xref: /linux/fs/smb/server/smb_common.c (revision 7db28abbea0f7dc1ec4fdfdc149db5fbd9e4c994)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
4  *   Copyright (C) 2018 Namjae Jeon <linkinjeon@kernel.org>
5  */
6 
7 #include <linux/user_namespace.h>
8 
9 #include "smb_common.h"
10 #include "server.h"
11 #include "misc.h"
12 #include "../common/smb2status.h"
13 #include "connection.h"
14 #include "ksmbd_work.h"
15 #include "mgmt/user_session.h"
16 #include "mgmt/user_config.h"
17 #include "mgmt/tree_connect.h"
18 #include "mgmt/share_config.h"
19 
20 /*for shortname implementation */
21 static const char *basechars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_-!@#$%";
22 #define MANGLE_BASE (strlen(basechars) - 1)
23 #define MAGIC_CHAR '~'
24 #define PERIOD '.'
25 #define mangle(V) ((char)(basechars[(V) % MANGLE_BASE]))
26 
27 struct smb_protocol {
28 	int		index;
29 	char		*name;
30 	char		*prot;
31 	__u16		prot_id;
32 };
33 
34 static struct smb_protocol smb1_protos[] = {
35 	{
36 		SMB21_PROT,
37 		"\2SMB 2.1",
38 		"SMB2_10",
39 		SMB21_PROT_ID
40 	},
41 	{
42 		SMB2X_PROT,
43 		"\2SMB 2.???",
44 		"SMB2_22",
45 		SMB2X_PROT_ID
46 	},
47 };
48 
49 static struct smb_protocol smb2_protos[] = {
50 	{
51 		SMB21_PROT,
52 		"\2SMB 2.1",
53 		"SMB2_10",
54 		SMB21_PROT_ID
55 	},
56 	{
57 		SMB30_PROT,
58 		"\2SMB 3.0",
59 		"SMB3_00",
60 		SMB30_PROT_ID
61 	},
62 	{
63 		SMB302_PROT,
64 		"\2SMB 3.02",
65 		"SMB3_02",
66 		SMB302_PROT_ID
67 	},
68 	{
69 		SMB311_PROT,
70 		"\2SMB 3.1.1",
71 		"SMB3_11",
72 		SMB311_PROT_ID
73 	},
74 };
75 
76 unsigned int ksmbd_server_side_copy_max_chunk_count(void)
77 {
78 	return 256;
79 }
80 
81 unsigned int ksmbd_server_side_copy_max_chunk_size(void)
82 {
83 	return (2U << 30) - 1;
84 }
85 
86 unsigned int ksmbd_server_side_copy_max_total_size(void)
87 {
88 	return (2U << 30) - 1;
89 }
90 
91 inline int ksmbd_min_protocol(void)
92 {
93 	return SMB21_PROT;
94 }
95 
96 inline int ksmbd_max_protocol(void)
97 {
98 	return SMB311_PROT;
99 }
100 
101 static const struct {
102 	int version;
103 	const char *string;
104 } version_strings[] = {
105 	{SMB2_PROT, SMB20_VERSION_STRING},
106 	{SMB21_PROT, SMB21_VERSION_STRING},
107 	{SMB30_PROT, SMB30_VERSION_STRING},
108 	{SMB302_PROT, SMB302_VERSION_STRING},
109 	{SMB311_PROT, SMB311_VERSION_STRING},
110 };
111 
112 const char *ksmbd_get_protocol_string(int version)
113 {
114 	int i;
115 
116 	for (i = 0; i < ARRAY_SIZE(version_strings); i++) {
117 		if (version_strings[i].version == version)
118 			return version_strings[i].string;
119 	}
120 	return "";
121 }
122 int ksmbd_lookup_protocol_idx(char *str)
123 {
124 	int offt = ARRAY_SIZE(smb1_protos) - 1;
125 	int len = strlen(str);
126 
127 	while (offt >= 0) {
128 		if (!strncmp(str, smb1_protos[offt].prot, len)) {
129 			ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
130 				    smb1_protos[offt].prot, offt);
131 			return smb1_protos[offt].index;
132 		}
133 		offt--;
134 	}
135 
136 	offt = ARRAY_SIZE(smb2_protos) - 1;
137 	while (offt >= 0) {
138 		if (!strncmp(str, smb2_protos[offt].prot, len)) {
139 			ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
140 				    smb2_protos[offt].prot, offt);
141 			return smb2_protos[offt].index;
142 		}
143 		offt--;
144 	}
145 	return -1;
146 }
147 
148 /**
149  * ksmbd_verify_smb_message() - check for valid smb2 request header
150  * @work:	smb work
151  *
152  * check for valid smb signature and packet direction(request/response)
153  *
154  * Return:      0 on success, otherwise -EINVAL
155  */
156 int ksmbd_verify_smb_message(struct ksmbd_work *work)
157 {
158 	struct smb2_hdr *smb2_hdr = ksmbd_req_buf_next(work);
159 	struct smb_hdr *hdr;
160 
161 	if (smb2_hdr->ProtocolId == SMB2_PROTO_NUMBER)
162 		return ksmbd_smb2_check_message(work);
163 
164 	hdr = smb_get_msg(work->request_buf);
165 	if (*(__le32 *)hdr->Protocol == SMB1_PROTO_NUMBER &&
166 	    hdr->Command == SMB_COM_NEGOTIATE) {
167 		struct ksmbd_conn *conn = work->conn;
168 
169 		conn->outstanding_credits++;
170 		/*
171 		 * A legacy SMB1 multi-protocol negotiate occupies sequence
172 		 * number 0 but does not pass through
173 		 * ksmbd_smb2_check_message(). Consume it here so that, after
174 		 * the connection is upgraded to SMB2, the command sequence
175 		 * window can advance instead of staying pinned at 0.
176 		 */
177 		spin_lock(&conn->credits_lock);
178 		if (conn->seq_low == 0) {
179 			__clear_bit(0, conn->seq_bitmap);
180 			conn->seq_low = 1;
181 		}
182 		spin_unlock(&conn->credits_lock);
183 		return 0;
184 	}
185 
186 	return -EINVAL;
187 }
188 
189 /**
190  * ksmbd_smb_request() - check for valid smb request type
191  * @conn:	connection instance
192  *
193  * Return:      true on success, otherwise false
194  */
195 bool ksmbd_smb_request(struct ksmbd_conn *conn)
196 {
197 	__le32 *proto;
198 
199 	if (conn->request_buf[0] != 0)
200 		return false;
201 
202 	proto = (__le32 *)smb_get_msg(conn->request_buf);
203 	if (*proto != SMB1_PROTO_NUMBER &&
204 	    *proto != SMB2_PROTO_NUMBER &&
205 	    *proto != SMB2_TRANSFORM_PROTO_NUM)
206 		return false;
207 
208 	return true;
209 }
210 
211 static bool supported_protocol(int idx)
212 {
213 	if (idx == SMB2X_PROT &&
214 	    (server_conf.min_protocol >= SMB21_PROT ||
215 	     server_conf.max_protocol <= SMB311_PROT))
216 		return true;
217 
218 	return (server_conf.min_protocol <= idx &&
219 		idx <= server_conf.max_protocol);
220 }
221 
222 static char *next_dialect(char *dialect, int *next_off, int bcount)
223 {
224 	dialect = dialect + *next_off;
225 	*next_off = strnlen(dialect, bcount);
226 	if (dialect[*next_off] != '\0')
227 		return NULL;
228 	return dialect;
229 }
230 
231 static int ksmbd_lookup_dialect_by_name(char *cli_dialects, __le16 byte_count)
232 {
233 	int i, seq_num, bcount, next;
234 	char *dialect;
235 
236 	for (i = ARRAY_SIZE(smb1_protos) - 1; i >= 0; i--) {
237 		seq_num = 0;
238 		next = 0;
239 		dialect = cli_dialects;
240 		bcount = le16_to_cpu(byte_count);
241 		do {
242 			dialect = next_dialect(dialect, &next, bcount);
243 			if (!dialect)
244 				break;
245 			ksmbd_debug(SMB, "client requested dialect %s\n",
246 				    dialect);
247 			if (!strcmp(dialect, smb1_protos[i].name)) {
248 				if (supported_protocol(smb1_protos[i].index)) {
249 					ksmbd_debug(SMB,
250 						    "selected %s dialect\n",
251 						    smb1_protos[i].name);
252 					if (smb1_protos[i].index == SMB1_PROT)
253 						return seq_num;
254 					return smb1_protos[i].prot_id;
255 				}
256 			}
257 			seq_num++;
258 			bcount -= (++next);
259 		} while (bcount > 0);
260 	}
261 
262 	return BAD_PROT_ID;
263 }
264 
265 int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count)
266 {
267 	int i;
268 	int count;
269 
270 	for (i = ARRAY_SIZE(smb2_protos) - 1; i >= 0; i--) {
271 		count = le16_to_cpu(dialects_count);
272 		while (--count >= 0) {
273 			ksmbd_debug(SMB, "client requested dialect 0x%x\n",
274 				    le16_to_cpu(cli_dialects[count]));
275 			if (le16_to_cpu(cli_dialects[count]) !=
276 					smb2_protos[i].prot_id)
277 				continue;
278 
279 			if (supported_protocol(smb2_protos[i].index)) {
280 				ksmbd_debug(SMB, "selected %s dialect\n",
281 					    smb2_protos[i].name);
282 				return smb2_protos[i].prot_id;
283 			}
284 		}
285 	}
286 
287 	return BAD_PROT_ID;
288 }
289 
290 static int ksmbd_negotiate_smb_dialect(void *buf)
291 {
292 	int smb_buf_length = get_rfc1002_len(buf);
293 	__le32 proto = ((struct smb2_hdr *)smb_get_msg(buf))->ProtocolId;
294 
295 	if (proto == SMB2_PROTO_NUMBER) {
296 		struct smb2_negotiate_req *req;
297 		int smb2_neg_size =
298 			offsetof(struct smb2_negotiate_req, Dialects);
299 
300 		req = (struct smb2_negotiate_req *)smb_get_msg(buf);
301 		if (smb2_neg_size > smb_buf_length)
302 			goto err_out;
303 
304 		if (struct_size(req, Dialects, le16_to_cpu(req->DialectCount)) >
305 		    smb_buf_length)
306 			goto err_out;
307 
308 		return ksmbd_lookup_dialect_by_id(req->Dialects,
309 						  req->DialectCount);
310 	}
311 
312 	if (proto == SMB1_PROTO_NUMBER) {
313 		struct smb_negotiate_req *req;
314 
315 		req = (struct smb_negotiate_req *)smb_get_msg(buf);
316 		if (le16_to_cpu(req->ByteCount) < 2)
317 			goto err_out;
318 
319 		if (offsetof(struct smb_negotiate_req, DialectsArray) +
320 			le16_to_cpu(req->ByteCount) > smb_buf_length) {
321 			goto err_out;
322 		}
323 
324 		return ksmbd_lookup_dialect_by_name(req->DialectsArray,
325 						    req->ByteCount);
326 	}
327 
328 err_out:
329 	return BAD_PROT_ID;
330 }
331 
332 #define SMB_COM_NEGOTIATE_EX	0x0
333 
334 /**
335  * get_smb1_cmd_val() - get smb command value from smb header
336  * @work:	smb work containing smb header
337  *
338  * Return:      smb command value
339  */
340 static u16 get_smb1_cmd_val(struct ksmbd_work *work)
341 {
342 	return SMB_COM_NEGOTIATE_EX;
343 }
344 
345 /**
346  * init_smb1_rsp_hdr() - initialize smb negotiate response header
347  * @work:	smb work containing smb request
348  *
349  * Return:      0 on success, otherwise -EINVAL
350  */
351 static int init_smb1_rsp_hdr(struct ksmbd_work *work)
352 {
353 	struct smb_hdr *rsp_hdr = (struct smb_hdr *)smb_get_msg(work->response_buf);
354 	struct smb_hdr *rcv_hdr = (struct smb_hdr *)smb_get_msg(work->request_buf);
355 
356 	rsp_hdr->Command = SMB_COM_NEGOTIATE;
357 	*(__le32 *)rsp_hdr->Protocol = SMB1_PROTO_NUMBER;
358 	rsp_hdr->Flags = SMBFLG_RESPONSE;
359 	rsp_hdr->Flags2 = SMBFLG2_UNICODE | SMBFLG2_ERR_STATUS |
360 		SMBFLG2_EXT_SEC | SMBFLG2_IS_LONG_NAME;
361 	rsp_hdr->Pid = rcv_hdr->Pid;
362 	rsp_hdr->Mid = rcv_hdr->Mid;
363 	return 0;
364 }
365 
366 /**
367  * smb1_check_user_session() - check for valid session for a user
368  * @work:	smb work containing smb request buffer
369  *
370  * Return:      0 on success, otherwise error
371  */
372 static int smb1_check_user_session(struct ksmbd_work *work)
373 {
374 	unsigned int cmd = work->conn->ops->get_cmd_val(work);
375 
376 	if (cmd == SMB_COM_NEGOTIATE_EX)
377 		return 0;
378 
379 	return -EINVAL;
380 }
381 
382 /**
383  * smb1_allocate_rsp_buf() - allocate response buffer for a command
384  * @work:	smb work containing smb request
385  *
386  * Return:      0 on success, otherwise -ENOMEM
387  */
388 static int smb1_allocate_rsp_buf(struct ksmbd_work *work)
389 {
390 	work->response_buf = kzalloc(MAX_CIFS_SMALL_BUFFER_SIZE,
391 			KSMBD_DEFAULT_GFP);
392 	work->response_sz = MAX_CIFS_SMALL_BUFFER_SIZE;
393 
394 	if (!work->response_buf) {
395 		pr_err("Failed to allocate %u bytes buffer\n",
396 				MAX_CIFS_SMALL_BUFFER_SIZE);
397 		return -ENOMEM;
398 	}
399 
400 	return 0;
401 }
402 
403 /**
404  * set_smb1_rsp_status() - set error type in smb response header
405  * @work:	smb work containing smb response header
406  * @err:	error code to set in response
407  */
408 static void set_smb1_rsp_status(struct ksmbd_work *work, __le32 err)
409 {
410 	work->send_no_response = 1;
411 }
412 
413 static struct smb_version_ops smb1_server_ops = {
414 	.get_cmd_val = get_smb1_cmd_val,
415 	.init_rsp_hdr = init_smb1_rsp_hdr,
416 	.allocate_rsp_buf = smb1_allocate_rsp_buf,
417 	.check_user_session = smb1_check_user_session,
418 	.set_rsp_status = set_smb1_rsp_status,
419 };
420 
421 static struct smb_version_values smb1_server_values = {
422 	.max_credits = SMB2_MAX_CREDITS,
423 };
424 
425 static int smb1_negotiate(struct ksmbd_work *work)
426 {
427 	return ksmbd_smb_negotiate_common(work, SMB_COM_NEGOTIATE);
428 }
429 
430 static struct smb_version_cmds smb1_server_cmds[1] = {
431 	[SMB_COM_NEGOTIATE_EX]	= { .proc = smb1_negotiate, },
432 };
433 
434 static int init_smb1_server(struct ksmbd_conn *conn)
435 {
436 	conn->vals = &smb1_server_values;
437 	conn->ops = &smb1_server_ops;
438 	conn->cmds = smb1_server_cmds;
439 	conn->max_cmds = ARRAY_SIZE(smb1_server_cmds);
440 	return 0;
441 }
442 
443 int ksmbd_init_smb_server(struct ksmbd_conn *conn)
444 {
445 	struct smb_hdr *rcv_hdr = (struct smb_hdr *)smb_get_msg(conn->request_buf);
446 	__le32 proto;
447 
448 	proto = *(__le32 *)rcv_hdr->Protocol;
449 	if (conn->need_neg == false) {
450 		if (proto == SMB1_PROTO_NUMBER)
451 			return -EINVAL;
452 		return 0;
453 	}
454 
455 	if (proto == SMB1_PROTO_NUMBER)
456 		return init_smb1_server(conn);
457 	return init_smb3_11_server(conn);
458 }
459 
460 int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work, int info_level,
461 				      struct ksmbd_file *dir,
462 				      struct ksmbd_dir_info *d_info,
463 				      char *search_pattern,
464 				      int (*fn)(struct ksmbd_conn *, int,
465 						struct ksmbd_dir_info *,
466 						struct ksmbd_kstat *))
467 {
468 	int i, rc = 0;
469 	struct ksmbd_conn *conn = work->conn;
470 	struct mnt_idmap *idmap = file_mnt_idmap(dir->filp);
471 
472 	for (i = 0; i < 2; i++) {
473 		struct kstat kstat;
474 		struct ksmbd_kstat ksmbd_kstat;
475 		struct dentry *dentry;
476 
477 		if (!dir->dot_dotdot[i]) { /* fill dot entry info */
478 			if (i == 0) {
479 				d_info->name = ".";
480 				d_info->name_len = 1;
481 				dentry = dir->filp->f_path.dentry;
482 			} else {
483 				d_info->name = "..";
484 				d_info->name_len = 2;
485 				dentry = dir->filp->f_path.dentry->d_parent;
486 			}
487 
488 			if (!match_pattern(d_info->name, d_info->name_len,
489 					   search_pattern)) {
490 				dir->dot_dotdot[i] = 1;
491 				continue;
492 			}
493 
494 			ksmbd_kstat.kstat = &kstat;
495 			rc = ksmbd_vfs_fill_dentry_attrs(work,
496 							 idmap,
497 							 dentry,
498 							 &ksmbd_kstat);
499 			if (rc)
500 				break;
501 
502 			rc = fn(conn, info_level, d_info, &ksmbd_kstat);
503 			if (rc)
504 				break;
505 			if (d_info->out_buf_len <= 0)
506 				break;
507 
508 			dir->dot_dotdot[i] = 1;
509 			if (d_info->flags & SMB2_RETURN_SINGLE_ENTRY) {
510 				d_info->out_buf_len = 0;
511 				break;
512 			}
513 		}
514 	}
515 
516 	return rc;
517 }
518 
519 /**
520  * ksmbd_extract_shortname() - get shortname from long filename
521  * @conn:	connection instance
522  * @longname:	source long filename
523  * @shortname:	destination short filename
524  *
525  * Return:	shortname length or 0 when source long name is '.' or '..'
526  * TODO: Though this function conforms the restriction of 8.3 Filename spec,
527  * but the result is different with Windows 7's one. need to check.
528  */
529 int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname,
530 			    char *shortname)
531 {
532 	const char *p;
533 	char base[9], extension[4];
534 	char out[13] = {0};
535 	int baselen = 0;
536 	int extlen = 0, len = 0;
537 	unsigned int csum = 0;
538 	const unsigned char *ptr;
539 	bool dot_present = true;
540 
541 	p = longname;
542 	if ((*p == '.') || (!(strcmp(p, "..")))) {
543 		/*no mangling required */
544 		return 0;
545 	}
546 
547 	p = strrchr(longname, '.');
548 	if (p == longname) { /*name starts with a dot*/
549 		strscpy(extension, "___", sizeof(extension));
550 	} else {
551 		if (p) {
552 			p++;
553 			while (*p && extlen < 3) {
554 				if (*p != '.')
555 					extension[extlen++] = toupper(*p);
556 				p++;
557 			}
558 			extension[extlen] = '\0';
559 		} else {
560 			dot_present = false;
561 		}
562 	}
563 
564 	p = longname;
565 	if (*p == '.') {
566 		p++;
567 		longname++;
568 	}
569 	while (*p && (baselen < 5)) {
570 		if (*p != '.')
571 			base[baselen++] = toupper(*p);
572 		p++;
573 	}
574 
575 	base[baselen] = MAGIC_CHAR;
576 	memcpy(out, base, baselen + 1);
577 
578 	ptr = longname;
579 	len = strlen(longname);
580 	for (; len > 0; len--, ptr++)
581 		csum += *ptr;
582 
583 	csum = csum % (MANGLE_BASE * MANGLE_BASE);
584 	out[baselen + 1] = mangle(csum / MANGLE_BASE);
585 	out[baselen + 2] = mangle(csum);
586 	out[baselen + 3] = PERIOD;
587 
588 	if (dot_present)
589 		memcpy(out + baselen + 4, extension, 4);
590 	else
591 		out[baselen + 4] = '\0';
592 	smbConvertToUTF16((__le16 *)shortname, out, PATH_MAX,
593 			  conn->local_nls, 0);
594 	len = strlen(out) * 2;
595 	return len;
596 }
597 
598 static int __smb2_negotiate(struct ksmbd_conn *conn)
599 {
600 	return (conn->dialect >= SMB20_PROT_ID &&
601 		conn->dialect <= SMB311_PROT_ID);
602 }
603 
604 static int smb_handle_negotiate(struct ksmbd_work *work)
605 {
606 	struct smb_negotiate_rsp *neg_rsp = smb_get_msg(work->response_buf);
607 
608 	ksmbd_debug(SMB, "Unsupported SMB1 protocol\n");
609 
610 	if (ksmbd_iov_pin_rsp(work, (void *)neg_rsp,
611 			      sizeof(struct smb_negotiate_rsp)))
612 		return -ENOMEM;
613 
614 	neg_rsp->hdr.Status.CifsError = STATUS_SUCCESS;
615 	neg_rsp->hdr.WordCount = 1;
616 	neg_rsp->DialectIndex = cpu_to_le16(work->conn->dialect);
617 	neg_rsp->ByteCount = 0;
618 	return 0;
619 }
620 
621 int ksmbd_smb_negotiate_common(struct ksmbd_work *work, unsigned int command)
622 {
623 	struct ksmbd_conn *conn = work->conn;
624 	int ret;
625 
626 	if (command == SMB2_NEGOTIATE_HE) {
627 		/*
628 		 * An SMB2 NEGOTIATE is valid for a new connection, or after an
629 		 * SMB1 multi-protocol negotiate has selected SMB2. Do not allow
630 		 * a second SMB2 NEGOTIATE to replace connection-wide state
631 		 * while a session setup is pending. KSMBD_SESS_NEED_RECONNECT
632 		 * is a transient session state and does not restart transport
633 		 * negotiation.
634 		 */
635 		ksmbd_conn_lock(conn);
636 		if (!ksmbd_conn_new(conn) &&
637 		    !ksmbd_conn_need_negotiate(conn)) {
638 			work->send_no_response = 1;
639 			ksmbd_conn_set_exiting(conn);
640 			ksmbd_conn_unlock(conn);
641 			return 0;
642 		}
643 
644 		conn->dialect =
645 			ksmbd_negotiate_smb_dialect(work->request_buf);
646 		ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
647 		ret = smb2_handle_negotiate(work);
648 		ksmbd_conn_unlock(conn);
649 		return ret;
650 	}
651 
652 	if (command == SMB_COM_NEGOTIATE) {
653 		ksmbd_conn_lock(conn);
654 		conn->dialect =
655 			ksmbd_negotiate_smb_dialect(work->request_buf);
656 		ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
657 		if (__smb2_negotiate(conn)) {
658 			init_smb3_11_server(conn);
659 			ret = init_smb2_neg_rsp(work);
660 			ksmbd_debug(SMB, "Upgrade to SMB2 negotiation\n");
661 		} else {
662 			ret = smb_handle_negotiate(work);
663 		}
664 		ksmbd_conn_unlock(conn);
665 		return ret;
666 	}
667 
668 	pr_err("Unknown SMB negotiation command: %u\n", command);
669 	return -EINVAL;
670 }
671 
672 enum SHARED_MODE_ERRORS {
673 	SHARE_DELETE_ERROR,
674 	SHARE_READ_ERROR,
675 	SHARE_WRITE_ERROR,
676 	FILE_READ_ERROR,
677 	FILE_WRITE_ERROR,
678 	FILE_DELETE_ERROR,
679 };
680 
681 static const char * const shared_mode_errors[] = {
682 	"Current access mode does not permit SHARE_DELETE",
683 	"Current access mode does not permit SHARE_READ",
684 	"Current access mode does not permit SHARE_WRITE",
685 	"Desired access mode does not permit FILE_READ",
686 	"Desired access mode does not permit FILE_WRITE",
687 	"Desired access mode does not permit FILE_DELETE",
688 };
689 
690 static void smb_shared_mode_error(int error, struct ksmbd_file *prev_fp,
691 				  struct ksmbd_file *curr_fp)
692 {
693 	ksmbd_debug(SMB, "%s\n", shared_mode_errors[error]);
694 	ksmbd_debug(SMB, "Current mode: 0x%x Desired mode: 0x%x\n",
695 		    prev_fp->saccess, curr_fp->daccess);
696 }
697 
698 int ksmbd_smb_check_shared_mode(struct file *filp, struct ksmbd_file *curr_fp)
699 {
700 	int rc = 0;
701 	struct ksmbd_file *prev_fp;
702 
703 	/*
704 	 * Lookup fp in master fp list, and check desired access and
705 	 * shared mode between previous open and current open.
706 	 */
707 	down_read(&curr_fp->f_ci->m_lock);
708 	list_for_each_entry(prev_fp, &curr_fp->f_ci->m_fp_list, node) {
709 		if (file_inode(filp) != file_inode(prev_fp->filp))
710 			continue;
711 
712 		if (filp == prev_fp->filp)
713 			continue;
714 
715 		if (ksmbd_stream_fd(prev_fp) && ksmbd_stream_fd(curr_fp))
716 			if (strcmp(prev_fp->stream.name, curr_fp->stream.name))
717 				continue;
718 
719 		if (prev_fp->attrib_only != curr_fp->attrib_only)
720 			continue;
721 
722 		if (!(prev_fp->saccess & FILE_SHARE_DELETE_LE) &&
723 		    curr_fp->daccess & FILE_DELETE_LE) {
724 			smb_shared_mode_error(SHARE_DELETE_ERROR,
725 					      prev_fp,
726 					      curr_fp);
727 			rc = -EPERM;
728 			break;
729 		}
730 
731 		/*
732 		 * Only check FILE_SHARE_DELETE if stream opened and
733 		 * normal file opened.
734 		 */
735 		if (ksmbd_stream_fd(prev_fp) && !ksmbd_stream_fd(curr_fp))
736 			continue;
737 
738 		if (!(prev_fp->saccess & FILE_SHARE_READ_LE) &&
739 		    curr_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE)) {
740 			smb_shared_mode_error(SHARE_READ_ERROR,
741 					      prev_fp,
742 					      curr_fp);
743 			rc = -EPERM;
744 			break;
745 		}
746 
747 		if (!(prev_fp->saccess & FILE_SHARE_WRITE_LE) &&
748 		    curr_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE)) {
749 			smb_shared_mode_error(SHARE_WRITE_ERROR,
750 					      prev_fp,
751 					      curr_fp);
752 			rc = -EPERM;
753 			break;
754 		}
755 
756 		if (prev_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE) &&
757 		    !(curr_fp->saccess & FILE_SHARE_READ_LE)) {
758 			smb_shared_mode_error(FILE_READ_ERROR,
759 					      prev_fp,
760 					      curr_fp);
761 			rc = -EPERM;
762 			break;
763 		}
764 
765 		if (prev_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE) &&
766 		    !(curr_fp->saccess & FILE_SHARE_WRITE_LE)) {
767 			smb_shared_mode_error(FILE_WRITE_ERROR,
768 					      prev_fp,
769 					      curr_fp);
770 			rc = -EPERM;
771 			break;
772 		}
773 
774 		if (prev_fp->daccess & FILE_DELETE_LE &&
775 		    !(curr_fp->saccess & FILE_SHARE_DELETE_LE)) {
776 			smb_shared_mode_error(FILE_DELETE_ERROR,
777 					      prev_fp,
778 					      curr_fp);
779 			rc = -EPERM;
780 			break;
781 		}
782 	}
783 	up_read(&curr_fp->f_ci->m_lock);
784 
785 	return rc;
786 }
787 
788 bool is_asterisk(char *p)
789 {
790 	return p && p[0] == '*';
791 }
792 
793 int __ksmbd_override_fsids(struct ksmbd_work *work,
794 		struct ksmbd_share_config *share)
795 {
796 	struct ksmbd_session *sess = work->sess;
797 	struct ksmbd_user *user = sess->user;
798 	struct cred *cred;
799 	struct group_info *gi;
800 	unsigned int uid;
801 	unsigned int gid;
802 	int i;
803 
804 	uid = user_uid(user);
805 	gid = user_gid(user);
806 	if (share->force_uid != KSMBD_SHARE_INVALID_UID)
807 		uid = share->force_uid;
808 	if (share->force_gid != KSMBD_SHARE_INVALID_GID)
809 		gid = share->force_gid;
810 
811 	cred = prepare_kernel_cred(&init_task);
812 	if (!cred)
813 		return -ENOMEM;
814 
815 	cred->fsuid = make_kuid(&init_user_ns, uid);
816 	cred->fsgid = make_kgid(&init_user_ns, gid);
817 
818 	gi = groups_alloc(user->ngroups);
819 	if (!gi) {
820 		abort_creds(cred);
821 		return -ENOMEM;
822 	}
823 
824 	for (i = 0; i < user->ngroups; i++)
825 		gi->gid[i] = make_kgid(&init_user_ns, user->sgid[i]);
826 
827 	if (user->ngroups)
828 		groups_sort(gi);
829 
830 	set_groups(cred, gi);
831 	put_group_info(gi);
832 
833 	if (!uid_eq(cred->fsuid, GLOBAL_ROOT_UID))
834 		cred->cap_effective = cap_drop_fs_set(cred->cap_effective);
835 
836 	WARN_ON(work->saved_cred);
837 	work->saved_cred = override_creds(cred);
838 	return 0;
839 }
840 
841 int ksmbd_override_fsids(struct ksmbd_work *work)
842 {
843 	return __ksmbd_override_fsids(work, work->tcon->share_conf);
844 }
845 
846 void ksmbd_revert_fsids(struct ksmbd_work *work)
847 {
848 	const struct cred *cred;
849 	WARN_ON(!work->saved_cred);
850 
851 	cred = revert_creds(work->saved_cred);
852 	work->saved_cred = NULL;
853 	put_cred(cred);
854 }
855 
856 __le32 smb_map_generic_desired_access(__le32 daccess)
857 {
858 	if (daccess & FILE_GENERIC_READ_LE) {
859 		daccess |= cpu_to_le32(GENERIC_READ_FLAGS);
860 		daccess &= ~FILE_GENERIC_READ_LE;
861 	}
862 
863 	if (daccess & FILE_GENERIC_WRITE_LE) {
864 		daccess |= cpu_to_le32(GENERIC_WRITE_FLAGS);
865 		daccess &= ~FILE_GENERIC_WRITE_LE;
866 	}
867 
868 	if (daccess & FILE_GENERIC_EXECUTE_LE) {
869 		daccess |= cpu_to_le32(GENERIC_EXECUTE_FLAGS);
870 		daccess &= ~FILE_GENERIC_EXECUTE_LE;
871 	}
872 
873 	if (daccess & FILE_GENERIC_ALL_LE) {
874 		daccess |= cpu_to_le32(GENERIC_ALL_FLAGS);
875 		daccess &= ~FILE_GENERIC_ALL_LE;
876 	}
877 
878 	return daccess;
879 }
880