xref: /openbmc/linux/fs/smb/server/connection.c (revision c4c3c32d) 
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 	down_write(&conn_list_lock);
88 	list_add(&conn->conns_list, &conn_list);
89 	up_write(&conn_list_lock);
90 	return conn;
91 }
92 
93 bool ksmbd_conn_lookup_dialect(struct ksmbd_conn *c)
94 {
95 	struct ksmbd_conn *t;
96 	bool ret = false;
97 
98 	down_read(&conn_list_lock);
99 	list_for_each_entry(t, &conn_list, conns_list) {
100 		if (memcmp(t->ClientGUID, c->ClientGUID, SMB2_CLIENT_GUID_SIZE))
101 			continue;
102 
103 		ret = true;
104 		break;
105 	}
106 	up_read(&conn_list_lock);
107 	return ret;
108 }
109 
110 void ksmbd_conn_enqueue_request(struct ksmbd_work *work)
111 {
112 	struct ksmbd_conn *conn = work->conn;
113 	struct list_head *requests_queue = NULL;
114 
115 	if (conn->ops->get_cmd_val(work) != SMB2_CANCEL_HE)
116 		requests_queue = &conn->requests;
117 
118 	if (requests_queue) {
119 		atomic_inc(&conn->req_running);
120 		spin_lock(&conn->request_lock);
121 		list_add_tail(&work->request_entry, requests_queue);
122 		spin_unlock(&conn->request_lock);
123 	}
124 }
125 
126 int ksmbd_conn_try_dequeue_request(struct ksmbd_work *work)
127 {
128 	struct ksmbd_conn *conn = work->conn;
129 	int ret = 1;
130 
131 	if (list_empty(&work->request_entry) &&
132 	    list_empty(&work->async_request_entry))
133 		return 0;
134 
135 	if (!work->multiRsp)
136 		atomic_dec(&conn->req_running);
137 	if (!work->multiRsp) {
138 		spin_lock(&conn->request_lock);
139 		list_del_init(&work->request_entry);
140 		spin_unlock(&conn->request_lock);
141 		if (work->asynchronous)
142 			release_async_work(work);
143 		ret = 0;
144 	}
145 
146 	wake_up_all(&conn->req_running_q);
147 	return ret;
148 }
149 
150 void ksmbd_conn_lock(struct ksmbd_conn *conn)
151 {
152 	mutex_lock(&conn->srv_mutex);
153 }
154 
155 void ksmbd_conn_unlock(struct ksmbd_conn *conn)
156 {
157 	mutex_unlock(&conn->srv_mutex);
158 }
159 
160 void ksmbd_all_conn_set_status(u64 sess_id, u32 status)
161 {
162 	struct ksmbd_conn *conn;
163 
164 	down_read(&conn_list_lock);
165 	list_for_each_entry(conn, &conn_list, conns_list) {
166 		if (conn->binding || xa_load(&conn->sessions, sess_id))
167 			WRITE_ONCE(conn->status, status);
168 	}
169 	up_read(&conn_list_lock);
170 }
171 
172 void ksmbd_conn_wait_idle(struct ksmbd_conn *conn, u64 sess_id)
173 {
174 	struct ksmbd_conn *bind_conn;
175 
176 	wait_event(conn->req_running_q, atomic_read(&conn->req_running) < 2);
177 
178 	down_read(&conn_list_lock);
179 	list_for_each_entry(bind_conn, &conn_list, conns_list) {
180 		if (bind_conn == conn)
181 			continue;
182 
183 		if ((bind_conn->binding || xa_load(&bind_conn->sessions, sess_id)) &&
184 		    !ksmbd_conn_releasing(bind_conn) &&
185 		    atomic_read(&bind_conn->req_running)) {
186 			wait_event(bind_conn->req_running_q,
187 				atomic_read(&bind_conn->req_running) == 0);
188 		}
189 	}
190 	up_read(&conn_list_lock);
191 }
192 
193 int ksmbd_conn_write(struct ksmbd_work *work)
194 {
195 	struct ksmbd_conn *conn = work->conn;
196 	size_t len = 0;
197 	int sent;
198 	struct kvec iov[3];
199 	int iov_idx = 0;
200 
201 	if (!work->response_buf) {
202 		pr_err("NULL response header\n");
203 		return -EINVAL;
204 	}
205 
206 	if (work->tr_buf) {
207 		iov[iov_idx] = (struct kvec) { work->tr_buf,
208 				sizeof(struct smb2_transform_hdr) + 4 };
209 		len += iov[iov_idx++].iov_len;
210 	}
211 
212 	if (work->aux_payload_sz) {
213 		iov[iov_idx] = (struct kvec) { work->response_buf, work->resp_hdr_sz };
214 		len += iov[iov_idx++].iov_len;
215 		iov[iov_idx] = (struct kvec) { work->aux_payload_buf, work->aux_payload_sz };
216 		len += iov[iov_idx++].iov_len;
217 	} else {
218 		if (work->tr_buf)
219 			iov[iov_idx].iov_len = work->resp_hdr_sz;
220 		else
221 			iov[iov_idx].iov_len = get_rfc1002_len(work->response_buf) + 4;
222 		iov[iov_idx].iov_base = work->response_buf;
223 		len += iov[iov_idx++].iov_len;
224 	}
225 
226 	ksmbd_conn_lock(conn);
227 	sent = conn->transport->ops->writev(conn->transport, &iov[0],
228 					iov_idx, len,
229 					work->need_invalidate_rkey,
230 					work->remote_key);
231 	ksmbd_conn_unlock(conn);
232 
233 	if (sent < 0) {
234 		pr_err("Failed to send message: %d\n", sent);
235 		return sent;
236 	}
237 
238 	return 0;
239 }
240 
241 int ksmbd_conn_rdma_read(struct ksmbd_conn *conn,
242 			 void *buf, unsigned int buflen,
243 			 struct smb2_buffer_desc_v1 *desc,
244 			 unsigned int desc_len)
245 {
246 	int ret = -EINVAL;
247 
248 	if (conn->transport->ops->rdma_read)
249 		ret = conn->transport->ops->rdma_read(conn->transport,
250 						      buf, buflen,
251 						      desc, desc_len);
252 	return ret;
253 }
254 
255 int ksmbd_conn_rdma_write(struct ksmbd_conn *conn,
256 			  void *buf, unsigned int buflen,
257 			  struct smb2_buffer_desc_v1 *desc,
258 			  unsigned int desc_len)
259 {
260 	int ret = -EINVAL;
261 
262 	if (conn->transport->ops->rdma_write)
263 		ret = conn->transport->ops->rdma_write(conn->transport,
264 						       buf, buflen,
265 						       desc, desc_len);
266 	return ret;
267 }
268 
269 bool ksmbd_conn_alive(struct ksmbd_conn *conn)
270 {
271 	if (!ksmbd_server_running())
272 		return false;
273 
274 	if (ksmbd_conn_exiting(conn))
275 		return false;
276 
277 	if (kthread_should_stop())
278 		return false;
279 
280 	if (atomic_read(&conn->stats.open_files_count) > 0)
281 		return true;
282 
283 	/*
284 	 * Stop current session if the time that get last request from client
285 	 * is bigger than deadtime user configured and opening file count is
286 	 * zero.
287 	 */
288 	if (server_conf.deadtime > 0 &&
289 	    time_after(jiffies, conn->last_active + server_conf.deadtime)) {
290 		ksmbd_debug(CONN, "No response from client in %lu minutes\n",
291 			    server_conf.deadtime / SMB_ECHO_INTERVAL);
292 		return false;
293 	}
294 	return true;
295 }
296 
297 #define SMB1_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb_hdr))
298 #define SMB2_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb2_hdr) + 4)
299 
300 /**
301  * ksmbd_conn_handler_loop() - session thread to listen on new smb requests
302  * @p:		connection instance
303  *
304  * One thread each per connection
305  *
306  * Return:	0 on success
307  */
308 int ksmbd_conn_handler_loop(void *p)
309 {
310 	struct ksmbd_conn *conn = (struct ksmbd_conn *)p;
311 	struct ksmbd_transport *t = conn->transport;
312 	unsigned int pdu_size, max_allowed_pdu_size;
313 	char hdr_buf[4] = {0,};
314 	int size;
315 
316 	mutex_init(&conn->srv_mutex);
317 	__module_get(THIS_MODULE);
318 
319 	if (t->ops->prepare && t->ops->prepare(t))
320 		goto out;
321 
322 	conn->last_active = jiffies;
323 	while (ksmbd_conn_alive(conn)) {
324 		if (try_to_freeze())
325 			continue;
326 
327 		kvfree(conn->request_buf);
328 		conn->request_buf = NULL;
329 
330 		size = t->ops->read(t, hdr_buf, sizeof(hdr_buf), -1);
331 		if (size != sizeof(hdr_buf))
332 			break;
333 
334 		pdu_size = get_rfc1002_len(hdr_buf);
335 		ksmbd_debug(CONN, "RFC1002 header %u bytes\n", pdu_size);
336 
337 		if (ksmbd_conn_good(conn))
338 			max_allowed_pdu_size =
339 				SMB3_MAX_MSGSIZE + conn->vals->max_write_size;
340 		else
341 			max_allowed_pdu_size = SMB3_MAX_MSGSIZE;
342 
343 		if (pdu_size > max_allowed_pdu_size) {
344 			pr_err_ratelimited("PDU length(%u) exceeded maximum allowed pdu size(%u) on connection(%d)\n",
345 					pdu_size, max_allowed_pdu_size,
346 					READ_ONCE(conn->status));
347 			break;
348 		}
349 
350 		/*
351 		 * Check maximum pdu size(0x00FFFFFF).
352 		 */
353 		if (pdu_size > MAX_STREAM_PROT_LEN)
354 			break;
355 
356 		if (pdu_size < SMB1_MIN_SUPPORTED_HEADER_SIZE)
357 			break;
358 
359 		/* 4 for rfc1002 length field */
360 		/* 1 for implied bcc[0] */
361 		size = pdu_size + 4 + 1;
362 		conn->request_buf = kvmalloc(size, GFP_KERNEL);
363 		if (!conn->request_buf)
364 			break;
365 
366 		memcpy(conn->request_buf, hdr_buf, sizeof(hdr_buf));
367 
368 		/*
369 		 * We already read 4 bytes to find out PDU size, now
370 		 * read in PDU
371 		 */
372 		size = t->ops->read(t, conn->request_buf + 4, pdu_size, 2);
373 		if (size < 0) {
374 			pr_err("sock_read failed: %d\n", size);
375 			break;
376 		}
377 
378 		if (size != pdu_size) {
379 			pr_err("PDU error. Read: %d, Expected: %d\n",
380 			       size, pdu_size);
381 			continue;
382 		}
383 
384 		if (!ksmbd_smb_request(conn))
385 			break;
386 
387 		if (((struct smb2_hdr *)smb2_get_msg(conn->request_buf))->ProtocolId ==
388 		    SMB2_PROTO_NUMBER) {
389 			if (pdu_size < SMB2_MIN_SUPPORTED_HEADER_SIZE)
390 				break;
391 		}
392 
393 		if (!default_conn_ops.process_fn) {
394 			pr_err("No connection request callback\n");
395 			break;
396 		}
397 
398 		if (default_conn_ops.process_fn(conn)) {
399 			pr_err("Cannot handle request\n");
400 			break;
401 		}
402 	}
403 
404 out:
405 	ksmbd_conn_set_releasing(conn);
406 	/* Wait till all reference dropped to the Server object*/
407 	wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);
408 
409 	if (IS_ENABLED(CONFIG_UNICODE))
410 		utf8_unload(conn->um);
411 	unload_nls(conn->local_nls);
412 	if (default_conn_ops.terminate_fn)
413 		default_conn_ops.terminate_fn(conn);
414 	t->ops->disconnect(t);
415 	module_put(THIS_MODULE);
416 	return 0;
417 }
418 
419 void ksmbd_conn_init_server_callbacks(struct ksmbd_conn_ops *ops)
420 {
421 	default_conn_ops.process_fn = ops->process_fn;
422 	default_conn_ops.terminate_fn = ops->terminate_fn;
423 }
424 
425 int ksmbd_conn_transport_init(void)
426 {
427 	int ret;
428 
429 	mutex_lock(&init_lock);
430 	ret = ksmbd_tcp_init();
431 	if (ret) {
432 		pr_err("Failed to init TCP subsystem: %d\n", ret);
433 		goto out;
434 	}
435 
436 	ret = ksmbd_rdma_init();
437 	if (ret) {
438 		pr_err("Failed to init RDMA subsystem: %d\n", ret);
439 		goto out;
440 	}
441 out:
442 	mutex_unlock(&init_lock);
443 	return ret;
444 }
445 
446 static void stop_sessions(void)
447 {
448 	struct ksmbd_conn *conn;
449 	struct ksmbd_transport *t;
450 
451 again:
452 	down_read(&conn_list_lock);
453 	list_for_each_entry(conn, &conn_list, conns_list) {
454 		struct task_struct *task;
455 
456 		t = conn->transport;
457 		task = t->handler;
458 		if (task)
459 			ksmbd_debug(CONN, "Stop session handler %s/%d\n",
460 				    task->comm, task_pid_nr(task));
461 		ksmbd_conn_set_exiting(conn);
462 		if (t->ops->shutdown) {
463 			up_read(&conn_list_lock);
464 			t->ops->shutdown(t);
465 			down_read(&conn_list_lock);
466 		}
467 	}
468 	up_read(&conn_list_lock);
469 
470 	if (!list_empty(&conn_list)) {
471 		schedule_timeout_interruptible(HZ / 10); /* 100ms */
472 		goto again;
473 	}
474 }
475 
476 void ksmbd_conn_transport_destroy(void)
477 {
478 	mutex_lock(&init_lock);
479 	ksmbd_tcp_destroy();
480 	ksmbd_rdma_destroy();
481 	stop_sessions();
482 	mutex_unlock(&init_lock);
483 }
484