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