xref: /linux/fs/smb/server/connection.c (revision 45d8b572fac3aa8b49d53c946b3685eaf78a2824) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) 2016 Namjae Jeon <namjae.jeon@protocolfreedom.org>
4  *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
5  */
6 
7 #include <linux/mutex.h>
8 #include <linux/freezer.h>
9 #include <linux/module.h>
10 
11 #include "server.h"
12 #include "smb_common.h"
13 #include "mgmt/ksmbd_ida.h"
14 #include "connection.h"
15 #include "transport_tcp.h"
16 #include "transport_rdma.h"
17 
18 static DEFINE_MUTEX(init_lock);
19 
20 static struct ksmbd_conn_ops default_conn_ops;
21 
22 LIST_HEAD(conn_list);
23 DECLARE_RWSEM(conn_list_lock);
24 
25 /**
26  * ksmbd_conn_free() - free resources of the connection instance
27  *
28  * @conn:	connection instance to be cleand up
29  *
30  * During the thread termination, the corresponding conn instance
31  * resources(sock/memory) are released and finally the conn object is freed.
32  */
33 void ksmbd_conn_free(struct ksmbd_conn *conn)
34 {
35 	down_write(&conn_list_lock);
36 	list_del(&conn->conns_list);
37 	up_write(&conn_list_lock);
38 
39 	xa_destroy(&conn->sessions);
40 	kvfree(conn->request_buf);
41 	kfree(conn->preauth_info);
42 	kfree(conn);
43 }
44 
45 /**
46  * ksmbd_conn_alloc() - initialize a new connection instance
47  *
48  * Return:	ksmbd_conn struct on success, otherwise NULL
49  */
50 struct ksmbd_conn *ksmbd_conn_alloc(void)
51 {
52 	struct ksmbd_conn *conn;
53 
54 	conn = kzalloc(sizeof(struct ksmbd_conn), GFP_KERNEL);
55 	if (!conn)
56 		return NULL;
57 
58 	conn->need_neg = true;
59 	ksmbd_conn_set_new(conn);
60 	conn->local_nls = load_nls("utf8");
61 	if (!conn->local_nls)
62 		conn->local_nls = load_nls_default();
63 	if (IS_ENABLED(CONFIG_UNICODE))
64 		conn->um = utf8_load(UNICODE_AGE(12, 1, 0));
65 	else
66 		conn->um = ERR_PTR(-EOPNOTSUPP);
67 	if (IS_ERR(conn->um))
68 		conn->um = NULL;
69 	atomic_set(&conn->req_running, 0);
70 	atomic_set(&conn->r_count, 0);
71 	conn->total_credits = 1;
72 	conn->outstanding_credits = 0;
73 
74 	init_waitqueue_head(&conn->req_running_q);
75 	init_waitqueue_head(&conn->r_count_q);
76 	INIT_LIST_HEAD(&conn->conns_list);
77 	INIT_LIST_HEAD(&conn->requests);
78 	INIT_LIST_HEAD(&conn->async_requests);
79 	spin_lock_init(&conn->request_lock);
80 	spin_lock_init(&conn->credits_lock);
81 	ida_init(&conn->async_ida);
82 	xa_init(&conn->sessions);
83 
84 	spin_lock_init(&conn->llist_lock);
85 	INIT_LIST_HEAD(&conn->lock_list);
86 
87 	init_rwsem(&conn->session_lock);
88 
89 	down_write(&conn_list_lock);
90 	list_add(&conn->conns_list, &conn_list);
91 	up_write(&conn_list_lock);
92 	return conn;
93 }
94 
95 bool ksmbd_conn_lookup_dialect(struct ksmbd_conn *c)
96 {
97 	struct ksmbd_conn *t;
98 	bool ret = false;
99 
100 	down_read(&conn_list_lock);
101 	list_for_each_entry(t, &conn_list, conns_list) {
102 		if (memcmp(t->ClientGUID, c->ClientGUID, SMB2_CLIENT_GUID_SIZE))
103 			continue;
104 
105 		ret = true;
106 		break;
107 	}
108 	up_read(&conn_list_lock);
109 	return ret;
110 }
111 
112 void ksmbd_conn_enqueue_request(struct ksmbd_work *work)
113 {
114 	struct ksmbd_conn *conn = work->conn;
115 	struct list_head *requests_queue = NULL;
116 
117 	if (conn->ops->get_cmd_val(work) != SMB2_CANCEL_HE)
118 		requests_queue = &conn->requests;
119 
120 	if (requests_queue) {
121 		atomic_inc(&conn->req_running);
122 		spin_lock(&conn->request_lock);
123 		list_add_tail(&work->request_entry, requests_queue);
124 		spin_unlock(&conn->request_lock);
125 	}
126 }
127 
128 void ksmbd_conn_try_dequeue_request(struct ksmbd_work *work)
129 {
130 	struct ksmbd_conn *conn = work->conn;
131 
132 	if (list_empty(&work->request_entry) &&
133 	    list_empty(&work->async_request_entry))
134 		return;
135 
136 	atomic_dec(&conn->req_running);
137 	spin_lock(&conn->request_lock);
138 	list_del_init(&work->request_entry);
139 	spin_unlock(&conn->request_lock);
140 	if (work->asynchronous)
141 		release_async_work(work);
142 
143 	wake_up_all(&conn->req_running_q);
144 }
145 
146 void ksmbd_conn_lock(struct ksmbd_conn *conn)
147 {
148 	mutex_lock(&conn->srv_mutex);
149 }
150 
151 void ksmbd_conn_unlock(struct ksmbd_conn *conn)
152 {
153 	mutex_unlock(&conn->srv_mutex);
154 }
155 
156 void ksmbd_all_conn_set_status(u64 sess_id, u32 status)
157 {
158 	struct ksmbd_conn *conn;
159 
160 	down_read(&conn_list_lock);
161 	list_for_each_entry(conn, &conn_list, conns_list) {
162 		if (conn->binding || xa_load(&conn->sessions, sess_id))
163 			WRITE_ONCE(conn->status, status);
164 	}
165 	up_read(&conn_list_lock);
166 }
167 
168 void ksmbd_conn_wait_idle(struct ksmbd_conn *conn, u64 sess_id)
169 {
170 	wait_event(conn->req_running_q, atomic_read(&conn->req_running) < 2);
171 }
172 
173 int ksmbd_conn_write(struct ksmbd_work *work)
174 {
175 	struct ksmbd_conn *conn = work->conn;
176 	int sent;
177 
178 	if (!work->response_buf) {
179 		pr_err("NULL response header\n");
180 		return -EINVAL;
181 	}
182 
183 	if (work->send_no_response)
184 		return 0;
185 
186 	if (!work->iov_idx)
187 		return -EINVAL;
188 
189 	ksmbd_conn_lock(conn);
190 	sent = conn->transport->ops->writev(conn->transport, work->iov,
191 			work->iov_cnt,
192 			get_rfc1002_len(work->iov[0].iov_base) + 4,
193 			work->need_invalidate_rkey,
194 			work->remote_key);
195 	ksmbd_conn_unlock(conn);
196 
197 	if (sent < 0) {
198 		pr_err("Failed to send message: %d\n", sent);
199 		return sent;
200 	}
201 
202 	return 0;
203 }
204 
205 int ksmbd_conn_rdma_read(struct ksmbd_conn *conn,
206 			 void *buf, unsigned int buflen,
207 			 struct smb2_buffer_desc_v1 *desc,
208 			 unsigned int desc_len)
209 {
210 	int ret = -EINVAL;
211 
212 	if (conn->transport->ops->rdma_read)
213 		ret = conn->transport->ops->rdma_read(conn->transport,
214 						      buf, buflen,
215 						      desc, desc_len);
216 	return ret;
217 }
218 
219 int ksmbd_conn_rdma_write(struct ksmbd_conn *conn,
220 			  void *buf, unsigned int buflen,
221 			  struct smb2_buffer_desc_v1 *desc,
222 			  unsigned int desc_len)
223 {
224 	int ret = -EINVAL;
225 
226 	if (conn->transport->ops->rdma_write)
227 		ret = conn->transport->ops->rdma_write(conn->transport,
228 						       buf, buflen,
229 						       desc, desc_len);
230 	return ret;
231 }
232 
233 bool ksmbd_conn_alive(struct ksmbd_conn *conn)
234 {
235 	if (!ksmbd_server_running())
236 		return false;
237 
238 	if (ksmbd_conn_exiting(conn))
239 		return false;
240 
241 	if (kthread_should_stop())
242 		return false;
243 
244 	if (atomic_read(&conn->stats.open_files_count) > 0)
245 		return true;
246 
247 	/*
248 	 * Stop current session if the time that get last request from client
249 	 * is bigger than deadtime user configured and opening file count is
250 	 * zero.
251 	 */
252 	if (server_conf.deadtime > 0 &&
253 	    time_after(jiffies, conn->last_active + server_conf.deadtime)) {
254 		ksmbd_debug(CONN, "No response from client in %lu minutes\n",
255 			    server_conf.deadtime / SMB_ECHO_INTERVAL);
256 		return false;
257 	}
258 	return true;
259 }
260 
261 #define SMB1_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb_hdr))
262 #define SMB2_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb2_hdr) + 4)
263 
264 /**
265  * ksmbd_conn_handler_loop() - session thread to listen on new smb requests
266  * @p:		connection instance
267  *
268  * One thread each per connection
269  *
270  * Return:	0 on success
271  */
272 int ksmbd_conn_handler_loop(void *p)
273 {
274 	struct ksmbd_conn *conn = (struct ksmbd_conn *)p;
275 	struct ksmbd_transport *t = conn->transport;
276 	unsigned int pdu_size, max_allowed_pdu_size;
277 	char hdr_buf[4] = {0,};
278 	int size;
279 
280 	mutex_init(&conn->srv_mutex);
281 	__module_get(THIS_MODULE);
282 
283 	if (t->ops->prepare && t->ops->prepare(t))
284 		goto out;
285 
286 	conn->last_active = jiffies;
287 	set_freezable();
288 	while (ksmbd_conn_alive(conn)) {
289 		if (try_to_freeze())
290 			continue;
291 
292 		kvfree(conn->request_buf);
293 		conn->request_buf = NULL;
294 
295 		size = t->ops->read(t, hdr_buf, sizeof(hdr_buf), -1);
296 		if (size != sizeof(hdr_buf))
297 			break;
298 
299 		pdu_size = get_rfc1002_len(hdr_buf);
300 		ksmbd_debug(CONN, "RFC1002 header %u bytes\n", pdu_size);
301 
302 		if (ksmbd_conn_good(conn))
303 			max_allowed_pdu_size =
304 				SMB3_MAX_MSGSIZE + conn->vals->max_write_size;
305 		else
306 			max_allowed_pdu_size = SMB3_MAX_MSGSIZE;
307 
308 		if (pdu_size > max_allowed_pdu_size) {
309 			pr_err_ratelimited("PDU length(%u) exceeded maximum allowed pdu size(%u) on connection(%d)\n",
310 					pdu_size, max_allowed_pdu_size,
311 					READ_ONCE(conn->status));
312 			break;
313 		}
314 
315 		/*
316 		 * Check maximum pdu size(0x00FFFFFF).
317 		 */
318 		if (pdu_size > MAX_STREAM_PROT_LEN)
319 			break;
320 
321 		if (pdu_size < SMB1_MIN_SUPPORTED_HEADER_SIZE)
322 			break;
323 
324 		/* 4 for rfc1002 length field */
325 		/* 1 for implied bcc[0] */
326 		size = pdu_size + 4 + 1;
327 		conn->request_buf = kvmalloc(size, GFP_KERNEL);
328 		if (!conn->request_buf)
329 			break;
330 
331 		memcpy(conn->request_buf, hdr_buf, sizeof(hdr_buf));
332 
333 		/*
334 		 * We already read 4 bytes to find out PDU size, now
335 		 * read in PDU
336 		 */
337 		size = t->ops->read(t, conn->request_buf + 4, pdu_size, 2);
338 		if (size < 0) {
339 			pr_err("sock_read failed: %d\n", size);
340 			break;
341 		}
342 
343 		if (size != pdu_size) {
344 			pr_err("PDU error. Read: %d, Expected: %d\n",
345 			       size, pdu_size);
346 			continue;
347 		}
348 
349 		if (!ksmbd_smb_request(conn))
350 			break;
351 
352 		if (((struct smb2_hdr *)smb2_get_msg(conn->request_buf))->ProtocolId ==
353 		    SMB2_PROTO_NUMBER) {
354 			if (pdu_size < SMB2_MIN_SUPPORTED_HEADER_SIZE)
355 				break;
356 		}
357 
358 		if (!default_conn_ops.process_fn) {
359 			pr_err("No connection request callback\n");
360 			break;
361 		}
362 
363 		if (default_conn_ops.process_fn(conn)) {
364 			pr_err("Cannot handle request\n");
365 			break;
366 		}
367 	}
368 
369 out:
370 	ksmbd_conn_set_releasing(conn);
371 	/* Wait till all reference dropped to the Server object*/
372 	wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);
373 
374 	if (IS_ENABLED(CONFIG_UNICODE))
375 		utf8_unload(conn->um);
376 	unload_nls(conn->local_nls);
377 	if (default_conn_ops.terminate_fn)
378 		default_conn_ops.terminate_fn(conn);
379 	t->ops->disconnect(t);
380 	module_put(THIS_MODULE);
381 	return 0;
382 }
383 
384 void ksmbd_conn_init_server_callbacks(struct ksmbd_conn_ops *ops)
385 {
386 	default_conn_ops.process_fn = ops->process_fn;
387 	default_conn_ops.terminate_fn = ops->terminate_fn;
388 }
389 
390 int ksmbd_conn_transport_init(void)
391 {
392 	int ret;
393 
394 	mutex_lock(&init_lock);
395 	ret = ksmbd_tcp_init();
396 	if (ret) {
397 		pr_err("Failed to init TCP subsystem: %d\n", ret);
398 		goto out;
399 	}
400 
401 	ret = ksmbd_rdma_init();
402 	if (ret) {
403 		pr_err("Failed to init RDMA subsystem: %d\n", ret);
404 		goto out;
405 	}
406 out:
407 	mutex_unlock(&init_lock);
408 	return ret;
409 }
410 
411 static void stop_sessions(void)
412 {
413 	struct ksmbd_conn *conn;
414 	struct ksmbd_transport *t;
415 
416 again:
417 	down_read(&conn_list_lock);
418 	list_for_each_entry(conn, &conn_list, conns_list) {
419 		t = conn->transport;
420 		ksmbd_conn_set_exiting(conn);
421 		if (t->ops->shutdown) {
422 			up_read(&conn_list_lock);
423 			t->ops->shutdown(t);
424 			down_read(&conn_list_lock);
425 		}
426 	}
427 	up_read(&conn_list_lock);
428 
429 	if (!list_empty(&conn_list)) {
430 		schedule_timeout_interruptible(HZ / 10); /* 100ms */
431 		goto again;
432 	}
433 }
434 
435 void ksmbd_conn_transport_destroy(void)
436 {
437 	mutex_lock(&init_lock);
438 	ksmbd_tcp_destroy();
439 	ksmbd_rdma_destroy();
440 	stop_sessions();
441 	mutex_unlock(&init_lock);
442 }
443