Merge tag '6.11-rc4-server-fixes' of git://git.samba.org/ksmbd

Pull smb server fixes from Steve French:

 - important reconnect fix

 - fix for memcpy issues on mount

 - two minor cleanup patches

* tag '6.11-rc4-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: Replace one-element arrays with flexible-array members
  ksmbd: fix spelling mistakes in documentation
  ksmbd: fix race condition between destroy_previous_session() and smb2 operations()
  ksmbd: Use unsafe_memcpy() for ntlm_negotiate

Author: torvalds

Documentation/filesystems/smb/ksmbd.rst

@@ -13,7 +13,7 @@ KSMBD architecture
 The subset of performance related operations belong in kernelspace and
 the other subset which belong to operations which are not really related with
 performance in userspace. So, DCE/RPC management that has historically resulted
-into number of buffer overflow issues and dangerous security bugs and user
+into a number of buffer overflow issues and dangerous security bugs and user
 account management are implemented in user space as ksmbd.mountd.
 File operations that are related with performance (open/read/write/close etc.)
 in kernel space (ksmbd). This also allows for easier integration with VFS
@@ -24,8 +24,8 @@ ksmbd (kernel daemon)
 
 When the server daemon is started, It starts up a forker thread
 (ksmbd/interface name) at initialization time and open a dedicated port 445
-for listening to SMB requests. Whenever new clients make request, Forker
-thread will accept the client connection and fork a new thread for dedicated
+for listening to SMB requests. Whenever new clients make a request, the Forker
+thread will accept the client connection and fork a new thread for a dedicated
 communication channel between the client and the server. It allows for parallel
 processing of SMB requests(commands) from clients as well as allowing for new
 clients to make new connections. Each instance is named ksmbd/1~n(port number)
@@ -34,12 +34,12 @@ thread can decide to pass through the commands to the user space (ksmbd.mountd),
 currently DCE/RPC commands are identified to be handled through the user space.
 To further utilize the linux kernel, it has been chosen to process the commands
 as workitems and to be executed in the handlers of the ksmbd-io kworker threads.
-It allows for multiplexing of the handlers as the kernel take care of initiating
+It allows for multiplexing of the handlers as the kernel takes care of initiating
 extra worker threads if the load is increased and vice versa, if the load is
-decreased it destroys the extra worker threads. So, after connection is
-established with client. Dedicated ksmbd/1..n(port number) takes complete
+decreased it destroys the extra worker threads. So, after the connection is
+established with the client. Dedicated ksmbd/1..n(port number) takes complete
 ownership of receiving/parsing of SMB commands. Each received command is worked
-in parallel i.e., There can be multiple clients commands which are worked in
+in parallel i.e., there can be multiple client commands which are worked in
 parallel. After receiving each command a separated kernel workitem is prepared
 for each command which is further queued to be handled by ksmbd-io kworkers.
 So, each SMB workitem is queued to the kworkers. This allows the benefit of load
@@ -49,9 +49,9 @@ performance by handling client commands in parallel.
 ksmbd.mountd (user space daemon)
 --------------------------------
 
-ksmbd.mountd is userspace process to, transfer user account and password that
+ksmbd.mountd is a userspace process to, transfer the user account and password that
 are registered using ksmbd.adduser (part of utils for user space). Further it
-allows sharing information parameters that parsed from smb.conf to ksmbd in
+allows sharing information parameters that are parsed from smb.conf to ksmbd in
 kernel. For the execution part it has a daemon which is continuously running
 and connected to the kernel interface using netlink socket, it waits for the
 requests (dcerpc and share/user info). It handles RPC calls (at a minimum few
@@ -124,7 +124,7 @@ How to run
 1. Download ksmbd-tools(https://github.com/cifsd-team/ksmbd-tools/releases) and
    compile them.
 
-   - Refer README(https://github.com/cifsd-team/ksmbd-tools/blob/master/README.md)
+   - Refer to README(https://github.com/cifsd-team/ksmbd-tools/blob/master/README.md)
      to know how to use ksmbd.mountd/adduser/addshare/control utils
 
      $ ./autogen.sh
@@ -133,7 +133,7 @@ How to run
 
 2. Create /usr/local/etc/ksmbd/ksmbd.conf file, add SMB share in ksmbd.conf file.
 
-   - Refer ksmbd.conf.example in ksmbd-utils, See ksmbd.conf manpage
+   - Refer to ksmbd.conf.example in ksmbd-utils, See ksmbd.conf manpage
      for details to configure shares.
 
         $ man ksmbd.conf
@@ -145,7 +145,7 @@ How to run
      $ man ksmbd.adduser
      $ sudo ksmbd.adduser -a <Enter USERNAME for SMB share access>
 
-4. Insert ksmbd.ko module after build your kernel. No need to load module
+4. Insert the ksmbd.ko module after you build your kernel. No need to load the module
    if ksmbd is built into the kernel.
 
    - Set ksmbd in menuconfig(e.g. $ make menuconfig)
@@ -175,7 +175,7 @@ Each layer
 1. Enable all component prints
 	# sudo ksmbd.control -d "all"
 
-2. Enable one of components (smb, auth, vfs, oplock, ipc, conn, rdma)
+2. Enable one of the components (smb, auth, vfs, oplock, ipc, conn, rdma)
 	# sudo ksmbd.control -d "smb"
 
 3. Show what prints are enabled.

fs/smb/server/connection.c

@@ -165,11 +165,43 @@ void ksmbd_all_conn_set_status(u64 sess_id, u32 status)
 	up_read(&conn_list_lock);
 }
 
-void ksmbd_conn_wait_idle(struct ksmbd_conn *conn, u64 sess_id)
+void ksmbd_conn_wait_idle(struct ksmbd_conn *conn)
 {
 	wait_event(conn->req_running_q, atomic_read(&conn->req_running) < 2);
 }
 
+int ksmbd_conn_wait_idle_sess_id(struct ksmbd_conn *curr_conn, u64 sess_id)
+{
+	struct ksmbd_conn *conn;
+	int rc, retry_count = 0, max_timeout = 120;
+	int rcount = 1;
+
+retry_idle:
+	if (retry_count >= max_timeout)
+		return -EIO;
+
+	down_read(&conn_list_lock);
+	list_for_each_entry(conn, &conn_list, conns_list) {
+		if (conn->binding || xa_load(&conn->sessions, sess_id)) {
+			if (conn == curr_conn)
+				rcount = 2;
+			if (atomic_read(&conn->req_running) >= rcount) {
+				rc = wait_event_timeout(conn->req_running_q,
+					atomic_read(&conn->req_running) < rcount,
+					HZ);
+				if (!rc) {
+					up_read(&conn_list_lock);
+					retry_count++;
+					goto retry_idle;
+				}
+			}
+		}
+	}
+	up_read(&conn_list_lock);
+
+	return 0;
+}
+
 int ksmbd_conn_write(struct ksmbd_work *work)
 {
 	struct ksmbd_conn *conn = work->conn;

fs/smb/server/connection.h

@@ -145,7 +145,8 @@ extern struct list_head conn_list;
 extern struct rw_semaphore conn_list_lock;
 
 bool ksmbd_conn_alive(struct ksmbd_conn *conn);
-void ksmbd_conn_wait_idle(struct ksmbd_conn *conn, u64 sess_id);
+void ksmbd_conn_wait_idle(struct ksmbd_conn *conn);
+int ksmbd_conn_wait_idle_sess_id(struct ksmbd_conn *curr_conn, u64 sess_id);
 struct ksmbd_conn *ksmbd_conn_alloc(void);
 void ksmbd_conn_free(struct ksmbd_conn *conn);
 bool ksmbd_conn_lookup_dialect(struct ksmbd_conn *c);

fs/smb/server/mgmt/user_session.c

@@ -311,6 +311,7 @@ void destroy_previous_session(struct ksmbd_conn *conn,
 {
 	struct ksmbd_session *prev_sess;
 	struct ksmbd_user *prev_user;
+	int err;
 
 	down_write(&sessions_table_lock);
 	down_write(&conn->session_lock);
@@ -325,8 +326,16 @@ void destroy_previous_session(struct ksmbd_conn *conn,
 	    memcmp(user->passkey, prev_user->passkey, user->passkey_sz))
 		goto out;
 
+	ksmbd_all_conn_set_status(id, KSMBD_SESS_NEED_RECONNECT);
+	err = ksmbd_conn_wait_idle_sess_id(conn, id);
+	if (err) {
+		ksmbd_all_conn_set_status(id, KSMBD_SESS_NEED_NEGOTIATE);
+		goto out;
+	}
+
 	ksmbd_destroy_file_table(&prev_sess->file_table);
 	prev_sess->state = SMB2_SESSION_EXPIRED;
+	ksmbd_all_conn_set_status(id, KSMBD_SESS_NEED_NEGOTIATE);
 	ksmbd_launch_ksmbd_durable_scavenger();
 out:
 	up_write(&conn->session_lock);

fs/smb/server/smb2pdu.c

@@ -1370,7 +1370,8 @@ static int ntlm_negotiate(struct ksmbd_work *work,
 	}
 
 	sz = le16_to_cpu(rsp->SecurityBufferOffset);
-	memcpy((char *)&rsp->hdr.ProtocolId + sz, spnego_blob, spnego_blob_len);
+	unsafe_memcpy((char *)&rsp->hdr.ProtocolId + sz, spnego_blob, spnego_blob_len,
+			/* alloc is larger than blob, see smb2_allocate_rsp_buf() */);
 	rsp->SecurityBufferLength = cpu_to_le16(spnego_blob_len);
 
 out:
@@ -1453,7 +1454,9 @@ static int ntlm_authenticate(struct ksmbd_work *work,
 			return -ENOMEM;
 
 		sz = le16_to_cpu(rsp->SecurityBufferOffset);
-		memcpy((char *)&rsp->hdr.ProtocolId + sz, spnego_blob, spnego_blob_len);
+		unsafe_memcpy((char *)&rsp->hdr.ProtocolId + sz, spnego_blob,
+				spnego_blob_len,
+				/* alloc is larger than blob, see smb2_allocate_rsp_buf() */);
 		rsp->SecurityBufferLength = cpu_to_le16(spnego_blob_len);
 		kfree(spnego_blob);
 	}
@@ -2210,7 +2213,7 @@ int smb2_session_logoff(struct ksmbd_work *work)
 	ksmbd_conn_unlock(conn);
 
 	ksmbd_close_session_fds(work);
-	ksmbd_conn_wait_idle(conn, sess_id);
+	ksmbd_conn_wait_idle(conn);
 
 	/*
 	 * Re-lookup session to validate if session is deleted
@@ -5357,7 +5360,7 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work,
 					"NTFS", PATH_MAX, conn->local_nls, 0);
 		len = len * 2;
 		info->FileSystemNameLen = cpu_to_le32(len);
-		sz = sizeof(struct filesystem_attribute_info) - 2 + len;
+		sz = sizeof(struct filesystem_attribute_info) + len;
 		rsp->OutputBufferLength = cpu_to_le32(sz);
 		break;
 	}
@@ -5383,7 +5386,7 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work,
 		len = len * 2;
 		info->VolumeLabelSize = cpu_to_le32(len);
 		info->Reserved = 0;
-		sz = sizeof(struct filesystem_vol_info) - 2 + len;
+		sz = sizeof(struct filesystem_vol_info) + len;
 		rsp->OutputBufferLength = cpu_to_le32(sz);
 		break;
 	}

fs/smb/server/smb_common.h

@@ -213,7 +213,7 @@ struct filesystem_attribute_info {
 	__le32 Attributes;
 	__le32 MaxPathNameComponentLength;
 	__le32 FileSystemNameLen;
-	__le16 FileSystemName[1]; /* do not have to save this - get subset? */
+	__le16 FileSystemName[]; /* do not have to save this - get subset? */
 } __packed;
 
 struct filesystem_device_info {
@@ -226,7 +226,7 @@ struct filesystem_vol_info {
 	__le32 SerialNumber;
 	__le32 VolumeLabelSize;
 	__le16 Reserved;
-	__le16 VolumeLabel[1];
+	__le16 VolumeLabel[];
 } __packed;
 
 struct filesystem_info {