xref: /linux/fs/smb/server/smb_common.c (revision ba23adb6533149df33b9a247f31a87227b3c86d5)
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 
ksmbd_server_side_copy_max_chunk_count(void)76 unsigned int ksmbd_server_side_copy_max_chunk_count(void)
77 {
78 	return 256;
79 }
80 
ksmbd_server_side_copy_max_chunk_size(void)81 unsigned int ksmbd_server_side_copy_max_chunk_size(void)
82 {
83 	return (2U << 30) - 1;
84 }
85 
ksmbd_server_side_copy_max_total_size(void)86 unsigned int ksmbd_server_side_copy_max_total_size(void)
87 {
88 	return (2U << 30) - 1;
89 }
90 
ksmbd_min_protocol(void)91 inline int ksmbd_min_protocol(void)
92 {
93 	return SMB21_PROT;
94 }
95 
ksmbd_max_protocol(void)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 #ifdef CONFIG_SMB_INSECURE_SERVER
106 	{SMB1_PROT, SMB1_VERSION_STRING},
107 #endif
108 	{SMB2_PROT, SMB20_VERSION_STRING},
109 	{SMB21_PROT, SMB21_VERSION_STRING},
110 	{SMB30_PROT, SMB30_VERSION_STRING},
111 	{SMB302_PROT, SMB302_VERSION_STRING},
112 	{SMB311_PROT, SMB311_VERSION_STRING},
113 };
114 
ksmbd_get_protocol_string(int version)115 const char *ksmbd_get_protocol_string(int version)
116 {
117 	int i;
118 
119 	for (i = 0; i < ARRAY_SIZE(version_strings); i++) {
120 		if (version_strings[i].version == version)
121 			return version_strings[i].string;
122 	}
123 	return "";
124 }
ksmbd_lookup_protocol_idx(char * str)125 int ksmbd_lookup_protocol_idx(char *str)
126 {
127 	int offt = ARRAY_SIZE(smb1_protos) - 1;
128 	int len = strlen(str);
129 
130 	while (offt >= 0) {
131 		if (!strncmp(str, smb1_protos[offt].prot, len)) {
132 			ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
133 				    smb1_protos[offt].prot, offt);
134 			return smb1_protos[offt].index;
135 		}
136 		offt--;
137 	}
138 
139 	offt = ARRAY_SIZE(smb2_protos) - 1;
140 	while (offt >= 0) {
141 		if (!strncmp(str, smb2_protos[offt].prot, len)) {
142 			ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
143 				    smb2_protos[offt].prot, offt);
144 			return smb2_protos[offt].index;
145 		}
146 		offt--;
147 	}
148 	return -1;
149 }
150 
151 /**
152  * ksmbd_verify_smb_message() - check for valid smb2 request header
153  * @work:	smb work
154  *
155  * check for valid smb signature and packet direction(request/response)
156  *
157  * Return:      0 on success, otherwise -EINVAL
158  */
ksmbd_verify_smb_message(struct ksmbd_work * work)159 int ksmbd_verify_smb_message(struct ksmbd_work *work)
160 {
161 	struct smb2_hdr *smb2_hdr = ksmbd_req_buf_next(work);
162 	struct smb_hdr *hdr;
163 
164 	if (smb2_hdr->ProtocolId == SMB2_PROTO_NUMBER)
165 		return ksmbd_smb2_check_message(work);
166 
167 	hdr = smb_get_msg(work->request_buf);
168 	if (*(__le32 *)hdr->Protocol == SMB1_PROTO_NUMBER &&
169 	    hdr->Command == SMB_COM_NEGOTIATE) {
170 		work->conn->outstanding_credits++;
171 		return 0;
172 	}
173 
174 	return -EINVAL;
175 }
176 
177 /**
178  * ksmbd_smb_request() - check for valid smb request type
179  * @conn:	connection instance
180  *
181  * Return:      true on success, otherwise false
182  */
ksmbd_smb_request(struct ksmbd_conn * conn)183 bool ksmbd_smb_request(struct ksmbd_conn *conn)
184 {
185 	__le32 *proto;
186 
187 	if (conn->request_buf[0] != 0)
188 		return false;
189 
190 	proto = (__le32 *)smb_get_msg(conn->request_buf);
191 	if (*proto == SMB2_COMPRESSION_TRANSFORM_ID) {
192 		pr_err_ratelimited("smb2 compression not support yet");
193 		return false;
194 	}
195 
196 	if (*proto != SMB1_PROTO_NUMBER &&
197 	    *proto != SMB2_PROTO_NUMBER &&
198 	    *proto != SMB2_TRANSFORM_PROTO_NUM)
199 		return false;
200 
201 	return true;
202 }
203 
supported_protocol(int idx)204 static bool supported_protocol(int idx)
205 {
206 	if (idx == SMB2X_PROT &&
207 	    (server_conf.min_protocol >= SMB21_PROT ||
208 	     server_conf.max_protocol <= SMB311_PROT))
209 		return true;
210 
211 	return (server_conf.min_protocol <= idx &&
212 		idx <= server_conf.max_protocol);
213 }
214 
next_dialect(char * dialect,int * next_off,int bcount)215 static char *next_dialect(char *dialect, int *next_off, int bcount)
216 {
217 	dialect = dialect + *next_off;
218 	*next_off = strnlen(dialect, bcount);
219 	if (dialect[*next_off] != '\0')
220 		return NULL;
221 	return dialect;
222 }
223 
ksmbd_lookup_dialect_by_name(char * cli_dialects,__le16 byte_count)224 static int ksmbd_lookup_dialect_by_name(char *cli_dialects, __le16 byte_count)
225 {
226 	int i, seq_num, bcount, next;
227 	char *dialect;
228 
229 	for (i = ARRAY_SIZE(smb1_protos) - 1; i >= 0; i--) {
230 		seq_num = 0;
231 		next = 0;
232 		dialect = cli_dialects;
233 		bcount = le16_to_cpu(byte_count);
234 		do {
235 			dialect = next_dialect(dialect, &next, bcount);
236 			if (!dialect)
237 				break;
238 			ksmbd_debug(SMB, "client requested dialect %s\n",
239 				    dialect);
240 			if (!strcmp(dialect, smb1_protos[i].name)) {
241 				if (supported_protocol(smb1_protos[i].index)) {
242 					ksmbd_debug(SMB,
243 						    "selected %s dialect\n",
244 						    smb1_protos[i].name);
245 					if (smb1_protos[i].index == SMB1_PROT)
246 						return seq_num;
247 					return smb1_protos[i].prot_id;
248 				}
249 			}
250 			seq_num++;
251 			bcount -= (++next);
252 		} while (bcount > 0);
253 	}
254 
255 	return BAD_PROT_ID;
256 }
257 
ksmbd_lookup_dialect_by_id(__le16 * cli_dialects,__le16 dialects_count)258 int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count)
259 {
260 	int i;
261 	int count;
262 
263 	for (i = ARRAY_SIZE(smb2_protos) - 1; i >= 0; i--) {
264 		count = le16_to_cpu(dialects_count);
265 		while (--count >= 0) {
266 			ksmbd_debug(SMB, "client requested dialect 0x%x\n",
267 				    le16_to_cpu(cli_dialects[count]));
268 			if (le16_to_cpu(cli_dialects[count]) !=
269 					smb2_protos[i].prot_id)
270 				continue;
271 
272 			if (supported_protocol(smb2_protos[i].index)) {
273 				ksmbd_debug(SMB, "selected %s dialect\n",
274 					    smb2_protos[i].name);
275 				return smb2_protos[i].prot_id;
276 			}
277 		}
278 	}
279 
280 	return BAD_PROT_ID;
281 }
282 
ksmbd_negotiate_smb_dialect(void * buf)283 static int ksmbd_negotiate_smb_dialect(void *buf)
284 {
285 	int smb_buf_length = get_rfc1002_len(buf);
286 	__le32 proto = ((struct smb2_hdr *)smb_get_msg(buf))->ProtocolId;
287 
288 	if (proto == SMB2_PROTO_NUMBER) {
289 		struct smb2_negotiate_req *req;
290 		int smb2_neg_size =
291 			offsetof(struct smb2_negotiate_req, Dialects);
292 
293 		req = (struct smb2_negotiate_req *)smb_get_msg(buf);
294 		if (smb2_neg_size > smb_buf_length)
295 			goto err_out;
296 
297 		if (struct_size(req, Dialects, le16_to_cpu(req->DialectCount)) >
298 		    smb_buf_length)
299 			goto err_out;
300 
301 		return ksmbd_lookup_dialect_by_id(req->Dialects,
302 						  req->DialectCount);
303 	}
304 
305 	if (proto == SMB1_PROTO_NUMBER) {
306 		struct smb_negotiate_req *req;
307 
308 		req = (struct smb_negotiate_req *)smb_get_msg(buf);
309 		if (le16_to_cpu(req->ByteCount) < 2)
310 			goto err_out;
311 
312 		if (offsetof(struct smb_negotiate_req, DialectsArray) +
313 			le16_to_cpu(req->ByteCount) > smb_buf_length) {
314 			goto err_out;
315 		}
316 
317 		return ksmbd_lookup_dialect_by_name(req->DialectsArray,
318 						    req->ByteCount);
319 	}
320 
321 err_out:
322 	return BAD_PROT_ID;
323 }
324 
325 #define SMB_COM_NEGOTIATE_EX	0x0
326 
327 /**
328  * get_smb1_cmd_val() - get smb command value from smb header
329  * @work:	smb work containing smb header
330  *
331  * Return:      smb command value
332  */
get_smb1_cmd_val(struct ksmbd_work * work)333 static u16 get_smb1_cmd_val(struct ksmbd_work *work)
334 {
335 	return SMB_COM_NEGOTIATE_EX;
336 }
337 
338 /**
339  * init_smb1_rsp_hdr() - initialize smb negotiate response header
340  * @work:	smb work containing smb request
341  *
342  * Return:      0 on success, otherwise -EINVAL
343  */
init_smb1_rsp_hdr(struct ksmbd_work * work)344 static int init_smb1_rsp_hdr(struct ksmbd_work *work)
345 {
346 	struct smb_hdr *rsp_hdr = (struct smb_hdr *)smb_get_msg(work->response_buf);
347 	struct smb_hdr *rcv_hdr = (struct smb_hdr *)smb_get_msg(work->request_buf);
348 
349 	rsp_hdr->Command = SMB_COM_NEGOTIATE;
350 	*(__le32 *)rsp_hdr->Protocol = SMB1_PROTO_NUMBER;
351 	rsp_hdr->Flags = SMBFLG_RESPONSE;
352 	rsp_hdr->Flags2 = SMBFLG2_UNICODE | SMBFLG2_ERR_STATUS |
353 		SMBFLG2_EXT_SEC | SMBFLG2_IS_LONG_NAME;
354 	rsp_hdr->Pid = rcv_hdr->Pid;
355 	rsp_hdr->Mid = rcv_hdr->Mid;
356 	return 0;
357 }
358 
359 /**
360  * smb1_check_user_session() - check for valid session for a user
361  * @work:	smb work containing smb request buffer
362  *
363  * Return:      0 on success, otherwise error
364  */
smb1_check_user_session(struct ksmbd_work * work)365 static int smb1_check_user_session(struct ksmbd_work *work)
366 {
367 	unsigned int cmd = work->conn->ops->get_cmd_val(work);
368 
369 	if (cmd == SMB_COM_NEGOTIATE_EX)
370 		return 0;
371 
372 	return -EINVAL;
373 }
374 
375 /**
376  * smb1_allocate_rsp_buf() - allocate response buffer for a command
377  * @work:	smb work containing smb request
378  *
379  * Return:      0 on success, otherwise -ENOMEM
380  */
smb1_allocate_rsp_buf(struct ksmbd_work * work)381 static int smb1_allocate_rsp_buf(struct ksmbd_work *work)
382 {
383 	work->response_buf = kzalloc(MAX_CIFS_SMALL_BUFFER_SIZE,
384 			KSMBD_DEFAULT_GFP);
385 	work->response_sz = MAX_CIFS_SMALL_BUFFER_SIZE;
386 
387 	if (!work->response_buf) {
388 		pr_err("Failed to allocate %u bytes buffer\n",
389 				MAX_CIFS_SMALL_BUFFER_SIZE);
390 		return -ENOMEM;
391 	}
392 
393 	return 0;
394 }
395 
396 /**
397  * set_smb1_rsp_status() - set error type in smb response header
398  * @work:	smb work containing smb response header
399  * @err:	error code to set in response
400  */
set_smb1_rsp_status(struct ksmbd_work * work,__le32 err)401 static void set_smb1_rsp_status(struct ksmbd_work *work, __le32 err)
402 {
403 	work->send_no_response = 1;
404 }
405 
406 static struct smb_version_ops smb1_server_ops = {
407 	.get_cmd_val = get_smb1_cmd_val,
408 	.init_rsp_hdr = init_smb1_rsp_hdr,
409 	.allocate_rsp_buf = smb1_allocate_rsp_buf,
410 	.check_user_session = smb1_check_user_session,
411 	.set_rsp_status = set_smb1_rsp_status,
412 };
413 
414 static struct smb_version_values smb1_server_values = {
415 	.max_credits = SMB2_MAX_CREDITS,
416 };
417 
smb1_negotiate(struct ksmbd_work * work)418 static int smb1_negotiate(struct ksmbd_work *work)
419 {
420 	return ksmbd_smb_negotiate_common(work, SMB_COM_NEGOTIATE);
421 }
422 
423 static struct smb_version_cmds smb1_server_cmds[1] = {
424 	[SMB_COM_NEGOTIATE_EX]	= { .proc = smb1_negotiate, },
425 };
426 
init_smb1_server(struct ksmbd_conn * conn)427 static int init_smb1_server(struct ksmbd_conn *conn)
428 {
429 	conn->vals = &smb1_server_values;
430 	conn->ops = &smb1_server_ops;
431 	conn->cmds = smb1_server_cmds;
432 	conn->max_cmds = ARRAY_SIZE(smb1_server_cmds);
433 	return 0;
434 }
435 
ksmbd_init_smb_server(struct ksmbd_conn * conn)436 int ksmbd_init_smb_server(struct ksmbd_conn *conn)
437 {
438 	struct smb_hdr *rcv_hdr = (struct smb_hdr *)smb_get_msg(conn->request_buf);
439 	__le32 proto;
440 
441 	proto = *(__le32 *)rcv_hdr->Protocol;
442 	if (conn->need_neg == false) {
443 		if (proto == SMB1_PROTO_NUMBER)
444 			return -EINVAL;
445 		return 0;
446 	}
447 
448 	if (proto == SMB1_PROTO_NUMBER)
449 		return init_smb1_server(conn);
450 	return init_smb3_11_server(conn);
451 }
452 
ksmbd_populate_dot_dotdot_entries(struct ksmbd_work * work,int info_level,struct ksmbd_file * dir,struct ksmbd_dir_info * d_info,char * search_pattern,int (* fn)(struct ksmbd_conn *,int,struct ksmbd_dir_info *,struct ksmbd_kstat *))453 int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work, int info_level,
454 				      struct ksmbd_file *dir,
455 				      struct ksmbd_dir_info *d_info,
456 				      char *search_pattern,
457 				      int (*fn)(struct ksmbd_conn *, int,
458 						struct ksmbd_dir_info *,
459 						struct ksmbd_kstat *))
460 {
461 	int i, rc = 0;
462 	struct ksmbd_conn *conn = work->conn;
463 	struct mnt_idmap *idmap = file_mnt_idmap(dir->filp);
464 
465 	for (i = 0; i < 2; i++) {
466 		struct kstat kstat;
467 		struct ksmbd_kstat ksmbd_kstat;
468 		struct dentry *dentry;
469 
470 		if (!dir->dot_dotdot[i]) { /* fill dot entry info */
471 			if (i == 0) {
472 				d_info->name = ".";
473 				d_info->name_len = 1;
474 				dentry = dir->filp->f_path.dentry;
475 			} else {
476 				d_info->name = "..";
477 				d_info->name_len = 2;
478 				dentry = dir->filp->f_path.dentry->d_parent;
479 			}
480 
481 			if (!match_pattern(d_info->name, d_info->name_len,
482 					   search_pattern)) {
483 				dir->dot_dotdot[i] = 1;
484 				continue;
485 			}
486 
487 			ksmbd_kstat.kstat = &kstat;
488 			rc = ksmbd_vfs_fill_dentry_attrs(work,
489 							 idmap,
490 							 dentry,
491 							 &ksmbd_kstat);
492 			if (rc)
493 				break;
494 
495 			rc = fn(conn, info_level, d_info, &ksmbd_kstat);
496 			if (rc)
497 				break;
498 			if (d_info->out_buf_len <= 0)
499 				break;
500 
501 			dir->dot_dotdot[i] = 1;
502 			if (d_info->flags & SMB2_RETURN_SINGLE_ENTRY) {
503 				d_info->out_buf_len = 0;
504 				break;
505 			}
506 		}
507 	}
508 
509 	return rc;
510 }
511 
512 /**
513  * ksmbd_extract_shortname() - get shortname from long filename
514  * @conn:	connection instance
515  * @longname:	source long filename
516  * @shortname:	destination short filename
517  *
518  * Return:	shortname length or 0 when source long name is '.' or '..'
519  * TODO: Though this function conforms the restriction of 8.3 Filename spec,
520  * but the result is different with Windows 7's one. need to check.
521  */
ksmbd_extract_shortname(struct ksmbd_conn * conn,const char * longname,char * shortname)522 int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname,
523 			    char *shortname)
524 {
525 	const char *p;
526 	char base[9], extension[4];
527 	char out[13] = {0};
528 	int baselen = 0;
529 	int extlen = 0, len = 0;
530 	unsigned int csum = 0;
531 	const unsigned char *ptr;
532 	bool dot_present = true;
533 
534 	p = longname;
535 	if ((*p == '.') || (!(strcmp(p, "..")))) {
536 		/*no mangling required */
537 		return 0;
538 	}
539 
540 	p = strrchr(longname, '.');
541 	if (p == longname) { /*name starts with a dot*/
542 		strscpy(extension, "___", sizeof(extension));
543 	} else {
544 		if (p) {
545 			p++;
546 			while (*p && extlen < 3) {
547 				if (*p != '.')
548 					extension[extlen++] = toupper(*p);
549 				p++;
550 			}
551 			extension[extlen] = '\0';
552 		} else {
553 			dot_present = false;
554 		}
555 	}
556 
557 	p = longname;
558 	if (*p == '.') {
559 		p++;
560 		longname++;
561 	}
562 	while (*p && (baselen < 5)) {
563 		if (*p != '.')
564 			base[baselen++] = toupper(*p);
565 		p++;
566 	}
567 
568 	base[baselen] = MAGIC_CHAR;
569 	memcpy(out, base, baselen + 1);
570 
571 	ptr = longname;
572 	len = strlen(longname);
573 	for (; len > 0; len--, ptr++)
574 		csum += *ptr;
575 
576 	csum = csum % (MANGLE_BASE * MANGLE_BASE);
577 	out[baselen + 1] = mangle(csum / MANGLE_BASE);
578 	out[baselen + 2] = mangle(csum);
579 	out[baselen + 3] = PERIOD;
580 
581 	if (dot_present)
582 		memcpy(out + baselen + 4, extension, 4);
583 	else
584 		out[baselen + 4] = '\0';
585 	smbConvertToUTF16((__le16 *)shortname, out, PATH_MAX,
586 			  conn->local_nls, 0);
587 	len = strlen(out) * 2;
588 	return len;
589 }
590 
__smb2_negotiate(struct ksmbd_conn * conn)591 static int __smb2_negotiate(struct ksmbd_conn *conn)
592 {
593 	return (conn->dialect >= SMB20_PROT_ID &&
594 		conn->dialect <= SMB311_PROT_ID);
595 }
596 
smb_handle_negotiate(struct ksmbd_work * work)597 static int smb_handle_negotiate(struct ksmbd_work *work)
598 {
599 	struct smb_negotiate_rsp *neg_rsp = smb_get_msg(work->response_buf);
600 
601 	ksmbd_debug(SMB, "Unsupported SMB1 protocol\n");
602 
603 	if (ksmbd_iov_pin_rsp(work, (void *)neg_rsp,
604 			      sizeof(struct smb_negotiate_rsp)))
605 		return -ENOMEM;
606 
607 	neg_rsp->hdr.Status.CifsError = STATUS_SUCCESS;
608 	neg_rsp->hdr.WordCount = 1;
609 	neg_rsp->DialectIndex = cpu_to_le16(work->conn->dialect);
610 	neg_rsp->ByteCount = 0;
611 	return 0;
612 }
613 
ksmbd_smb_negotiate_common(struct ksmbd_work * work,unsigned int command)614 int ksmbd_smb_negotiate_common(struct ksmbd_work *work, unsigned int command)
615 {
616 	struct ksmbd_conn *conn = work->conn;
617 	int ret;
618 
619 	conn->dialect =
620 		ksmbd_negotiate_smb_dialect(work->request_buf);
621 	ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
622 
623 	if (command == SMB2_NEGOTIATE_HE) {
624 		ret = smb2_handle_negotiate(work);
625 		return ret;
626 	}
627 
628 	if (command == SMB_COM_NEGOTIATE) {
629 		if (__smb2_negotiate(conn)) {
630 			init_smb3_11_server(conn);
631 			init_smb2_neg_rsp(work);
632 			ksmbd_debug(SMB, "Upgrade to SMB2 negotiation\n");
633 			return 0;
634 		}
635 		return smb_handle_negotiate(work);
636 	}
637 
638 	pr_err("Unknown SMB negotiation command: %u\n", command);
639 	return -EINVAL;
640 }
641 
642 enum SHARED_MODE_ERRORS {
643 	SHARE_DELETE_ERROR,
644 	SHARE_READ_ERROR,
645 	SHARE_WRITE_ERROR,
646 	FILE_READ_ERROR,
647 	FILE_WRITE_ERROR,
648 	FILE_DELETE_ERROR,
649 };
650 
651 static const char * const shared_mode_errors[] = {
652 	"Current access mode does not permit SHARE_DELETE",
653 	"Current access mode does not permit SHARE_READ",
654 	"Current access mode does not permit SHARE_WRITE",
655 	"Desired access mode does not permit FILE_READ",
656 	"Desired access mode does not permit FILE_WRITE",
657 	"Desired access mode does not permit FILE_DELETE",
658 };
659 
smb_shared_mode_error(int error,struct ksmbd_file * prev_fp,struct ksmbd_file * curr_fp)660 static void smb_shared_mode_error(int error, struct ksmbd_file *prev_fp,
661 				  struct ksmbd_file *curr_fp)
662 {
663 	ksmbd_debug(SMB, "%s\n", shared_mode_errors[error]);
664 	ksmbd_debug(SMB, "Current mode: 0x%x Desired mode: 0x%x\n",
665 		    prev_fp->saccess, curr_fp->daccess);
666 }
667 
ksmbd_smb_check_shared_mode(struct file * filp,struct ksmbd_file * curr_fp)668 int ksmbd_smb_check_shared_mode(struct file *filp, struct ksmbd_file *curr_fp)
669 {
670 	int rc = 0;
671 	struct ksmbd_file *prev_fp;
672 
673 	/*
674 	 * Lookup fp in master fp list, and check desired access and
675 	 * shared mode between previous open and current open.
676 	 */
677 	down_read(&curr_fp->f_ci->m_lock);
678 	list_for_each_entry(prev_fp, &curr_fp->f_ci->m_fp_list, node) {
679 		if (file_inode(filp) != file_inode(prev_fp->filp))
680 			continue;
681 
682 		if (filp == prev_fp->filp)
683 			continue;
684 
685 		if (ksmbd_stream_fd(prev_fp) && ksmbd_stream_fd(curr_fp))
686 			if (strcmp(prev_fp->stream.name, curr_fp->stream.name))
687 				continue;
688 
689 		if (prev_fp->attrib_only != curr_fp->attrib_only)
690 			continue;
691 
692 		if (!(prev_fp->saccess & FILE_SHARE_DELETE_LE) &&
693 		    curr_fp->daccess & FILE_DELETE_LE) {
694 			smb_shared_mode_error(SHARE_DELETE_ERROR,
695 					      prev_fp,
696 					      curr_fp);
697 			rc = -EPERM;
698 			break;
699 		}
700 
701 		/*
702 		 * Only check FILE_SHARE_DELETE if stream opened and
703 		 * normal file opened.
704 		 */
705 		if (ksmbd_stream_fd(prev_fp) && !ksmbd_stream_fd(curr_fp))
706 			continue;
707 
708 		if (!(prev_fp->saccess & FILE_SHARE_READ_LE) &&
709 		    curr_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE)) {
710 			smb_shared_mode_error(SHARE_READ_ERROR,
711 					      prev_fp,
712 					      curr_fp);
713 			rc = -EPERM;
714 			break;
715 		}
716 
717 		if (!(prev_fp->saccess & FILE_SHARE_WRITE_LE) &&
718 		    curr_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE)) {
719 			smb_shared_mode_error(SHARE_WRITE_ERROR,
720 					      prev_fp,
721 					      curr_fp);
722 			rc = -EPERM;
723 			break;
724 		}
725 
726 		if (prev_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE) &&
727 		    !(curr_fp->saccess & FILE_SHARE_READ_LE)) {
728 			smb_shared_mode_error(FILE_READ_ERROR,
729 					      prev_fp,
730 					      curr_fp);
731 			rc = -EPERM;
732 			break;
733 		}
734 
735 		if (prev_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE) &&
736 		    !(curr_fp->saccess & FILE_SHARE_WRITE_LE)) {
737 			smb_shared_mode_error(FILE_WRITE_ERROR,
738 					      prev_fp,
739 					      curr_fp);
740 			rc = -EPERM;
741 			break;
742 		}
743 
744 		if (prev_fp->daccess & FILE_DELETE_LE &&
745 		    !(curr_fp->saccess & FILE_SHARE_DELETE_LE)) {
746 			smb_shared_mode_error(FILE_DELETE_ERROR,
747 					      prev_fp,
748 					      curr_fp);
749 			rc = -EPERM;
750 			break;
751 		}
752 	}
753 	up_read(&curr_fp->f_ci->m_lock);
754 
755 	return rc;
756 }
757 
is_asterisk(char * p)758 bool is_asterisk(char *p)
759 {
760 	return p && p[0] == '*';
761 }
762 
__ksmbd_override_fsids(struct ksmbd_work * work,struct ksmbd_share_config * share)763 int __ksmbd_override_fsids(struct ksmbd_work *work,
764 		struct ksmbd_share_config *share)
765 {
766 	struct ksmbd_session *sess = work->sess;
767 	struct ksmbd_user *user = sess->user;
768 	struct cred *cred;
769 	struct group_info *gi;
770 	unsigned int uid;
771 	unsigned int gid;
772 	int i;
773 
774 	uid = user_uid(user);
775 	gid = user_gid(user);
776 	if (share->force_uid != KSMBD_SHARE_INVALID_UID)
777 		uid = share->force_uid;
778 	if (share->force_gid != KSMBD_SHARE_INVALID_GID)
779 		gid = share->force_gid;
780 
781 	cred = prepare_kernel_cred(&init_task);
782 	if (!cred)
783 		return -ENOMEM;
784 
785 	cred->fsuid = make_kuid(&init_user_ns, uid);
786 	cred->fsgid = make_kgid(&init_user_ns, gid);
787 
788 	gi = groups_alloc(user->ngroups);
789 	if (!gi) {
790 		abort_creds(cred);
791 		return -ENOMEM;
792 	}
793 
794 	for (i = 0; i < user->ngroups; i++)
795 		gi->gid[i] = make_kgid(&init_user_ns, user->sgid[i]);
796 
797 	if (user->ngroups)
798 		groups_sort(gi);
799 
800 	set_groups(cred, gi);
801 	put_group_info(gi);
802 
803 	if (!uid_eq(cred->fsuid, GLOBAL_ROOT_UID))
804 		cred->cap_effective = cap_drop_fs_set(cred->cap_effective);
805 
806 	WARN_ON(work->saved_cred);
807 	work->saved_cred = override_creds(cred);
808 	return 0;
809 }
810 
ksmbd_override_fsids(struct ksmbd_work * work)811 int ksmbd_override_fsids(struct ksmbd_work *work)
812 {
813 	return __ksmbd_override_fsids(work, work->tcon->share_conf);
814 }
815 
ksmbd_revert_fsids(struct ksmbd_work * work)816 void ksmbd_revert_fsids(struct ksmbd_work *work)
817 {
818 	const struct cred *cred;
819 	WARN_ON(!work->saved_cred);
820 
821 	cred = revert_creds(work->saved_cred);
822 	work->saved_cred = NULL;
823 	put_cred(cred);
824 }
825 
smb_map_generic_desired_access(__le32 daccess)826 __le32 smb_map_generic_desired_access(__le32 daccess)
827 {
828 	if (daccess & FILE_GENERIC_READ_LE) {
829 		daccess |= cpu_to_le32(GENERIC_READ_FLAGS);
830 		daccess &= ~FILE_GENERIC_READ_LE;
831 	}
832 
833 	if (daccess & FILE_GENERIC_WRITE_LE) {
834 		daccess |= cpu_to_le32(GENERIC_WRITE_FLAGS);
835 		daccess &= ~FILE_GENERIC_WRITE_LE;
836 	}
837 
838 	if (daccess & FILE_GENERIC_EXECUTE_LE) {
839 		daccess |= cpu_to_le32(GENERIC_EXECUTE_FLAGS);
840 		daccess &= ~FILE_GENERIC_EXECUTE_LE;
841 	}
842 
843 	if (daccess & FILE_GENERIC_ALL_LE) {
844 		daccess |= cpu_to_le32(GENERIC_ALL_FLAGS);
845 		daccess &= ~FILE_GENERIC_ALL_LE;
846 	}
847 
848 	return daccess;
849 }
850