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 "smb_common.h"
8 #include "server.h"
9 #include "misc.h"
10 #include "smbstatus.h"
11 #include "connection.h"
12 #include "ksmbd_work.h"
13 #include "mgmt/user_session.h"
14 #include "mgmt/user_config.h"
15 #include "mgmt/tree_connect.h"
16 #include "mgmt/share_config.h"
17
18 /*for shortname implementation */
19 static const char basechars[43] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_-!@#$%";
20 #define MANGLE_BASE (sizeof(basechars) / sizeof(char) - 1)
21 #define MAGIC_CHAR '~'
22 #define PERIOD '.'
23 #define mangle(V) ((char)(basechars[(V) % MANGLE_BASE]))
24
25 struct smb_protocol {
26 int index;
27 char *name;
28 char *prot;
29 __u16 prot_id;
30 };
31
32 static struct smb_protocol smb1_protos[] = {
33 {
34 SMB21_PROT,
35 "\2SMB 2.1",
36 "SMB2_10",
37 SMB21_PROT_ID
38 },
39 {
40 SMB2X_PROT,
41 "\2SMB 2.???",
42 "SMB2_22",
43 SMB2X_PROT_ID
44 },
45 };
46
47 static struct smb_protocol smb2_protos[] = {
48 {
49 SMB21_PROT,
50 "\2SMB 2.1",
51 "SMB2_10",
52 SMB21_PROT_ID
53 },
54 {
55 SMB30_PROT,
56 "\2SMB 3.0",
57 "SMB3_00",
58 SMB30_PROT_ID
59 },
60 {
61 SMB302_PROT,
62 "\2SMB 3.02",
63 "SMB3_02",
64 SMB302_PROT_ID
65 },
66 {
67 SMB311_PROT,
68 "\2SMB 3.1.1",
69 "SMB3_11",
70 SMB311_PROT_ID
71 },
72 };
73
ksmbd_server_side_copy_max_chunk_count(void)74 unsigned int ksmbd_server_side_copy_max_chunk_count(void)
75 {
76 return 256;
77 }
78
ksmbd_server_side_copy_max_chunk_size(void)79 unsigned int ksmbd_server_side_copy_max_chunk_size(void)
80 {
81 return (2U << 30) - 1;
82 }
83
ksmbd_server_side_copy_max_total_size(void)84 unsigned int ksmbd_server_side_copy_max_total_size(void)
85 {
86 return (2U << 30) - 1;
87 }
88
ksmbd_min_protocol(void)89 inline int ksmbd_min_protocol(void)
90 {
91 return SMB21_PROT;
92 }
93
ksmbd_max_protocol(void)94 inline int ksmbd_max_protocol(void)
95 {
96 return SMB311_PROT;
97 }
98
ksmbd_lookup_protocol_idx(char * str)99 int ksmbd_lookup_protocol_idx(char *str)
100 {
101 int offt = ARRAY_SIZE(smb1_protos) - 1;
102 int len = strlen(str);
103
104 while (offt >= 0) {
105 if (!strncmp(str, smb1_protos[offt].prot, len)) {
106 ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
107 smb1_protos[offt].prot, offt);
108 return smb1_protos[offt].index;
109 }
110 offt--;
111 }
112
113 offt = ARRAY_SIZE(smb2_protos) - 1;
114 while (offt >= 0) {
115 if (!strncmp(str, smb2_protos[offt].prot, len)) {
116 ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
117 smb2_protos[offt].prot, offt);
118 return smb2_protos[offt].index;
119 }
120 offt--;
121 }
122 return -1;
123 }
124
125 /**
126 * ksmbd_verify_smb_message() - check for valid smb2 request header
127 * @work: smb work
128 *
129 * check for valid smb signature and packet direction(request/response)
130 *
131 * Return: 0 on success, otherwise -EINVAL
132 */
ksmbd_verify_smb_message(struct ksmbd_work * work)133 int ksmbd_verify_smb_message(struct ksmbd_work *work)
134 {
135 struct smb2_hdr *smb2_hdr = work->request_buf + work->next_smb2_rcv_hdr_off;
136 struct smb_hdr *hdr;
137
138 if (smb2_hdr->ProtocolId == SMB2_PROTO_NUMBER)
139 return ksmbd_smb2_check_message(work);
140
141 hdr = work->request_buf;
142 if (*(__le32 *)hdr->Protocol == SMB1_PROTO_NUMBER &&
143 hdr->Command == SMB_COM_NEGOTIATE)
144 return 0;
145
146 return -EINVAL;
147 }
148
149 /**
150 * ksmbd_smb_request() - check for valid smb request type
151 * @conn: connection instance
152 *
153 * Return: true on success, otherwise false
154 */
ksmbd_smb_request(struct ksmbd_conn * conn)155 bool ksmbd_smb_request(struct ksmbd_conn *conn)
156 {
157 return conn->request_buf[0] == 0;
158 }
159
supported_protocol(int idx)160 static bool supported_protocol(int idx)
161 {
162 if (idx == SMB2X_PROT &&
163 (server_conf.min_protocol >= SMB21_PROT ||
164 server_conf.max_protocol <= SMB311_PROT))
165 return true;
166
167 return (server_conf.min_protocol <= idx &&
168 idx <= server_conf.max_protocol);
169 }
170
next_dialect(char * dialect,int * next_off,int bcount)171 static char *next_dialect(char *dialect, int *next_off, int bcount)
172 {
173 dialect = dialect + *next_off;
174 *next_off = strnlen(dialect, bcount);
175 if (dialect[*next_off] != '\0')
176 return NULL;
177 return dialect;
178 }
179
ksmbd_lookup_dialect_by_name(char * cli_dialects,__le16 byte_count)180 static int ksmbd_lookup_dialect_by_name(char *cli_dialects, __le16 byte_count)
181 {
182 int i, seq_num, bcount, next;
183 char *dialect;
184
185 for (i = ARRAY_SIZE(smb1_protos) - 1; i >= 0; i--) {
186 seq_num = 0;
187 next = 0;
188 dialect = cli_dialects;
189 bcount = le16_to_cpu(byte_count);
190 do {
191 dialect = next_dialect(dialect, &next, bcount);
192 if (!dialect)
193 break;
194 ksmbd_debug(SMB, "client requested dialect %s\n",
195 dialect);
196 if (!strcmp(dialect, smb1_protos[i].name)) {
197 if (supported_protocol(smb1_protos[i].index)) {
198 ksmbd_debug(SMB,
199 "selected %s dialect\n",
200 smb1_protos[i].name);
201 if (smb1_protos[i].index == SMB1_PROT)
202 return seq_num;
203 return smb1_protos[i].prot_id;
204 }
205 }
206 seq_num++;
207 bcount -= (++next);
208 } while (bcount > 0);
209 }
210
211 return BAD_PROT_ID;
212 }
213
ksmbd_lookup_dialect_by_id(__le16 * cli_dialects,__le16 dialects_count)214 int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count)
215 {
216 int i;
217 int count;
218
219 for (i = ARRAY_SIZE(smb2_protos) - 1; i >= 0; i--) {
220 count = le16_to_cpu(dialects_count);
221 while (--count >= 0) {
222 ksmbd_debug(SMB, "client requested dialect 0x%x\n",
223 le16_to_cpu(cli_dialects[count]));
224 if (le16_to_cpu(cli_dialects[count]) !=
225 smb2_protos[i].prot_id)
226 continue;
227
228 if (supported_protocol(smb2_protos[i].index)) {
229 ksmbd_debug(SMB, "selected %s dialect\n",
230 smb2_protos[i].name);
231 return smb2_protos[i].prot_id;
232 }
233 }
234 }
235
236 return BAD_PROT_ID;
237 }
238
ksmbd_negotiate_smb_dialect(void * buf)239 static int ksmbd_negotiate_smb_dialect(void *buf)
240 {
241 int smb_buf_length = get_rfc1002_len(buf);
242 __le32 proto = ((struct smb2_hdr *)buf)->ProtocolId;
243
244 if (proto == SMB2_PROTO_NUMBER) {
245 struct smb2_negotiate_req *req;
246 int smb2_neg_size =
247 offsetof(struct smb2_negotiate_req, Dialects) - 4;
248
249 req = (struct smb2_negotiate_req *)buf;
250 if (smb2_neg_size > smb_buf_length)
251 goto err_out;
252
253 if (smb2_neg_size + le16_to_cpu(req->DialectCount) * sizeof(__le16) >
254 smb_buf_length)
255 goto err_out;
256
257 return ksmbd_lookup_dialect_by_id(req->Dialects,
258 req->DialectCount);
259 }
260
261 proto = *(__le32 *)((struct smb_hdr *)buf)->Protocol;
262 if (proto == SMB1_PROTO_NUMBER) {
263 struct smb_negotiate_req *req;
264
265 req = (struct smb_negotiate_req *)buf;
266 if (le16_to_cpu(req->ByteCount) < 2)
267 goto err_out;
268
269 if (offsetof(struct smb_negotiate_req, DialectsArray) - 4 +
270 le16_to_cpu(req->ByteCount) > smb_buf_length) {
271 goto err_out;
272 }
273
274 return ksmbd_lookup_dialect_by_name(req->DialectsArray,
275 req->ByteCount);
276 }
277
278 err_out:
279 return BAD_PROT_ID;
280 }
281
ksmbd_init_smb_server(struct ksmbd_work * work)282 int ksmbd_init_smb_server(struct ksmbd_work *work)
283 {
284 struct ksmbd_conn *conn = work->conn;
285
286 if (conn->need_neg == false)
287 return 0;
288
289 init_smb3_11_server(conn);
290
291 if (conn->ops->get_cmd_val(work) != SMB_COM_NEGOTIATE)
292 conn->need_neg = false;
293 return 0;
294 }
295
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 *))296 int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work, int info_level,
297 struct ksmbd_file *dir,
298 struct ksmbd_dir_info *d_info,
299 char *search_pattern,
300 int (*fn)(struct ksmbd_conn *, int,
301 struct ksmbd_dir_info *,
302 struct ksmbd_kstat *))
303 {
304 int i, rc = 0;
305 struct ksmbd_conn *conn = work->conn;
306 struct user_namespace *user_ns = file_mnt_user_ns(dir->filp);
307
308 for (i = 0; i < 2; i++) {
309 struct kstat kstat;
310 struct ksmbd_kstat ksmbd_kstat;
311
312 if (!dir->dot_dotdot[i]) { /* fill dot entry info */
313 if (i == 0) {
314 d_info->name = ".";
315 d_info->name_len = 1;
316 } else {
317 d_info->name = "..";
318 d_info->name_len = 2;
319 }
320
321 if (!match_pattern(d_info->name, d_info->name_len,
322 search_pattern)) {
323 dir->dot_dotdot[i] = 1;
324 continue;
325 }
326
327 ksmbd_kstat.kstat = &kstat;
328 ksmbd_vfs_fill_dentry_attrs(work,
329 user_ns,
330 dir->filp->f_path.dentry->d_parent,
331 &ksmbd_kstat);
332 rc = fn(conn, info_level, d_info, &ksmbd_kstat);
333 if (rc)
334 break;
335 if (d_info->out_buf_len <= 0)
336 break;
337
338 dir->dot_dotdot[i] = 1;
339 if (d_info->flags & SMB2_RETURN_SINGLE_ENTRY) {
340 d_info->out_buf_len = 0;
341 break;
342 }
343 }
344 }
345
346 return rc;
347 }
348
349 /**
350 * ksmbd_extract_shortname() - get shortname from long filename
351 * @conn: connection instance
352 * @longname: source long filename
353 * @shortname: destination short filename
354 *
355 * Return: shortname length or 0 when source long name is '.' or '..'
356 * TODO: Though this function comforms the restriction of 8.3 Filename spec,
357 * but the result is different with Windows 7's one. need to check.
358 */
ksmbd_extract_shortname(struct ksmbd_conn * conn,const char * longname,char * shortname)359 int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname,
360 char *shortname)
361 {
362 const char *p;
363 char base[9], extension[4];
364 char out[13] = {0};
365 int baselen = 0;
366 int extlen = 0, len = 0;
367 unsigned int csum = 0;
368 const unsigned char *ptr;
369 bool dot_present = true;
370
371 p = longname;
372 if ((*p == '.') || (!(strcmp(p, "..")))) {
373 /*no mangling required */
374 return 0;
375 }
376
377 p = strrchr(longname, '.');
378 if (p == longname) { /*name starts with a dot*/
379 strscpy(extension, "___", strlen("___"));
380 } else {
381 if (p) {
382 p++;
383 while (*p && extlen < 3) {
384 if (*p != '.')
385 extension[extlen++] = toupper(*p);
386 p++;
387 }
388 extension[extlen] = '\0';
389 } else {
390 dot_present = false;
391 }
392 }
393
394 p = longname;
395 if (*p == '.') {
396 p++;
397 longname++;
398 }
399 while (*p && (baselen < 5)) {
400 if (*p != '.')
401 base[baselen++] = toupper(*p);
402 p++;
403 }
404
405 base[baselen] = MAGIC_CHAR;
406 memcpy(out, base, baselen + 1);
407
408 ptr = longname;
409 len = strlen(longname);
410 for (; len > 0; len--, ptr++)
411 csum += *ptr;
412
413 csum = csum % (MANGLE_BASE * MANGLE_BASE);
414 out[baselen + 1] = mangle(csum / MANGLE_BASE);
415 out[baselen + 2] = mangle(csum);
416 out[baselen + 3] = PERIOD;
417
418 if (dot_present)
419 memcpy(&out[baselen + 4], extension, 4);
420 else
421 out[baselen + 4] = '\0';
422 smbConvertToUTF16((__le16 *)shortname, out, PATH_MAX,
423 conn->local_nls, 0);
424 len = strlen(out) * 2;
425 return len;
426 }
427
__smb2_negotiate(struct ksmbd_conn * conn)428 static int __smb2_negotiate(struct ksmbd_conn *conn)
429 {
430 return (conn->dialect >= SMB21_PROT_ID &&
431 conn->dialect <= SMB311_PROT_ID);
432 }
433
smb_handle_negotiate(struct ksmbd_work * work)434 static int smb_handle_negotiate(struct ksmbd_work *work)
435 {
436 struct smb_negotiate_rsp *neg_rsp = work->response_buf;
437
438 ksmbd_debug(SMB, "Unsupported SMB protocol\n");
439 neg_rsp->hdr.Status.CifsError = STATUS_INVALID_LOGON_TYPE;
440 return -EINVAL;
441 }
442
ksmbd_smb_negotiate_common(struct ksmbd_work * work,unsigned int command)443 int ksmbd_smb_negotiate_common(struct ksmbd_work *work, unsigned int command)
444 {
445 struct ksmbd_conn *conn = work->conn;
446 int ret;
447
448 conn->dialect = ksmbd_negotiate_smb_dialect(work->request_buf);
449 ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
450
451 if (command == SMB2_NEGOTIATE_HE) {
452 struct smb2_hdr *smb2_hdr = work->request_buf;
453
454 if (smb2_hdr->ProtocolId != SMB2_PROTO_NUMBER) {
455 ksmbd_debug(SMB, "Downgrade to SMB1 negotiation\n");
456 command = SMB_COM_NEGOTIATE;
457 }
458 }
459
460 if (command == SMB2_NEGOTIATE_HE && __smb2_negotiate(conn)) {
461 ret = smb2_handle_negotiate(work);
462 init_smb2_neg_rsp(work);
463 return ret;
464 }
465
466 if (command == SMB_COM_NEGOTIATE) {
467 if (__smb2_negotiate(conn)) {
468 conn->need_neg = true;
469 init_smb3_11_server(conn);
470 init_smb2_neg_rsp(work);
471 ksmbd_debug(SMB, "Upgrade to SMB2 negotiation\n");
472 return 0;
473 }
474 return smb_handle_negotiate(work);
475 }
476
477 pr_err("Unknown SMB negotiation command: %u\n", command);
478 return -EINVAL;
479 }
480
481 enum SHARED_MODE_ERRORS {
482 SHARE_DELETE_ERROR,
483 SHARE_READ_ERROR,
484 SHARE_WRITE_ERROR,
485 FILE_READ_ERROR,
486 FILE_WRITE_ERROR,
487 FILE_DELETE_ERROR,
488 };
489
490 static const char * const shared_mode_errors[] = {
491 "Current access mode does not permit SHARE_DELETE",
492 "Current access mode does not permit SHARE_READ",
493 "Current access mode does not permit SHARE_WRITE",
494 "Desired access mode does not permit FILE_READ",
495 "Desired access mode does not permit FILE_WRITE",
496 "Desired access mode does not permit FILE_DELETE",
497 };
498
smb_shared_mode_error(int error,struct ksmbd_file * prev_fp,struct ksmbd_file * curr_fp)499 static void smb_shared_mode_error(int error, struct ksmbd_file *prev_fp,
500 struct ksmbd_file *curr_fp)
501 {
502 ksmbd_debug(SMB, "%s\n", shared_mode_errors[error]);
503 ksmbd_debug(SMB, "Current mode: 0x%x Desired mode: 0x%x\n",
504 prev_fp->saccess, curr_fp->daccess);
505 }
506
ksmbd_smb_check_shared_mode(struct file * filp,struct ksmbd_file * curr_fp)507 int ksmbd_smb_check_shared_mode(struct file *filp, struct ksmbd_file *curr_fp)
508 {
509 int rc = 0;
510 struct ksmbd_file *prev_fp;
511
512 /*
513 * Lookup fp in master fp list, and check desired access and
514 * shared mode between previous open and current open.
515 */
516 read_lock(&curr_fp->f_ci->m_lock);
517 list_for_each_entry(prev_fp, &curr_fp->f_ci->m_fp_list, node) {
518 if (file_inode(filp) != file_inode(prev_fp->filp))
519 continue;
520
521 if (filp == prev_fp->filp)
522 continue;
523
524 if (ksmbd_stream_fd(prev_fp) && ksmbd_stream_fd(curr_fp))
525 if (strcmp(prev_fp->stream.name, curr_fp->stream.name))
526 continue;
527
528 if (prev_fp->attrib_only != curr_fp->attrib_only)
529 continue;
530
531 if (!(prev_fp->saccess & FILE_SHARE_DELETE_LE) &&
532 curr_fp->daccess & FILE_DELETE_LE) {
533 smb_shared_mode_error(SHARE_DELETE_ERROR,
534 prev_fp,
535 curr_fp);
536 rc = -EPERM;
537 break;
538 }
539
540 /*
541 * Only check FILE_SHARE_DELETE if stream opened and
542 * normal file opened.
543 */
544 if (ksmbd_stream_fd(prev_fp) && !ksmbd_stream_fd(curr_fp))
545 continue;
546
547 if (!(prev_fp->saccess & FILE_SHARE_READ_LE) &&
548 curr_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE)) {
549 smb_shared_mode_error(SHARE_READ_ERROR,
550 prev_fp,
551 curr_fp);
552 rc = -EPERM;
553 break;
554 }
555
556 if (!(prev_fp->saccess & FILE_SHARE_WRITE_LE) &&
557 curr_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE)) {
558 smb_shared_mode_error(SHARE_WRITE_ERROR,
559 prev_fp,
560 curr_fp);
561 rc = -EPERM;
562 break;
563 }
564
565 if (prev_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE) &&
566 !(curr_fp->saccess & FILE_SHARE_READ_LE)) {
567 smb_shared_mode_error(FILE_READ_ERROR,
568 prev_fp,
569 curr_fp);
570 rc = -EPERM;
571 break;
572 }
573
574 if (prev_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE) &&
575 !(curr_fp->saccess & FILE_SHARE_WRITE_LE)) {
576 smb_shared_mode_error(FILE_WRITE_ERROR,
577 prev_fp,
578 curr_fp);
579 rc = -EPERM;
580 break;
581 }
582
583 if (prev_fp->daccess & FILE_DELETE_LE &&
584 !(curr_fp->saccess & FILE_SHARE_DELETE_LE)) {
585 smb_shared_mode_error(FILE_DELETE_ERROR,
586 prev_fp,
587 curr_fp);
588 rc = -EPERM;
589 break;
590 }
591 }
592 read_unlock(&curr_fp->f_ci->m_lock);
593
594 return rc;
595 }
596
is_asterisk(char * p)597 bool is_asterisk(char *p)
598 {
599 return p && p[0] == '*';
600 }
601
ksmbd_override_fsids(struct ksmbd_work * work)602 int ksmbd_override_fsids(struct ksmbd_work *work)
603 {
604 struct ksmbd_session *sess = work->sess;
605 struct ksmbd_share_config *share = work->tcon->share_conf;
606 struct cred *cred;
607 struct group_info *gi;
608 unsigned int uid;
609 unsigned int gid;
610
611 uid = user_uid(sess->user);
612 gid = user_gid(sess->user);
613 if (share->force_uid != KSMBD_SHARE_INVALID_UID)
614 uid = share->force_uid;
615 if (share->force_gid != KSMBD_SHARE_INVALID_GID)
616 gid = share->force_gid;
617
618 cred = prepare_kernel_cred(NULL);
619 if (!cred)
620 return -ENOMEM;
621
622 cred->fsuid = make_kuid(current_user_ns(), uid);
623 cred->fsgid = make_kgid(current_user_ns(), gid);
624
625 gi = groups_alloc(0);
626 if (!gi) {
627 abort_creds(cred);
628 return -ENOMEM;
629 }
630 set_groups(cred, gi);
631 put_group_info(gi);
632
633 if (!uid_eq(cred->fsuid, GLOBAL_ROOT_UID))
634 cred->cap_effective = cap_drop_fs_set(cred->cap_effective);
635
636 WARN_ON(work->saved_cred);
637 work->saved_cred = override_creds(cred);
638 if (!work->saved_cred) {
639 abort_creds(cred);
640 return -EINVAL;
641 }
642 return 0;
643 }
644
ksmbd_revert_fsids(struct ksmbd_work * work)645 void ksmbd_revert_fsids(struct ksmbd_work *work)
646 {
647 const struct cred *cred;
648
649 WARN_ON(!work->saved_cred);
650
651 cred = current_cred();
652 revert_creds(work->saved_cred);
653 put_cred(cred);
654 work->saved_cred = NULL;
655 }
656
smb_map_generic_desired_access(__le32 daccess)657 __le32 smb_map_generic_desired_access(__le32 daccess)
658 {
659 if (daccess & FILE_GENERIC_READ_LE) {
660 daccess |= cpu_to_le32(GENERIC_READ_FLAGS);
661 daccess &= ~FILE_GENERIC_READ_LE;
662 }
663
664 if (daccess & FILE_GENERIC_WRITE_LE) {
665 daccess |= cpu_to_le32(GENERIC_WRITE_FLAGS);
666 daccess &= ~FILE_GENERIC_WRITE_LE;
667 }
668
669 if (daccess & FILE_GENERIC_EXECUTE_LE) {
670 daccess |= cpu_to_le32(GENERIC_EXECUTE_FLAGS);
671 daccess &= ~FILE_GENERIC_EXECUTE_LE;
672 }
673
674 if (daccess & FILE_GENERIC_ALL_LE) {
675 daccess |= cpu_to_le32(GENERIC_ALL_FLAGS);
676 daccess &= ~FILE_GENERIC_ALL_LE;
677 }
678
679 return daccess;
680 }
681
