Merge branch 'next' into for-linus
[linux-block.git] / fs / ksmbd / smb_common.c
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 "smbstatus.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[43] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_-!@#$%";
22 #define MANGLE_BASE (sizeof(basechars) / sizeof(char) - 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 int ksmbd_lookup_protocol_idx(char *str)
102 {
103         int offt = ARRAY_SIZE(smb1_protos) - 1;
104         int len = strlen(str);
105
106         while (offt >= 0) {
107                 if (!strncmp(str, smb1_protos[offt].prot, len)) {
108                         ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
109                                     smb1_protos[offt].prot, offt);
110                         return smb1_protos[offt].index;
111                 }
112                 offt--;
113         }
114
115         offt = ARRAY_SIZE(smb2_protos) - 1;
116         while (offt >= 0) {
117                 if (!strncmp(str, smb2_protos[offt].prot, len)) {
118                         ksmbd_debug(SMB, "selected %s dialect idx = %d\n",
119                                     smb2_protos[offt].prot, offt);
120                         return smb2_protos[offt].index;
121                 }
122                 offt--;
123         }
124         return -1;
125 }
126
127 /**
128  * ksmbd_verify_smb_message() - check for valid smb2 request header
129  * @work:       smb work
130  *
131  * check for valid smb signature and packet direction(request/response)
132  *
133  * Return:      0 on success, otherwise -EINVAL
134  */
135 int ksmbd_verify_smb_message(struct ksmbd_work *work)
136 {
137         struct smb2_hdr *smb2_hdr = ksmbd_req_buf_next(work);
138         struct smb_hdr *hdr;
139
140         if (smb2_hdr->ProtocolId == SMB2_PROTO_NUMBER)
141                 return ksmbd_smb2_check_message(work);
142
143         hdr = work->request_buf;
144         if (*(__le32 *)hdr->Protocol == SMB1_PROTO_NUMBER &&
145             hdr->Command == SMB_COM_NEGOTIATE) {
146                 work->conn->outstanding_credits++;
147                 return 0;
148         }
149
150         return -EINVAL;
151 }
152
153 /**
154  * ksmbd_smb_request() - check for valid smb request type
155  * @conn:       connection instance
156  *
157  * Return:      true on success, otherwise false
158  */
159 bool ksmbd_smb_request(struct ksmbd_conn *conn)
160 {
161         return conn->request_buf[0] == 0;
162 }
163
164 static bool supported_protocol(int idx)
165 {
166         if (idx == SMB2X_PROT &&
167             (server_conf.min_protocol >= SMB21_PROT ||
168              server_conf.max_protocol <= SMB311_PROT))
169                 return true;
170
171         return (server_conf.min_protocol <= idx &&
172                 idx <= server_conf.max_protocol);
173 }
174
175 static char *next_dialect(char *dialect, int *next_off, int bcount)
176 {
177         dialect = dialect + *next_off;
178         *next_off = strnlen(dialect, bcount);
179         if (dialect[*next_off] != '\0')
180                 return NULL;
181         return dialect;
182 }
183
184 static int ksmbd_lookup_dialect_by_name(char *cli_dialects, __le16 byte_count)
185 {
186         int i, seq_num, bcount, next;
187         char *dialect;
188
189         for (i = ARRAY_SIZE(smb1_protos) - 1; i >= 0; i--) {
190                 seq_num = 0;
191                 next = 0;
192                 dialect = cli_dialects;
193                 bcount = le16_to_cpu(byte_count);
194                 do {
195                         dialect = next_dialect(dialect, &next, bcount);
196                         if (!dialect)
197                                 break;
198                         ksmbd_debug(SMB, "client requested dialect %s\n",
199                                     dialect);
200                         if (!strcmp(dialect, smb1_protos[i].name)) {
201                                 if (supported_protocol(smb1_protos[i].index)) {
202                                         ksmbd_debug(SMB,
203                                                     "selected %s dialect\n",
204                                                     smb1_protos[i].name);
205                                         if (smb1_protos[i].index == SMB1_PROT)
206                                                 return seq_num;
207                                         return smb1_protos[i].prot_id;
208                                 }
209                         }
210                         seq_num++;
211                         bcount -= (++next);
212                 } while (bcount > 0);
213         }
214
215         return BAD_PROT_ID;
216 }
217
218 int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count)
219 {
220         int i;
221         int count;
222
223         for (i = ARRAY_SIZE(smb2_protos) - 1; i >= 0; i--) {
224                 count = le16_to_cpu(dialects_count);
225                 while (--count >= 0) {
226                         ksmbd_debug(SMB, "client requested dialect 0x%x\n",
227                                     le16_to_cpu(cli_dialects[count]));
228                         if (le16_to_cpu(cli_dialects[count]) !=
229                                         smb2_protos[i].prot_id)
230                                 continue;
231
232                         if (supported_protocol(smb2_protos[i].index)) {
233                                 ksmbd_debug(SMB, "selected %s dialect\n",
234                                             smb2_protos[i].name);
235                                 return smb2_protos[i].prot_id;
236                         }
237                 }
238         }
239
240         return BAD_PROT_ID;
241 }
242
243 static int ksmbd_negotiate_smb_dialect(void *buf)
244 {
245         int smb_buf_length = get_rfc1002_len(buf);
246         __le32 proto = ((struct smb2_hdr *)smb2_get_msg(buf))->ProtocolId;
247
248         if (proto == SMB2_PROTO_NUMBER) {
249                 struct smb2_negotiate_req *req;
250                 int smb2_neg_size =
251                         offsetof(struct smb2_negotiate_req, Dialects);
252
253                 req = (struct smb2_negotiate_req *)smb2_get_msg(buf);
254                 if (smb2_neg_size > smb_buf_length)
255                         goto err_out;
256
257                 if (smb2_neg_size + le16_to_cpu(req->DialectCount) * sizeof(__le16) >
258                     smb_buf_length)
259                         goto err_out;
260
261                 return ksmbd_lookup_dialect_by_id(req->Dialects,
262                                                   req->DialectCount);
263         }
264
265         proto = *(__le32 *)((struct smb_hdr *)buf)->Protocol;
266         if (proto == SMB1_PROTO_NUMBER) {
267                 struct smb_negotiate_req *req;
268
269                 req = (struct smb_negotiate_req *)buf;
270                 if (le16_to_cpu(req->ByteCount) < 2)
271                         goto err_out;
272
273                 if (offsetof(struct smb_negotiate_req, DialectsArray) - 4 +
274                         le16_to_cpu(req->ByteCount) > smb_buf_length) {
275                         goto err_out;
276                 }
277
278                 return ksmbd_lookup_dialect_by_name(req->DialectsArray,
279                                                     req->ByteCount);
280         }
281
282 err_out:
283         return BAD_PROT_ID;
284 }
285
286 int ksmbd_init_smb_server(struct ksmbd_work *work)
287 {
288         struct ksmbd_conn *conn = work->conn;
289
290         if (conn->need_neg == false)
291                 return 0;
292
293         init_smb3_11_server(conn);
294
295         if (conn->ops->get_cmd_val(work) != SMB_COM_NEGOTIATE)
296                 conn->need_neg = false;
297         return 0;
298 }
299
300 int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work, int info_level,
301                                       struct ksmbd_file *dir,
302                                       struct ksmbd_dir_info *d_info,
303                                       char *search_pattern,
304                                       int (*fn)(struct ksmbd_conn *, int,
305                                                 struct ksmbd_dir_info *,
306                                                 struct ksmbd_kstat *))
307 {
308         int i, rc = 0;
309         struct ksmbd_conn *conn = work->conn;
310         struct mnt_idmap *idmap = file_mnt_idmap(dir->filp);
311
312         for (i = 0; i < 2; i++) {
313                 struct kstat kstat;
314                 struct ksmbd_kstat ksmbd_kstat;
315                 struct dentry *dentry;
316
317                 if (!dir->dot_dotdot[i]) { /* fill dot entry info */
318                         if (i == 0) {
319                                 d_info->name = ".";
320                                 d_info->name_len = 1;
321                                 dentry = dir->filp->f_path.dentry;
322                         } else {
323                                 d_info->name = "..";
324                                 d_info->name_len = 2;
325                                 dentry = dir->filp->f_path.dentry->d_parent;
326                         }
327
328                         if (!match_pattern(d_info->name, d_info->name_len,
329                                            search_pattern)) {
330                                 dir->dot_dotdot[i] = 1;
331                                 continue;
332                         }
333
334                         ksmbd_kstat.kstat = &kstat;
335                         ksmbd_vfs_fill_dentry_attrs(work,
336                                                     idmap,
337                                                     dentry,
338                                                     &ksmbd_kstat);
339                         rc = fn(conn, info_level, d_info, &ksmbd_kstat);
340                         if (rc)
341                                 break;
342                         if (d_info->out_buf_len <= 0)
343                                 break;
344
345                         dir->dot_dotdot[i] = 1;
346                         if (d_info->flags & SMB2_RETURN_SINGLE_ENTRY) {
347                                 d_info->out_buf_len = 0;
348                                 break;
349                         }
350                 }
351         }
352
353         return rc;
354 }
355
356 /**
357  * ksmbd_extract_shortname() - get shortname from long filename
358  * @conn:       connection instance
359  * @longname:   source long filename
360  * @shortname:  destination short filename
361  *
362  * Return:      shortname length or 0 when source long name is '.' or '..'
363  * TODO: Though this function comforms the restriction of 8.3 Filename spec,
364  * but the result is different with Windows 7's one. need to check.
365  */
366 int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname,
367                             char *shortname)
368 {
369         const char *p;
370         char base[9], extension[4];
371         char out[13] = {0};
372         int baselen = 0;
373         int extlen = 0, len = 0;
374         unsigned int csum = 0;
375         const unsigned char *ptr;
376         bool dot_present = true;
377
378         p = longname;
379         if ((*p == '.') || (!(strcmp(p, "..")))) {
380                 /*no mangling required */
381                 return 0;
382         }
383
384         p = strrchr(longname, '.');
385         if (p == longname) { /*name starts with a dot*/
386                 strscpy(extension, "___", strlen("___"));
387         } else {
388                 if (p) {
389                         p++;
390                         while (*p && extlen < 3) {
391                                 if (*p != '.')
392                                         extension[extlen++] = toupper(*p);
393                                 p++;
394                         }
395                         extension[extlen] = '\0';
396                 } else {
397                         dot_present = false;
398                 }
399         }
400
401         p = longname;
402         if (*p == '.') {
403                 p++;
404                 longname++;
405         }
406         while (*p && (baselen < 5)) {
407                 if (*p != '.')
408                         base[baselen++] = toupper(*p);
409                 p++;
410         }
411
412         base[baselen] = MAGIC_CHAR;
413         memcpy(out, base, baselen + 1);
414
415         ptr = longname;
416         len = strlen(longname);
417         for (; len > 0; len--, ptr++)
418                 csum += *ptr;
419
420         csum = csum % (MANGLE_BASE * MANGLE_BASE);
421         out[baselen + 1] = mangle(csum / MANGLE_BASE);
422         out[baselen + 2] = mangle(csum);
423         out[baselen + 3] = PERIOD;
424
425         if (dot_present)
426                 memcpy(&out[baselen + 4], extension, 4);
427         else
428                 out[baselen + 4] = '\0';
429         smbConvertToUTF16((__le16 *)shortname, out, PATH_MAX,
430                           conn->local_nls, 0);
431         len = strlen(out) * 2;
432         return len;
433 }
434
435 static int __smb2_negotiate(struct ksmbd_conn *conn)
436 {
437         return (conn->dialect >= SMB21_PROT_ID &&
438                 conn->dialect <= SMB311_PROT_ID);
439 }
440
441 static int smb_handle_negotiate(struct ksmbd_work *work)
442 {
443         struct smb_negotiate_rsp *neg_rsp = work->response_buf;
444
445         ksmbd_debug(SMB, "Unsupported SMB protocol\n");
446         neg_rsp->hdr.Status.CifsError = STATUS_INVALID_LOGON_TYPE;
447         return -EINVAL;
448 }
449
450 int ksmbd_smb_negotiate_common(struct ksmbd_work *work, unsigned int command)
451 {
452         struct ksmbd_conn *conn = work->conn;
453         int ret;
454
455         conn->dialect =
456                 ksmbd_negotiate_smb_dialect(work->request_buf);
457         ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
458
459         if (command == SMB2_NEGOTIATE_HE) {
460                 struct smb2_hdr *smb2_hdr = smb2_get_msg(work->request_buf);
461
462                 if (smb2_hdr->ProtocolId != SMB2_PROTO_NUMBER) {
463                         ksmbd_debug(SMB, "Downgrade to SMB1 negotiation\n");
464                         command = SMB_COM_NEGOTIATE;
465                 }
466         }
467
468         if (command == SMB2_NEGOTIATE_HE && __smb2_negotiate(conn)) {
469                 ret = smb2_handle_negotiate(work);
470                 init_smb2_neg_rsp(work);
471                 return ret;
472         }
473
474         if (command == SMB_COM_NEGOTIATE) {
475                 if (__smb2_negotiate(conn)) {
476                         conn->need_neg = true;
477                         init_smb3_11_server(conn);
478                         init_smb2_neg_rsp(work);
479                         ksmbd_debug(SMB, "Upgrade to SMB2 negotiation\n");
480                         return 0;
481                 }
482                 return smb_handle_negotiate(work);
483         }
484
485         pr_err("Unknown SMB negotiation command: %u\n", command);
486         return -EINVAL;
487 }
488
489 enum SHARED_MODE_ERRORS {
490         SHARE_DELETE_ERROR,
491         SHARE_READ_ERROR,
492         SHARE_WRITE_ERROR,
493         FILE_READ_ERROR,
494         FILE_WRITE_ERROR,
495         FILE_DELETE_ERROR,
496 };
497
498 static const char * const shared_mode_errors[] = {
499         "Current access mode does not permit SHARE_DELETE",
500         "Current access mode does not permit SHARE_READ",
501         "Current access mode does not permit SHARE_WRITE",
502         "Desired access mode does not permit FILE_READ",
503         "Desired access mode does not permit FILE_WRITE",
504         "Desired access mode does not permit FILE_DELETE",
505 };
506
507 static void smb_shared_mode_error(int error, struct ksmbd_file *prev_fp,
508                                   struct ksmbd_file *curr_fp)
509 {
510         ksmbd_debug(SMB, "%s\n", shared_mode_errors[error]);
511         ksmbd_debug(SMB, "Current mode: 0x%x Desired mode: 0x%x\n",
512                     prev_fp->saccess, curr_fp->daccess);
513 }
514
515 int ksmbd_smb_check_shared_mode(struct file *filp, struct ksmbd_file *curr_fp)
516 {
517         int rc = 0;
518         struct ksmbd_file *prev_fp;
519
520         /*
521          * Lookup fp in master fp list, and check desired access and
522          * shared mode between previous open and current open.
523          */
524         read_lock(&curr_fp->f_ci->m_lock);
525         list_for_each_entry(prev_fp, &curr_fp->f_ci->m_fp_list, node) {
526                 if (file_inode(filp) != file_inode(prev_fp->filp))
527                         continue;
528
529                 if (filp == prev_fp->filp)
530                         continue;
531
532                 if (ksmbd_stream_fd(prev_fp) && ksmbd_stream_fd(curr_fp))
533                         if (strcmp(prev_fp->stream.name, curr_fp->stream.name))
534                                 continue;
535
536                 if (prev_fp->attrib_only != curr_fp->attrib_only)
537                         continue;
538
539                 if (!(prev_fp->saccess & FILE_SHARE_DELETE_LE) &&
540                     curr_fp->daccess & FILE_DELETE_LE) {
541                         smb_shared_mode_error(SHARE_DELETE_ERROR,
542                                               prev_fp,
543                                               curr_fp);
544                         rc = -EPERM;
545                         break;
546                 }
547
548                 /*
549                  * Only check FILE_SHARE_DELETE if stream opened and
550                  * normal file opened.
551                  */
552                 if (ksmbd_stream_fd(prev_fp) && !ksmbd_stream_fd(curr_fp))
553                         continue;
554
555                 if (!(prev_fp->saccess & FILE_SHARE_READ_LE) &&
556                     curr_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE)) {
557                         smb_shared_mode_error(SHARE_READ_ERROR,
558                                               prev_fp,
559                                               curr_fp);
560                         rc = -EPERM;
561                         break;
562                 }
563
564                 if (!(prev_fp->saccess & FILE_SHARE_WRITE_LE) &&
565                     curr_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE)) {
566                         smb_shared_mode_error(SHARE_WRITE_ERROR,
567                                               prev_fp,
568                                               curr_fp);
569                         rc = -EPERM;
570                         break;
571                 }
572
573                 if (prev_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE) &&
574                     !(curr_fp->saccess & FILE_SHARE_READ_LE)) {
575                         smb_shared_mode_error(FILE_READ_ERROR,
576                                               prev_fp,
577                                               curr_fp);
578                         rc = -EPERM;
579                         break;
580                 }
581
582                 if (prev_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE) &&
583                     !(curr_fp->saccess & FILE_SHARE_WRITE_LE)) {
584                         smb_shared_mode_error(FILE_WRITE_ERROR,
585                                               prev_fp,
586                                               curr_fp);
587                         rc = -EPERM;
588                         break;
589                 }
590
591                 if (prev_fp->daccess & FILE_DELETE_LE &&
592                     !(curr_fp->saccess & FILE_SHARE_DELETE_LE)) {
593                         smb_shared_mode_error(FILE_DELETE_ERROR,
594                                               prev_fp,
595                                               curr_fp);
596                         rc = -EPERM;
597                         break;
598                 }
599         }
600         read_unlock(&curr_fp->f_ci->m_lock);
601
602         return rc;
603 }
604
605 bool is_asterisk(char *p)
606 {
607         return p && p[0] == '*';
608 }
609
610 int ksmbd_override_fsids(struct ksmbd_work *work)
611 {
612         struct ksmbd_session *sess = work->sess;
613         struct ksmbd_share_config *share = work->tcon->share_conf;
614         struct cred *cred;
615         struct group_info *gi;
616         unsigned int uid;
617         unsigned int gid;
618
619         uid = user_uid(sess->user);
620         gid = user_gid(sess->user);
621         if (share->force_uid != KSMBD_SHARE_INVALID_UID)
622                 uid = share->force_uid;
623         if (share->force_gid != KSMBD_SHARE_INVALID_GID)
624                 gid = share->force_gid;
625
626         cred = prepare_kernel_cred(&init_task);
627         if (!cred)
628                 return -ENOMEM;
629
630         cred->fsuid = make_kuid(&init_user_ns, uid);
631         cred->fsgid = make_kgid(&init_user_ns, gid);
632
633         gi = groups_alloc(0);
634         if (!gi) {
635                 abort_creds(cred);
636                 return -ENOMEM;
637         }
638         set_groups(cred, gi);
639         put_group_info(gi);
640
641         if (!uid_eq(cred->fsuid, GLOBAL_ROOT_UID))
642                 cred->cap_effective = cap_drop_fs_set(cred->cap_effective);
643
644         WARN_ON(work->saved_cred);
645         work->saved_cred = override_creds(cred);
646         if (!work->saved_cred) {
647                 abort_creds(cred);
648                 return -EINVAL;
649         }
650         return 0;
651 }
652
653 void ksmbd_revert_fsids(struct ksmbd_work *work)
654 {
655         const struct cred *cred;
656
657         WARN_ON(!work->saved_cred);
658
659         cred = current_cred();
660         revert_creds(work->saved_cred);
661         put_cred(cred);
662         work->saved_cred = NULL;
663 }
664
665 __le32 smb_map_generic_desired_access(__le32 daccess)
666 {
667         if (daccess & FILE_GENERIC_READ_LE) {
668                 daccess |= cpu_to_le32(GENERIC_READ_FLAGS);
669                 daccess &= ~FILE_GENERIC_READ_LE;
670         }
671
672         if (daccess & FILE_GENERIC_WRITE_LE) {
673                 daccess |= cpu_to_le32(GENERIC_WRITE_FLAGS);
674                 daccess &= ~FILE_GENERIC_WRITE_LE;
675         }
676
677         if (daccess & FILE_GENERIC_EXECUTE_LE) {
678                 daccess |= cpu_to_le32(GENERIC_EXECUTE_FLAGS);
679                 daccess &= ~FILE_GENERIC_EXECUTE_LE;
680         }
681
682         if (daccess & FILE_GENERIC_ALL_LE) {
683                 daccess |= cpu_to_le32(GENERIC_ALL_FLAGS);
684                 daccess &= ~FILE_GENERIC_ALL_LE;
685         }
686
687         return daccess;
688 }