1 /*- 2 * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org> 3 * based on work by Toshiharu OHNO <tony-o@iij.ad.jp> 4 * Internet Initiative Japan, Inc (IIJ) 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 #include <sys/param.h> 32 33 #include <ctype.h> 34 #include <pwd.h> 35 #include <stdio.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <termios.h> 39 40 #include "defs.h" 41 #include "command.h" 42 #include "log.h" 43 #include "id.h" 44 #include "systems.h" 45 46 #define issep(ch) ((ch) == ' ' || (ch) == '\t') 47 48 FILE * 49 OpenSecret(const char *file) 50 { 51 FILE *fp; 52 char line[100]; 53 54 snprintf(line, sizeof line, "%s/%s", PPP_CONFDIR, file); 55 fp = ID0fopen(line, "r"); 56 if (fp == NULL) 57 log_Printf(LogWARN, "OpenSecret: Can't open %s.\n", line); 58 return (fp); 59 } 60 61 void 62 CloseSecret(FILE *fp) 63 { 64 fclose(fp); 65 } 66 67 /* Move string from ``from'' to ``to'', interpreting ``~'' and $.... */ 68 const char * 69 InterpretArg(const char *from, char *to) 70 { 71 char *ptr, *startto, *endto; 72 struct passwd *pwd; 73 int instring; 74 size_t len; 75 const char *env; 76 77 instring = 0; 78 startto = to; 79 endto = to + LINE_LEN - 1; 80 81 while(issep(*from)) 82 from++; 83 84 while (*from != '\0') { 85 switch (*from) { 86 case '"': 87 instring = !instring; 88 *to++ = *from++; 89 break; 90 case '\\': 91 switch (*++from) { 92 case '$': 93 case '~': 94 break; /* Swallow the escapes */ 95 96 default: 97 *to++ = '\\'; /* Pass the escapes on, maybe skipping \# */ 98 break; 99 } 100 *to++ = *from++; 101 break; 102 case '$': 103 if (from[1] == '$') { 104 *to = '\0'; /* For an empty var name below */ 105 from += 2; 106 } else if (from[1] == '{') { 107 ptr = strchr(from+2, '}'); 108 if (ptr) { 109 len = ptr - from - 2; 110 if (endto - to < (int)len ) 111 len = endto - to; 112 if (len) { 113 strncpy(to, from+2, len); 114 to[len] = '\0'; 115 from = ptr+1; 116 } else { 117 *to++ = *from++; 118 continue; 119 } 120 } else { 121 *to++ = *from++; 122 continue; 123 } 124 } else { 125 ptr = to; 126 for (from++; (isalnum(*from) || *from == '_') && ptr < endto; from++) 127 *ptr++ = *from; 128 *ptr = '\0'; 129 } 130 if (*to == '\0') 131 *to++ = '$'; 132 else if ((env = getenv(to)) != NULL) { 133 strncpy(to, env, endto - to); 134 *endto = '\0'; 135 to += strlen(to); 136 } 137 break; 138 139 case '~': 140 ptr = strchr(++from, '/'); 141 len = ptr ? (size_t)(ptr - from) : strlen(from); 142 if (len == 0) 143 pwd = getpwuid(ID0realuid()); 144 else { 145 strncpy(to, from, len); 146 to[len] = '\0'; 147 pwd = getpwnam(to); 148 } 149 if (pwd == NULL) 150 *to++ = '~'; 151 else { 152 strncpy(to, pwd->pw_dir, endto - to); 153 *endto = '\0'; 154 to += strlen(to); 155 from += len; 156 } 157 endpwent(); 158 break; 159 160 default: 161 *to++ = *from++; 162 break; 163 } 164 } 165 166 while (to > startto) { 167 to--; 168 if (!issep(*to)) { 169 to++; 170 break; 171 } 172 } 173 *to = '\0'; 174 175 return from; 176 } 177 178 #define CTRL_UNKNOWN (0) 179 #define CTRL_INCLUDE (1) 180 181 static int 182 DecodeCtrlCommand(char *line, char *arg) 183 { 184 const char *end; 185 186 if (!strncasecmp(line, "include", 7) && issep(line[7])) { 187 end = InterpretArg(line+8, arg); 188 if (*end && *end != '#') 189 log_Printf(LogWARN, "usage: !include filename\n"); 190 else 191 return CTRL_INCLUDE; 192 } 193 return CTRL_UNKNOWN; 194 } 195 196 /* 197 * Initialised in system_IsValid(), set in ReadSystem(), 198 * used by system_IsValid() 199 */ 200 static int modeok; 201 static int userok; 202 static int modereq; 203 204 int 205 AllowUsers(struct cmdargs const *arg) 206 { 207 /* arg->bundle may be NULL (see system_IsValid()) ! */ 208 int f; 209 struct passwd *pwd; 210 211 if (userok == -1) 212 userok = 0; 213 214 pwd = getpwuid(ID0realuid()); 215 if (pwd != NULL) 216 for (f = arg->argn; f < arg->argc; f++) 217 if (!strcmp("*", arg->argv[f]) || !strcmp(pwd->pw_name, arg->argv[f])) { 218 userok = 1; 219 break; 220 } 221 endpwent(); 222 223 return 0; 224 } 225 226 int 227 AllowModes(struct cmdargs const *arg) 228 { 229 /* arg->bundle may be NULL (see system_IsValid()) ! */ 230 int f, mode, allowed; 231 232 allowed = 0; 233 for (f = arg->argn; f < arg->argc; f++) { 234 mode = Nam2mode(arg->argv[f]); 235 if (mode == PHYS_NONE || mode == PHYS_ALL) 236 log_Printf(LogWARN, "allow modes: %s: Invalid mode\n", arg->argv[f]); 237 else 238 allowed |= mode; 239 } 240 241 modeok = modereq & allowed ? 1 : 0; 242 return 0; 243 } 244 245 static char * 246 strip(char *line) 247 { 248 int len; 249 250 len = strlen(line); 251 while (len && (line[len-1] == '\n' || line[len-1] == '\r' || 252 issep(line[len-1]))) 253 line[--len] = '\0'; 254 255 while (issep(*line)) 256 line++; 257 258 if (*line == '#') 259 *line = '\0'; 260 261 return line; 262 } 263 264 static int 265 xgets(char *buf, int buflen, FILE *fp) 266 { 267 int len, n; 268 269 n = 0; 270 while (fgets(buf, buflen-1, fp)) { 271 n++; 272 buf[buflen-1] = '\0'; 273 len = strlen(buf); 274 while (len && (buf[len-1] == '\n' || buf[len-1] == '\r')) 275 buf[--len] = '\0'; 276 if (len && buf[len-1] == '\\') { 277 buf += len - 1; 278 buflen -= len - 1; 279 if (!buflen) /* No buffer space */ 280 break; 281 } else 282 break; 283 } 284 return n; 285 } 286 287 /* Values for ``how'' in ReadSystem */ 288 #define SYSTEM_EXISTS 1 289 #define SYSTEM_VALIDATE 2 290 #define SYSTEM_EXEC 3 291 292 static char * 293 GetLabel(char *line, const char *filename, int linenum) 294 { 295 char *argv[MAXARGS]; 296 int argc, len; 297 298 argc = MakeArgs(line, argv, MAXARGS, PARSE_REDUCE); 299 300 if (argc == 2 && !strcmp(argv[1], ":")) 301 return argv[0]; 302 303 if (argc != 1 || (len = strlen(argv[0])) < 2 || argv[0][len-1] != ':') { 304 log_Printf(LogWARN, "Bad label in %s (line %d) - missing colon\n", 305 filename, linenum); 306 return NULL; 307 } 308 argv[0][len-1] = '\0'; /* Lose the ':' */ 309 310 return argv[0]; 311 } 312 313 /* Returns -2 for ``file not found'' and -1 for ``label not found'' */ 314 315 static int 316 ReadSystem(struct bundle *bundle, const char *name, const char *file, 317 struct prompt *prompt, struct datalink *cx, int how) 318 { 319 FILE *fp; 320 char *cp; 321 int n, len; 322 char line[LINE_LEN]; 323 char filename[PATH_MAX]; 324 int linenum; 325 int argc; 326 char *argv[MAXARGS]; 327 int allowcmd; 328 int indent; 329 char arg[LINE_LEN]; 330 struct prompt *op; 331 332 if (*file == '/') 333 snprintf(filename, sizeof filename, "%s", file); 334 else 335 snprintf(filename, sizeof filename, "%s/%s", PPP_CONFDIR, file); 336 fp = ID0fopen(filename, "r"); 337 if (fp == NULL) { 338 log_Printf(LogDEBUG, "ReadSystem: Can't open %s.\n", filename); 339 return -2; 340 } 341 log_Printf(LogDEBUG, "ReadSystem: Checking %s (%s).\n", name, filename); 342 343 linenum = 0; 344 while ((n = xgets(line, sizeof line, fp))) { 345 linenum += n; 346 if (issep(*line)) 347 continue; 348 349 cp = strip(line); 350 351 switch (*cp) { 352 case '\0': /* empty/comment */ 353 break; 354 355 case '!': 356 switch (DecodeCtrlCommand(cp+1, arg)) { 357 case CTRL_INCLUDE: 358 log_Printf(LogCOMMAND, "%s: Including \"%s\"\n", filename, arg); 359 n = ReadSystem(bundle, name, arg, prompt, cx, how); 360 log_Printf(LogCOMMAND, "%s: Done include of \"%s\"\n", filename, arg); 361 if (!n) { 362 fclose(fp); 363 return 0; /* got it */ 364 } 365 break; 366 default: 367 log_Printf(LogWARN, "%s: %s: Invalid command\n", filename, cp); 368 break; 369 } 370 break; 371 372 default: 373 if ((cp = GetLabel(cp, filename, linenum)) == NULL) 374 continue; 375 376 if (strcmp(cp, name) == 0) { 377 /* We're in business */ 378 if (how == SYSTEM_EXISTS) { 379 fclose(fp); 380 return 0; 381 } 382 while ((n = xgets(line, sizeof line, fp))) { 383 linenum += n; 384 indent = issep(*line); 385 cp = strip(line); 386 387 if (*cp == '\0') /* empty / comment */ 388 continue; 389 390 if (!indent) { /* start of next section */ 391 if (*cp != '!' && how == SYSTEM_EXEC) 392 cp = GetLabel(cp, filename, linenum); 393 break; 394 } 395 396 len = strlen(cp); 397 if ((argc = command_Expand_Interpret(cp, len, argv, cp - line)) < 0) 398 log_Printf(LogWARN, "%s: %d: Syntax error\n", filename, linenum); 399 else { 400 allowcmd = argc > 0 && !strcasecmp(argv[0], "allow"); 401 if ((how != SYSTEM_EXEC && allowcmd) || 402 (how == SYSTEM_EXEC && !allowcmd)) { 403 /* 404 * Disable any context so that warnings are given to everyone, 405 * including syslog. 406 */ 407 op = log_PromptContext; 408 log_PromptContext = NULL; 409 command_Run(bundle, argc, (char const *const *)argv, prompt, 410 name, cx); 411 log_PromptContext = op; 412 } 413 } 414 } 415 416 fclose(fp); /* everything read - get out */ 417 return 0; 418 } 419 break; 420 } 421 } 422 fclose(fp); 423 return -1; 424 } 425 426 const char * 427 system_IsValid(const char *name, struct prompt *prompt, int mode) 428 { 429 /* 430 * Note: The ReadSystem() calls only result in calls to the Allow* 431 * functions. arg->bundle will be set to NULL for these commands ! 432 */ 433 int def, how, rs; 434 int defuserok; 435 436 def = !strcmp(name, "default"); 437 how = ID0realuid() == 0 ? SYSTEM_EXISTS : SYSTEM_VALIDATE; 438 userok = -1; 439 modeok = 1; 440 modereq = mode; 441 442 rs = ReadSystem(NULL, "default", CONFFILE, prompt, NULL, how); 443 444 defuserok = userok; 445 userok = -1; 446 447 if (!def) { 448 if (rs == -1) 449 rs = 0; /* we don't care that ``default'' doesn't exist */ 450 451 if (rs == 0) 452 rs = ReadSystem(NULL, name, CONFFILE, prompt, NULL, how); 453 454 if (rs == -1) 455 return "Configuration label not found"; 456 457 if (rs == -2) 458 return PPP_CONFDIR "/" CONFFILE " : File not found"; 459 } 460 461 if (userok == -1) 462 userok = defuserok; 463 464 if (how == SYSTEM_EXISTS) 465 userok = modeok = 1; 466 467 if (!userok) 468 return "User access denied"; 469 470 if (!modeok) 471 return "Mode denied for this label"; 472 473 return NULL; 474 } 475 476 int 477 system_Select(struct bundle *bundle, const char *name, const char *file, 478 struct prompt *prompt, struct datalink *cx) 479 { 480 userok = modeok = 1; 481 modereq = PHYS_ALL; 482 return ReadSystem(bundle, name, file, prompt, cx, SYSTEM_EXEC); 483 } 484