmbd-for-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/smb: (142 commits)
MAINTAINERS: update ksmbd repository URL
MAINTAINERS: add myself as KSMBD reviewer
smb: server: remove unused DES crypto header
smb: server: Remove obsolete "select CRYPTO_LIB_DES" from Kconfig file
ksmbd: keep TCP timers alive for kernel sockets
ksmbd: enable TCP keepalive for accepted connections
smb/server: fix session counter on session removal
smb/server: update session counter under sessions table lock
smb/server: fix session leak in ksmbd_session_register()
smb/server: warn if ksmbd_proc_create() fails
ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size
ksmbd: make RDMA encryption diagnostics conditional
ksmbd: add SMB Direct RDMA encryption transform
ksmbd: handle encrypted compressed requests
ksmbd: decrypt requests from expired encrypted sessions
ksmbd: disconnect on SMB3 decryption failure
ksmbd: encrypt interim responses to encrypted requests
ksmbd: scope session state changes to bound connections
ksmbd: fix encrypted request lookup on bound channels
ksmbd: add per-share SMB3 encryption enforcement
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull kthread vfs updates from Christian Brauner:
"This stops kernel threads from sharing filesystem state with
userspace. This work is about 3 cycles old and has been in -next
for about that time.
When the kernel boots init_task creates PID 1 and then kthreadd. From
that point every kthread and PID 1 share the same fs_struct. That is
why pivot_root() has to rewrite the fs_struct of all kthreads. The
rewriting exists so that kthreads can use init's filesystem state when
they want to. It also means userspace can move the ground out from
under the kernel.
PID 1 now gets a completely separate fs_struct. All kthreads are
anchored in a private SB_KERNMOUNT instance of nullfs that cannot be
mounted on and cannot be used to follow other mounts. Userspace init
can no longer affect kthread filesystem state and kthreads can no
longer affect userspace fs state without explicit opting in to that.
Path lookup from a kthread now fails by default. It makes it
deliberately hard to offload security sensitive operations into init's
filesystem state from a kthread.
Places that legitimately need to look something up there opt in
through the new scoped_with_init_fs() which temporarily overrides the
caller's fs_struct with init's. usermodehelpers remain the only kernel
tasks that genuinely share init's filesystem state, since they execute
random binaries in the root filesystem (excellent...).
The visible result is that /proc/2/root is a nullfs with an empty
mountinfo while /proc/1/root is the real root"
* tag 'vfs-7.3-rc1.kthread' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
initramfs_test: use test init/exit hooks to override init fs
fs: stop rewriting paths for PF_EXITING | PF_DUMPCORE
fs: stop rewriting kthread fs structs
fs: start all kthreads in nullfs
nullfs: make nullfs multi-instance
devtmpfs: create private mount namespace
fs: add umh argument to struct kernel_clone_args
fs: stop sharing fs_struct between init_task and pid 1
af_unix: use scoped_with_init_fs() for coredump socket lookup
initramfs: use scoped_with_init_fs() for rootfs unpacking
pnfs/blocklayout: use scoped_with_init_fs() for SCSI device lookup
ksmbd: use scoped_with_init_fs() for VFS path operations
ksmbd: use scoped_with_init_fs() for filesystem info path lookup
ksmbd: use scoped_with_init_fs() for share path resolution
fs: use scoped_with_init_fs() for kernel_read_file_from_path_initns()
coredump: use scoped_with_init_fs() for coredump path resolution
btrfs: use scoped_with_init_fs() for update_dev_time()
scsi: target: use scoped_with_init_fs() for APTPL metadata
scsi: target: use scoped_with_init_fs() for ALUA metadata
crypto: ccp: use scoped_with_init_fs() for SEV file access
...
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See the procedure below:
smb2_sess_setup
ksmbd_smb2_session_create
__session_create
hash_add(sessions_table, &sess->hlist, sess->id)
ksmbd_counter_inc(KSMBD_COUNTER_SESSIONS)
ksmbd_conn_handler_loop
ksmbd_server_terminate_conn
ksmbd_sessions_deregister
hash_del(&sess->hlist)
// do not decrement KSMBD_COUNTER_SESSIONS
KSMBD_COUNTER_SESSIONS tracks sessions published in sessions_table, but
session removal does not decrement it. The value therefore keeps growing
after sessions are expired, rejected during registration, or removed on
the last channel disconnect.
Fixes: b38f99c1217a ("ksmbd: add procfs interface for runtime monitoring and statistics")
Signed-off-by: Ze Tan <tanze@kylinos.cn>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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KSMBD_COUNTER_SESSIONS tracks sessions published in sessions_table.
Increment it while holding sessions_table_lock so publishing a session and
updating the counter happen together.
Fixes: b38f99c1217a ("ksmbd: add procfs interface for runtime monitoring and statistics")
Signed-off-by: Ze Tan <tanze@kylinos.cn>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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See the procedure below:
smb2_sess_setup
ksmbd_smb2_session_create
__session_create
atomic_set(&sess->refcnt, 2)
hash_add(sessions_table, &sess->hlist, sess->id)
ksmbd_session_register
xa_store(&conn->sessions, sess->id, sess) // fail
ksmbd_user_session_put
atomic_dec(&sess->refcnt) // refcnt is 1, session is not freed
Remove the session from sessions_table and drop its table reference if
xa_store() fails.
Fixes: f5c779b7ddbd ("ksmbd: fix racy issue from session setup and logoff")
Signed-off-by: Ze Tan <tanze@kylinos.cn>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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Print a warning if the sessions procfs entry cannot be created.
Signed-off-by: Ze Tan <tanze@kylinos.cn>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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ksmbd_all_conn_set_status() treats every connection whose transient
binding flag is set as belonging to the target SessionId. A logoff or
session replacement can consequently move an unrelated connection to
NEED_RECONNECT or NEED_SETUP.
Pass the target session itself and select connections using either the
connection-local session xarray or the session's permanent channel list.
Use the same association test while waiting for requests to drain.
Serialize session-wide status changes under request_lock and do not
overwrite EXITING or RELEASING. Protect the shutdown transition with the
same lock so a concurrent session update cannot revive a closing
connection.
Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel")
Fixes: abcc506a9a71 ("ksmbd: fix racy issue from smb2 close and logoff with multichannel")
Fixes: c444139cb747 ("ksmbd: rewrite stop_sessions() with restartable iteration")
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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An SMB3 multichannel binding registers the secondary connection in the
session channel list, but does not insert the session into the secondary
connection's session xarray.
The decryption path only searches the connection-local xarray. As a
result, every encrypted request received on a bound channel fails with
"Could not get decryption key".
Use the channel-aware session lookup for decryption. Also stop using the
temporary conn->binding flag to decide whether the global lookup is
allowed. Validate the permanent channel association under chann_lock
instead.
Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel")
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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Add a share flag for requiring SMB3 encryption on an individual share.
Advertise SMB2_SHAREFLAG_ENCRYPT_DATA in TREE_CONNECT responses and
reject both unencrypted TREE_CONNECT attempts and plaintext requests for
shares carrying the flag.
Keep BIT(19) reserved for the existing ksmbd-tools WIDE_LINKS flag and
use BIT(20) for the new netlink ABI flag.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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struct ksmbd_session contains some arrays with sensitive information, like
sess_key, smb3encryptionkey, smb3decryptionkey and smb3signingkey. Thus
let's make sure that this information cannot leak via the heap and use
kfree_sensitive() to free it.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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Use kfree_sensitive() to free the user->passkey (and the struct
ksmbd_login_response in ksmbd_login_user() that contains the same
information) to avoid that this information could leak somewhere
else via the heap.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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See the procedure below:
ksmbd_tree_conn_connect
ksmbd_share_config_get
share->name = kstrdup() // fail
if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) // false
// do not check `share->name`
ksmbd_ipc_tree_connect_request
strlen(share->name) // null-ptr-deref
Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Signed-off-by: ZhangGuoDong <zhangguodong@kylinos.cn>
Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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Store the expiry time from the Kerberos authentication response in
the session and reject requests after that time with
STATUS_NETWORK_SESSION_EXPIRED.
Allow an expired Kerberos session to be reauthenticated. Keep the old SMB
signing key until its SESSION_SETUP response has been signed, then install
the new session key and regenerate the SMB3 keys.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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SMB3.1.1 multichannel binding preserves the preauthentication hash in a
preauth_session between the NTLM negotiate and authenticate requests.
The binding NTLM negotiate allocates this object and returns
STATUS_MORE_PROCESSING_REQUIRED. If the client disconnects before it sends
the authenticate request, neither the authenticate nor error cleanup paths
free the object.
Release any remaining preauthentication sessions when tearing down the
connection. Initialize the list when allocating the connection so that this
cleanup is safe regardless of the negotiated dialect.
Reported-by: Runa Takemoto <takemotoruna223@gmail.com>
Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel")
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
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ksmbd_alloc_user() copies resp->hash_sz bytes out of the mountd IPC
login response with
user->passkey_sz = resp->hash_sz;
user->passkey = kmalloc(resp->hash_sz, KSMBD_DEFAULT_GFP);
if (user->passkey)
memcpy(user->passkey, resp->hash, resp->hash_sz);
resp->hash_sz is a __u16 supplied by the response, but resp->hash[] is
only KSMBD_REQ_MAX_HASH_SZ bytes. A malformed or malicious login
response can set hash_sz well beyond that (up to 65535), so the memcpy()
reads past the end of the response object. ipc_validate_msg() does not
bound hash_sz, so reject any response whose hash_sz exceeds the on-stack
hash[] buffer before allocating and copying.
[ 2030.238706] BUG: KASAN: slab-out-of-bounds in ksmbd_alloc_user+0x278/0x680
[ 2030.240549] Read of size 65535 at addr ffff888121bb6680 by task kworker/4:1/18611
[ 2030.242296]
[ 2030.242710] CPU: 4 UID: 0 PID: 18611 Comm: kworker/4:1 Not tainted 7.1.0-next-20260623-virtme #96 PREEMPT(lazy)
[ 2030.242732] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
[ 2030.242743] Workqueue: ksmbd-io handle_ksmbd_work
[ 2030.242763] Call Trace:
[ 2030.242769] <TASK>
[ 2030.242776] dump_stack_lvl+0xa2/0xd0
[ 2030.242794] print_address_description+0x77/0x200
[ 2030.242815] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242831] print_report+0x58/0x70
[ 2030.242848] kasan_report+0x117/0x150
[ 2030.242869] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242888] kasan_check_range+0x3c7/0x3f0
[ 2030.242908] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242925] __asan_memcpy+0x29/0x70
[ 2030.242942] ksmbd_alloc_user+0x278/0x680
[ 2030.242960] ksmbd_login_user+0xc3/0x120
[ 2030.242978] ntlm_authenticate+0x5e6/0x1b00
[ 2030.243017] ? __pfx_ntlm_authenticate+0x10/0x10
[ 2030.243035] ? ksmbd_session_lookup+0x188/0x1d0
[ 2030.243054] ? __pfx_ksmbd_session_lookup+0x10/0x10
[ 2030.243090] ? __sanitizer_cov_trace_switch+0x7b/0x140
[ 2030.243108] smb2_sess_setup+0x1e4a/0x27b0
[ 2030.243126] ? copy_from_kernel_nofault+0x199/0x300
[ 2030.243156] ? __pfx_smb2_sess_setup+0x10/0x10
[ 2030.243173] ? get_smb2_cmd_val+0xe3/0x1c0
[ 2030.243208] handle_ksmbd_work+0x954/0x1280
[ 2030.243230] ? __pfx_handle_ksmbd_work+0x10/0x10
[ 2030.243249] ? process_scheduled_works+0xa07/0x1490
[ 2030.243270] ? process_scheduled_works+0xa07/0x1490
[ 2030.243291] process_scheduled_works+0xa70/0x1490
[ 2030.243320] ? __pfx_process_scheduled_works+0x10/0x10
[ 2030.243340] ? do_raw_spin_lock+0x130/0x300
[ 2030.243358] ? lock_is_held_type+0x7b/0x110
[ 2030.243388] worker_thread+0x932/0xe20
[ 2030.243415] kthread+0x38a/0x470
[ 2030.243431] ? __pfx_worker_thread+0x10/0x10
[ 2030.243451] ? __pfx_kthread+0x10/0x10
[ 2030.243467] ret_from_fork+0x484/0x910
[ 2030.243485] ? __pfx_ret_from_fork+0x10/0x10
[ 2030.243501] ? __switch_to+0xc77/0x12c0
[ 2030.243523] ? __pfx_kthread+0x10/0x10
[ 2030.243540] ret_from_fork_asm+0x1a/0x30
[ 2030.243564] </TASK>
[ 2030.243570]
[ 2030.290164] Allocated by task 19279:
[ 2030.290911] kasan_save_track+0x3e/0x80
[ 2030.292179] __kasan_kmalloc+0x72/0x90
[ 2030.293217] __kvmalloc_node_noprof+0x3ff/0x6b0
[ 2030.294467] handle_generic_event+0x59b/0x750
[ 2030.295345] genl_family_rcv_msg_doit+0x238/0x340
[ 2030.296553] genl_rcv_msg+0x606/0x7b0
[ 2030.297129] netlink_rcv_skb+0x22b/0x4a0
[ 2030.298500] genl_rcv+0x2d/0x40
[ 2030.299273] netlink_unicast+0x7ba/0x930
[ 2030.300019] netlink_sendmsg+0x8c3/0xb00
[ 2030.301073] __sock_sendmsg+0xec/0x140
[ 2030.301579] __sys_sendto+0x357/0x470
[ 2030.302255] __x64_sys_sendto+0xe3/0x100
[ 2030.303425] do_syscall_64+0x135/0x460
[ 2030.304763] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 2030.305594]
[ 2030.305819] The buggy address belongs to the object at ffff888121bb6640
[ 2030.305819] which belongs to the cache kmalloc-192 of size 192
[ 2030.309595] The buggy address is located 64 bytes inside of
[ 2030.309595] allocated 166-byte region [ffff888121bb6640, ffff888121bb66e6)
[ 2030.312484]
[ 2030.312719] The buggy address belongs to the physical page:
[ 2030.314315] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x121bb6
[ 2030.316481] head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[ 2030.318248] flags: 0x100000000000040(head|node=0|zone=2)
[ 2030.319662] page_type: f5(slab)
[ 2030.320242] raw: 0100000000000040 ffff8881000424c0 ffffea00047c1510 ffff888100040468
[ 2030.321911] raw: 0000000000000000 0000000000150015 00000000f5000000 0000000000000000
[ 2030.324413] head: 0100000000000040 ffff8881000424c0 ffffea00047c1510 ffff888100040468
[ 2030.326150] head: 0000000000000000 0000000000150015 00000000f5000000 0000000000000000
[ 2030.327960] head: 0100000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
[ 2030.329615] head: ffff888121bb7ab0 0000000000000000 00000000ffffffff 0000000000000000
[ 2030.331861] page dumped because: kasan: bad access detected
[ 2030.332946]
[ 2030.333502] Memory state around the buggy address:
[ 2030.334698] ffff888121bb6580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 2030.336475] ffff888121bb6600: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
[ 2030.338143] >ffff888121bb6680: 00 00 00 00 00 00 00 00 00 00 00 00 06 fc fc fc
[ 2030.339116] ^
[ 2030.341315] ffff888121bb6700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 2030.342801] ffff888121bb6780: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
[ 2030.344643] ==================================================================
Found with ksmbdzzer [2], a KSMBD fuzzer that drives libFuzzer with a
kcov-dataflow [1] coverage vector: it folds each instrumented
comparison/argument's runtime operand value together with its PC (the
default arm mixes them as pc⊕val) so that a new operand value at a known
site counts as new coverage.
[1] https://lwn.net/Articles/1077606/
[2] https://github.com/yskzalloc/kcov-dataflow
Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Signed-off-by: Yunseong Kim <yunseong.kim@est.tech>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
|
|
There is no kernel-side view of the share configurations currently cached
by active tree connections.
Add a shares proc entry that reports each active share name, type,
tree-connection count, create masks, and descriptive configuration flags.
Maintain a per-share tree-connection counter with the existing global
counter so the value can be read without walking every session.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
|
|
Session and file proc entries lack the state needed to correlate inactive
sessions with durable or delete-pending opens.
Add the account type, dialect, idle time, open-file count, tree-connect
count, and per-channel POSIX negotiation state to session entries. Extend
the open-file table with the file state, durable timeout, create options,
share access, and descriptive flags for durable, persistent, resilient,
delete-on-close, stream, POSIX, and attribute-only opens.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
|
|
The ksmbd procfs monitoring files produce misleading or malformed output.
The constant-name helper uses a bitwise test for enum values. This omits
zero-valued constants and can print multiple names for one lease state. It
also unconditionally emits a newline, splitting entries in the open-file
table across two lines. Session capabilities are printed as numeric flag
values even though a table of descriptive names is available.
Use exact matching for enum values. Print flag names as a comma-separated
list, preserving unknown bits as hexadecimal values. Let callers control
line termination so each open-file entry remains on one line. Print common
session properties once, and report signing and encryption independently.
Adjust client and open-file column widths for IPv6 addresses and 64-bit
file IDs, and fix the misspelled OPLOCK_EXCLUSIVE name. Also expose and
maintain the total request count alongside the per-command counters.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
|
|
SMB3 clients can replay selected requests after a channel disconnect by
setting SMB2_FLAGS_REPLAY_OPERATION. The command sequence window rejects
duplicate MessageIds on one connection, but it does not validate requests
resent on another channel with a new MessageId.
Add the state and validation required to replay durable CREATE and
file-handle operations:
- track each open ChannelSequence, outstanding request counts, and lock
sequence entries.
- retain a request-owned open reference until the common response path
completes ChannelSequence accounting.
- replay DurableHandleReqV2 CREATE requests by CreateGuid, validating the
durable state, SecurityContext, session, lease key, and persistent flag.
- publish CreateGuid and SecurityContext before an oplock or lease break
can defer CREATE, rejecting replays of that pending CREATE with
STATUS_FILE_NOT_AVAILABLE.
- retain the original CREATE action and replay completed CreateGuid
requests, including requests that did not receive a durable-handle grant,
without modifying the existing open.
- make replayed oplock and lease break acknowledgements idempotent. And
- preserve SMB2_FLAGS_REPLAY_OPERATION in responses.
Return STATUS_FILE_NOT_AVAILABLE when ChannelSequence validation rejects a
replayed WRITE, IOCTL, or SET_INFO request.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
|
|
Free it unconditionally after ksmbd_alloc_user() calls.
kmemleak splat:
unreferenced object 0xffff888103b83540 (size 192):
comm "pool-0", pid 16970, jiffies 4377290937
hex dump (first 32 bytes):
00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 408ccc66):
__kvmalloc_node_noprof+0x730/0x920
handle_generic_event+0xec/0x1a0 [ksmbd]
genl_family_rcv_msg_doit+0xe0/0x130
genl_rcv_msg+0x181/0x290
netlink_rcv_skb+0x4f/0x100
genl_rcv+0x28/0x40
netlink_unicast+0x1e6/0x2c0
netlink_sendmsg+0x20a/0x450
____sys_sendmsg+0x2e8/0x310
___sys_sendmsg+0x78/0xc0
__sys_sendmsg+0x63/0xc0
do_syscall_64+0xa1/0x670
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fixes: a77e0e02af1c ("ksmbd: add support for supplementary groups")
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
|
|
Unknown RPC pipe names and malformed CREATE parameters both use
-EINVAL. Mapping that errno to STATUS_OBJECT_NAME_NOT_FOUND therefore
also hides invalid request parameters as a missing pipe.
Return -ENOENT when RPC method lookup cannot find a supported pipe and
map only that error to STATUS_OBJECT_NAME_NOT_FOUND. Preserve
STATUS_INVALID_PARAMETER for -EINVAL returned by request validation.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
|
|
macOS routinely probes the mdssvc RPC pipe to check for Spotlight
search support. __rpc_method() already falls through to returning 0
(unsupported) for it via the default case, but that path also logs
"Unsupported RPC: mdssvc" via pr_err on every single probe -- which
happens often enough during normal macOS browsing/backup activity to
spam the kernel log. Add an explicit case that returns the same value
without the log line; behavior is unchanged, this only removes noise
for an expected, routine client behavior.
Assisted-by: Claude:claude-sonnet-5
Signed-off-by: Gael Blivet <gael.blivet@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
|
|
ksmbd_sessions_deregister() removes a connection's channels from other
sessions' channel lists only while conn->binding is still set:
if (conn->binding) {
hash_for_each_safe(sessions_table, ...)
ksmbd_chann_del(conn, sess);
}
conn->binding is a transient flag: it is cleared once a binding
SESSION_SETUP completes, and also by a subsequent non-binding
SESSION_SETUP on the same connection (a reauthentication on a bound
channel, or a new SessionId==0 setup). A connection that has bound a
channel into another session's ksmbd_chann_list and then clears
conn->binding leaves that channel behind when it disconnects: the
channel, whose chann->conn points at the now freed struct ksmbd_conn,
stays on the owner session's list.
When the owning connection later tears down, the second loop
dereferences the stale channel:
xa_for_each(&sess->ksmbd_chann_list, chann_id, chann)
if (chann->conn != conn)
ksmbd_conn_set_exiting(chann->conn); /* freed */
which is a use-after-free write into the freed ksmbd_conn (the same
stale channel is also walked by show_proc_session() through /proc). The
session is leaked as well, because its channel list never empties.
Remove the conn->binding gate so a connection always removes its
channels from every session on teardown.
Fixes: faf8578c77f3 ("ksmbd: find bound sessions during reauthentication")
Signed-off-by: Gil Portnoy <dddhkts1@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
Commit 4b706360ffb7 ("ksmbd: fix multichannel binding and enforce channel
limit") moved the binding-path session key out of the session-wide
sess->sess_key (CIFS_KEY_SIZE = 40) into a new per-channel buffer, and
sized both that buffer and the on-stack copy used during binding with
SMB2_NTLMV2_SESSKEY_SIZE (16):
struct channel {
char sess_key[SMB2_NTLMV2_SESSKEY_SIZE]; /* 16 */
...
};
ntlm_authenticate() / krb5_authenticate():
char channel_key[SMB2_NTLMV2_SESSKEY_SIZE] = {}; /* 16 */
char *auth_key = conn->binding ? channel_key : sess->sess_key;
The two writers that fill this destination still bound the copy length
against CIFS_KEY_SIZE (40), not against the 16-byte buffer:
ksmbd_decode_ntlmssp_auth_blob() (NTLM key exchange):
if (sess_key_len > CIFS_KEY_SIZE) /* 40 */
return -EINVAL;
arc4_crypt(ctx_arc4, sess_key,
(char *)authblob + sess_key_off, sess_key_len);
ksmbd_krb5_authenticate():
if (resp->session_key_len > sizeof(sess->sess_key)) /* 40 */
...
memcpy(sess_key, resp->payload, resp->session_key_len);
On a binding SESSION_SETUP, auth_key points at the 16-byte channel_key,
so a client that supplies an NTLM EncryptedRandomSessionKey of up to 40
bytes (with NTLMSSP_NEGOTIATE_KEY_EXCH), or a Kerberos ticket whose
session key is longer than 16 bytes (a normal AES256 key is 32), writes
past the 16-byte stack buffer -- up to a 24-byte kernel stack overflow.
KASAN reports it as a stack-out-of-bounds write in arc4_crypt() called
from ksmbd_decode_ntlmssp_auth_blob().
The destinations must be able to hold the full session key the length
checks already permit. Size the per-channel key buffer and the two
on-stack channel_key buffers with CIFS_KEY_SIZE, matching sess->sess_key.
Fixes: 4b706360ffb7 ("ksmbd: fix multichannel binding and enforce channel limit")
Signed-off-by: Gil Portnoy <dddhkts1@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
A signed multichannel SESSION_SETUP binding request can require multiple
authentication rounds. ksmbd excludes SESSION_SETUP from the signed
request check and tries to sign every binding response with the channel
signing key. The channel does not exist for
STATUS_MORE_PROCESSING_REQUIRED, so that response is sent unsigned.
Clients reject it with STATUS_ACCESS_DENIED.
The final channel signing key also needs the key exported by the binding
authentication context. Keep that key in the channel instead of
overwriting the established session key, and use the session signing key
for intermediate and failed binding responses. Retain the binding session
reference until an error response has been signed and sent.
Limit a session to 32 channels while holding the channel lock. Return
STATUS_INSUFFICIENT_RESOURCES for an additional binding, matching the
server limit expected by clients.
This fixes smb2.multichannel.generic.num_channels, which previously
failed the first binding with STATUS_ACCESS_DENIED and returned the same
status instead of STATUS_INSUFFICIENT_RESOURCES for channel 33.
Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel")
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
Use scoped_with_init_fs() to temporarily override current->fs for
the kern_path() call in share_config_request() so the share path
lookup happens in init's filesystem context.
All ksmbd paths ← SMB command handlers ← handle_ksmbd_work() ← workqueue
← ksmbd_conn_handler_loop() ← kthread
Link: https://patch.msgid.link/20260601-work-kthread-nullfs-v4-13-77ee053060e0@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
|
|
Non-pipe shares must have a duplicated backing path before they can be
published. share_config_request() currently calls kstrndup() for that
path, but if the allocation fails it leaves ret unchanged. If veto list
parsing succeeds and share->name exists, the partially built share is
still inserted into the global share table with share->path left NULL.
A later share-root SMB2 create uses tree_conn->share_conf->path as the
lookup root. If the share was published with path == NULL, that request
passes a NULL pathname into do_getname_kernel()/strlen() and can crash
the ksmbd worker.
Set ret = -ENOMEM when path duplication fails so the incomplete share is
destroyed before publication.
Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
Signed-off-by: Shuhao Fu <sfual@cse.ust.hk>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
When the binding SESSION_SETUP sets conn->binding = true, the flag stays
set after the call so that the global session lookup in
ksmbd_session_lookup_all() can find the session, which was not added to
conn->sessions. Because the flag is connection-wide, the global lookup
path will also resolve any other session by id if asked.
Tighten the global lookup so that the returned session must have this
connection registered in its channel xarray (sess->ksmbd_chann_list).
The channel entry is installed by the existing binding_session path in
ntlm_authenticate()/krb5_authenticate() when a SESSION_SETUP completes
successfully, so this condition is a strict equivalent of "this
connection has been accepted as a channel of this session". Connections
that have not bound to a given session cannot reach it via the global
table.
The existing conn->binding gate for entering the slowpath is preserved
so that non-binding connections keep the fast-path-only behavior, and
the session->state check is unchanged.
Fixes: f5a544e3bab7 ("ksmbd: add support for SMB3 multichannel")
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
When per-session tree_conn_ida was converted from a dynamically
allocated ksmbd_ida to an embedded struct ida, ksmbd_ida_free() was
removed from ksmbd_session_destroy() but no matching ida_destroy()
was added. The session is therefore freed with the IDA's backing
xarray still intact.
The kernel IDA API expects ida_init() and ida_destroy() to be paired
over an object's lifetime, so add the missing cleanup before the
enclosing session is freed.
Also move ida_init() to right after the session is allocated so that
it is always paired with the destroy call even on the early error
paths of __session_create() (ksmbd_init_file_table() or
__init_smb2_session() failures), both of which jump to the error
label and invoke ksmbd_session_destroy() on a partially initialised
session.
No leak has been observed in testing; this is a pairing fix to match
the IDA lifetime rules, not a response to a reproduced regression.
Fixes: d40012a83f87 ("cifsd: declare ida statically")
Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
ipc_validate_msg() computes the expected message size for each
response type by adding (or multiplying) attacker-controlled fields
from the daemon response to a fixed struct size in unsigned int
arithmetic. Three cases can overflow:
KSMBD_EVENT_RPC_REQUEST:
msg_sz = sizeof(struct ksmbd_rpc_command) + resp->payload_sz;
KSMBD_EVENT_SHARE_CONFIG_REQUEST:
msg_sz = sizeof(struct ksmbd_share_config_response) +
resp->payload_sz;
KSMBD_EVENT_LOGIN_REQUEST_EXT:
msg_sz = sizeof(struct ksmbd_login_response_ext) +
resp->ngroups * sizeof(gid_t);
resp->payload_sz is __u32 and resp->ngroups is __s32. Each addition
can wrap in unsigned int; the multiplication by sizeof(gid_t) mixes
signed and size_t, so a negative ngroups is converted to SIZE_MAX
before the multiply. A wrapped value of msg_sz that happens to
equal entry->msg_sz bypasses the size check on the next line, and
downstream consumers (smb2pdu.c:6742 memcpy using rpc_resp->payload_sz,
kmemdup in ksmbd_alloc_user using resp_ext->ngroups) then trust the
unverified length.
Use check_add_overflow() on the RPC_REQUEST and SHARE_CONFIG_REQUEST
paths to detect integer overflow without constraining functional
payload size; userspace ksmbd-tools grows NDR responses in 4096-byte
chunks for calls like NetShareEnumAll, so a hard transport cap is
unworkable on the response side. For LOGIN_REQUEST_EXT, reject
resp->ngroups outside the signed [0, NGROUPS_MAX] range up front and
report the error from ipc_validate_msg() so it fires at the IPC
boundary; with that bound the subsequent multiplication and addition
stay well below UINT_MAX. The now-redundant ngroups check and
pr_err in ksmbd_alloc_user() are removed.
This is the response-side analogue of aab98e2dbd64 ("ksmbd: fix
integer overflows on 32 bit systems"), which hardened the request
side.
Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers")
Fixes: a77e0e02af1c ("ksmbd: add support for supplementary groups")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-6
Assisted-by: Codex:gpt-5-4
Signed-off-by: Michael Bommarito <michael.bommarito@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: c8efcc786146 ("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>
|
|
__ksmbd_tree_conn_disconnect() drops the share_conf reference before
checking tree_conn->refcount. When someone uses SMB3 multichannel and
binds two connections to one session, a SESSION_LOGOFF on connection A
calls ksmbd_conn_wait_idle(conn) which only drains connection A's
request counter, not connection B's. This means there's a race condition:
requests already dispatched on connection B hold tree_conn references via
work->tcon. The disconnect path frees share_conf while those requests
are still walking work->tcon->share_conf, causing a use-after-free.
This fix combines the share_conf put with the tree_conn free so it
only happens when the last reference is dropped.
Fixes: b39a1833cc4a ("ksmbd: fix use-after-free in ksmbd_tree_connect_put under concurrency")
Signed-off-by: Nicholas Carlini <nicholas@carlini.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
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>
|
|
The newly added procfs code fails to build when CONFIG_IPv6 is disabled:
fs/smb/server/connection.c: In function 'proc_show_clients':
fs/smb/server/connection.c:47:58: error: 'struct ksmbd_conn' has no member named 'inet6_addr'; did you mean 'inet_addr'?
47 | seq_printf(m, "%-20pI6c", &conn->inet6_addr);
| ^~~~~~~~~~
| inet_addr
make[7]: *** [scripts/Makefile.build:279: fs/smb/server/connection.o] Error 1
fs/smb/server/mgmt/user_session.c: In function 'show_proc_sessions':
fs/smb/server/mgmt/user_session.c:215:65: error: 'struct ksmbd_conn' has no member named 'inet6_addr'; did you mean 'inet_addr'?
215 | seq_printf(m, " %-40pI6c", &chan->conn->inet6_addr);
| ^~~~~~~~~~
| inet_addr
Rearrange the condition to allow adding a simple preprocessor conditional.
Fixes: b38f99c1217a ("ksmbd: add procfs interface for runtime monitoring and statistics")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
Converts tree_conns_lock to an rw_semaphore to allow sleeping while
the lock is held. Additionally, it simplifies the locking logic in
ksmbd_tree_conn_session_logoff() and introduces
__ksmbd_tree_conn_disconnect() to avoid redundant locking.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
Add chann_lock while iterating ksmbd_chann_list in show_proc_session() and
show_proc_sessions(). This will prevents a race condition with concurrent
channel list modifications.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
ksmbd_chann_list xarray lacks synchronization, allowing use-after-free in
multi-channel sessions (between lookup_chann_list() and ksmbd_chann_del).
Adds rw_semaphore chann_lock to struct ksmbd_session and protects
all xa_load/xa_store/xa_erase accesses.
Cc: stable@vger.kernel.org
Reported-by: Igor Stepansky <igor.stepansky@orca.security>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
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>
|
|
When a session is found but its state is not SMB2_SESSION_VALID, It
indicates that no valid session was found, but it is missing to decrement
the reference count acquired by the session lookup, which results in
a reference count leak. This patch fixes the issue by explicitly calling
ksmbd_user_session_put to release the reference to the session.
Cc: stable@vger.kernel.org
Reported-by: Alexandre <roger.andersen@protonmail.com>
Reported-by: Stanislas Polu <spolu@dust.tt>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
Under high concurrency, A tree-connection object (tcon) is freed on
a disconnect path while another path still holds a reference and later
executes *_put()/write on it.
Reported-by: Qianchang Zhao <pioooooooooip@gmail.com>
Reported-by: Zhitong Liu <liuzhitong1993@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
|
|
Since commit 305853cce3794 ("ksmbd: Fix race condition in RPC handle list
access"), ksmbd_session_rpc_method() attempts to lock sess->rpc_lock.
This causes hung connections / tasks when a client attempts to open
a named pipe. Using Samba's rpcclient tool:
$ rpcclient //192.168.1.254 -U user%password
$ rpcclient $> srvinfo
<connection hung here>
Kernel side:
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0 state:D stack:0 pid:5021 tgid:5021 ppid:2 flags:0x00200000
Workqueue: ksmbd-io handle_ksmbd_work
Call trace:
__schedule from schedule+0x3c/0x58
schedule from schedule_preempt_disabled+0xc/0x10
schedule_preempt_disabled from rwsem_down_read_slowpath+0x1b0/0x1d8
rwsem_down_read_slowpath from down_read+0x28/0x30
down_read from ksmbd_session_rpc_method+0x18/0x3c
ksmbd_session_rpc_method from ksmbd_rpc_open+0x34/0x68
ksmbd_rpc_open from ksmbd_session_rpc_open+0x194/0x228
ksmbd_session_rpc_open from create_smb2_pipe+0x8c/0x2c8
create_smb2_pipe from smb2_open+0x10c/0x27ac
smb2_open from handle_ksmbd_work+0x238/0x3dc
handle_ksmbd_work from process_scheduled_works+0x160/0x25c
process_scheduled_works from worker_thread+0x16c/0x1e8
worker_thread from kthread+0xa8/0xb8
kthread from ret_from_fork+0x14/0x38
Exception stack(0x8529ffb0 to 0x8529fff8)
The task deadlocks because the lock is already held:
ksmbd_session_rpc_open
down_write(&sess->rpc_lock)
ksmbd_rpc_open
ksmbd_session_rpc_method
down_read(&sess->rpc_lock) <-- deadlock
Adjust ksmbd_session_rpc_method() callers to take the lock when necessary.
Fixes: 305853cce3794 ("ksmbd: Fix race condition in RPC handle list access")
Signed-off-by: Marios Makassikis <mmakassikis@freebox.fr>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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Increases the number of bits for the hash table from 3 to 12.
The thousands of sessions and shares can be connected.
So the current 3-bit size can lead to frequent hash collisions.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The 'sess->rpc_handle_list' XArray manages RPC handles within a ksmbd
session. Access to this list is intended to be protected by
'sess->rpc_lock' (an rw_semaphore). However, the locking implementation was
flawed, leading to potential race conditions.
In ksmbd_session_rpc_open(), the code incorrectly acquired only a read lock
before calling xa_store() and xa_erase(). Since these operations modify
the XArray structure, a write lock is required to ensure exclusive access
and prevent data corruption from concurrent modifications.
Furthermore, ksmbd_session_rpc_method() accessed the list using xa_load()
without holding any lock at all. This could lead to reading inconsistent
data or a potential use-after-free if an entry is concurrently removed and
the pointer is dereferenced.
Fix these issues by:
1. Using down_write() and up_write() in ksmbd_session_rpc_open()
to ensure exclusive access during XArray modification, and ensuring
the lock is correctly released on error paths.
2. Adding down_read() and up_read() in ksmbd_session_rpc_method()
to safely protect the lookup.
Fixes: a1f46c99d9ea ("ksmbd: fix use-after-free in ksmbd_session_rpc_open")
Fixes: b685757c7b08 ("ksmbd: Implements sess->rpc_handle_list as xarray")
Cc: stable@vger.kernel.org
Signed-off-by: Yunseong Kim <ysk@kzalloc.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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A UAF issue can occur due to a race condition between
ksmbd_session_rpc_open() and __session_rpc_close().
Add rpc_lock to the session to protect it.
Cc: stable@vger.kernel.org
Reported-by: Norbert Szetei <norbert@doyensec.com>
Tested-by: Norbert Szetei <norbert@doyensec.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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The Client send malformed smb2 negotiate request. ksmbd return error
response. Subsequently, the client can send smb2 session setup even
thought conn->preauth_info is not allocated.
This patch add KSMBD_SESS_NEED_SETUP status of connection to ignore
session setup request if smb2 negotiate phase is not complete.
Cc: stable@vger.kernel.org
Tested-by: Steve French <stfrench@microsoft.com>
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-26505
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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There is a race condition between session setup and
ksmbd_sessions_deregister. The session can be freed before the connection
is added to channel list of session.
This patch check reference count of session before freeing it.
Cc: stable@vger.kernel.org
Reported-by: Sean Heelan <seanheelan@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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ksmbd check that the session of second channel is in the session list of
first connection. If it is in session list, multichannel connection
should not be allowed.
Fixes: b95629435b84 ("ksmbd: fix racy issue from session lookup and expire")
Reported-by: Sean Heelan <seanheelan@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
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