source3/smbd/filename.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    filename handling routines
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 1999-2007
   6    Copyright (C) Ying Chen 2000
   7    Copyright (C) Volker Lendecke 2007
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 /*
  24  * New hash table stat cache code added by Ying Chen.
  25  */
  26
  27 #include "includes.h"
  28 #include "system/filesys.h"
  29 #include "fake_file.h"
  30 #include "smbd/smbd.h"
  31 #include "smbd/globals.h"
  32 #include "lib/util/memcache.h"
  33
  34 uint32_t ucf_flags_from_smb_request(struct smb_request *req)
  35 {
  36         uint32_t ucf_flags = 0;
  37
  38         if (req == NULL) {
  39                 return 0;
  40         }
  41
  42         if (req->posix_pathnames) {
  43                 ucf_flags |= UCF_POSIX_PATHNAMES;
  44
  45                 if (!req->sconn->using_smb2) {
  46                         ucf_flags |= UCF_LCOMP_LNK_OK;
  47                 }
  48         }
  49         if (req->flags2 & FLAGS2_DFS_PATHNAMES) {
  50                 ucf_flags |= UCF_DFS_PATHNAME;
  51         }
  52         if (req->flags2 & FLAGS2_REPARSE_PATH) {
  53                 ucf_flags |= UCF_GMT_PATHNAME;
  54         }
  55
  56         return ucf_flags;
  57 }
  58
  59 uint32_t filename_create_ucf_flags(struct smb_request *req, uint32_t create_disposition)
  60 {
  61         uint32_t ucf_flags = 0;
  62
  63         ucf_flags |= ucf_flags_from_smb_request(req);
  64
  65         switch (create_disposition) {
  66         case FILE_OPEN:
  67         case FILE_OVERWRITE:
  68                 break;
  69         case FILE_SUPERSEDE:
  70         case FILE_CREATE:
  71         case FILE_OPEN_IF:
  72         case FILE_OVERWRITE_IF:
  73                 ucf_flags |= UCF_PREP_CREATEFILE;
  74                 break;
  75         }
  76
  77         return ucf_flags;
  78 }
  79
  80 /****************************************************************************
  81  Mangle the 2nd name and check if it is then equal to the first name.
  82 ****************************************************************************/
  83
  84 static bool mangled_equal(const char *name1,
  85                         const char *name2,
  86                         const struct share_params *p)
  87 {
  88         char mname[13];
  89
  90         if (!name_to_8_3(name2, mname, False, p)) {
  91                 return False;
  92         }
  93         return strequal(name1, mname);
  94 }
  95
  96 /*
  97  * Strip a valid @GMT-token from any incoming filename path,
  98  * adding any NTTIME encoded in the pathname into the
  99  * twrp field of the passed in smb_fname.
 100  *
 101  * Valid @GMT-tokens look like @GMT-YYYY-MM-DD-HH-MM-SS
 102  * at the *start* of a pathname component.
 103  *
 104  * If twrp is passed in then smb_fname->twrp is set to that
 105  * value, and the @GMT-token part of the filename is removed
 106  * and does not change the stored smb_fname->twrp.
 107  *
 108  */
 109
 110 NTSTATUS canonicalize_snapshot_path(struct smb_filename *smb_fname,
 111                                     uint32_t ucf_flags,
 112                                     NTTIME twrp)
 113 {
 114         bool found;
 115
 116         if (twrp != 0) {
 117                 smb_fname->twrp = twrp;
 118         }
 119
 120         if (!(ucf_flags & UCF_GMT_PATHNAME)) {
 121                 return NT_STATUS_OK;
 122         }
 123
 124         found = extract_snapshot_token(smb_fname->base_name, &twrp);
 125         if (!found) {
 126                 return NT_STATUS_OK;
 127         }
 128
 129         if (smb_fname->twrp == 0) {
 130                 smb_fname->twrp = twrp;
 131         }
 132
 133         return NT_STATUS_OK;
 134 }
 135
 136 static bool strnorm(char *s, int case_default)
 137 {
 138         if (case_default == CASE_UPPER)
 139                 return strupper_m(s);
 140         else
 141                 return strlower_m(s);
 142 }
 143
 144 /*
 145  * Utility function to normalize case on an incoming client filename
 146  * if required on this connection struct.
 147  * Performs an in-place case conversion guaranteed to stay the same size.
 148  */
 149
 150 static NTSTATUS normalize_filename_case(connection_struct *conn,
 151                                         char *filename,
 152                                         uint32_t ucf_flags)
 153 {
 154         bool ok;
 155
 156         if (ucf_flags & UCF_POSIX_PATHNAMES) {
 157                 /*
 158                  * POSIX never normalizes filename case.
 159                  */
 160                 return NT_STATUS_OK;
 161         }
 162         if (!conn->case_sensitive) {
 163                 return NT_STATUS_OK;
 164         }
 165         if (conn->case_preserve) {
 166                 return NT_STATUS_OK;
 167         }
 168         if (conn->short_case_preserve) {
 169                 return NT_STATUS_OK;
 170         }
 171         ok = strnorm(filename, lp_default_case(SNUM(conn)));
 172         if (!ok) {
 173                 return NT_STATUS_INVALID_PARAMETER;
 174         }
 175         return NT_STATUS_OK;
 176 }
 177
 178 /****************************************************************************
 179  Check if two filenames are equal.
 180  This needs to be careful about whether we are case sensitive.
 181 ****************************************************************************/
 182
 183 static bool fname_equal(const char *name1, const char *name2,
 184                 bool case_sensitive)
 185 {
 186         /* Normal filename handling */
 187         if (case_sensitive) {
 188                 return(strcmp(name1,name2) == 0);
 189         }
 190
 191         return(strequal(name1,name2));
 192 }
 193
 194 static bool sname_equal(const char *name1, const char *name2,
 195                 bool case_sensitive)
 196 {
 197         bool match;
 198         const char *s1 = NULL;
 199         const char *s2 = NULL;
 200         size_t n1;
 201         size_t n2;
 202         const char *e1 = NULL;
 203         const char *e2 = NULL;
 204         char *c1 = NULL;
 205         char *c2 = NULL;
 206
 207         match = fname_equal(name1, name2, case_sensitive);
 208         if (match) {
 209                 return true;
 210         }
 211
 212         if (name1[0] != ':') {
 213                 return false;
 214         }
 215         if (name2[0] != ':') {
 216                 return false;
 217         }
 218         s1 = &name1[1];
 219         e1 = strchr(s1, ':');
 220         if (e1 == NULL) {
 221                 n1 = strlen(s1);
 222         } else {
 223                 n1 = PTR_DIFF(e1, s1);
 224         }
 225         s2 = &name2[1];
 226         e2 = strchr(s2, ':');
 227         if (e2 == NULL) {
 228                 n2 = strlen(s2);
 229         } else {
 230                 n2 = PTR_DIFF(e2, s2);
 231         }
 232
 233         /* Normal filename handling */
 234         if (case_sensitive) {
 235                 return (strncmp(s1, s2, n1) == 0);
 236         }
 237
 238         /*
 239          * We can't use strnequal() here
 240          * as it takes the number of codepoints
 241          * and not the number of bytes.
 242          *
 243          * So we make a copy before calling
 244          * strequal().
 245          *
 246          * Note that we TALLOC_FREE() in reverse order
 247          * in order to avoid memory fragmentation.
 248          */
 249
 250         c1 = talloc_strndup(talloc_tos(), s1, n1);
 251         c2 = talloc_strndup(talloc_tos(), s2, n2);
 252         if (c1 == NULL || c2 == NULL) {
 253                 TALLOC_FREE(c2);
 254                 TALLOC_FREE(c1);
 255                 return (strncmp(s1, s2, n1) == 0);
 256         }
 257
 258         match = strequal(c1, c2);
 259         TALLOC_FREE(c2);
 260         TALLOC_FREE(c1);
 261         return match;
 262 }
 263
 264 /****************************************************************************
 265  Scan a directory to find a filename, matching without case sensitivity.
 266  If the name looks like a mangled name then try via the mangling functions
 267 ****************************************************************************/
 268
 269 NTSTATUS get_real_filename_full_scan_at(struct files_struct *dirfsp,
 270                                         const char *name,
 271                                         bool mangled,
 272                                         TALLOC_CTX *mem_ctx,
 273                                         char **found_name)
 274 {
 275         struct connection_struct *conn = dirfsp->conn;
 276         struct smb_Dir *cur_dir = NULL;
 277         const char *dname = NULL;
 278         char *talloced = NULL;
 279         char *unmangled_name = NULL;
 280         long curpos;
 281         NTSTATUS status;
 282
 283         /* If we have a case-sensitive filesystem, it doesn't do us any
 284          * good to search for a name. If a case variation of the name was
 285          * there, then the original stat(2) would have found it.
 286          */
 287         if (!mangled && !(conn->fs_capabilities & FILE_CASE_SENSITIVE_SEARCH)) {
 288                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 289         }
 290
 291         /*
 292          * The incoming name can be mangled, and if we de-mangle it
 293          * here it will not compare correctly against the filename (name2)
 294          * read from the directory and then mangled by the name_to_8_3()
 295          * call. We need to mangle both names or neither.
 296          * (JRA).
 297          *
 298          * Fix for bug found by Dina Fine. If in case sensitive mode then
 299          * the mangle cache is no good (3 letter extension could be wrong
 300          * case - so don't demangle in this case - leave as mangled and
 301          * allow the mangling of the directory entry read (which is done
 302          * case insensitively) to match instead. This will lead to more
 303          * false positive matches but we fail completely without it. JRA.
 304          */
 305
 306         if (mangled && !conn->case_sensitive) {
 307                 mangled = !mangle_lookup_name_from_8_3(talloc_tos(), name,
 308                                                        &unmangled_name,
 309                                                        conn->params);
 310                 if (!mangled) {
 311                         /* Name is now unmangled. */
 312                         name = unmangled_name;
 313                 }
 314         }
 315
 316         /* open the directory */
 317         status = OpenDir_from_pathref(talloc_tos(), dirfsp, NULL, 0, &cur_dir);
 318         if (!NT_STATUS_IS_OK(status)) {
 319                 DBG_NOTICE("scan dir didn't open dir [%s]: %s\n",
 320                            fsp_str_dbg(dirfsp),
 321                            nt_errstr(status));
 322                 TALLOC_FREE(unmangled_name);
 323                 return status;
 324         }
 325
 326         /* now scan for matching names */
 327         curpos = 0;
 328         while ((dname = ReadDirName(cur_dir, &curpos, NULL, &talloced))) {
 329
 330                 /* Is it dot or dot dot. */
 331                 if (ISDOT(dname) || ISDOTDOT(dname)) {
 332                         TALLOC_FREE(talloced);
 333                         continue;
 334                 }
 335
 336                 /*
 337                  * At this point dname is the unmangled name.
 338                  * name is either mangled or not, depending on the state
 339                  * of the "mangled" variable. JRA.
 340                  */
 341
 342                 /*
 343                  * Check mangled name against mangled name, or unmangled name
 344                  * against unmangled name.
 345                  */
 346
 347                 if ((mangled && mangled_equal(name,dname,conn->params)) ||
 348                         fname_equal(name, dname, conn->case_sensitive)) {
 349                         /* we've found the file, change it's name and return */
 350                         *found_name = talloc_strdup(mem_ctx, dname);
 351                         TALLOC_FREE(unmangled_name);
 352                         TALLOC_FREE(cur_dir);
 353                         if (!*found_name) {
 354                                 TALLOC_FREE(talloced);
 355                                 return NT_STATUS_NO_MEMORY;
 356                         }
 357                         TALLOC_FREE(talloced);
 358                         return NT_STATUS_OK;
 359                 }
 360                 TALLOC_FREE(talloced);
 361         }
 362
 363         TALLOC_FREE(unmangled_name);
 364         TALLOC_FREE(cur_dir);
 365         return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 366 }
 367
 368 /****************************************************************************
 369  Wrapper around the vfs get_real_filename and the full directory scan
 370  fallback.
 371 ****************************************************************************/
 372
 373 NTSTATUS get_real_filename_at(struct files_struct *dirfsp,
 374                               const char *name,
 375                               TALLOC_CTX *mem_ctx,
 376                               char **found_name)
 377 {
 378         struct connection_struct *conn = dirfsp->conn;
 379         NTSTATUS status;
 380         bool mangled;
 381
 382         mangled = mangle_is_mangled(name, conn->params);
 383
 384         if (mangled) {
 385                 status = get_real_filename_full_scan_at(
 386                         dirfsp, name, mangled, mem_ctx, found_name);
 387                 return status;
 388         }
 389
 390         /* Try the vfs first to take advantage of case-insensitive stat. */
 391         status = SMB_VFS_GET_REAL_FILENAME_AT(
 392                 dirfsp->conn, dirfsp, name, mem_ctx, found_name);
 393
 394         /*
 395          * If the case-insensitive stat was successful, or returned an error
 396          * other than EOPNOTSUPP then there is no need to fall back on the
 397          * full directory scan.
 398          */
 399         if (NT_STATUS_IS_OK(status) ||
 400             !NT_STATUS_EQUAL(status, NT_STATUS_NOT_SUPPORTED)) {
 401                 return status;
 402         }
 403
 404         status = get_real_filename_full_scan_at(
 405                 dirfsp, name, mangled, mem_ctx, found_name);
 406         return status;
 407 }
 408
 409 /*
 410  * Create the memcache-key for GETREALFILENAME_CACHE: This supplements
 411  * the stat cache for the last component to be looked up. Cache
 412  * contents is the correctly capitalized translation of the parameter
 413  * "name" as it exists on disk. This is indexed by inode of the dirfsp
 414  * and name, and contrary to stat_cahce_lookup() it does not
 415  * vfs_stat() the last component. This will be taken care of by an
 416  * attempt to do a openat_pathref_fsp().
 417  */
 418 static bool get_real_filename_cache_key(
 419         TALLOC_CTX *mem_ctx,
 420         struct files_struct *dirfsp,
 421         const char *name,
 422         DATA_BLOB *_key)
 423 {
 424         struct file_id fid = vfs_file_id_from_sbuf(
 425                 dirfsp->conn, &dirfsp->fsp_name->st);
 426         char *upper = NULL;
 427         uint8_t *key = NULL;
 428         size_t namelen, keylen;
 429
 430         upper = talloc_strdup_upper(mem_ctx, name);
 431         if (upper == NULL) {
 432                 return false;
 433         }
 434         namelen = talloc_get_size(upper);
 435
 436         keylen = namelen + sizeof(fid);
 437         if (keylen < sizeof(fid)) {
 438                 TALLOC_FREE(upper);
 439                 return false;
 440         }
 441
 442         key = talloc_size(mem_ctx, keylen);
 443         if (key == NULL) {
 444                 TALLOC_FREE(upper);
 445                 return false;
 446         }
 447
 448         memcpy(key, &fid, sizeof(fid));
 449         memcpy(key + sizeof(fid), upper, namelen);
 450         TALLOC_FREE(upper);
 451
 452         *_key = (DATA_BLOB) { .data = key, .length = keylen, };
 453         return true;
 454 }
 455
 456 /*
 457  * Lightweight function to just get last component
 458  * for rename / enumerate directory calls.
 459  */
 460
 461 char *get_original_lcomp(TALLOC_CTX *ctx,
 462                         connection_struct *conn,
 463                         const char *filename_in,
 464                         uint32_t ucf_flags)
 465 {
 466         char *last_slash = NULL;
 467         char *orig_lcomp;
 468         NTSTATUS status;
 469
 470         last_slash = strrchr(filename_in, '/');
 471         if (last_slash != NULL) {
 472                 orig_lcomp = talloc_strdup(ctx, last_slash+1);
 473         } else {
 474                 orig_lcomp = talloc_strdup(ctx, filename_in);
 475         }
 476         if (orig_lcomp == NULL) {
 477                 return NULL;
 478         }
 479         status = normalize_filename_case(conn, orig_lcomp, ucf_flags);
 480         if (!NT_STATUS_IS_OK(status)) {
 481                 TALLOC_FREE(orig_lcomp);
 482                 return NULL;
 483         }
 484         return orig_lcomp;
 485 }
 486
 487 /*
 488  * Deal with the SMB1 semantics of sending a pathname with a
 489  * wildcard as the terminal component for a SMB1search or
 490  * trans2 findfirst.
 491  */
 492
 493 NTSTATUS filename_convert_smb1_search_path(TALLOC_CTX *ctx,
 494                                            connection_struct *conn,
 495                                            char *name_in,
 496                                            uint32_t ucf_flags,
 497                                            struct files_struct **_dirfsp,
 498                                            struct smb_filename **_smb_fname_out,
 499                                            char **_mask_out)
 500 {
 501         NTSTATUS status;
 502         char *p = NULL;
 503         char *mask = NULL;
 504         struct smb_filename *smb_fname = NULL;
 505         NTTIME twrp = 0;
 506
 507         *_smb_fname_out = NULL;
 508         *_dirfsp = NULL;
 509         *_mask_out = NULL;
 510
 511         DBG_DEBUG("name_in: %s\n", name_in);
 512
 513         if (ucf_flags & UCF_GMT_PATHNAME) {
 514                 extract_snapshot_token(name_in, &twrp);
 515                 ucf_flags &= ~UCF_GMT_PATHNAME;
 516         }
 517
 518         /* Get the original lcomp. */
 519         mask = get_original_lcomp(ctx,
 520                                   conn,
 521                                   name_in,
 522                                   ucf_flags);
 523         if (mask == NULL) {
 524                 return NT_STATUS_NO_MEMORY;
 525         }
 526
 527         if (mask[0] == '\0') {
 528                 /* Windows and OS/2 systems treat search on the root as * */
 529                 TALLOC_FREE(mask);
 530                 mask = talloc_strdup(ctx, "*");
 531                 if (mask == NULL) {
 532                         return NT_STATUS_NO_MEMORY;
 533                 }
 534         }
 535
 536         DBG_DEBUG("mask = %s\n", mask);
 537
 538         /*
 539          * Remove the terminal component so
 540          * filename_convert_dirfsp never sees the mask.
 541          */
 542         p = strrchr_m(name_in,'/');
 543         if (p == NULL) {
 544                 /* filename_convert_dirfsp handles a '\0' name. */
 545                 name_in[0] = '\0';
 546         } else {
 547                 *p = '\0';
 548         }
 549
 550         DBG_DEBUG("For filename_convert_dirfsp: name_in = %s\n",
 551                 name_in);
 552
 553         /* Convert the parent directory path. */
 554         status = filename_convert_dirfsp(ctx,
 555                                          conn,
 556                                          name_in,
 557                                          ucf_flags,
 558                                          twrp,
 559                                          _dirfsp,
 560                                          &smb_fname);
 561
 562         if (!NT_STATUS_IS_OK(status)) {
 563                 DBG_DEBUG("filename_convert error for %s: %s\n",
 564                         name_in,
 565                         nt_errstr(status));
 566         }
 567
 568         *_smb_fname_out = talloc_move(ctx, &smb_fname);
 569         *_mask_out = talloc_move(ctx, &mask);
 570
 571         return status;
 572 }
 573
 574 /*
 575  * Get the correct capitalized stream name hanging off
 576  * base_fsp. Equivalent of get_real_filename(), but for streams.
 577  */
 578 static NTSTATUS get_real_stream_name(
 579         TALLOC_CTX *mem_ctx,
 580         struct files_struct *base_fsp,
 581         const char *stream_name,
 582         char **_found)
 583 {
 584         unsigned int i, num_streams = 0;
 585         struct stream_struct *streams = NULL;
 586         NTSTATUS status;
 587
 588         status = vfs_fstreaminfo(
 589                 base_fsp, talloc_tos(), &num_streams, &streams);
 590         if (!NT_STATUS_IS_OK(status)) {
 591                 return status;
 592         }
 593
 594         for (i=0; i<num_streams; i++) {
 595                 bool equal = sname_equal(stream_name, streams[i].name, false);
 596
 597                 DBG_DEBUG("comparing [%s] and [%s]: %sequal\n",
 598                           stream_name,
 599                           streams[i].name,
 600                           equal ? "" : "not ");
 601
 602                 if (equal) {
 603                         *_found = talloc_move(mem_ctx, &streams[i].name);
 604                         TALLOC_FREE(streams);
 605                         return NT_STATUS_OK;
 606                 }
 607         }
 608
 609         TALLOC_FREE(streams);
 610         return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 611 }
 612
 613 static bool filename_split_lcomp(
 614         TALLOC_CTX *mem_ctx,
 615         const char *name_in,
 616         bool posix,
 617         char **_dirname,
 618         const char **_fname_rel,
 619         const char **_streamname)
 620 {
 621         const char *lcomp = NULL;
 622         const char *fname_rel = NULL;
 623         const char *streamname = NULL;
 624         char *dirname = NULL;
 625
 626         if (name_in[0] == '\0') {
 627                 fname_rel = ".";
 628                 dirname = talloc_strdup(mem_ctx, "");
 629                 if (dirname == NULL) {
 630                         return false;
 631                 }
 632                 goto done;
 633         }
 634
 635         lcomp = strrchr_m(name_in, '/');
 636         if (lcomp != NULL) {
 637                 fname_rel = lcomp+1;
 638                 dirname = talloc_strndup(mem_ctx, name_in, lcomp - name_in);
 639                 if (dirname == NULL) {
 640                         return false;
 641                 }
 642                 goto find_stream;
 643         }
 644
 645         /*
 646          * No slash, dir is emtpy
 647          */
 648         dirname = talloc_strdup(mem_ctx, "");
 649         if (dirname == NULL) {
 650                 return false;
 651         }
 652
 653         if (!posix && (name_in[0] == ':')) {
 654                 /*
 655                  * Special case for stream on root directory
 656                  */
 657                 fname_rel = ".";
 658                 streamname = name_in;
 659                 goto done;
 660         }
 661
 662         fname_rel = name_in;
 663
 664 find_stream:
 665         if (!posix) {
 666                 streamname = strchr_m(fname_rel, ':');
 667
 668                 if (streamname != NULL) {
 669                         fname_rel = talloc_strndup(
 670                                 mem_ctx,
 671                                 fname_rel,
 672                                 streamname - fname_rel);
 673                         if (fname_rel == NULL) {
 674                                 TALLOC_FREE(dirname);
 675                                 return false;
 676                         }
 677                 }
 678         }
 679
 680 done:
 681         *_dirname = dirname;
 682         *_fname_rel = fname_rel;
 683         *_streamname = streamname;
 684         return true;
 685 }
 686
 687 /*
 688  * Create the correct capitalization of a file name to be created.
 689  */
 690 static NTSTATUS filename_convert_normalize_new(
 691         TALLOC_CTX *mem_ctx,
 692         struct connection_struct *conn,
 693         char *name_in,
 694         char **_normalized)
 695 {
 696         char *name = name_in;
 697
 698         *_normalized = NULL;
 699
 700         if (!conn->case_preserve ||
 701             (mangle_is_8_3(name, false,
 702                            conn->params) &&
 703              !conn->short_case_preserve)) {
 704
 705                 char *normalized = talloc_strdup(mem_ctx, name);
 706                 if (normalized == NULL) {
 707                         return NT_STATUS_NO_MEMORY;
 708                 }
 709
 710                 strnorm(normalized, lp_default_case(SNUM(conn)));
 711                 name = normalized;
 712         }
 713
 714         if (mangle_is_mangled(name, conn->params)) {
 715                 bool found;
 716                 char *unmangled = NULL;
 717
 718                 found = mangle_lookup_name_from_8_3(
 719                         mem_ctx, name, &unmangled, conn->params);
 720                 if (found) {
 721                         name = unmangled;
 722                 }
 723         }
 724
 725         if (name != name_in) {
 726                 *_normalized = name;
 727         }
 728
 729         return NT_STATUS_OK;
 730 }
 731
 732 /*
 733  * Open smb_fname_rel->fsp as a pathref fsp with a case insensitive
 734  * fallback using GETREALFILENAME_CACHE and get_real_filename_at() if
 735  * the first attempt based on the filename sent by the client gives
 736  * ENOENT.
 737  */
 738 static NTSTATUS openat_pathref_fsp_case_insensitive(
 739         struct files_struct *dirfsp,
 740         struct smb_filename *smb_fname_rel,
 741         uint32_t ucf_flags)
 742 {
 743         const bool posix = (ucf_flags & UCF_POSIX_PATHNAMES);
 744         DATA_BLOB cache_key = { .data = NULL, };
 745         char *found_name = NULL;
 746         NTSTATUS status;
 747         bool ok;
 748
 749         SET_STAT_INVALID(smb_fname_rel->st);
 750
 751         /* Check veto files - only looks at last component. */
 752         if (IS_VETO_PATH(dirfsp->conn, smb_fname_rel->base_name)) {
 753                 DBG_DEBUG("veto files rejecting last component %s\n",
 754                           smb_fname_str_dbg(smb_fname_rel));
 755                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 756         }
 757
 758         status = openat_pathref_fsp(dirfsp, smb_fname_rel);
 759
 760         if (NT_STATUS_IS_OK(status)) {
 761                 return NT_STATUS_OK;
 762         }
 763
 764         if (VALID_STAT(smb_fname_rel->st)) {
 765                 /*
 766                  * We got an error although the object existed. Might
 767                  * be a symlink we don't want.
 768                  */
 769                 return status;
 770         }
 771
 772         if (!NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
 773                 /*
 774                  * Only retry on ENOENT
 775                  */
 776                 return status;
 777         }
 778
 779         if (posix || dirfsp->conn->case_sensitive) {
 780                 /*
 781                  * Only return case insensitive if required
 782                  */
 783                 return status;
 784         }
 785
 786         if (lp_stat_cache()) {
 787                 char *base_name = smb_fname_rel->base_name;
 788                 DATA_BLOB value = { .data = NULL };
 789
 790                 ok = get_real_filename_cache_key(
 791                         talloc_tos(), dirfsp, base_name, &cache_key);
 792                 if (!ok) {
 793                         /*
 794                          * probably ENOMEM, just bail
 795                          */
 796                         return status;
 797                 }
 798
 799                 DO_PROFILE_INC(statcache_lookups);
 800
 801                 ok = memcache_lookup(
 802                         NULL, GETREALFILENAME_CACHE, cache_key, &value);
 803                 if (!ok) {
 804                         DO_PROFILE_INC(statcache_misses);
 805                         goto lookup;
 806                 }
 807                 DO_PROFILE_INC(statcache_hits);
 808
 809                 TALLOC_FREE(smb_fname_rel->base_name);
 810                 smb_fname_rel->base_name = talloc_memdup(
 811                         smb_fname_rel, value.data, value.length);
 812                 if (smb_fname_rel->base_name == NULL) {
 813                         TALLOC_FREE(cache_key.data);
 814                         return NT_STATUS_NO_MEMORY;
 815                 }
 816
 817                 if (IS_VETO_PATH(dirfsp->conn, smb_fname_rel->base_name)) {
 818                         DBG_DEBUG("veto files rejecting last component %s\n",
 819                                   smb_fname_str_dbg(smb_fname_rel));
 820                         TALLOC_FREE(cache_key.data);
 821                         return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 822                 }
 823
 824                 status = openat_pathref_fsp(dirfsp, smb_fname_rel);
 825                 if (NT_STATUS_IS_OK(status)) {
 826                         TALLOC_FREE(cache_key.data);
 827                         return NT_STATUS_OK;
 828                 }
 829
 830                 memcache_delete(NULL, GETREALFILENAME_CACHE, cache_key);
 831         }
 832
 833 lookup:
 834         status = get_real_filename_at(
 835                 dirfsp, smb_fname_rel->base_name, smb_fname_rel, &found_name);
 836         if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED) &&
 837             (ucf_flags & UCF_PREP_CREATEFILE)) {
 838                 /*
 839                  * dropbox
 840                  */
 841                 status = NT_STATUS_OBJECT_NAME_NOT_FOUND;
 842         }
 843
 844         if (NT_STATUS_IS_OK(status)) {
 845                 TALLOC_FREE(smb_fname_rel->base_name);
 846                 smb_fname_rel->base_name = found_name;
 847
 848                 if (IS_VETO_PATH(dirfsp->conn, smb_fname_rel->base_name)) {
 849                         DBG_DEBUG("veto files rejecting last component %s\n",
 850                                 smb_fname_str_dbg(smb_fname_rel));
 851                         return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 852                 }
 853
 854                 status = openat_pathref_fsp(dirfsp, smb_fname_rel);
 855         }
 856
 857         if (NT_STATUS_IS_OK(status) && (cache_key.data != NULL)) {
 858                 DATA_BLOB value = {
 859                         .data = (uint8_t *)smb_fname_rel->base_name,
 860                         .length = strlen(smb_fname_rel->base_name) + 1,
 861                 };
 862
 863                 memcache_add(NULL, GETREALFILENAME_CACHE, cache_key, value);
 864         }
 865
 866         TALLOC_FREE(cache_key.data);
 867
 868         return status;
 869 }
 870
 871 static const char *previous_slash(const char *name_in, const char *slash)
 872 {
 873         const char *prev = name_in;
 874
 875         while (true) {
 876                 const char *next = strchr_m(prev, '/');
 877
 878                 SMB_ASSERT(next != NULL); /* we have at least one slash */
 879
 880                 if (next == slash) {
 881                         break;
 882                 }
 883
 884                 prev = next+1;
 885         };
 886
 887         if (prev == name_in) {
 888                 /* no previous slash */
 889                 return NULL;
 890         }
 891
 892         return prev;
 893 }
 894
 895 static char *symlink_target_path(
 896         TALLOC_CTX *mem_ctx,
 897         const char *name_in,
 898         const char *substitute,
 899         size_t unparsed)
 900 {
 901         size_t name_in_len = strlen(name_in);
 902         const char *p_unparsed = NULL;
 903         const char *parent = NULL;
 904         char *ret;
 905
 906         SMB_ASSERT(unparsed <= name_in_len);
 907
 908         p_unparsed = name_in + (name_in_len - unparsed);
 909
 910         if (substitute[0] == '/') {
 911                 ret = talloc_asprintf(mem_ctx, "%s%s", substitute, p_unparsed);
 912                 return ret;
 913         }
 914
 915         if (unparsed == 0) {
 916                 parent = strrchr_m(name_in, '/');
 917         } else {
 918                 parent = previous_slash(name_in, p_unparsed);
 919         }
 920
 921         if (parent == NULL) {
 922                 /* no previous slash */
 923                 parent = name_in;
 924         }
 925
 926         ret = talloc_asprintf(
 927                 mem_ctx,
 928                 "%.*s%s%s",
 929                 (int)(parent - name_in),
 930                 name_in,
 931                 substitute,
 932                 p_unparsed);
 933         return ret;
 934 }
 935
 936 static NTSTATUS safe_symlink_target_path(
 937         TALLOC_CTX *mem_ctx,
 938         const char *connectpath,
 939         const char *name_in,
 940         const char *substitute,
 941         size_t unparsed,
 942         char **_name_out)
 943 {
 944         char *target = NULL;
 945         char *abs_target = NULL;
 946         char *abs_target_canon = NULL;
 947         const char *relative = NULL;
 948         char *name_out = NULL;
 949         NTSTATUS status = NT_STATUS_NO_MEMORY;
 950         bool in_share;
 951
 952         target = symlink_target_path(mem_ctx, name_in, substitute, unparsed);
 953         if (target == NULL) {
 954                 goto fail;
 955         }
 956
 957         DBG_DEBUG("name_in: %s, substitute: %s, unparsed: %zu, target=%s\n",
 958                   name_in,
 959                   substitute,
 960                   unparsed,
 961                   target);
 962
 963         if (target[0] == '/') {
 964                 abs_target = target;
 965         } else {
 966                 abs_target = talloc_asprintf(
 967                         target, "%s/%s", connectpath, target);
 968                 if (abs_target == NULL) {
 969                         goto fail;
 970                 }
 971         }
 972
 973         abs_target_canon = canonicalize_absolute_path(target, abs_target);
 974         if (abs_target_canon == NULL) {
 975                 goto fail;
 976         }
 977
 978         DBG_DEBUG("abs_target_canon=%s\n", abs_target_canon);
 979
 980         in_share = subdir_of(
 981                 connectpath, strlen(connectpath), abs_target_canon, &relative);
 982         if (!in_share) {
 983                 DBG_DEBUG("wide link to %s\n", abs_target_canon);
 984                 status = NT_STATUS_OBJECT_PATH_NOT_FOUND;
 985                 goto fail;
 986         }
 987
 988         name_out = talloc_strdup(mem_ctx, relative);
 989         if (name_out == NULL) {
 990                 goto fail;
 991         }
 992
 993         status = NT_STATUS_OK;
 994         *_name_out = name_out;
 995 fail:
 996         TALLOC_FREE(target);
 997         return status;
 998 }
 999
1000 /*
1001  * Split up name_in as sent by the client into a directory pathref fsp
1002  * and a relative smb_filename.
1003  */
1004 static NTSTATUS filename_convert_dirfsp_nosymlink(
1005         TALLOC_CTX *mem_ctx,
1006         connection_struct *conn,
1007         const char *name_in,
1008         uint32_t ucf_flags,
1009         NTTIME twrp,
1010         struct files_struct **_dirfsp,
1011         struct smb_filename **_smb_fname,
1012         char **_substitute,
1013         size_t *_unparsed)
1014 {
1015         struct smb_filename *smb_dirname = NULL;
1016         struct smb_filename *smb_fname_rel = NULL;
1017         struct smb_filename *smb_fname = NULL;
1018         const bool posix = (ucf_flags & UCF_POSIX_PATHNAMES);
1019         char *dirname = NULL;
1020         const char *fname_rel = NULL;
1021         const char *streamname = NULL;
1022         char *saved_streamname = NULL;
1023         struct files_struct *base_fsp = NULL;
1024         bool ok;
1025         NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
1026
1027         if (ucf_flags & UCF_DFS_PATHNAME) {
1028                 /*
1029                  * We've been given a raw DFS pathname.
1030                  */
1031                 char *pathname = NULL;
1032                 DBG_DEBUG("Before dfs_filename_convert name_in: %s\n",
1033                           name_in);
1034                 status = dfs_filename_convert(mem_ctx,
1035                                               conn,
1036                                               ucf_flags,
1037                                               name_in,
1038                                               &pathname);
1039                 if (!NT_STATUS_IS_OK(status)) {
1040                         DBG_DEBUG("dfs_filename_convert "
1041                                 "failed for name %s with %s\n",
1042                                 name_in,
1043                                 nt_errstr(status));
1044                         return status;
1045                 }
1046                 ucf_flags &= ~UCF_DFS_PATHNAME;
1047                 name_in = pathname;
1048                 DBG_DEBUG("After dfs_filename_convert name_in: %s\n",
1049                           name_in);
1050         }
1051
1052         if (is_fake_file_path(name_in)) {
1053                 smb_fname = synthetic_smb_fname_split(mem_ctx, name_in, posix);
1054                 if (smb_fname == NULL) {
1055                         return NT_STATUS_NO_MEMORY;
1056                 }
1057                 smb_fname->st = (SMB_STRUCT_STAT) { .st_ex_nlink = 1 };
1058                 smb_fname->st.st_ex_btime =
1059                         (struct timespec){0, SAMBA_UTIME_OMIT};
1060                 smb_fname->st.st_ex_atime =
1061                         (struct timespec){0, SAMBA_UTIME_OMIT};
1062                 smb_fname->st.st_ex_mtime =
1063                         (struct timespec){0, SAMBA_UTIME_OMIT};
1064                 smb_fname->st.st_ex_ctime =
1065                         (struct timespec){0, SAMBA_UTIME_OMIT};
1066
1067                 *_dirfsp = conn->cwd_fsp;
1068                 *_smb_fname = smb_fname;
1069                 return NT_STATUS_OK;
1070         }
1071
1072         /*
1073          * Catch an invalid path of "." before we
1074          * call filename_split_lcomp(). We need to
1075          * do this as filename_split_lcomp() will
1076          * use "." for the missing relative component
1077          * when an empty name_in path is sent by
1078          * the client.
1079          */
1080         if (ISDOT(name_in)) {
1081                 status = NT_STATUS_OBJECT_NAME_INVALID;
1082                 goto fail;
1083         }
1084
1085         ok = filename_split_lcomp(
1086                 talloc_tos(),
1087                 name_in,
1088                 posix,
1089                 &dirname,
1090                 &fname_rel,
1091                 &streamname);
1092         if (!ok) {
1093                 status = NT_STATUS_NO_MEMORY;
1094                 goto fail;
1095         }
1096
1097         if ((streamname != NULL) &&
1098             ((conn->fs_capabilities & FILE_NAMED_STREAMS) == 0)) {
1099                 status = NT_STATUS_OBJECT_NAME_INVALID;
1100                 goto fail;
1101         }
1102
1103         if (!posix) {
1104                 bool name_has_wild = ms_has_wild(dirname);
1105                 name_has_wild |= ms_has_wild(fname_rel);
1106                 if (name_has_wild) {
1107                         status = NT_STATUS_OBJECT_NAME_INVALID;
1108                         goto fail;
1109                 }
1110         }
1111
1112         if (dirname[0] == '\0') {
1113                 status = synthetic_pathref(
1114                         mem_ctx,
1115                         conn->cwd_fsp,
1116                         ".",
1117                         NULL,
1118                         NULL,
1119                         0,
1120                         posix ? SMB_FILENAME_POSIX_PATH : 0,
1121                         &smb_dirname);
1122         } else {
1123                 char *substitute = NULL;
1124                 size_t unparsed = 0;
1125
1126                 status = normalize_filename_case(conn, dirname, ucf_flags);
1127                 if (!NT_STATUS_IS_OK(status)) {
1128                         DBG_ERR("normalize_filename_case %s failed: %s\n",
1129                                 dirname,
1130                                 nt_errstr(status));
1131                         goto fail;
1132                 }
1133
1134                 status = openat_pathref_dirfsp_nosymlink(
1135                         mem_ctx,
1136                         conn,
1137                         dirname,
1138                         0,
1139                         posix,
1140                         &smb_dirname,
1141                         &unparsed,
1142                         &substitute);
1143
1144                 if (NT_STATUS_EQUAL(status, NT_STATUS_STOPPED_ON_SYMLINK)) {
1145
1146                         size_t name_in_len = strlen(name_in);
1147                         size_t dirname_len = strlen(dirname);
1148
1149                         SMB_ASSERT(name_in_len >= dirname_len);
1150
1151                         *_substitute = substitute;
1152                         *_unparsed = unparsed + (name_in_len - dirname_len);
1153
1154                         goto fail;
1155                 }
1156         }
1157
1158         if (!NT_STATUS_IS_OK(status)) {
1159                 DBG_DEBUG("opening directory %s failed: %s\n",
1160                           dirname,
1161                           nt_errstr(status));
1162                 TALLOC_FREE(dirname);
1163
1164                 if (NT_STATUS_EQUAL(status, NT_STATUS_PATH_NOT_COVERED)) {
1165                         /* MS-DFS error must propagate back out. */
1166                         goto fail;
1167                 }
1168
1169                 if (!NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
1170                         /*
1171                          * Except ACCESS_DENIED, everything else leads
1172                          * to PATH_NOT_FOUND.
1173                          */
1174                         status = NT_STATUS_OBJECT_PATH_NOT_FOUND;
1175                 }
1176
1177                 goto fail;
1178         }
1179
1180         if (!VALID_STAT_OF_DIR(smb_dirname->st)) {
1181                 status = NT_STATUS_OBJECT_PATH_NOT_FOUND;
1182                 goto fail;
1183         }
1184
1185         /*
1186          * Only look at bad last component values
1187          * once we know we have a valid directory. That
1188          * way we won't confuse error messages from
1189          * opening the directory path with error
1190          * messages from a bad last component.
1191          */
1192
1193         /* Relative filename can't be empty */
1194         if (fname_rel[0] == '\0') {
1195                 status = NT_STATUS_OBJECT_NAME_INVALID;
1196                 goto fail;
1197         }
1198
1199         /* Relative filename can't be ".." */
1200         if (ISDOTDOT(fname_rel)) {
1201                 status = NT_STATUS_OBJECT_NAME_INVALID;
1202                 goto fail;
1203         }
1204         /* Relative name can only be dot if directory is empty. */
1205         if (ISDOT(fname_rel) && dirname[0] != '\0') {
1206                 status = NT_STATUS_OBJECT_NAME_INVALID;
1207                 goto fail;
1208         }
1209
1210         TALLOC_FREE(dirname);
1211
1212         smb_fname_rel = synthetic_smb_fname(
1213                 mem_ctx,
1214                 fname_rel,
1215                 streamname,
1216                 NULL,
1217                 twrp,
1218                 posix ? SMB_FILENAME_POSIX_PATH : 0);
1219         if (smb_fname_rel == NULL) {
1220                 status = NT_STATUS_NO_MEMORY;
1221                 goto fail;
1222         }
1223
1224         if ((conn->fs_capabilities & FILE_NAMED_STREAMS) &&
1225             is_named_stream(smb_fname_rel)) {
1226                 /*
1227                  * Find the base_fsp first without the stream.
1228                  */
1229                 saved_streamname = smb_fname_rel->stream_name;
1230                 smb_fname_rel->stream_name = NULL;
1231         }
1232
1233         status = normalize_filename_case(
1234                 conn, smb_fname_rel->base_name, ucf_flags);
1235         if (!NT_STATUS_IS_OK(status)) {
1236                 DBG_ERR("normalize_filename_case %s failed: %s\n",
1237                         smb_fname_rel->base_name,
1238                         nt_errstr(status));
1239                 goto fail;
1240         }
1241
1242         status = openat_pathref_fsp_case_insensitive(
1243                 smb_dirname->fsp, smb_fname_rel, ucf_flags);
1244
1245         if (NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND) &&
1246             VALID_STAT(smb_fname_rel->st) &&
1247             S_ISLNK(smb_fname_rel->st.st_ex_mode)) {
1248
1249                 /*
1250                  * If we're on an MSDFS share, see if this is
1251                  * an MSDFS link.
1252                  */
1253                 if (lp_host_msdfs() &&
1254                     lp_msdfs_root(SNUM(conn)) &&
1255                     is_msdfs_link(smb_dirname->fsp, smb_fname_rel))
1256                 {
1257                         status = NT_STATUS_PATH_NOT_COVERED;
1258                         goto fail;
1259                 }
1260
1261 #if defined(WITH_SMB1SERVER)
1262                 /*
1263                  * In SMB1 posix mode, if this is a symlink,
1264                  * allow access to the name with a NULL smb_fname->fsp.
1265                  */
1266                 if (ucf_flags & UCF_LCOMP_LNK_OK) {
1267                         SMB_ASSERT(smb_fname_rel->fsp == NULL);
1268                         SMB_ASSERT(streamname == NULL);
1269
1270                         smb_fname = full_path_from_dirfsp_atname(
1271                                 mem_ctx,
1272                                 smb_dirname->fsp,
1273                                 smb_fname_rel);
1274                         if (smb_fname == NULL) {
1275                                 status = NT_STATUS_NO_MEMORY;
1276                                 goto fail;
1277                         }
1278                         goto done;
1279                 }
1280 #endif
1281         }
1282
1283         if (NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND) &&
1284             !VALID_STAT(smb_fname_rel->st)) {
1285
1286                 char *normalized = NULL;
1287
1288                 /*
1289                  * Creating a new file
1290                  */
1291
1292                 status = filename_convert_normalize_new(
1293                         smb_fname_rel,
1294                         conn,
1295                         smb_fname_rel->base_name,
1296                         &normalized);
1297                 if (!NT_STATUS_IS_OK(status)) {
1298                         DBG_DEBUG("filename_convert_normalize_new failed: "
1299                                   "%s\n",
1300                                   nt_errstr(status));
1301                         goto fail;
1302                 }
1303                 if (normalized != NULL) {
1304                         smb_fname_rel->base_name = normalized;
1305                 }
1306
1307                 smb_fname_rel->stream_name = saved_streamname;
1308
1309                 smb_fname = full_path_from_dirfsp_atname(
1310                         mem_ctx, smb_dirname->fsp, smb_fname_rel);
1311                 if (smb_fname == NULL) {
1312                         status = NT_STATUS_NO_MEMORY;
1313                         goto fail;
1314                 }
1315                 goto done;
1316         }
1317
1318         if (!NT_STATUS_IS_OK(status)) {
1319                 goto fail;
1320         }
1321
1322         if (saved_streamname == NULL) {
1323                 /* smb_fname must be allocated off mem_ctx. */
1324                 smb_fname = cp_smb_filename(mem_ctx,
1325                                             smb_fname_rel->fsp->fsp_name);
1326                 if (smb_fname == NULL) {
1327                         goto fail;
1328                 }
1329                 status = move_smb_fname_fsp_link(smb_fname, smb_fname_rel);
1330                 if (!NT_STATUS_IS_OK(status)) {
1331                         goto fail;
1332                 }
1333                 goto done;
1334         }
1335
1336         base_fsp = smb_fname_rel->fsp;
1337         smb_fname_fsp_unlink(smb_fname_rel);
1338         SET_STAT_INVALID(smb_fname_rel->st);
1339
1340         smb_fname_rel->stream_name = saved_streamname;
1341
1342         status = open_stream_pathref_fsp(&base_fsp, smb_fname_rel);
1343
1344         if (NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND) &&
1345             !conn->case_sensitive) {
1346                 char *found = NULL;
1347
1348                 status = get_real_stream_name(
1349                         smb_fname_rel,
1350                         base_fsp,
1351                         smb_fname_rel->stream_name,
1352                         &found);
1353
1354                 if (NT_STATUS_IS_OK(status)) {
1355                         smb_fname_rel->stream_name = found;
1356                         found = NULL;
1357                         status = open_stream_pathref_fsp(
1358                                 &base_fsp, smb_fname_rel);
1359                 }
1360         }
1361
1362         if (NT_STATUS_IS_OK(status)) {
1363                 /* smb_fname must be allocated off mem_ctx. */
1364                 smb_fname = cp_smb_filename(mem_ctx,
1365                                             smb_fname_rel->fsp->fsp_name);
1366                 if (smb_fname == NULL) {
1367                         goto fail;
1368                 }
1369                 status = move_smb_fname_fsp_link(smb_fname, smb_fname_rel);
1370                 if (!NT_STATUS_IS_OK(status)) {
1371                         goto fail;
1372                 }
1373                 goto done;
1374         }
1375
1376         if (NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
1377                 /*
1378                  * Creating a new stream
1379                  *
1380                  * We should save the already-open base fsp for
1381                  * create_file_unixpath() somehow.
1382                  */
1383                 smb_fname = full_path_from_dirfsp_atname(
1384                         mem_ctx, smb_dirname->fsp, smb_fname_rel);
1385                 if (smb_fname == NULL) {
1386                         status = NT_STATUS_NO_MEMORY;
1387                         goto fail;
1388                 }
1389                 goto done;
1390         }
1391
1392         if (!NT_STATUS_IS_OK(status)) {
1393                 goto fail;
1394         }
1395
1396 done:
1397         *_dirfsp = smb_dirname->fsp;
1398         *_smb_fname = smb_fname;
1399
1400         smb_fname_fsp_unlink(smb_fname_rel);
1401         TALLOC_FREE(smb_fname_rel);
1402         return NT_STATUS_OK;
1403
1404 fail:
1405         TALLOC_FREE(dirname);
1406         TALLOC_FREE(smb_dirname);
1407         TALLOC_FREE(smb_fname_rel);
1408         return status;
1409 }
1410
1411 NTSTATUS filename_convert_dirfsp(
1412         TALLOC_CTX *mem_ctx,
1413         connection_struct *conn,
1414         const char *name_in,
1415         uint32_t ucf_flags,
1416         NTTIME twrp,
1417         struct files_struct **_dirfsp,
1418         struct smb_filename **_smb_fname)
1419 {
1420         char *substitute = NULL;
1421         size_t unparsed = 0;
1422         NTSTATUS status;
1423         char *target = NULL;
1424         size_t symlink_redirects = 0;
1425
1426 next:
1427         if (symlink_redirects > 40) {
1428                 return NT_STATUS_OBJECT_PATH_NOT_FOUND;
1429         }
1430
1431         status = filename_convert_dirfsp_nosymlink(
1432                 mem_ctx,
1433                 conn,
1434                 name_in,
1435                 ucf_flags,
1436                 twrp,
1437                 _dirfsp,
1438                 _smb_fname,
1439                 &substitute,
1440                 &unparsed);
1441
1442         if (!NT_STATUS_EQUAL(status, NT_STATUS_STOPPED_ON_SYMLINK)) {
1443                 return status;
1444         }
1445
1446         if (!lp_follow_symlinks(SNUM(conn))) {
1447                 return NT_STATUS_OBJECT_PATH_NOT_FOUND;
1448         }
1449
1450         /*
1451          * Right now, SMB2 and SMB1 always traverse symlinks
1452          * within the share. SMB1+POSIX traverses non-terminal
1453          * symlinks within the share.
1454          *
1455          * When we add SMB2+POSIX we need to return
1456          * a NT_STATUS_STOPPED_ON_SYMLINK error here, using the
1457          * symlink target data read below if SMB2+POSIX has
1458          * UCF_POSIX_PATHNAMES set to cause the client to
1459          * resolve all symlinks locally.
1460          */
1461
1462         status = safe_symlink_target_path(
1463                 mem_ctx,
1464                 conn->connectpath,
1465                 name_in,
1466                 substitute,
1467                 unparsed,
1468                 &target);
1469         if (!NT_STATUS_IS_OK(status)) {
1470                 return status;
1471         }
1472         name_in = target;
1473
1474         symlink_redirects += 1;
1475
1476         goto next;
1477 }
1478
1479 /*
1480  * Build the full path from a dirfsp and dirfsp relative name
1481  */
1482 struct smb_filename *full_path_from_dirfsp_atname(
1483         TALLOC_CTX *mem_ctx,
1484         const struct files_struct *dirfsp,
1485         const struct smb_filename *atname)
1486 {
1487         struct smb_filename *fname = NULL;
1488         char *path = NULL;
1489
1490         if (dirfsp == dirfsp->conn->cwd_fsp ||
1491             ISDOT(dirfsp->fsp_name->base_name) ||
1492             atname->base_name[0] == '/')
1493         {
1494                 path = talloc_strdup(mem_ctx, atname->base_name);
1495         } else {
1496                 path = talloc_asprintf(mem_ctx, "%s/%s",
1497                                        dirfsp->fsp_name->base_name,
1498                                        atname->base_name);
1499         }
1500         if (path == NULL) {
1501                 return NULL;
1502         }
1503
1504         fname = synthetic_smb_fname(mem_ctx,
1505                                     path,
1506                                     atname->stream_name,
1507                                     &atname->st,
1508                                     atname->twrp,
1509                                     atname->flags);
1510         TALLOC_FREE(path);
1511         if (fname == NULL) {
1512                 return NULL;
1513         }
1514
1515         return fname;
1516 }