lib/krb5/expand_path.c

   1
   2 /***********************************************************************
   3  * Copyright (c) 2009, Secure Endpoints Inc.
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * - Redistributions of source code must retain the above copyright
  11  *   notice, this list of conditions and the following disclaimer.
  12  *
  13  * - Redistributions in binary form must reproduce the above copyright
  14  *   notice, this list of conditions and the following disclaimer in
  15  *   the documentation and/or other materials provided with the
  16  *   distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  22  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  23  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  24  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  25  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  27  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  29  * OF THE POSSIBILITY OF SUCH DAMAGE.
  30  *
  31  **********************************************************************/
  32
  33 #include "krb5_locl.h"
  34
  35 #include <stdarg.h>
  36
  37 typedef int PTYPE;
  38
  39 #ifdef _WIN32
  40 #include <shlobj.h>
  41 #include <sddl.h>
  42
  43 /*
  44  * Expand a %{TEMP} token
  45  *
  46  * The %{TEMP} token expands to the temporary path for the current
  47  * user as returned by GetTempPath().
  48  *
  49  * @note: Since the GetTempPath() function relies on the TMP or TEMP
  50  * environment variables, this function will failover to the system
  51  * temporary directory until the user profile is loaded.  In addition,
  52  * the returned path may or may not exist.
  53  */
  54 static krb5_error_code
  55 _expand_temp_folder(krb5_context context, PTYPE param, const char *postfix, char **ret)
  56 {
  57     TCHAR tpath[MAX_PATH];
  58     size_t len;
  59
  60     if (!GetTempPath(sizeof(tpath)/sizeof(tpath[0]), tpath)) {
  61         if (context)
  62             krb5_set_error_message(context, EINVAL,
  63                                    "Failed to get temporary path (GLE=%d)",
  64                                    GetLastError());
  65         return EINVAL;
  66     }
  67
  68     len = strlen(tpath);
  69
  70     if (len > 0 && tpath[len - 1] == '\\')
  71         tpath[len - 1] = '\0';
  72
  73     *ret = strdup(tpath);
  74
  75     if (*ret == NULL)
  76         return krb5_enomem(context);
  77
  78     return 0;
  79 }
  80
  81 extern HINSTANCE _krb5_hInstance;
  82
  83 /*
  84  * Expand a %{BINDIR} token
  85  *
  86  * This is also used to expand a few other tokens on Windows, since
  87  * most of the executable binaries end up in the same directory.  The
  88  * "bin" directory is considered to be the directory in which the
  89  * krb5.dll is located.
  90  */
  91 static krb5_error_code
  92 _expand_bin_dir(krb5_context context, PTYPE param, const char *postfix, char **ret)
  93 {
  94     TCHAR path[MAX_PATH];
  95     TCHAR *lastSlash;
  96     DWORD nc;
  97
  98     nc = GetModuleFileName(_krb5_hInstance, path, sizeof(path)/sizeof(path[0]));
  99     if (nc == 0 ||
 100         nc == sizeof(path)/sizeof(path[0])) {
 101         return EINVAL;
 102     }
 103
 104     lastSlash = strrchr(path, '\\');
 105     if (lastSlash != NULL) {
 106         TCHAR *fslash = strrchr(lastSlash, '/');
 107
 108         if (fslash != NULL)
 109             lastSlash = fslash;
 110
 111         *lastSlash = '\0';
 112     }
 113
 114     if (postfix) {
 115         if (strlcat(path, postfix, sizeof(path)/sizeof(path[0])) >= sizeof(path)/sizeof(path[0]))
 116             return EINVAL;
 117     }
 118
 119     *ret = strdup(path);
 120     if (*ret == NULL)
 121         return krb5_enomem(context);
 122
 123     return 0;
 124 }
 125
 126 /*
 127  *  Expand a %{USERID} token
 128  *
 129  *  The %{USERID} token expands to the string representation of the
 130  *  user's SID.  The user account that will be used is the account
 131  *  corresponding to the current thread's security token.  This means
 132  *  that:
 133  *
 134  *  - If the current thread token has the anonymous impersonation
 135  *    level, the call will fail.
 136  *
 137  *  - If the current thread is impersonating a token at
 138  *    SecurityIdentification level the call will fail.
 139  *
 140  */
 141 static krb5_error_code
 142 _expand_userid(krb5_context context, PTYPE param, const char *postfix, char **ret)
 143 {
 144     int rv = EINVAL;
 145     HANDLE hThread = NULL;
 146     HANDLE hToken = NULL;
 147     PTOKEN_OWNER pOwner = NULL;
 148     DWORD len = 0;
 149     LPTSTR strSid = NULL;
 150
 151     hThread = GetCurrentThread();
 152
 153     if (!OpenThreadToken(hThread, TOKEN_QUERY,
 154                          FALSE, /* Open the thread token as the
 155                                    current thread user. */
 156                          &hToken)) {
 157
 158         DWORD le = GetLastError();
 159
 160         if (le == ERROR_NO_TOKEN) {
 161             HANDLE hProcess = GetCurrentProcess();
 162
 163             le = 0;
 164             if (!OpenProcessToken(hProcess, TOKEN_QUERY, &hToken))
 165                 le = GetLastError();
 166         }
 167
 168         if (le != 0) {
 169             if (context)
 170                 krb5_set_error_message(context, rv,
 171                                        "Can't open thread token (GLE=%d)", le);
 172             goto _exit;
 173         }
 174     }
 175
 176     if (!GetTokenInformation(hToken, TokenOwner, NULL, 0, &len)) {
 177         if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
 178             if (context)
 179                 krb5_set_error_message(context, rv,
 180                                        "Unexpected error reading token information (GLE=%d)",
 181                                        GetLastError());
 182             goto _exit;
 183         }
 184
 185         if (len == 0) {
 186             if (context)
 187                 krb5_set_error_message(context, rv,
 188                                       "GetTokenInformation() returned truncated buffer");
 189             goto _exit;
 190         }
 191
 192         pOwner = malloc(len);
 193         if (pOwner == NULL) {
 194             if (context)
 195                 krb5_set_error_message(context, rv, "Out of memory");
 196             goto _exit;
 197         }
 198     } else {
 199         if (context)
 200             krb5_set_error_message(context, rv, "GetTokenInformation() returned truncated buffer");
 201         goto _exit;
 202     }
 203
 204     if (!GetTokenInformation(hToken, TokenOwner, pOwner, len, &len)) {
 205         if (context)
 206             krb5_set_error_message(context, rv, "GetTokenInformation() failed. GLE=%d", GetLastError());
 207         goto _exit;
 208     }
 209
 210     if (!ConvertSidToStringSid(pOwner->Owner, &strSid)) {
 211         if (context)
 212             krb5_set_error_message(context, rv, "Can't convert SID to string. GLE=%d", GetLastError());
 213         goto _exit;
 214     }
 215
 216     *ret = strdup(strSid);
 217     if (*ret == NULL && context)
 218         krb5_set_error_message(context, rv, "Out of memory");
 219
 220     rv = 0;
 221
 222  _exit:
 223     if (hToken != NULL)
 224         CloseHandle(hToken);
 225
 226     if (pOwner != NULL)
 227         free (pOwner);
 228
 229     if (strSid != NULL)
 230         LocalFree(strSid);
 231
 232     return rv;
 233 }
 234
 235 /*
 236  * Expand a folder identified by a CSIDL
 237  */
 238
 239 static krb5_error_code
 240 _expand_csidl(krb5_context context, PTYPE folder, const char *postfix, char **ret)
 241 {
 242     TCHAR path[MAX_PATH];
 243     size_t len;
 244
 245     if (SHGetFolderPath(NULL, folder, NULL, SHGFP_TYPE_CURRENT, path) != S_OK) {
 246         if (context)
 247             krb5_set_error_message(context, EINVAL, "Unable to determine folder path");
 248         return EINVAL;
 249     }
 250
 251     len = strlen(path);
 252
 253     if (len > 0 && path[len - 1] == '\\')
 254         path[len - 1] = '\0';
 255
 256     if (postfix &&
 257         strlcat(path, postfix, sizeof(path)/sizeof(path[0])) >= sizeof(path)/sizeof(path[0]))
 258         return krb5_enomem(context);
 259
 260     *ret = strdup(path);
 261     if (*ret == NULL)
 262         return krb5_enomem(context);
 263     return 0;
 264 }
 265
 266 #else
 267
 268 static krb5_error_code
 269 _expand_path(krb5_context context, PTYPE param, const char *postfix, char **ret)
 270 {
 271     *ret = strdup(postfix);
 272     if (*ret == NULL)
 273         return krb5_enomem(context);
 274     return 0;
 275 }
 276
 277 static krb5_error_code
 278 _expand_temp_folder(krb5_context context, PTYPE param, const char *postfix, char **ret)
 279 {
 280     const char *p = NULL;
 281
 282     if (!issuid())
 283         p = getenv("TEMP");
 284
 285     if (p)
 286         *ret = strdup(p);
 287     else
 288         *ret = strdup("/tmp");
 289     if (*ret == NULL)
 290         return krb5_enomem(context);
 291     return 0;
 292 }
 293
 294 static krb5_error_code
 295 _expand_userid(krb5_context context, PTYPE param, const char *postfix, char **str)
 296 {
 297     int ret = asprintf(str, "%ld", (unsigned long)getuid());
 298     if (ret < 0 || *str == NULL)
 299         return krb5_enomem(context);
 300     return 0;
 301 }
 302
 303
 304 #endif /* _WIN32 */
 305
 306 /**
 307  * Expand an extra token
 308  */
 309
 310 static krb5_error_code
 311 _expand_extra_token(krb5_context context, const char *value, char **ret)
 312 {
 313     *ret = strdup(value);
 314     if (*ret == NULL)
 315         return krb5_enomem(context);
 316     return 0;
 317 }
 318
 319 /**
 320  * Expand a %{null} token
 321  *
 322  * The expansion of a %{null} token is always the empty string.
 323  */
 324
 325 static krb5_error_code
 326 _expand_null(krb5_context context, PTYPE param, const char *postfix, char **ret)
 327 {
 328     *ret = strdup("");
 329     if (*ret == NULL)
 330         return krb5_enomem(context);
 331     return 0;
 332 }
 333
 334
 335 static const struct {
 336     const char * tok;
 337     int ftype;
 338 #define FTYPE_CSIDL 0
 339 #define FTYPE_SPECIAL 1
 340
 341     PTYPE param;
 342     const char * postfix;
 343
 344     int (*exp_func)(krb5_context, PTYPE, const char *, char **);
 345
 346 #define SPECIALP(f, P) FTYPE_SPECIAL, 0, P, f
 347 #define SPECIAL(f) SPECIALP(f, NULL)
 348
 349 } tokens[] = {
 350 #ifdef _WIN32
 351 #define CSIDLP(C,P) FTYPE_CSIDL, C, P, _expand_csidl
 352 #define CSIDL(C) CSIDLP(C, NULL)
 353
 354     {"APPDATA", CSIDL(CSIDL_APPDATA)}, /* Roaming application data (for current user) */
 355     {"COMMON_APPDATA", CSIDL(CSIDL_COMMON_APPDATA)}, /* Application data (all users) */
 356     {"LOCAL_APPDATA", CSIDL(CSIDL_LOCAL_APPDATA)}, /* Local application data (for current user) */
 357     {"SYSTEM", CSIDL(CSIDL_SYSTEM)}, /* Windows System folder (e.g. %WINDIR%\System32) */
 358     {"WINDOWS", CSIDL(CSIDL_WINDOWS)}, /* Windows folder */
 359     {"USERCONFIG", CSIDLP(CSIDL_APPDATA, "\\" PACKAGE)}, /* Per user Heimdal configuration file path */
 360     {"COMMONCONFIG", CSIDLP(CSIDL_COMMON_APPDATA, "\\" PACKAGE)}, /* Common Heimdal configuration file path */
 361     {"LIBDIR", SPECIAL(_expand_bin_dir)},
 362     {"BINDIR", SPECIAL(_expand_bin_dir)},
 363     {"LIBEXEC", SPECIAL(_expand_bin_dir)},
 364     {"SBINDIR", SPECIAL(_expand_bin_dir)},
 365 #else
 366     {"LIBDIR", FTYPE_SPECIAL, 0, LIBDIR, _expand_path},
 367     {"BINDIR", FTYPE_SPECIAL, 0, BINDIR, _expand_path},
 368     {"LIBEXEC", FTYPE_SPECIAL, 0, LIBEXECDIR, _expand_path},
 369     {"SBINDIR", FTYPE_SPECIAL, 0, SBINDIR, _expand_path},
 370 #endif
 371     {"TEMP", SPECIAL(_expand_temp_folder)},
 372     {"USERID", SPECIAL(_expand_userid)},
 373     {"uid", SPECIAL(_expand_userid)},
 374     {"null", SPECIAL(_expand_null)}
 375 };
 376
 377 static krb5_error_code
 378 _expand_token(krb5_context context,
 379               const char *token,
 380               const char *token_end,
 381               char **extra_tokens,
 382               char **ret)
 383 {
 384     size_t i;
 385     char **p;
 386
 387     *ret = NULL;
 388
 389     if (token[0] != '%' || token[1] != '{' || token_end[0] != '}' ||
 390         token_end - token <= 2) {
 391         if (context)
 392             krb5_set_error_message(context, EINVAL,"Invalid token.");
 393         return EINVAL;
 394     }
 395
 396     for (p = extra_tokens; p && p[0]; p += 2) {
 397         if (strncmp(token+2, p[0], (token_end - token) - 2) == 0)
 398             return _expand_extra_token(context, p[1], ret);
 399     }
 400
 401     for (i = 0; i < sizeof(tokens)/sizeof(tokens[0]); i++) {
 402         if (!strncmp(token+2, tokens[i].tok, (token_end - token) - 2))
 403             return tokens[i].exp_func(context, tokens[i].param,
 404                                       tokens[i].postfix, ret);
 405     }
 406
 407     if (context)
 408         krb5_set_error_message(context, EINVAL, "Invalid token.");
 409     return EINVAL;
 410 }
 411
 412 /**
 413  * Internal function to expand tokens in paths.
 414  *
 415  * Inputs:
 416  *
 417  * @context   A krb5_context
 418  * @path_in   The path to expand tokens from
 419  *
 420  * Outputs:
 421  *
 422  * @ppath_out Path with expanded tokens (caller must free() this)
 423  */
 424 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 425 _krb5_expand_path_tokens(krb5_context context,
 426                          const char *path_in,
 427                          char **ppath_out)
 428 {
 429     return _krb5_expand_path_tokensv(context, path_in, ppath_out, NULL);
 430 }
 431
 432 static void
 433 free_extra_tokens(char **extra_tokens)
 434 {
 435     char **p;
 436
 437     for (p = extra_tokens; p && *p; p++)
 438         free(*p);
 439     free(extra_tokens);
 440 }
 441
 442 /**
 443  * Internal function to expand tokens in paths.
 444  *
 445  * Inputs:
 446  *
 447  * @context   A krb5_context
 448  * @path_in   The path to expand tokens from
 449  * @ppath_out The expanded path
 450  * @...       Variable number of pairs of strings, the first of each
 451  *            being a token (e.g., "luser") and the second a string to
 452  *            replace it with.  The list is terminated by a NULL.
 453  *
 454  * Outputs:
 455  *
 456  * @ppath_out Path with expanded tokens (caller must free() this)
 457  */
 458 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 459 _krb5_expand_path_tokensv(krb5_context context,
 460                           const char *path_in,
 461                           char **ppath_out, ...)
 462 {
 463     char *tok_begin, *tok_end, *append;
 464     char **extra_tokens = NULL;
 465     const char *path_left;
 466     const char *s;
 467     size_t nargs = 0;
 468     size_t len = 0;
 469     va_list ap;
 470
 471     if (path_in == NULL || *path_in == '\0') {
 472         *ppath_out = strdup("");
 473         return 0;
 474     }
 475
 476     *ppath_out = NULL;
 477
 478     va_start(ap, ppath_out);
 479     while ((s = va_arg(ap, const char *))) {
 480         nargs++;
 481         s = va_arg(ap, const char *);
 482     }
 483     va_end(ap);
 484     nargs *= 2;
 485
 486     /* Get extra tokens */
 487     if (nargs) {
 488         size_t i;
 489
 490         extra_tokens = calloc(nargs + 1, sizeof (*extra_tokens));
 491         if (extra_tokens == NULL)
 492             return krb5_enomem(context);
 493         va_start(ap, ppath_out);
 494         for (i = 0; i < nargs; i++) {
 495             s = va_arg(ap, const char *); /* token key */
 496             if (s == NULL)
 497                 break;
 498             extra_tokens[i] = strdup(s);
 499             if (extra_tokens[i++] == NULL) {
 500                 free_extra_tokens(extra_tokens);
 501                 return krb5_enomem(context);
 502             }
 503             s = va_arg(ap, const char *); /* token value */
 504             if (s == NULL)
 505                 s = "";
 506             extra_tokens[i] = strdup(s);
 507             if (extra_tokens[i] == NULL) {
 508                 free_extra_tokens(extra_tokens);
 509                 return krb5_enomem(context);
 510             }
 511         }
 512         va_end(ap);
 513     }
 514
 515     for (path_left = path_in; path_left && *path_left; ) {
 516
 517         tok_begin = strstr(path_left, "%{");
 518
 519         if (tok_begin && tok_begin != path_left) {
 520
 521             append = malloc((tok_begin - path_left) + 1);
 522             if (append) {
 523                 memcpy(append, path_left, tok_begin - path_left);
 524                 append[tok_begin - path_left] = '\0';
 525             }
 526             path_left = tok_begin;
 527
 528         } else if (tok_begin) {
 529
 530             tok_end = strchr(tok_begin, '}');
 531             if (tok_end == NULL) {
 532                 free_extra_tokens(extra_tokens);
 533                 if (*ppath_out)
 534                     free(*ppath_out);
 535                 *ppath_out = NULL;
 536                 if (context)
 537                     krb5_set_error_message(context, EINVAL, "variable missing }");
 538                 return EINVAL;
 539             }
 540
 541             if (_expand_token(context, tok_begin, tok_end, extra_tokens,
 542                               &append)) {
 543                 free_extra_tokens(extra_tokens);
 544                 if (*ppath_out)
 545                     free(*ppath_out);
 546                 *ppath_out = NULL;
 547                 return EINVAL;
 548             }
 549
 550             path_left = tok_end + 1;
 551         } else {
 552
 553             append = strdup(path_left);
 554             path_left = NULL;
 555
 556         }
 557
 558         if (append == NULL) {
 559
 560             free_extra_tokens(extra_tokens);
 561             if (*ppath_out)
 562                 free(*ppath_out);
 563             *ppath_out = NULL;
 564             return krb5_enomem(context);
 565
 566         }
 567
 568         {
 569             size_t append_len = strlen(append);
 570             char * new_str = realloc(*ppath_out, len + append_len + 1);
 571
 572             if (new_str == NULL) {
 573                 free_extra_tokens(extra_tokens);
 574                 free(append);
 575                 if (*ppath_out)
 576                     free(*ppath_out);
 577                 *ppath_out = NULL;
 578                 return krb5_enomem(context);
 579             }
 580
 581             *ppath_out = new_str;
 582             memcpy(*ppath_out + len, append, append_len + 1);
 583             len = len + append_len;
 584             free(append);
 585         }
 586     }
 587
 588 #ifdef _WIN32
 589     /* Also deal with slashes */
 590     if (*ppath_out) {
 591         char * c;
 592         for (c = *ppath_out; *c; c++)
 593             if (*c == '/')
 594                 *c = '\\';
 595     }
 596 #endif
 597
 598     free_extra_tokens(extra_tokens);
 599     return 0;
 600 }