usr.sbin/inetd/builtins.c

   1 /*-
   2  * Copyright (c) 1983, 1991, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/usr.sbin/inetd/builtins.c,v 1.19.2.7 2002/07/22 14:05:56 fanf Exp $
  27  * $DragonFly: src/usr.sbin/inetd/builtins.c,v 1.5 2004/12/18 22:48:03 swildner Exp $
  28  *
  29  */
  30
  31 #include <sys/filio.h>
  32 #include <sys/param.h>
  33 #include <sys/stat.h>
  34 #include <sys/socket.h>
  35 #include <sys/sysctl.h>
  36 #include <sys/ucred.h>
  37 #include <sys/uio.h>
  38 #include <sys/utsname.h>
  39
  40 #include <ctype.h>
  41 #include <err.h>
  42 #include <errno.h>
  43 #include <fcntl.h>
  44 #include <limits.h>
  45 #include <pwd.h>
  46 #include <signal.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <sysexits.h>
  50 #include <syslog.h>
  51 #include <unistd.h>
  52
  53 #include "inetd.h"
  54
  55 void            chargen_dg(int, struct servtab *);
  56 void            chargen_stream(int, struct servtab *);
  57 void            daytime_dg(int, struct servtab *);
  58 void            daytime_stream(int, struct servtab *);
  59 void            discard_dg(int, struct servtab *);
  60 void            discard_stream(int, struct servtab *);
  61 void            echo_dg(int, struct servtab *);
  62 void            echo_stream(int, struct servtab *);
  63 static int      getline(int, char *, int);
  64 void            iderror(int, int, int, const char *);
  65 void            ident_stream(int, struct servtab *);
  66 void            initring(void);
  67 unsigned long   machtime(void);
  68 void            machtime_dg(int, struct servtab *);
  69 void            machtime_stream(int, struct servtab *);
  70
  71 char ring[128];
  72 char *endring;
  73
  74
  75 struct biltin biltins[] = {
  76         /* Echo received data */
  77         { "echo",       SOCK_STREAM,    1, -1,  echo_stream },
  78         { "echo",       SOCK_DGRAM,     0, 1,   echo_dg },
  79
  80         /* Internet /dev/null */
  81         { "discard",    SOCK_STREAM,    1, -1,  discard_stream },
  82         { "discard",    SOCK_DGRAM,     0, 1,   discard_dg },
  83
  84         /* Return 32 bit time since 1900 */
  85         { "time",       SOCK_STREAM,    0, -1,  machtime_stream },
  86         { "time",       SOCK_DGRAM,     0, 1,   machtime_dg },
  87
  88         /* Return human-readable time */
  89         { "daytime",    SOCK_STREAM,    0, -1,  daytime_stream },
  90         { "daytime",    SOCK_DGRAM,     0, 1,   daytime_dg },
  91
  92         /* Familiar character generator */
  93         { "chargen",    SOCK_STREAM,    1, -1,  chargen_stream },
  94         { "chargen",    SOCK_DGRAM,     0, 1,   chargen_dg },
  95
  96         { "tcpmux",     SOCK_STREAM,    1, -1,  (bi_fn_t *)tcpmux },
  97
  98         { "auth",       SOCK_STREAM,    1, -1,  ident_stream },
  99
 100         { NULL,         0,              0, 0,   NULL }
 101 };
 102
 103 /*
 104  * RFC864 Character Generator Protocol. Generates character data without
 105  * any regard for input.
 106  */
 107
 108 void
 109 initring(void)
 110 {
 111         int i;
 112
 113         endring = ring;
 114
 115         for (i = 0; i <= 128; ++i)
 116                 if (isprint(i))
 117                         *endring++ = i;
 118 }
 119
 120 /* ARGSUSED */
 121 void
 122 chargen_dg(int s, struct servtab *sep)          /* Character generator */
 123 {
 124         struct sockaddr_storage ss;
 125         static char *rs;
 126         int len;
 127         socklen_t size;
 128         char text[LINESIZ+2];
 129
 130         if (endring == 0) {
 131                 initring();
 132                 rs = ring;
 133         }
 134
 135         size = sizeof(ss);
 136         if (recvfrom(s, text, sizeof(text), 0,
 137                      (struct sockaddr *)&ss, &size) < 0)
 138                 return;
 139
 140         if (check_loop((struct sockaddr *)&ss, sep))
 141                 return;
 142
 143         if ((len = endring - rs) >= LINESIZ)
 144                 memmove(text, rs, LINESIZ);
 145         else {
 146                 memmove(text, rs, len);
 147                 memmove(text + len, ring, LINESIZ - len);
 148         }
 149         if (++rs == endring)
 150                 rs = ring;
 151         text[LINESIZ] = '\r';
 152         text[LINESIZ + 1] = '\n';
 153         sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size);
 154 }
 155
 156 /* ARGSUSED */
 157 void
 158 chargen_stream(int s, struct servtab *sep)              /* Character generator */
 159 {
 160         int len;
 161         char *rs, text[LINESIZ+2];
 162
 163         inetd_setproctitle(sep->se_service, s);
 164
 165         if (!endring) {
 166                 initring();
 167                 rs = ring;
 168         }
 169
 170         text[LINESIZ] = '\r';
 171         text[LINESIZ + 1] = '\n';
 172         for (rs = ring;;) {
 173                 if ((len = endring - rs) >= LINESIZ)
 174                         memmove(text, rs, LINESIZ);
 175                 else {
 176                         memmove(text, rs, len);
 177                         memmove(text + len, ring, LINESIZ - len);
 178                 }
 179                 if (++rs == endring)
 180                         rs = ring;
 181                 if (write(s, text, sizeof(text)) != sizeof(text))
 182                         break;
 183         }
 184         exit(0);
 185 }
 186
 187 /*
 188  * RFC867 Daytime Protocol. Sends the current date and time as an ascii
 189  * character string without any regard for input.
 190  */
 191
 192 /* ARGSUSED */
 193 void
 194 daytime_dg(int s, struct servtab *sep)          /* Return human-readable time of day */
 195 {
 196         char buffer[256];
 197         time_t now;
 198         struct sockaddr_storage ss;
 199         socklen_t size;
 200
 201         now = time(NULL);
 202
 203         size = sizeof(ss);
 204         if (recvfrom(s, buffer, sizeof(buffer), 0,
 205                      (struct sockaddr *)&ss, &size) < 0)
 206                 return;
 207
 208         if (check_loop((struct sockaddr *)&ss, sep))
 209                 return;
 210
 211         sprintf(buffer, "%.24s\r\n", ctime(&now));
 212         sendto(s, buffer, strlen(buffer), 0, (struct sockaddr *)&ss, size);
 213 }
 214
 215 /* ARGSUSED */
 216 void
 217 daytime_stream(int s, struct servtab *sep __unused) /* Return human-readable time of day */
 218 {
 219         char buffer[256];
 220         time_t now;
 221
 222         now = time(NULL);
 223
 224         sprintf(buffer, "%.24s\r\n", ctime(&now));
 225         send(s, buffer, strlen(buffer), MSG_EOF);
 226 }
 227
 228 /*
 229  * RFC863 Discard Protocol. Any data received is thrown away and no response
 230  * is sent.
 231  */
 232
 233 /* ARGSUSED */
 234 void
 235 discard_dg(int s, struct servtab *sep __unused) /* Discard service -- ignore data */
 236 {
 237         char buffer[BUFSIZE];
 238
 239         read(s, buffer, sizeof(buffer));
 240 }
 241
 242 /* ARGSUSED */
 243 void
 244 discard_stream(int s, struct servtab *sep) /* Discard service -- ignore data */
 245 {
 246         int ret;
 247         char buffer[BUFSIZE];
 248
 249         inetd_setproctitle(sep->se_service, s);
 250         while (1) {
 251                 while ((ret = read(s, buffer, sizeof(buffer))) > 0)
 252                         ;
 253                 if (ret == 0 || errno != EINTR)
 254                         break;
 255         }
 256         exit(0);
 257 }
 258
 259 /*
 260  * RFC862 Echo Protocol. Any data received is sent back to the sender as
 261  * received.
 262  */
 263
 264 /* ARGSUSED */
 265 void
 266 echo_dg(int s, struct servtab *sep) /* Echo service -- echo data back */
 267 {
 268         char buffer[65536]; /* Should be sizeof(max datagram). */
 269         int i;
 270         socklen_t size;
 271         struct sockaddr_storage ss;
 272
 273         size = sizeof(ss);
 274         if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
 275                           (struct sockaddr *)&ss, &size)) < 0)
 276                 return;
 277
 278         if (check_loop((struct sockaddr *)&ss, sep))
 279                 return;
 280
 281         sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
 282 }
 283
 284 /* ARGSUSED */
 285 void
 286 echo_stream(int s, struct servtab *sep)         /* Echo service -- echo data back */
 287 {
 288         char buffer[BUFSIZE];
 289         int i;
 290
 291         inetd_setproctitle(sep->se_service, s);
 292         while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
 293             write(s, buffer, i) > 0)
 294                 ;
 295         exit(0);
 296 }
 297
 298 /*
 299  * RFC1413 Identification Protocol. Given a TCP port number pair, return a
 300  * character string which identifies the owner of that connection on the
 301  * server's system. Extended to allow for ~/.fakeid support and ~/.noident
 302  * support.
 303  */
 304
 305 /* RFC 1413 says the following are the only errors you can return. */
 306 #define ID_INVALID      "INVALID-PORT"  /* Port number improperly specified. */
 307 #define ID_NOUSER       "NO-USER"       /* Port not in use/not identifable. */
 308 #define ID_HIDDEN       "HIDDEN-USER"   /* Hiden at user's request. */
 309 #define ID_UNKNOWN      "UNKNOWN-ERROR" /* Everything else. */
 310
 311 /* ARGSUSED */
 312 void
 313 iderror(int lport, int fport, int s, const char *er)    /* Generic ident_stream error-sending func */
 314 {
 315         char *p;
 316
 317         asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
 318         if (p == NULL) {
 319                 syslog(LOG_ERR, "asprintf: %m");
 320                 exit(EX_OSERR);
 321         }
 322         send(s, p, strlen(p), MSG_EOF);
 323         free(p);
 324
 325         exit(0);
 326 }
 327
 328 /* ARGSUSED */
 329 void
 330 ident_stream(int s, struct servtab *sep)                /* Ident service (AKA "auth") */
 331 {
 332         struct utsname un;
 333         struct stat sb;
 334         struct sockaddr_in sin4[2];
 335 #ifdef INET6
 336         struct sockaddr_in6 sin6[2];
 337 #endif
 338         struct sockaddr_storage ss[2];
 339         struct ucred uc;
 340         struct timeval tv = {
 341                 10,
 342                 0
 343         }, to;
 344         struct passwd *pw = NULL;
 345         fd_set fdset;
 346         char buf[BUFSIZE], *p, **av, *osname = NULL, e;
 347         char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
 348         socklen_t socklen;
 349         ssize_t ssize;
 350         size_t size, bufsiz;
 351         int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
 352         int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
 353         u_short lport, fport;
 354
 355         inetd_setproctitle(sep->se_service, s);
 356         /*
 357          * Reset getopt() since we are a fork() but not an exec() from
 358          * a parent which used getopt() already.
 359          */
 360         optind = 1;
 361         optreset = 1;
 362         /*
 363          * Take the internal argument vector and count it out to make an
 364          * argument count for getopt. This can be used for any internal
 365          * service to read arguments and use getopt() easily.
 366          */
 367         for (av = sep->se_argv; *av; av++)
 368                 argc++;
 369         if (argc) {
 370                 int sec, usec;
 371                 size_t i;
 372                 u_int32_t rnd32;
 373
 374                 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
 375                         switch (c) {
 376                         case 'd':
 377                                 if (!gflag)
 378                                         strlcpy(idbuf, optarg, sizeof(idbuf));
 379                                 break;
 380                         case 'f':
 381                                 fflag = 1;
 382                                 break;
 383                         case 'F':
 384                                 fflag = 1;
 385                                 Fflag=1;
 386                                 break;
 387                         case 'g':
 388                                 gflag = 1;
 389                                 rnd32 = 0;      /* Shush, compiler. */
 390                                 /*
 391                                  * The number of bits in "rnd32" divided
 392                                  * by the number of bits needed per iteration
 393                                  * gives a more optimal way to reload the
 394                                  * random number only when necessary.
 395                                  *
 396                                  * 32 bits from arc4random corresponds to
 397                                  * about 6 base-36 digits, so we reseed evey 6.
 398                                  */
 399                                 for (i = 0; i < sizeof(idbuf) - 1; i++) {
 400                                         static const char *const base36 =
 401                                             "0123456789"
 402                                             "abcdefghijklmnopqrstuvwxyz";
 403                                         if (i % 6 == 0)
 404                                                 rnd32 = arc4random();
 405                                         idbuf[i] = base36[rnd32 % 36];
 406                                         rnd32 /= 36;
 407                                 }
 408                                 idbuf[i] = '\0';
 409                                 break;
 410                         case 'i':
 411                                 iflag = 1;
 412                                 break;
 413                         case 'n':
 414                                 nflag = 1;
 415                                 break;
 416                         case 'o':
 417                                 osname = optarg;
 418                                 break;
 419                         case 'r':
 420                                 rflag = 1;
 421                                 break;
 422                         case 't':
 423                                 switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
 424                                 case 2:
 425                                         tv.tv_usec = usec;
 426                                         /* FALLTHROUGH */
 427                                 case 1:
 428                                         tv.tv_sec = sec;
 429                                         break;
 430                                 default:
 431                                         if (debug)
 432                                                 warnx("bad -t argument");
 433                                         break;
 434                                 }
 435                                 break;
 436                         default:
 437                                 break;
 438                         }
 439         }
 440         if (osname == NULL) {
 441                 if (uname(&un) == -1)
 442                         iderror(0, 0, s, ID_UNKNOWN);
 443                 osname = un.sysname;
 444         }
 445
 446         /*
 447          * We're going to prepare for and execute reception of a
 448          * packet of data from the user. The data is in the format
 449          * "local_port , foreign_port\r\n" (with local being the
 450          * server's port and foreign being the client's.)
 451          */
 452         gettimeofday(&to, NULL);
 453         to.tv_sec += tv.tv_sec;
 454         to.tv_usec += tv.tv_usec;
 455         if (to.tv_usec >= 1000000) {
 456                 to.tv_usec -= 1000000;
 457                 to.tv_sec++;
 458         }
 459
 460         size = 0;
 461         bufsiz = sizeof(buf) - 1;
 462         FD_ZERO(&fdset);
 463         while (bufsiz > 0) {
 464                 gettimeofday(&tv, NULL);
 465                 tv.tv_sec = to.tv_sec - tv.tv_sec;
 466                 tv.tv_usec = to.tv_usec - tv.tv_usec;
 467                 if (tv.tv_usec < 0) {
 468                         tv.tv_usec += 1000000;
 469                         tv.tv_sec--;
 470                 }
 471                 if (tv.tv_sec < 0)
 472                         break;
 473                 FD_SET(s, &fdset);
 474                 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
 475                         iderror(0, 0, s, ID_UNKNOWN);
 476                 if (ioctl(s, FIONREAD, &onreadlen) == -1)
 477                         iderror(0, 0, s, ID_UNKNOWN);
 478                 if ((size_t)onreadlen > bufsiz)
 479                         onreadlen = bufsiz;
 480                 ssize = read(s, &buf[size], (size_t)onreadlen);
 481                 if (ssize == -1)
 482                         iderror(0, 0, s, ID_UNKNOWN);
 483                 else if (ssize == 0)
 484                         break;
 485                 bufsiz -= ssize;
 486                 size += ssize;
 487                 if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
 488                         break;
 489         }
 490         buf[size] = '\0';
 491         /* Read two characters, and check for a delimiting character */
 492         if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
 493                 iderror(0, 0, s, ID_INVALID);
 494
 495         /* Send garbage? */
 496         if (gflag)
 497                 goto printit;
 498
 499         /*
 500          * If not "real" (-r), send a HIDDEN-USER error for everything.
 501          * If -d is used to set a fallback username, this is used to
 502          * override it, and the fallback is returned instead.
 503          */
 504         if (!rflag) {
 505                 if (*idbuf == '\0')
 506                         iderror(lport, fport, s, ID_HIDDEN);
 507                 goto printit;
 508         }
 509
 510         /*
 511          * We take the input and construct an array of two sockaddr_ins
 512          * which contain the local address information and foreign
 513          * address information, respectively, used to look up the
 514          * credentials for the socket (which are returned by the
 515          * sysctl "net.inet.tcp.getcred" when we call it.)
 516          */
 517         socklen = sizeof(ss[0]);
 518         if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
 519                 iderror(lport, fport, s, ID_UNKNOWN);
 520         socklen = sizeof(ss[1]);
 521         if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
 522                 iderror(lport, fport, s, ID_UNKNOWN);
 523         if (ss[0].ss_family != ss[1].ss_family)
 524                 iderror(lport, fport, s, ID_UNKNOWN);
 525         size = sizeof(uc);
 526         switch (ss[0].ss_family) {
 527         case AF_INET:
 528                 sin4[0] = *(struct sockaddr_in *)&ss[0];
 529                 sin4[0].sin_port = htons(lport);
 530                 sin4[1] = *(struct sockaddr_in *)&ss[1];
 531                 sin4[1].sin_port = htons(fport);
 532                 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
 533                                  sizeof(sin4)) == -1)
 534                         getcredfail = errno;
 535                 break;
 536 #ifdef INET6
 537         case AF_INET6:
 538                 sin6[0] = *(struct sockaddr_in6 *)&ss[0];
 539                 sin6[0].sin6_port = htons(lport);
 540                 sin6[1] = *(struct sockaddr_in6 *)&ss[1];
 541                 sin6[1].sin6_port = htons(fport);
 542                 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
 543                                  sizeof(sin6)) == -1)
 544                         getcredfail = errno;
 545                 break;
 546 #endif
 547         default: /* should not reach here */
 548                 getcredfail = EAFNOSUPPORT;
 549                 break;
 550         }
 551         if (getcredfail != 0) {
 552                 if (*idbuf == '\0')
 553                         iderror(lport, fport, s,
 554                             getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
 555                 goto printit;
 556         }
 557
 558         /* Look up the pw to get the username and home directory*/
 559         errno = 0;
 560         pw = getpwuid(uc.cr_uid);
 561         if (pw == NULL)
 562                 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
 563
 564         if (iflag)
 565                 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
 566         else
 567                 strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
 568
 569         /*
 570          * If enabled, we check for a file named ".noident" in the user's
 571          * home directory. If found, we return HIDDEN-USER.
 572          */
 573         if (nflag) {
 574                 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
 575                         iderror(lport, fport, s, ID_UNKNOWN);
 576                 if (lstat(p, &sb) == 0) {
 577                         free(p);
 578                         iderror(lport, fport, s, ID_HIDDEN);
 579                 }
 580                 free(p);
 581         }
 582
 583         /*
 584          * Here, if enabled, we read a user's ".fakeid" file in their
 585          * home directory. It consists of a line containing the name
 586          * they want.
 587          */
 588         if (fflag) {
 589                 int fakeid_fd;
 590
 591                 /*
 592                  * Here we set ourself to effectively be the user, so we don't
 593                  * open any files we have no permission to open, especially
 594                  * symbolic links to sensitive root-owned files or devices.
 595                  */
 596                 if (initgroups(pw->pw_name, pw->pw_gid) == -1)
 597                         iderror(lport, fport, s, ID_UNKNOWN);
 598                 if (seteuid(pw->pw_uid) == -1)
 599                         iderror(lport, fport, s, ID_UNKNOWN);
 600                 /*
 601                  * We can't stat() here since that would be a race
 602                  * condition.
 603                  * Therefore, we open the file we have permissions to open
 604                  * and if it's not a regular file, we close it and end up
 605                  * returning the user's real username.
 606                  */
 607                 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
 608                         iderror(lport, fport, s, ID_UNKNOWN);
 609                 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
 610                 free(p);
 611                 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
 612                     !S_ISREG(sb.st_mode))
 613                         goto fakeid_fail;
 614
 615                 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
 616                         goto fakeid_fail;
 617                 buf[ssize] = '\0';
 618
 619                 /*
 620                  * Usually, the file will have the desired identity
 621                  * in the form "identity\n". Allow for leading white
 622                  * space and trailing white space/end of line.
 623                  */
 624                 p = buf;
 625                 p += strspn(p, " \t");
 626                 p[strcspn(p, " \t\r\n")] = '\0';
 627                 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
 628                         p[MAXLOGNAME - 1] = '\0';
 629
 630                 /*
 631                  * If the name is a zero-length string or matches it
 632                  * the id or name of another user (unless permitted by -F)
 633                  * then it is invalid.
 634                  */
 635                 if (*p == '\0')
 636                         goto fakeid_fail;
 637                 if (!Fflag) {
 638                         if (iflag) {
 639                                 if (p[strspn(p, "0123456789")] == '\0' &&
 640                                     getpwuid(atoi(p)) != NULL)
 641                                         goto fakeid_fail;
 642                         } else {
 643                                 if (getpwnam(p) != NULL)
 644                                         goto fakeid_fail;
 645                         }
 646                 }
 647
 648                 strlcpy(idbuf, p, sizeof(idbuf));
 649
 650 fakeid_fail:
 651                 if (fakeid_fd != -1)
 652                         close(fakeid_fd);
 653         }
 654
 655 printit:
 656         /* Finally, we make and send the reply. */
 657         if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
 658             idbuf) == -1) {
 659                 syslog(LOG_ERR, "asprintf: %m");
 660                 exit(EX_OSERR);
 661         }
 662         send(s, p, strlen(p), MSG_EOF);
 663         free(p);
 664
 665         exit(0);
 666 }
 667
 668 /*
 669  * RFC738 Time Server.
 670  * Return a machine readable date and time, in the form of the
 671  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
 672  * returns the number of seconds since midnight, Jan 1, 1970,
 673  * we must add 2208988800 seconds to this figure to make up for
 674  * some seventy years Bell Labs was asleep.
 675  */
 676
 677 unsigned long
 678 machtime(void)
 679 {
 680         struct timeval tv;
 681
 682         if (gettimeofday(&tv, NULL) < 0) {
 683                 if (debug)
 684                         warnx("unable to get time of day");
 685                 return (0L);
 686         }
 687 #define OFFSET ((u_long)25567 * 24*60*60)
 688         return (htonl((long)(tv.tv_sec + OFFSET)));
 689 #undef OFFSET
 690 }
 691
 692 /* ARGSUSED */
 693 void
 694 machtime_dg(int s, struct servtab *sep)
 695 {
 696         unsigned long result;
 697         struct sockaddr_storage ss;
 698         socklen_t size;
 699
 700         size = sizeof(ss);
 701         if (recvfrom(s, (char *)&result, sizeof(result), 0,
 702                      (struct sockaddr *)&ss, &size) < 0)
 703                 return;
 704
 705         if (check_loop((struct sockaddr *)&ss, sep))
 706                 return;
 707
 708         result = machtime();
 709         sendto(s, (char *) &result, sizeof(result), 0,
 710                       (struct sockaddr *)&ss, size);
 711 }
 712
 713 /* ARGSUSED */
 714 void
 715 machtime_stream(int s, struct servtab *sep __unused)
 716 {
 717         unsigned long result;
 718
 719         result = machtime();
 720         send(s, (char *) &result, sizeof(result), MSG_EOF);
 721 }
 722
 723 /*
 724  * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
 725  * services based on the service name sent.
 726  *
 727  *  Based on TCPMUX.C by Mark K. Lottor November 1988
 728  *  sri-nic::ps:<mkl>tcpmux.c
 729  */
 730
 731 #define MAX_SERV_LEN    (256+2)         /* 2 bytes for \r\n */
 732 #define strwrite(fd, buf)       write(fd, buf, sizeof(buf)-1)
 733
 734 static int              /* # of characters upto \r,\n or \0 */
 735 getline(int fd, char *buf, int len)
 736 {
 737         int count = 0, n;
 738         struct sigaction sa;
 739
 740         sa.sa_flags = 0;
 741         sigemptyset(&sa.sa_mask);
 742         sa.sa_handler = SIG_DFL;
 743         sigaction(SIGALRM, &sa, NULL);
 744         do {
 745                 alarm(10);
 746                 n = read(fd, buf, len-count);
 747                 alarm(0);
 748                 if (n == 0)
 749                         return (count);
 750                 if (n < 0)
 751                         return (-1);
 752                 while (--n >= 0) {
 753                         if (*buf == '\r' || *buf == '\n' || *buf == '\0')
 754                                 return (count);
 755                         count++;
 756                         buf++;
 757                 }
 758         } while (count < len);
 759         return (count);
 760 }
 761
 762 struct servtab *
 763 tcpmux(int s)
 764 {
 765         struct servtab *sep;
 766         char service[MAX_SERV_LEN+1];
 767         int len;
 768
 769         /* Get requested service name */
 770         if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
 771                 strwrite(s, "-Error reading service name\r\n");
 772                 return (NULL);
 773         }
 774         service[len] = '\0';
 775
 776         if (debug)
 777                 warnx("tcpmux: someone wants %s", service);
 778
 779         /*
 780          * Help is a required command, and lists available services,
 781          * one per line.
 782          */
 783         if (!strcasecmp(service, "help")) {
 784                 for (sep = servtab; sep; sep = sep->se_next) {
 785                         if (!ISMUX(sep))
 786                                 continue;
 787                         write(s,sep->se_service,strlen(sep->se_service));
 788                         strwrite(s, "\r\n");
 789                 }
 790                 return (NULL);
 791         }
 792
 793         /* Try matching a service in inetd.conf with the request */
 794         for (sep = servtab; sep; sep = sep->se_next) {
 795                 if (!ISMUX(sep))
 796                         continue;
 797                 if (!strcasecmp(service, sep->se_service)) {
 798                         if (ISMUXPLUS(sep)) {
 799                                 strwrite(s, "+Go\r\n");
 800                         }
 801                         return (sep);
 802                 }
 803         }
 804         strwrite(s, "-Service not available\r\n");
 805         return (NULL);
 806 }