1 /* $OpenBSD: vacation.c,v 1.36 2015/03/15 00:41:28 millert Exp $ */ 2 /* $NetBSD: vacation.c,v 1.7 1995/04/29 05:58:27 cgd Exp $ */ 3 4 /* 5 * Copyright (c) 1983, 1987, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /* 34 ** Vacation 35 ** Copyright (c) 1983 Eric P. Allman 36 ** Berkeley, California 37 */ 38 39 #include <sys/stat.h> 40 #include <fcntl.h> 41 #include <pwd.h> 42 #include <db.h> 43 #include <time.h> 44 #include <syslog.h> 45 #include <errno.h> 46 #include <unistd.h> 47 #include <stdio.h> 48 #include <ctype.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <paths.h> 52 53 /* 54 * VACATION -- return a message to the sender when on vacation. 55 * 56 * This program is invoked as a message receiver. It returns a 57 * message specified by the user to whomever sent the mail, taking 58 * care not to return a message too often to prevent "I am on 59 * vacation" loops. 60 */ 61 62 #define MAXLINE 1024 /* max line from mail header */ 63 #define VDB ".vacation.db" /* dbm's database */ 64 #define VMSG ".vacation.msg" /* vacation message */ 65 66 typedef struct alias { 67 struct alias *next; 68 char *name; 69 } ALIAS; 70 ALIAS *names; 71 72 DB *db; 73 char from[MAXLINE]; 74 char subj[MAXLINE]; 75 76 int junkmail(void); 77 int nsearch(char *, char *); 78 void readheaders(void); 79 int recent(void); 80 void sendmessage(char *); 81 void setinterval(time_t); 82 void setreply(void); 83 void usage(void); 84 85 #define SECSPERDAY (24 * 60 * 60) 86 87 int 88 main(int argc, char *argv[]) 89 { 90 int ch, iflag, flags; 91 struct passwd *pw; 92 time_t interval; 93 struct stat sb; 94 ALIAS *cur; 95 96 opterr = iflag = 0; 97 interval = -1; 98 while ((ch = getopt(argc, argv, "a:Iir:")) != -1) 99 switch ((char)ch) { 100 case 'a': /* alias */ 101 if (!(cur = (ALIAS *)malloc((u_int)sizeof(ALIAS)))) 102 break; 103 cur->name = optarg; 104 cur->next = names; 105 names = cur; 106 break; 107 case 'I': /* backward compatible */ 108 case 'i': /* init the database */ 109 iflag = 1; 110 break; 111 case 'r': 112 if (isdigit((unsigned char)*optarg)) { 113 interval = atol(optarg) * SECSPERDAY; 114 if (interval < 0) 115 usage(); 116 } else 117 interval = 0; /* one time only */ 118 break; 119 default: 120 usage(); 121 } 122 argc -= optind; 123 argv += optind; 124 125 if (argc != 1) { 126 if (!iflag) 127 usage(); 128 if (!(pw = getpwuid(getuid()))) { 129 syslog(LOG_ERR, 130 "no such user uid %u.", getuid()); 131 exit(1); 132 } 133 } else if (!(pw = getpwnam(*argv))) { 134 syslog(LOG_ERR, "no such user %s.", *argv); 135 exit(1); 136 } 137 if (chdir(pw->pw_dir)) { 138 syslog(LOG_NOTICE, 139 "no such directory %s.", pw->pw_dir); 140 exit(1); 141 } 142 143 /* 144 * dbopen(3) can not deal with a zero-length file w/o O_TRUNC. 145 */ 146 if (iflag == 1 || (stat(VDB, &sb) == 0 && sb.st_size == (off_t)0)) 147 flags = O_CREAT|O_RDWR|O_TRUNC; 148 else 149 flags = O_CREAT|O_RDWR; 150 151 db = dbopen(VDB, flags, S_IRUSR|S_IWUSR, DB_HASH, NULL); 152 if (!db) { 153 syslog(LOG_NOTICE, "%s: %m", VDB); 154 exit(1); 155 } 156 157 if (interval != -1) 158 setinterval(interval); 159 160 if (iflag) { 161 (void)(db->close)(db); 162 exit(0); 163 } 164 165 if (!(cur = malloc((u_int)sizeof(ALIAS)))) 166 exit(1); 167 cur->name = pw->pw_name; 168 cur->next = names; 169 names = cur; 170 171 readheaders(); 172 if (!recent()) { 173 setreply(); 174 (void)(db->close)(db); 175 sendmessage(pw->pw_name); 176 } else 177 (void)(db->close)(db); 178 exit(0); 179 /* NOTREACHED */ 180 } 181 182 /* 183 * readheaders -- 184 * read mail headers 185 */ 186 void 187 readheaders(void) 188 { 189 char buf[MAXLINE], *p; 190 int tome, cont; 191 ALIAS *cur; 192 193 cont = tome = 0; 194 while (fgets(buf, sizeof(buf), stdin) && *buf != '\n') 195 switch (*buf) { 196 case 'A': /* "Auto-Submitted:" */ 197 case 'a': 198 cont = 0; 199 if (strncasecmp(buf, "Auto-Submitted:", 15)) 200 break; 201 for (p = buf + 15; isspace((unsigned char)*p); ++p) 202 ; 203 /* 204 * RFC 3834 section 2: 205 * Automatic responses SHOULD NOT be issued in response 206 * to any message which contains an Auto-Submitted 207 * header where the field has any value other than "no". 208 */ 209 if ((p[0] == 'n' || p[0] == 'N') && 210 (p[1] == 'o' || p[1] == 'O')) { 211 for (p += 2; isspace((unsigned char)*p); ++p) 212 ; 213 if (*p == '\0') 214 break; /* Auto-Submitted: no */ 215 } 216 exit(0); 217 case 'F': /* "From " */ 218 case 'f': 219 cont = 0; 220 if (!strncasecmp(buf, "From ", 5)) { 221 for (p = buf + 5; *p && *p != ' '; ++p) 222 ; 223 *p = '\0'; 224 (void)strlcpy(from, buf + 5, sizeof(from)); 225 from[strcspn(from, "\n")] = '\0'; 226 if (junkmail()) 227 exit(0); 228 } 229 break; 230 case 'L': /* "List-Id:" */ 231 case 'l': 232 cont = 0; 233 /* 234 * If present (with any value), message is coming from a 235 * mailing list, cf. RFC2919. 236 */ 237 if (strncasecmp(buf, "List-Id:", 8) == 0) 238 exit(0); 239 break; 240 case 'R': /* "Return-Path:" */ 241 case 'r': 242 cont = 0; 243 if (strncasecmp(buf, "Return-Path:", 244 sizeof("Return-Path:")-1) || 245 (buf[12] != ' ' && buf[12] != '\t')) 246 break; 247 for (p = buf + 12; isspace((unsigned char)*p); ++p) 248 ; 249 if (strlcpy(from, p, sizeof(from)) >= sizeof(from)) { 250 syslog(LOG_NOTICE, 251 "Return-Path %s exceeds limits", p); 252 exit(1); 253 } 254 from[strcspn(from, "\n")] = '\0'; 255 if (junkmail()) 256 exit(0); 257 break; 258 case 'P': /* "Precedence:" */ 259 case 'p': 260 cont = 0; 261 if (strncasecmp(buf, "Precedence:", 11)) 262 break; 263 for (p = buf + 11; isspace((unsigned char)*p); ++p) 264 ; 265 if (!strncasecmp(p, "junk", 4) || 266 !strncasecmp(p, "bulk", 4) || 267 !strncasecmp(p, "list", 4)) 268 exit(0); 269 break; 270 case 'S': /* Subject: */ 271 case 's': 272 cont = 0; 273 if (strncasecmp(buf, "Subject:", 274 sizeof("Subject:")-1) || 275 (buf[8] != ' ' && buf[8] != '\t')) 276 break; 277 for (p = buf + 8; isspace((unsigned char)*p); ++p) 278 ; 279 if (strlcpy(subj, p, sizeof(subj)) >= sizeof(subj)) { 280 syslog(LOG_NOTICE, 281 "Subject %s exceeds limits", p); 282 exit(1); 283 } 284 subj[strcspn(subj, "\n")] = '\0'; 285 break; 286 case 'C': /* "Cc:" */ 287 case 'c': 288 if (strncasecmp(buf, "Cc:", 3)) 289 break; 290 cont = 1; 291 goto findme; 292 case 'T': /* "To:" */ 293 case 't': 294 if (strncasecmp(buf, "To:", 3)) 295 break; 296 cont = 1; 297 goto findme; 298 default: 299 if (!isspace((unsigned char)*buf) || !cont || tome) { 300 cont = 0; 301 break; 302 } 303 findme: for (cur = names; !tome && cur; cur = cur->next) 304 tome += nsearch(cur->name, buf); 305 } 306 if (!tome) 307 exit(0); 308 if (!*from) { 309 syslog(LOG_NOTICE, 310 "no initial \"From\" or \"Return-Path\"line."); 311 exit(1); 312 } 313 } 314 315 /* 316 * nsearch -- 317 * do a nice, slow, search of a string for a substring. 318 */ 319 int 320 nsearch(char *name, char *str) 321 { 322 int len; 323 324 for (len = strlen(name); *str; ++str) 325 if (!strncasecmp(name, str, len)) 326 return(1); 327 return(0); 328 } 329 330 /* 331 * junkmail -- 332 * read the header and return if automagic/junk/bulk/list mail 333 */ 334 int 335 junkmail(void) 336 { 337 static struct ignore { 338 char *name; 339 int len; 340 } ignore[] = { 341 { "-request", 8 }, 342 { "postmaster", 10 }, 343 { "uucp", 4 }, 344 { "mailer-daemon", 13 }, 345 { "mailer", 6 }, 346 { "-relay", 6 }, 347 { NULL, 0 } 348 }; 349 struct ignore *cur; 350 int len; 351 char *p; 352 353 /* 354 * This is mildly amusing, and I'm not positive it's right; trying 355 * to find the "real" name of the sender, assuming that addresses 356 * will be some variant of: 357 * 358 * From site!site!SENDER%site.domain%site.domain@site.domain 359 */ 360 if (!(p = strchr(from, '%'))) { 361 if (!(p = strchr(from, '@'))) { 362 if ((p = strrchr(from, '!'))) 363 ++p; 364 else 365 p = from; 366 for (; *p; ++p) 367 ; 368 } 369 } 370 len = p - from; 371 for (cur = ignore; cur->name; ++cur) 372 if (len >= cur->len && 373 !strncasecmp(cur->name, p - cur->len, cur->len)) 374 return(1); 375 return(0); 376 } 377 378 #define VIT "__VACATION__INTERVAL__TIMER__" 379 380 /* 381 * recent -- 382 * find out if user has gotten a vacation message recently. 383 * use bcopy for machines with alignment restrictions 384 */ 385 int 386 recent(void) 387 { 388 time_t then, next; 389 DBT key, data; 390 391 /* get interval time */ 392 key.data = VIT; 393 key.size = sizeof(VIT); 394 if ((db->get)(db, &key, &data, 0)) 395 next = SECSPERDAY * 7; 396 else 397 bcopy(data.data, &next, sizeof(next)); 398 399 /* get record for this address */ 400 key.data = from; 401 key.size = strlen(from); 402 if (!(db->get)(db, &key, &data, 0)) { 403 bcopy(data.data, &then, sizeof(then)); 404 if (next == 0 || 405 then + next > time(NULL)) 406 return(1); 407 } 408 return(0); 409 } 410 411 /* 412 * setinterval -- 413 * store the reply interval 414 */ 415 void 416 setinterval(time_t interval) 417 { 418 DBT key, data; 419 420 key.data = VIT; 421 key.size = sizeof(VIT); 422 data.data = &interval; 423 data.size = sizeof(interval); 424 (void)(db->put)(db, &key, &data, 0); 425 } 426 427 /* 428 * setreply -- 429 * store that this user knows about the vacation. 430 */ 431 void 432 setreply(void) 433 { 434 DBT key, data; 435 time_t now; 436 437 key.data = from; 438 key.size = strlen(from); 439 (void)time(&now); 440 data.data = &now; 441 data.size = sizeof(now); 442 (void)(db->put)(db, &key, &data, 0); 443 } 444 445 /* 446 * sendmessage -- 447 * exec sendmail to send the vacation file to sender 448 */ 449 void 450 sendmessage(char *myname) 451 { 452 char buf[MAXLINE]; 453 FILE *mfp, *sfp; 454 int pvect[2], i; 455 456 mfp = fopen(VMSG, "r"); 457 if (mfp == NULL) { 458 syslog(LOG_NOTICE, "no ~%s/%s file.", myname, VMSG); 459 exit(1); 460 } 461 if (pipe(pvect) < 0) { 462 syslog(LOG_ERR, "pipe: %m"); 463 exit(1); 464 } 465 i = vfork(); 466 if (i < 0) { 467 syslog(LOG_ERR, "fork: %m"); 468 exit(1); 469 } 470 if (i == 0) { 471 dup2(pvect[0], 0); 472 close(pvect[0]); 473 close(pvect[1]); 474 close(fileno(mfp)); 475 execl(_PATH_SENDMAIL, "sendmail", "-f", myname, "--", 476 from, (char *)NULL); 477 syslog(LOG_ERR, "can't exec %s: %m", _PATH_SENDMAIL); 478 _exit(1); 479 } 480 close(pvect[0]); 481 sfp = fdopen(pvect[1], "w"); 482 if (sfp == NULL) { 483 /* XXX could not fdopen; likely out of memory */ 484 fclose(mfp); 485 close(pvect[1]); 486 return; 487 } 488 fprintf(sfp, "To: %s\n", from); 489 fputs("Auto-Submitted: auto-replied\n", sfp); 490 while (fgets(buf, sizeof buf, mfp)) { 491 char *s = strstr(buf, "$SUBJECT"); 492 493 if (s) { 494 *s = 0; 495 fputs(buf, sfp); 496 fputs(subj, sfp); 497 fputs(s+8, sfp); 498 } else { 499 fputs(buf, sfp); 500 } 501 } 502 fclose(mfp); 503 fclose(sfp); 504 } 505 506 void 507 usage(void) 508 { 509 syslog(LOG_NOTICE, "uid %u: usage: vacation [-i] [-a alias] login", 510 getuid()); 511 exit(1); 512 } 513