source3/lib/substitute.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    string substitution functions
   4    Copyright (C) Andrew Tridgell 1992-2000
   5    Copyright (C) Gerald Carter   2006
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21
  22 #include "includes.h"
  23 #include "substitute.h"
  24 #include "system/passwd.h"
  25 #include "secrets.h"
  26 #include "auth.h"
  27 #include "lib/util/string_wrappers.h"
  28
  29 /* Max DNS name is 253 + '\0' */
  30 #define MACHINE_NAME_SIZE 254
  31
  32 static char local_machine[MACHINE_NAME_SIZE];
  33 static char remote_machine[MACHINE_NAME_SIZE];
  34
  35 userdom_struct current_user_info;
  36 static fstring remote_proto="UNKNOWN";
  37
  38 void set_remote_proto(const char *proto)
  39 {
  40         fstrcpy(remote_proto, proto);
  41 }
  42
  43 /**
  44  * Set the 'local' machine name
  45  * @param local_name the name we are being called
  46  * @param if this is the 'final' name for us, not be be changed again
  47  */
  48 bool set_local_machine_name(const char *local_name, bool perm)
  49 {
  50         static bool already_perm = false;
  51         char tmp[MACHINE_NAME_SIZE];
  52
  53         if (already_perm) {
  54                 return true;
  55         }
  56
  57         strlcpy(tmp, local_name, sizeof(tmp));
  58         trim_char(tmp, ' ', ' ');
  59
  60         alpha_strcpy(local_machine,
  61                      tmp,
  62                      SAFE_NETBIOS_CHARS,
  63                      sizeof(local_machine) - 1);
  64         if (!strlower_m(local_machine)) {
  65                 return false;
  66         }
  67
  68         already_perm = perm;
  69
  70         return true;
  71 }
  72
  73 const char *get_local_machine_name(void)
  74 {
  75         if (local_machine[0] == '\0') {
  76                 return lp_netbios_name();
  77         }
  78
  79         return local_machine;
  80 }
  81
  82 /**
  83  * Set the 'remote' machine name
  84  *
  85  * @param remote_name the name our client wants to be called by
  86  * @param if this is the 'final' name for them, not be be changed again
  87  */
  88 bool set_remote_machine_name(const char *remote_name, bool perm)
  89 {
  90         static bool already_perm = False;
  91         char tmp[MACHINE_NAME_SIZE];
  92
  93         if (already_perm) {
  94                 return true;
  95         }
  96
  97         strlcpy(tmp, remote_name, sizeof(tmp));
  98         trim_char(tmp, ' ', ' ');
  99
 100         alpha_strcpy(remote_machine,
 101                      tmp,
 102                      SAFE_NETBIOS_CHARS,
 103                      sizeof(remote_machine) - 1);
 104         if (!strlower_m(remote_machine)) {
 105                 return false;
 106         }
 107
 108         already_perm = perm;
 109
 110         return true;
 111 }
 112
 113 const char *get_remote_machine_name(void)
 114 {
 115         return remote_machine;
 116 }
 117
 118 static char sub_peeraddr[INET6_ADDRSTRLEN];
 119 static const char *sub_peername = NULL;
 120 static char sub_sockaddr[INET6_ADDRSTRLEN];
 121
 122 void sub_set_socket_ids(const char *peeraddr, const char *peername,
 123                         const char *sockaddr)
 124 {
 125         const char *addr = peeraddr;
 126
 127         if (strnequal(addr, "::ffff:", 7)) {
 128                 addr += 7;
 129         }
 130         strlcpy(sub_peeraddr, addr, sizeof(sub_peeraddr));
 131
 132         if (sub_peername != NULL &&
 133                         sub_peername != sub_peeraddr) {
 134                 talloc_free(discard_const_p(char,sub_peername));
 135                 sub_peername = NULL;
 136         }
 137         sub_peername = talloc_strdup(NULL, peername);
 138         if (sub_peername == NULL) {
 139                 sub_peername = sub_peeraddr;
 140         }
 141
 142         /*
 143          * Shouldn't we do the ::ffff: cancellation here as well? The
 144          * original code in talloc_sub_basic() did not do it, so I'm
 145          * leaving it out here as well for compatibility.
 146          */
 147         strlcpy(sub_sockaddr, sockaddr, sizeof(sub_sockaddr));
 148 }
 149
 150 /*******************************************************************
 151  Setup the strings used by substitutions. Called per packet. Ensure
 152  %U name is set correctly also.
 153
 154  smb_name must be sanitized by alpha_strcpy
 155 ********************************************************************/
 156
 157 void set_current_user_info(const char *smb_name, const char *unix_name,
 158                            const char *domain)
 159 {
 160         static const void *last_smb_name;
 161         static const void *last_unix_name;
 162         static const void *last_domain;
 163
 164         if (likely(last_smb_name == smb_name &&
 165             last_unix_name == unix_name &&
 166             last_domain == domain))
 167         {
 168                 return;
 169         }
 170
 171         fstrcpy(current_user_info.smb_name, smb_name);
 172         fstrcpy(current_user_info.unix_name, unix_name);
 173         fstrcpy(current_user_info.domain, domain);
 174
 175         last_smb_name = smb_name;
 176         last_unix_name = unix_name;
 177         last_domain = domain;
 178 }
 179
 180 /*******************************************************************
 181  Return the current active user name.
 182 *******************************************************************/
 183
 184 const char *get_current_username(void)
 185 {
 186         return current_user_info.smb_name;
 187 }
 188
 189 const char *get_current_user_info_domain(void)
 190 {
 191         return current_user_info.domain;
 192 }
 193
 194 /*******************************************************************
 195  Given a pointer to a %$(NAME) in p and the whole string in str
 196  expand it as an environment variable.
 197  str must be a talloced string.
 198  Return a new allocated and expanded string.
 199  Based on code by Branko Cibej <branko.cibej@hermes.si>
 200  When this is called p points at the '%' character.
 201  May substitute multiple occurrences of the same env var.
 202 ********************************************************************/
 203
 204 static char *realloc_expand_env_var(char *str, char *p)
 205 {
 206         char *envname;
 207         char *envval;
 208         char *q, *r;
 209         int copylen;
 210
 211         if (p[0] != '%' || p[1] != '$' || p[2] != '(') {
 212                 return str;
 213         }
 214
 215         /*
 216          * Look for the terminating ')'.
 217          */
 218
 219         if ((q = strchr_m(p,')')) == NULL) {
 220                 DEBUG(0,("expand_env_var: Unterminated environment variable [%s]\n", p));
 221                 return str;
 222         }
 223
 224         /*
 225          * Extract the name from within the %$(NAME) string.
 226          */
 227
 228         r = p + 3;
 229         copylen = q - r;
 230
 231         /* reserve space for use later add %$() chars */
 232         if ( (envname = talloc_array(talloc_tos(), char, copylen + 1 + 4)) == NULL ) {
 233                 return NULL;
 234         }
 235
 236         strncpy(envname,r,copylen);
 237         envname[copylen] = '\0';
 238
 239         if ((envval = getenv(envname)) == NULL) {
 240                 DEBUG(0,("expand_env_var: Environment variable [%s] not set\n", envname));
 241                 TALLOC_FREE(envname);
 242                 return str;
 243         }
 244
 245         /*
 246          * Copy the full %$(NAME) into envname so it
 247          * can be replaced.
 248          */
 249
 250         copylen = q + 1 - p;
 251         strncpy(envname,p,copylen);
 252         envname[copylen] = '\0';
 253         r = realloc_string_sub(str, envname, envval);
 254         TALLOC_FREE(envname);
 255
 256         return r;
 257 }
 258
 259 /****************************************************************************
 260  Do some standard substitutions in a string.
 261  len is the length in bytes of the space allowed in string str. If zero means
 262  don't allow expansions.
 263 ****************************************************************************/
 264
 265 void standard_sub_basic(const char *smb_name, const char *domain_name,
 266                         char *str, size_t len)
 267 {
 268         char *s;
 269
 270         if ( (s = talloc_sub_basic(talloc_tos(), smb_name, domain_name, str )) != NULL ) {
 271                 strncpy( str, s, len );
 272         }
 273
 274         TALLOC_FREE( s );
 275 }
 276
 277 /*
 278  * Limit addresses to hexalpha characters and underscore, safe for path
 279  * components for Windows clients.
 280  */
 281 static void make_address_pathsafe(char *addr)
 282 {
 283         while(addr && *addr) {
 284                 if(!isxdigit(*addr)) {
 285                         *addr = '_';
 286                 }
 287                 ++addr;
 288         }
 289 }
 290
 291 /****************************************************************************
 292  Do some standard substitutions in a string.
 293  This function will return a talloced string that has to be freed.
 294 ****************************************************************************/
 295
 296 char *talloc_sub_basic(TALLOC_CTX *mem_ctx,
 297                         const char *smb_name,
 298                         const char *domain_name,
 299                         const char *str)
 300 {
 301         char *b, *p, *s, *r, *a_string;
 302         fstring pidstr, vnnstr;
 303         const char *local_machine_name = get_local_machine_name();
 304         TALLOC_CTX *tmp_ctx = NULL;
 305
 306         /* workaround to prevent a crash while looking at bug #687 */
 307
 308         if (!str) {
 309                 DEBUG(0,("talloc_sub_basic: NULL source string!  This should not happen\n"));
 310                 return NULL;
 311         }
 312
 313         a_string = talloc_strdup(mem_ctx, str);
 314         if (a_string == NULL) {
 315                 DEBUG(0, ("talloc_sub_basic: Out of memory!\n"));
 316                 return NULL;
 317         }
 318
 319         tmp_ctx = talloc_stackframe();
 320
 321         for (s = a_string; (p = strchr_m(s, '%')); s = a_string + (p - b)) {
 322
 323                 r = NULL;
 324                 b = a_string;
 325
 326                 switch (*(p+1)) {
 327                 case 'U' :
 328                         r = strlower_talloc(tmp_ctx, smb_name);
 329                         if (r == NULL) {
 330                                 goto error;
 331                         }
 332                         a_string = realloc_string_sub(a_string, "%U", r);
 333                         break;
 334                 case 'G' : {
 335                         struct passwd *pass;
 336                         bool is_domain_name = false;
 337                         const char *sep = lp_winbind_separator();
 338
 339                         if (domain_name != NULL && domain_name[0] != '\0' &&
 340                             (lp_security() == SEC_ADS ||
 341                              lp_security() == SEC_DOMAIN)) {
 342                                 r = talloc_asprintf(tmp_ctx,
 343                                                     "%s%c%s",
 344                                                     domain_name,
 345                                                     *sep,
 346                                                     smb_name);
 347                                 is_domain_name = true;
 348                         } else {
 349                                 r = talloc_strdup(tmp_ctx, smb_name);
 350                         }
 351                         if (r == NULL) {
 352                                 goto error;
 353                         }
 354
 355                         pass = Get_Pwnam_alloc(tmp_ctx, r);
 356                         if (pass != NULL) {
 357                                 char *group_name;
 358
 359                                 group_name = gidtoname(pass->pw_gid);
 360                                 if (is_domain_name) {
 361                                         char *group_sep;
 362                                         group_sep = strchr_m(group_name, *sep);
 363                                         if (group_sep != NULL) {
 364                                                 group_name = group_sep + 1;
 365                                         }
 366                                 }
 367                                 a_string = realloc_string_sub(a_string,
 368                                                               "%G",
 369                                                               group_name);
 370                         }
 371                         TALLOC_FREE(pass);
 372                         break;
 373                 }
 374                 case 'D' :
 375                         r = strupper_talloc(tmp_ctx, domain_name);
 376                         if (r == NULL) {
 377                                 goto error;
 378                         }
 379                         a_string = realloc_string_sub(a_string, "%D", r);
 380                         break;
 381                 case 'I' : {
 382                         a_string = realloc_string_sub(
 383                                 a_string, "%I",
 384                                 sub_peeraddr[0] ? sub_peeraddr : "0.0.0.0");
 385                         break;
 386                 }
 387                 case 'J' : {
 388                         r = talloc_strdup(tmp_ctx,
 389                                 sub_peeraddr[0] ? sub_peeraddr : "0.0.0.0");
 390                         make_address_pathsafe(r);
 391                         a_string = realloc_string_sub(a_string, "%J", r);
 392                         break;
 393                 }
 394                 case 'i':
 395                         a_string = realloc_string_sub(
 396                                 a_string, "%i",
 397                                 sub_sockaddr[0] ? sub_sockaddr : "0.0.0.0");
 398                         break;
 399                 case 'j' : {
 400                         r = talloc_strdup(tmp_ctx,
 401                                 sub_sockaddr[0] ? sub_sockaddr : "0.0.0.0");
 402                         make_address_pathsafe(r);
 403                         a_string = realloc_string_sub(a_string, "%j", r);
 404                         break;
 405                 }
 406                 case 'L' :
 407                         if ( strncasecmp_m(p, "%LOGONSERVER%", strlen("%LOGONSERVER%")) == 0 ) {
 408                                 break;
 409                         }
 410                         if (local_machine_name && *local_machine_name) {
 411                                 a_string = realloc_string_sub(a_string, "%L", local_machine_name);
 412                         } else {
 413                                 a_string = realloc_string_sub(a_string, "%L", lp_netbios_name());
 414                         }
 415                         break;
 416                 case 'N' :
 417                         a_string = realloc_string_sub(a_string,
 418                                                       "%N",
 419                                                       lp_netbios_name());
 420                         break;
 421                 case 'M' :
 422                         a_string = realloc_string_sub(a_string, "%M",
 423                                                       sub_peername ? sub_peername : "");
 424                         break;
 425                 case 'R' :
 426                         a_string = realloc_string_sub(a_string, "%R", remote_proto);
 427                         break;
 428                 case 'T' :
 429                         a_string = realloc_string_sub(a_string, "%T", current_timestring(tmp_ctx, False));
 430                         break;
 431                 case 't' :
 432                         a_string = realloc_string_sub(a_string, "%t",
 433                                                       current_minimal_timestring(tmp_ctx, False));
 434                         break;
 435                 case 'a' :
 436                         a_string = realloc_string_sub(a_string, "%a",
 437                                         get_remote_arch_str());
 438                         break;
 439                 case 'd' :
 440                         slprintf(pidstr,sizeof(pidstr)-1, "%d",(int)getpid());
 441                         a_string = realloc_string_sub(a_string, "%d", pidstr);
 442                         break;
 443                 case 'h' :
 444                         a_string = realloc_string_sub(a_string, "%h", myhostname());
 445                         break;
 446                 case 'm' :
 447                         a_string = realloc_string_sub(a_string, "%m",
 448                                                       remote_machine);
 449                         break;
 450                 case 'v' :
 451                         a_string = realloc_string_sub(a_string, "%v", samba_version_string());
 452                         break;
 453                 case 'w' :
 454                         a_string = realloc_string_sub(a_string, "%w", lp_winbind_separator());
 455                         break;
 456                 case '$' :
 457                         a_string = realloc_expand_env_var(a_string, p); /* Expand environment variables */
 458                         break;
 459                 case 'V' :
 460                         slprintf(vnnstr,sizeof(vnnstr)-1, "%u", get_my_vnn());
 461                         a_string = realloc_string_sub(a_string, "%V", vnnstr);
 462                         break;
 463                 default:
 464                         break;
 465                 }
 466
 467                 p++;
 468                 TALLOC_FREE(r);
 469
 470                 if (a_string == NULL) {
 471                         goto done;
 472                 }
 473         }
 474
 475         goto done;
 476
 477 error:
 478         TALLOC_FREE(a_string);
 479
 480 done:
 481         TALLOC_FREE(tmp_ctx);
 482         return a_string;
 483 }
 484
 485 /****************************************************************************
 486  Do some specific substitutions in a string.
 487  This function will return an allocated string that have to be freed.
 488 ****************************************************************************/
 489
 490 char *talloc_sub_specified(TALLOC_CTX *mem_ctx,
 491                         const char *input_string,
 492                         const char *username,
 493                         const char *grpname,
 494                         const char *domain,
 495                         uid_t uid,
 496                         gid_t gid)
 497 {
 498         char *a_string;
 499         char *ret_string = NULL;
 500         char *b, *p, *s;
 501         TALLOC_CTX *tmp_ctx;
 502
 503         if (!(tmp_ctx = talloc_new(mem_ctx))) {
 504                 DEBUG(0, ("talloc_new failed\n"));
 505                 return NULL;
 506         }
 507
 508         a_string = talloc_strdup(tmp_ctx, input_string);
 509         if (a_string == NULL) {
 510                 DEBUG(0, ("talloc_sub_specified: Out of memory!\n"));
 511                 goto done;
 512         }
 513
 514         for (s = a_string; (p = strchr_m(s, '%')); s = a_string + (p - b)) {
 515
 516                 b = a_string;
 517
 518                 switch (*(p+1)) {
 519                 case 'U' :
 520                         a_string = talloc_string_sub(
 521                                 tmp_ctx, a_string, "%U", username);
 522                         break;
 523                 case 'u' :
 524                         a_string = talloc_string_sub(
 525                                 tmp_ctx, a_string, "%u", username);
 526                         break;
 527                 case 'G' :
 528                         if (gid != -1) {
 529                                 const char *name;
 530
 531                                 if (grpname != NULL) {
 532                                         name = grpname;
 533                                 } else {
 534                                         name = gidtoname(gid);
 535                                 }
 536
 537                                 a_string = talloc_string_sub(tmp_ctx,
 538                                                              a_string,
 539                                                              "%G",
 540                                                              name);
 541                         } else {
 542                                 a_string = talloc_string_sub(
 543                                         tmp_ctx, a_string,
 544                                         "%G", "NO_GROUP");
 545                         }
 546                         break;
 547                 case 'g' :
 548                         if (gid != -1) {
 549                                 const char *name;
 550
 551                                 if (grpname != NULL) {
 552                                         name = grpname;
 553                                 } else {
 554                                         name = gidtoname(gid);
 555                                 }
 556
 557                                 a_string = talloc_string_sub(tmp_ctx,
 558                                                              a_string,
 559                                                              "%g",
 560                                                              name);
 561                         } else {
 562                                 a_string = talloc_string_sub(
 563                                         tmp_ctx, a_string, "%g", "NO_GROUP");
 564                         }
 565                         break;
 566                 case 'D' :
 567                         a_string = talloc_string_sub(tmp_ctx, a_string,
 568                                                      "%D", domain);
 569                         break;
 570                 case 'N' :
 571                         a_string = talloc_string_sub(tmp_ctx, a_string,
 572                                                      "%N", lp_netbios_name());
 573                         break;
 574                 default:
 575                         break;
 576                 }
 577
 578                 p++;
 579                 if (a_string == NULL) {
 580                         goto done;
 581                 }
 582         }
 583
 584         /* Watch out, using "mem_ctx" here, so all intermediate stuff goes
 585          * away with the TALLOC_FREE(tmp_ctx) further down. */
 586
 587         ret_string = talloc_sub_basic(mem_ctx, username, domain, a_string);
 588
 589  done:
 590         TALLOC_FREE(tmp_ctx);
 591         return ret_string;
 592 }
 593
 594 /****************************************************************************
 595 ****************************************************************************/
 596
 597 char *talloc_sub_advanced(TALLOC_CTX *ctx,
 598                         const char *servicename,
 599                         const char *user,
 600                         const char *connectpath,
 601                         gid_t gid,
 602                         const char *str)
 603 {
 604         char *a_string;
 605         char *b, *p, *s;
 606
 607         a_string = talloc_strdup(talloc_tos(), str);
 608         if (a_string == NULL) {
 609                 DEBUG(0, ("talloc_sub_advanced_only: Out of memory!\n"));
 610                 return NULL;
 611         }
 612
 613         for (s = a_string; (p = strchr_m(s, '%')); s = a_string + (p - b)) {
 614
 615                 b = a_string;
 616
 617                 switch (*(p+1)) {
 618                 case 'N':
 619                         a_string = realloc_string_sub(a_string,
 620                                                       "%N",
 621                                                       lp_netbios_name());
 622                         break;
 623                 case 'H': {
 624                         char *h;
 625                         if ((h = get_user_home_dir(talloc_tos(), user)))
 626                                 a_string = realloc_string_sub(a_string, "%H", h);
 627                         TALLOC_FREE(h);
 628                         break;
 629                 }
 630                 case 'P':
 631                         a_string = realloc_string_sub(a_string, "%P", connectpath);
 632                         break;
 633                 case 'S':
 634                         a_string = realloc_string_sub(a_string, "%S", servicename);
 635                         break;
 636                 case 'g':
 637                         a_string = realloc_string_sub(a_string, "%g", gidtoname(gid));
 638                         break;
 639                 case 'u':
 640                         a_string = realloc_string_sub(a_string, "%u", user);
 641                         break;
 642                 default:
 643                         break;
 644                 }
 645
 646                 p++;
 647                 if (a_string == NULL) {
 648                         return NULL;
 649                 }
 650         }
 651
 652         return a_string;
 653 }
 654
 655 char *talloc_sub_full(TALLOC_CTX *ctx,
 656                         const char *servicename,
 657                         const char *user,
 658                         const char *connectpath,
 659                         gid_t gid,
 660                         const char *smb_name,
 661                         const char *domain_name,
 662                         const char *str)
 663 {
 664         char *a_string, *ret_string;
 665
 666         a_string = talloc_sub_advanced(ctx, servicename, user, connectpath,
 667                                        gid, str);
 668         if (a_string == NULL) {
 669                 return NULL;
 670         }
 671
 672         ret_string = talloc_sub_basic(ctx, smb_name, domain_name, a_string);
 673         TALLOC_FREE(a_string);
 674         return ret_string;
 675 }