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 #define SMB_COM_NEGOTIATE_EX    0x0
 287
 288 /**
 289  * get_smb1_cmd_val() - get smb command value from smb header
 290  * @work:       smb work containing smb header
 291  *
 292  * Return:      smb command value
 293  */
 294 static u16 get_smb1_cmd_val(struct ksmbd_work *work)
 295 {
 296         return SMB_COM_NEGOTIATE_EX;
 297 }
 298
 299 /**
 300  * init_smb1_rsp_hdr() - initialize smb negotiate response header
 301  * @work:       smb work containing smb request
 302  *
 303  * Return:      0 on success, otherwise -EINVAL
 304  */
 305 static int init_smb1_rsp_hdr(struct ksmbd_work *work)
 306 {
 307         struct smb_hdr *rsp_hdr = (struct smb_hdr *)work->response_buf;
 308         struct smb_hdr *rcv_hdr = (struct smb_hdr *)work->request_buf;
 309
 310         /*
 311          * Remove 4 byte direct TCP header.
 312          */
 313         *(__be32 *)work->response_buf =
 314                 cpu_to_be32(sizeof(struct smb_hdr) - 4);
 315
 316         rsp_hdr->Command = SMB_COM_NEGOTIATE;
 317         *(__le32 *)rsp_hdr->Protocol = SMB1_PROTO_NUMBER;
 318         rsp_hdr->Flags = SMBFLG_RESPONSE;
 319         rsp_hdr->Flags2 = SMBFLG2_UNICODE | SMBFLG2_ERR_STATUS |
 320                 SMBFLG2_EXT_SEC | SMBFLG2_IS_LONG_NAME;
 321         rsp_hdr->Pid = rcv_hdr->Pid;
 322         rsp_hdr->Mid = rcv_hdr->Mid;
 323         return 0;
 324 }
 325
 326 /**
 327  * smb1_check_user_session() - check for valid session for a user
 328  * @work:       smb work containing smb request buffer
 329  *
 330  * Return:      0 on success, otherwise error
 331  */
 332 static int smb1_check_user_session(struct ksmbd_work *work)
 333 {
 334         unsigned int cmd = work->conn->ops->get_cmd_val(work);
 335
 336         if (cmd == SMB_COM_NEGOTIATE_EX)
 337                 return 0;
 338
 339         return -EINVAL;
 340 }
 341
 342 /**
 343  * smb1_allocate_rsp_buf() - allocate response buffer for a command
 344  * @work:       smb work containing smb request
 345  *
 346  * Return:      0 on success, otherwise -ENOMEM
 347  */
 348 static int smb1_allocate_rsp_buf(struct ksmbd_work *work)
 349 {
 350         work->response_buf = kmalloc(MAX_CIFS_SMALL_BUFFER_SIZE,
 351                         GFP_KERNEL | __GFP_ZERO);
 352         work->response_sz = MAX_CIFS_SMALL_BUFFER_SIZE;
 353
 354         if (!work->response_buf) {
 355                 pr_err("Failed to allocate %u bytes buffer\n",
 356                                 MAX_CIFS_SMALL_BUFFER_SIZE);
 357                 return -ENOMEM;
 358         }
 359
 360         return 0;
 361 }
 362
 363 static struct smb_version_ops smb1_server_ops = {
 364         .get_cmd_val = get_smb1_cmd_val,
 365         .init_rsp_hdr = init_smb1_rsp_hdr,
 366         .allocate_rsp_buf = smb1_allocate_rsp_buf,
 367         .check_user_session = smb1_check_user_session,
 368 };
 369
 370 static int smb1_negotiate(struct ksmbd_work *work)
 371 {
 372         return ksmbd_smb_negotiate_common(work, SMB_COM_NEGOTIATE);
 373 }
 374
 375 static struct smb_version_cmds smb1_server_cmds[1] = {
 376         [SMB_COM_NEGOTIATE_EX]  = { .proc = smb1_negotiate, },
 377 };
 378
 379 static void init_smb1_server(struct ksmbd_conn *conn)
 380 {
 381         conn->ops = &smb1_server_ops;
 382         conn->cmds = smb1_server_cmds;
 383         conn->max_cmds = ARRAY_SIZE(smb1_server_cmds);
 384 }
 385
 386 void ksmbd_init_smb_server(struct ksmbd_work *work)
 387 {
 388         struct ksmbd_conn *conn = work->conn;
 389         __le32 proto;
 390
 391         if (conn->need_neg == false)
 392                 return;
 393
 394         proto = *(__le32 *)((struct smb_hdr *)work->request_buf)->Protocol;
 395         if (proto == SMB1_PROTO_NUMBER)
 396                 init_smb1_server(conn);
 397         else
 398                 init_smb3_11_server(conn);
 399 }
 400
 401 int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work, int info_level,
 402                                       struct ksmbd_file *dir,
 403                                       struct ksmbd_dir_info *d_info,
 404                                       char *search_pattern,
 405                                       int (*fn)(struct ksmbd_conn *, int,
 406                                                 struct ksmbd_dir_info *,
 407                                                 struct ksmbd_kstat *))
 408 {
 409         int i, rc = 0;
 410         struct ksmbd_conn *conn = work->conn;
 411         struct mnt_idmap *idmap = file_mnt_idmap(dir->filp);
 412
 413         for (i = 0; i < 2; i++) {
 414                 struct kstat kstat;
 415                 struct ksmbd_kstat ksmbd_kstat;
 416                 struct dentry *dentry;
 417
 418                 if (!dir->dot_dotdot[i]) { /* fill dot entry info */
 419                         if (i == 0) {
 420                                 d_info->name = ".";
 421                                 d_info->name_len = 1;
 422                                 dentry = dir->filp->f_path.dentry;
 423                         } else {
 424                                 d_info->name = "..";
 425                                 d_info->name_len = 2;
 426                                 dentry = dir->filp->f_path.dentry->d_parent;
 427                         }
 428
 429                         if (!match_pattern(d_info->name, d_info->name_len,
 430                                            search_pattern)) {
 431                                 dir->dot_dotdot[i] = 1;
 432                                 continue;
 433                         }
 434
 435                         ksmbd_kstat.kstat = &kstat;
 436                         ksmbd_vfs_fill_dentry_attrs(work,
 437                                                     idmap,
 438                                                     dentry,
 439                                                     &ksmbd_kstat);
 440                         rc = fn(conn, info_level, d_info, &ksmbd_kstat);
 441                         if (rc)
 442                                 break;
 443                         if (d_info->out_buf_len <= 0)
 444                                 break;
 445
 446                         dir->dot_dotdot[i] = 1;
 447                         if (d_info->flags & SMB2_RETURN_SINGLE_ENTRY) {
 448                                 d_info->out_buf_len = 0;
 449                                 break;
 450                         }
 451                 }
 452         }
 453
 454         return rc;
 455 }
 456
 457 /**
 458  * ksmbd_extract_shortname() - get shortname from long filename
 459  * @conn:       connection instance
 460  * @longname:   source long filename
 461  * @shortname:  destination short filename
 462  *
 463  * Return:      shortname length or 0 when source long name is '.' or '..'
 464  * TODO: Though this function comforms the restriction of 8.3 Filename spec,
 465  * but the result is different with Windows 7's one. need to check.
 466  */
 467 int ksmbd_extract_shortname(struct ksmbd_conn *conn, const char *longname,
 468                             char *shortname)
 469 {
 470         const char *p;
 471         char base[9], extension[4];
 472         char out[13] = {0};
 473         int baselen = 0;
 474         int extlen = 0, len = 0;
 475         unsigned int csum = 0;
 476         const unsigned char *ptr;
 477         bool dot_present = true;
 478
 479         p = longname;
 480         if ((*p == '.') || (!(strcmp(p, "..")))) {
 481                 /*no mangling required */
 482                 return 0;
 483         }
 484
 485         p = strrchr(longname, '.');
 486         if (p == longname) { /*name starts with a dot*/
 487                 strscpy(extension, "___", strlen("___"));
 488         } else {
 489                 if (p) {
 490                         p++;
 491                         while (*p && extlen < 3) {
 492                                 if (*p != '.')
 493                                         extension[extlen++] = toupper(*p);
 494                                 p++;
 495                         }
 496                         extension[extlen] = '\0';
 497                 } else {
 498                         dot_present = false;
 499                 }
 500         }
 501
 502         p = longname;
 503         if (*p == '.') {
 504                 p++;
 505                 longname++;
 506         }
 507         while (*p && (baselen < 5)) {
 508                 if (*p != '.')
 509                         base[baselen++] = toupper(*p);
 510                 p++;
 511         }
 512
 513         base[baselen] = MAGIC_CHAR;
 514         memcpy(out, base, baselen + 1);
 515
 516         ptr = longname;
 517         len = strlen(longname);
 518         for (; len > 0; len--, ptr++)
 519                 csum += *ptr;
 520
 521         csum = csum % (MANGLE_BASE * MANGLE_BASE);
 522         out[baselen + 1] = mangle(csum / MANGLE_BASE);
 523         out[baselen + 2] = mangle(csum);
 524         out[baselen + 3] = PERIOD;
 525
 526         if (dot_present)
 527                 memcpy(&out[baselen + 4], extension, 4);
 528         else
 529                 out[baselen + 4] = '\0';
 530         smbConvertToUTF16((__le16 *)shortname, out, PATH_MAX,
 531                           conn->local_nls, 0);
 532         len = strlen(out) * 2;
 533         return len;
 534 }
 535
 536 static int __smb2_negotiate(struct ksmbd_conn *conn)
 537 {
 538         return (conn->dialect >= SMB20_PROT_ID &&
 539                 conn->dialect <= SMB311_PROT_ID);
 540 }
 541
 542 static int smb_handle_negotiate(struct ksmbd_work *work)
 543 {
 544         struct smb_negotiate_rsp *neg_rsp = work->response_buf;
 545
 546         ksmbd_debug(SMB, "Unsupported SMB1 protocol\n");
 547
 548         /* Add 2 byte bcc and 2 byte DialectIndex. */
 549         inc_rfc1001_len(work->response_buf, 4);
 550         neg_rsp->hdr.Status.CifsError = STATUS_SUCCESS;
 551
 552         neg_rsp->hdr.WordCount = 1;
 553         neg_rsp->DialectIndex = cpu_to_le16(work->conn->dialect);
 554         neg_rsp->ByteCount = 0;
 555         return 0;
 556 }
 557
 558 int ksmbd_smb_negotiate_common(struct ksmbd_work *work, unsigned int command)
 559 {
 560         struct ksmbd_conn *conn = work->conn;
 561         int ret;
 562
 563         conn->dialect =
 564                 ksmbd_negotiate_smb_dialect(work->request_buf);
 565         ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
 566
 567         if (command == SMB2_NEGOTIATE_HE) {
 568                 ret = smb2_handle_negotiate(work);
 569                 return ret;
 570         }
 571
 572         if (command == SMB_COM_NEGOTIATE) {
 573                 if (__smb2_negotiate(conn)) {
 574                         init_smb3_11_server(conn);
 575                         init_smb2_neg_rsp(work);
 576                         ksmbd_debug(SMB, "Upgrade to SMB2 negotiation\n");
 577                         return 0;
 578                 }
 579                 return smb_handle_negotiate(work);
 580         }
 581
 582         pr_err("Unknown SMB negotiation command: %u\n", command);
 583         return -EINVAL;
 584 }
 585
 586 enum SHARED_MODE_ERRORS {
 587         SHARE_DELETE_ERROR,
 588         SHARE_READ_ERROR,
 589         SHARE_WRITE_ERROR,
 590         FILE_READ_ERROR,
 591         FILE_WRITE_ERROR,
 592         FILE_DELETE_ERROR,
 593 };
 594
 595 static const char * const shared_mode_errors[] = {
 596         "Current access mode does not permit SHARE_DELETE",
 597         "Current access mode does not permit SHARE_READ",
 598         "Current access mode does not permit SHARE_WRITE",
 599         "Desired access mode does not permit FILE_READ",
 600         "Desired access mode does not permit FILE_WRITE",
 601         "Desired access mode does not permit FILE_DELETE",
 602 };
 603
 604 static void smb_shared_mode_error(int error, struct ksmbd_file *prev_fp,
 605                                   struct ksmbd_file *curr_fp)
 606 {
 607         ksmbd_debug(SMB, "%s\n", shared_mode_errors[error]);
 608         ksmbd_debug(SMB, "Current mode: 0x%x Desired mode: 0x%x\n",
 609                     prev_fp->saccess, curr_fp->daccess);
 610 }
 611
 612 int ksmbd_smb_check_shared_mode(struct file *filp, struct ksmbd_file *curr_fp)
 613 {
 614         int rc = 0;
 615         struct ksmbd_file *prev_fp;
 616
 617         /*
 618          * Lookup fp in master fp list, and check desired access and
 619          * shared mode between previous open and current open.
 620          */
 621         read_lock(&curr_fp->f_ci->m_lock);
 622         list_for_each_entry(prev_fp, &curr_fp->f_ci->m_fp_list, node) {
 623                 if (file_inode(filp) != file_inode(prev_fp->filp))
 624                         continue;
 625
 626                 if (filp == prev_fp->filp)
 627                         continue;
 628
 629                 if (ksmbd_stream_fd(prev_fp) && ksmbd_stream_fd(curr_fp))
 630                         if (strcmp(prev_fp->stream.name, curr_fp->stream.name))
 631                                 continue;
 632
 633                 if (prev_fp->attrib_only != curr_fp->attrib_only)
 634                         continue;
 635
 636                 if (!(prev_fp->saccess & FILE_SHARE_DELETE_LE) &&
 637                     curr_fp->daccess & FILE_DELETE_LE) {
 638                         smb_shared_mode_error(SHARE_DELETE_ERROR,
 639                                               prev_fp,
 640                                               curr_fp);
 641                         rc = -EPERM;
 642                         break;
 643                 }
 644
 645                 /*
 646                  * Only check FILE_SHARE_DELETE if stream opened and
 647                  * normal file opened.
 648                  */
 649                 if (ksmbd_stream_fd(prev_fp) && !ksmbd_stream_fd(curr_fp))
 650                         continue;
 651
 652                 if (!(prev_fp->saccess & FILE_SHARE_READ_LE) &&
 653                     curr_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE)) {
 654                         smb_shared_mode_error(SHARE_READ_ERROR,
 655                                               prev_fp,
 656                                               curr_fp);
 657                         rc = -EPERM;
 658                         break;
 659                 }
 660
 661                 if (!(prev_fp->saccess & FILE_SHARE_WRITE_LE) &&
 662                     curr_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE)) {
 663                         smb_shared_mode_error(SHARE_WRITE_ERROR,
 664                                               prev_fp,
 665                                               curr_fp);
 666                         rc = -EPERM;
 667                         break;
 668                 }
 669
 670                 if (prev_fp->daccess & (FILE_EXECUTE_LE | FILE_READ_DATA_LE) &&
 671                     !(curr_fp->saccess & FILE_SHARE_READ_LE)) {
 672                         smb_shared_mode_error(FILE_READ_ERROR,
 673                                               prev_fp,
 674                                               curr_fp);
 675                         rc = -EPERM;
 676                         break;
 677                 }
 678
 679                 if (prev_fp->daccess & (FILE_WRITE_DATA_LE | FILE_APPEND_DATA_LE) &&
 680                     !(curr_fp->saccess & FILE_SHARE_WRITE_LE)) {
 681                         smb_shared_mode_error(FILE_WRITE_ERROR,
 682                                               prev_fp,
 683                                               curr_fp);
 684                         rc = -EPERM;
 685                         break;
 686                 }
 687
 688                 if (prev_fp->daccess & FILE_DELETE_LE &&
 689                     !(curr_fp->saccess & FILE_SHARE_DELETE_LE)) {
 690                         smb_shared_mode_error(FILE_DELETE_ERROR,
 691                                               prev_fp,
 692                                               curr_fp);
 693                         rc = -EPERM;
 694                         break;
 695                 }
 696         }
 697         read_unlock(&curr_fp->f_ci->m_lock);
 698
 699         return rc;
 700 }
 701
 702 bool is_asterisk(char *p)
 703 {
 704         return p && p[0] == '*';
 705 }
 706
 707 int ksmbd_override_fsids(struct ksmbd_work *work)
 708 {
 709         struct ksmbd_session *sess = work->sess;
 710         struct ksmbd_share_config *share = work->tcon->share_conf;
 711         struct cred *cred;
 712         struct group_info *gi;
 713         unsigned int uid;
 714         unsigned int gid;
 715
 716         uid = user_uid(sess->user);
 717         gid = user_gid(sess->user);
 718         if (share->force_uid != KSMBD_SHARE_INVALID_UID)
 719                 uid = share->force_uid;
 720         if (share->force_gid != KSMBD_SHARE_INVALID_GID)
 721                 gid = share->force_gid;
 722
 723         cred = prepare_kernel_cred(&init_task);
 724         if (!cred)
 725                 return -ENOMEM;
 726
 727         cred->fsuid = make_kuid(&init_user_ns, uid);
 728         cred->fsgid = make_kgid(&init_user_ns, gid);
 729
 730         gi = groups_alloc(0);
 731         if (!gi) {
 732                 abort_creds(cred);
 733                 return -ENOMEM;
 734         }
 735         set_groups(cred, gi);
 736         put_group_info(gi);
 737
 738         if (!uid_eq(cred->fsuid, GLOBAL_ROOT_UID))
 739                 cred->cap_effective = cap_drop_fs_set(cred->cap_effective);
 740
 741         WARN_ON(work->saved_cred);
 742         work->saved_cred = override_creds(cred);
 743         if (!work->saved_cred) {
 744                 abort_creds(cred);
 745                 return -EINVAL;
 746         }
 747         return 0;
 748 }
 749
 750 void ksmbd_revert_fsids(struct ksmbd_work *work)
 751 {
 752         const struct cred *cred;
 753
 754         WARN_ON(!work->saved_cred);
 755
 756         cred = current_cred();
 757         revert_creds(work->saved_cred);
 758         put_cred(cred);
 759         work->saved_cred = NULL;
 760 }
 761
 762 __le32 smb_map_generic_desired_access(__le32 daccess)
 763 {
 764         if (daccess & FILE_GENERIC_READ_LE) {
 765                 daccess |= cpu_to_le32(GENERIC_READ_FLAGS);
 766                 daccess &= ~FILE_GENERIC_READ_LE;
 767         }
 768
 769         if (daccess & FILE_GENERIC_WRITE_LE) {
 770                 daccess |= cpu_to_le32(GENERIC_WRITE_FLAGS);
 771                 daccess &= ~FILE_GENERIC_WRITE_LE;
 772         }
 773
 774         if (daccess & FILE_GENERIC_EXECUTE_LE) {
 775                 daccess |= cpu_to_le32(GENERIC_EXECUTE_FLAGS);
 776                 daccess &= ~FILE_GENERIC_EXECUTE_LE;
 777         }
 778
 779         if (daccess & FILE_GENERIC_ALL_LE) {
 780                 daccess |= cpu_to_le32(GENERIC_ALL_FLAGS);
 781                 daccess &= ~FILE_GENERIC_ALL_LE;
 782         }
 783
 784         return daccess;
 785 }