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/ioccom.h>
  33 #include <sys/param.h>
  34 #include <sys/stat.h>
  35 #include <sys/socket.h>
  36 #include <sys/sysctl.h>
  37 #include <sys/ucred.h>
  38 #include <sys/uio.h>
  39 #include <sys/utsname.h>
  40
  41 #include <ctype.h>
  42 #include <err.h>
  43 #include <errno.h>
  44 #include <fcntl.h>
  45 #include <limits.h>
  46 #include <pwd.h>
  47 #include <signal.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include <sysexits.h>
  51 #include <syslog.h>
  52 #include <unistd.h>
  53
  54 #include "inetd.h"
  55
  56 void            chargen_dg(int, struct servtab *);
  57 void            chargen_stream(int, struct servtab *);
  58 void            daytime_dg(int, struct servtab *);
  59 void            daytime_stream(int, struct servtab *);
  60 void            discard_dg(int, struct servtab *);
  61 void            discard_stream(int, struct servtab *);
  62 void            echo_dg(int, struct servtab *);
  63 void            echo_stream(int, struct servtab *);
  64 static int      getline(int, char *, int);
  65 void            iderror(int, int, int, const char *);
  66 void            ident_stream(int, struct servtab *);
  67 void            initring(void);
  68 unsigned long   machtime(void);
  69 void            machtime_dg(int, struct servtab *);
  70 void            machtime_stream(int, struct servtab *);
  71
  72 char ring[128];
  73 char *endring;
  74
  75
  76 struct biltin biltins[] = {
  77         /* Echo received data */
  78         { "echo",       SOCK_STREAM,    1, -1,  echo_stream },
  79         { "echo",       SOCK_DGRAM,     0, 1,   echo_dg },
  80
  81         /* Internet /dev/null */
  82         { "discard",    SOCK_STREAM,    1, -1,  discard_stream },
  83         { "discard",    SOCK_DGRAM,     0, 1,   discard_dg },
  84
  85         /* Return 32 bit time since 1900 */
  86         { "time",       SOCK_STREAM,    0, -1,  machtime_stream },
  87         { "time",       SOCK_DGRAM,     0, 1,   machtime_dg },
  88
  89         /* Return human-readable time */
  90         { "daytime",    SOCK_STREAM,    0, -1,  daytime_stream },
  91         { "daytime",    SOCK_DGRAM,     0, 1,   daytime_dg },
  92
  93         /* Familiar character generator */
  94         { "chargen",    SOCK_STREAM,    1, -1,  chargen_stream },
  95         { "chargen",    SOCK_DGRAM,     0, 1,   chargen_dg },
  96
  97         { "tcpmux",     SOCK_STREAM,    1, -1,  (bi_fn_t *)tcpmux },
  98
  99         { "auth",       SOCK_STREAM,    1, -1,  ident_stream },
 100
 101         { NULL,         0,              0, 0,   NULL }
 102 };
 103
 104 /*
 105  * RFC864 Character Generator Protocol. Generates character data without
 106  * any regard for input.
 107  */
 108
 109 void
 110 initring(void)
 111 {
 112         int i;
 113
 114         endring = ring;
 115
 116         for (i = 0; i <= 128; ++i)
 117                 if (isprint(i))
 118                         *endring++ = i;
 119 }
 120
 121 /* ARGSUSED */
 122 void
 123 chargen_dg(int s, struct servtab *sep)          /* Character generator */
 124 {
 125         struct sockaddr_storage ss;
 126         static char *rs;
 127         int len;
 128         socklen_t size;
 129         char text[LINESIZ+2];
 130
 131         if (endring == 0) {
 132                 initring();
 133                 rs = ring;
 134         }
 135
 136         size = sizeof(ss);
 137         if (recvfrom(s, text, sizeof(text), 0,
 138                      (struct sockaddr *)&ss, &size) < 0)
 139                 return;
 140
 141         if (check_loop((struct sockaddr *)&ss, sep))
 142                 return;
 143
 144         if ((len = endring - rs) >= LINESIZ)
 145                 memmove(text, rs, LINESIZ);
 146         else {
 147                 memmove(text, rs, len);
 148                 memmove(text + len, ring, LINESIZ - len);
 149         }
 150         if (++rs == endring)
 151                 rs = ring;
 152         text[LINESIZ] = '\r';
 153         text[LINESIZ + 1] = '\n';
 154         sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size);
 155 }
 156
 157 /* ARGSUSED */
 158 void
 159 chargen_stream(int s, struct servtab *sep)              /* Character generator */
 160 {
 161         int len;
 162         char *rs, text[LINESIZ+2];
 163
 164         inetd_setproctitle(sep->se_service, s);
 165
 166         if (!endring) {
 167                 initring();
 168                 rs = ring;
 169         }
 170
 171         text[LINESIZ] = '\r';
 172         text[LINESIZ + 1] = '\n';
 173         for (rs = ring;;) {
 174                 if ((len = endring - rs) >= LINESIZ)
 175                         memmove(text, rs, LINESIZ);
 176                 else {
 177                         memmove(text, rs, len);
 178                         memmove(text + len, ring, LINESIZ - len);
 179                 }
 180                 if (++rs == endring)
 181                         rs = ring;
 182                 if (write(s, text, sizeof(text)) != sizeof(text))
 183                         break;
 184         }
 185         exit(0);
 186 }
 187
 188 /*
 189  * RFC867 Daytime Protocol. Sends the current date and time as an ascii
 190  * character string without any regard for input.
 191  */
 192
 193 /* ARGSUSED */
 194 void
 195 daytime_dg(int s, struct servtab *sep)          /* Return human-readable time of day */
 196 {
 197         char buffer[256];
 198         time_t now;
 199         struct sockaddr_storage ss;
 200         socklen_t size;
 201
 202         now = time((time_t *) 0);
 203
 204         size = sizeof(ss);
 205         if (recvfrom(s, buffer, sizeof(buffer), 0,
 206                      (struct sockaddr *)&ss, &size) < 0)
 207                 return;
 208
 209         if (check_loop((struct sockaddr *)&ss, sep))
 210                 return;
 211
 212         sprintf(buffer, "%.24s\r\n", ctime(&now));
 213         sendto(s, buffer, strlen(buffer), 0, (struct sockaddr *)&ss, size);
 214 }
 215
 216 /* ARGSUSED */
 217 void
 218 daytime_stream(int s, struct servtab *sep __unused) /* Return human-readable time of day */
 219 {
 220         char buffer[256];
 221         time_t now;
 222
 223         now = time((time_t *) 0);
 224
 225         sprintf(buffer, "%.24s\r\n", ctime(&now));
 226         send(s, buffer, strlen(buffer), MSG_EOF);
 227 }
 228
 229 /*
 230  * RFC863 Discard Protocol. Any data received is thrown away and no response
 231  * is sent.
 232  */
 233
 234 /* ARGSUSED */
 235 void
 236 discard_dg(int s, struct servtab *sep __unused) /* Discard service -- ignore data */
 237 {
 238         char buffer[BUFSIZE];
 239
 240         read(s, buffer, sizeof(buffer));
 241 }
 242
 243 /* ARGSUSED */
 244 void
 245 discard_stream(int s, struct servtab *sep) /* Discard service -- ignore data */
 246 {
 247         int ret;
 248         char buffer[BUFSIZE];
 249
 250         inetd_setproctitle(sep->se_service, s);
 251         while (1) {
 252                 while ((ret = read(s, buffer, sizeof(buffer))) > 0)
 253                         ;
 254                 if (ret == 0 || errno != EINTR)
 255                         break;
 256         }
 257         exit(0);
 258 }
 259
 260 /*
 261  * RFC862 Echo Protocol. Any data received is sent back to the sender as
 262  * received.
 263  */
 264
 265 /* ARGSUSED */
 266 void
 267 echo_dg(int s, struct servtab *sep) /* Echo service -- echo data back */
 268 {
 269         char buffer[65536]; /* Should be sizeof(max datagram). */
 270         int i;
 271         socklen_t size;
 272         struct sockaddr_storage ss;
 273
 274         size = sizeof(ss);
 275         if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
 276                           (struct sockaddr *)&ss, &size)) < 0)
 277                 return;
 278
 279         if (check_loop((struct sockaddr *)&ss, sep))
 280                 return;
 281
 282         sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
 283 }
 284
 285 /* ARGSUSED */
 286 void
 287 echo_stream(int s, struct servtab *sep)         /* Echo service -- echo data back */
 288 {
 289         char buffer[BUFSIZE];
 290         int i;
 291
 292         inetd_setproctitle(sep->se_service, s);
 293         while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
 294             write(s, buffer, i) > 0)
 295                 ;
 296         exit(0);
 297 }
 298
 299 /*
 300  * RFC1413 Identification Protocol. Given a TCP port number pair, return a
 301  * character string which identifies the owner of that connection on the
 302  * server's system. Extended to allow for ~/.fakeid support and ~/.noident
 303  * support.
 304  */
 305
 306 /* RFC 1413 says the following are the only errors you can return. */
 307 #define ID_INVALID      "INVALID-PORT"  /* Port number improperly specified. */
 308 #define ID_NOUSER       "NO-USER"       /* Port not in use/not identifable. */
 309 #define ID_HIDDEN       "HIDDEN-USER"   /* Hiden at user's request. */
 310 #define ID_UNKNOWN      "UNKNOWN-ERROR" /* Everything else. */
 311
 312 /* ARGSUSED */
 313 void
 314 iderror(int lport, int fport, int s, const char *er)    /* Generic ident_stream error-sending func */
 315 {
 316         char *p;
 317
 318         asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
 319         if (p == NULL) {
 320                 syslog(LOG_ERR, "asprintf: %m");
 321                 exit(EX_OSERR);
 322         }
 323         send(s, p, strlen(p), MSG_EOF);
 324         free(p);
 325
 326         exit(0);
 327 }
 328
 329 /* ARGSUSED */
 330 void
 331 ident_stream(int s, struct servtab *sep)                /* Ident service (AKA "auth") */
 332 {
 333         struct utsname un;
 334         struct stat sb;
 335         struct sockaddr_in sin4[2];
 336 #ifdef INET6
 337         struct sockaddr_in6 sin6[2];
 338 #endif
 339         struct sockaddr_storage ss[2];
 340         struct ucred uc;
 341         struct timeval tv = {
 342                 10,
 343                 0
 344         }, to;
 345         struct passwd *pw = NULL;
 346         fd_set fdset;
 347         char buf[BUFSIZE], *p, **av, *osname = NULL, e;
 348         char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
 349         socklen_t socklen;
 350         ssize_t ssize;
 351         size_t size, bufsiz;
 352         int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
 353         int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
 354         u_short lport, fport;
 355
 356         inetd_setproctitle(sep->se_service, s);
 357         /*
 358          * Reset getopt() since we are a fork() but not an exec() from
 359          * a parent which used getopt() already.
 360          */
 361         optind = 1;
 362         optreset = 1;
 363         /*
 364          * Take the internal argument vector and count it out to make an
 365          * argument count for getopt. This can be used for any internal
 366          * service to read arguments and use getopt() easily.
 367          */
 368         for (av = sep->se_argv; *av; av++)
 369                 argc++;
 370         if (argc) {
 371                 int sec, usec;
 372                 size_t i;
 373                 u_int32_t rnd32;
 374
 375                 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
 376                         switch (c) {
 377                         case 'd':
 378                                 if (!gflag)
 379                                         strlcpy(idbuf, optarg, sizeof(idbuf));
 380                                 break;
 381                         case 'f':
 382                                 fflag = 1;
 383                                 break;
 384                         case 'F':
 385                                 fflag = 1;
 386                                 Fflag=1;
 387                                 break;
 388                         case 'g':
 389                                 gflag = 1;
 390                                 rnd32 = 0;      /* Shush, compiler. */
 391                                 /*
 392                                  * The number of bits in "rnd32" divided
 393                                  * by the number of bits needed per iteration
 394                                  * gives a more optimal way to reload the
 395                                  * random number only when necessary.
 396                                  *
 397                                  * 32 bits from arc4random corresponds to
 398                                  * about 6 base-36 digits, so we reseed evey 6.
 399                                  */
 400                                 for (i = 0; i < sizeof(idbuf) - 1; i++) {
 401                                         static const char *const base36 =
 402                                             "0123456789"
 403                                             "abcdefghijklmnopqrstuvwxyz";
 404                                         if (i % 6 == 0)
 405                                                 rnd32 = arc4random();
 406                                         idbuf[i] = base36[rnd32 % 36];
 407                                         rnd32 /= 36;
 408                                 }
 409                                 idbuf[i] = '\0';
 410                                 break;
 411                         case 'i':
 412                                 iflag = 1;
 413                                 break;
 414                         case 'n':
 415                                 nflag = 1;
 416                                 break;
 417                         case 'o':
 418                                 osname = optarg;
 419                                 break;
 420                         case 'r':
 421                                 rflag = 1;
 422                                 break;
 423                         case 't':
 424                                 switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
 425                                 case 2:
 426                                         tv.tv_usec = usec;
 427                                         /* FALLTHROUGH */
 428                                 case 1:
 429                                         tv.tv_sec = sec;
 430                                         break;
 431                                 default:
 432                                         if (debug)
 433                                                 warnx("bad -t argument");
 434                                         break;
 435                                 }
 436                                 break;
 437                         default:
 438                                 break;
 439                         }
 440         }
 441         if (osname == NULL) {
 442                 if (uname(&un) == -1)
 443                         iderror(0, 0, s, ID_UNKNOWN);
 444                 osname = un.sysname;
 445         }
 446
 447         /*
 448          * We're going to prepare for and execute reception of a
 449          * packet of data from the user. The data is in the format
 450          * "local_port , foreign_port\r\n" (with local being the
 451          * server's port and foreign being the client's.)
 452          */
 453         gettimeofday(&to, NULL);
 454         to.tv_sec += tv.tv_sec;
 455         to.tv_usec += tv.tv_usec;
 456         if (to.tv_usec >= 1000000) {
 457                 to.tv_usec -= 1000000;
 458                 to.tv_sec++;
 459         }
 460
 461         size = 0;
 462         bufsiz = sizeof(buf) - 1;
 463         FD_ZERO(&fdset);
 464         while (bufsiz > 0) {
 465                 gettimeofday(&tv, NULL);
 466                 tv.tv_sec = to.tv_sec - tv.tv_sec;
 467                 tv.tv_usec = to.tv_usec - tv.tv_usec;
 468                 if (tv.tv_usec < 0) {
 469                         tv.tv_usec += 1000000;
 470                         tv.tv_sec--;
 471                 }
 472                 if (tv.tv_sec < 0)
 473                         break;
 474                 FD_SET(s, &fdset);
 475                 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
 476                         iderror(0, 0, s, ID_UNKNOWN);
 477                 if (ioctl(s, FIONREAD, &onreadlen) == -1)
 478                         iderror(0, 0, s, ID_UNKNOWN);
 479                 if ((size_t)onreadlen > bufsiz)
 480                         onreadlen = bufsiz;
 481                 ssize = read(s, &buf[size], (size_t)onreadlen);
 482                 if (ssize == -1)
 483                         iderror(0, 0, s, ID_UNKNOWN);
 484                 else if (ssize == 0)
 485                         break;
 486                 bufsiz -= ssize;
 487                 size += ssize;
 488                 if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
 489                         break;
 490         }
 491         buf[size] = '\0';
 492         /* Read two characters, and check for a delimiting character */
 493         if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
 494                 iderror(0, 0, s, ID_INVALID);
 495
 496         /* Send garbage? */
 497         if (gflag)
 498                 goto printit;
 499
 500         /*
 501          * If not "real" (-r), send a HIDDEN-USER error for everything.
 502          * If -d is used to set a fallback username, this is used to
 503          * override it, and the fallback is returned instead.
 504          */
 505         if (!rflag) {
 506                 if (*idbuf == '\0')
 507                         iderror(lport, fport, s, ID_HIDDEN);
 508                 goto printit;
 509         }
 510
 511         /*
 512          * We take the input and construct an array of two sockaddr_ins
 513          * which contain the local address information and foreign
 514          * address information, respectively, used to look up the
 515          * credentials for the socket (which are returned by the
 516          * sysctl "net.inet.tcp.getcred" when we call it.)
 517          */
 518         socklen = sizeof(ss[0]);
 519         if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
 520                 iderror(lport, fport, s, ID_UNKNOWN);
 521         socklen = sizeof(ss[1]);
 522         if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
 523                 iderror(lport, fport, s, ID_UNKNOWN);
 524         if (ss[0].ss_family != ss[1].ss_family)
 525                 iderror(lport, fport, s, ID_UNKNOWN);
 526         size = sizeof(uc);
 527         switch (ss[0].ss_family) {
 528         case AF_INET:
 529                 sin4[0] = *(struct sockaddr_in *)&ss[0];
 530                 sin4[0].sin_port = htons(lport);
 531                 sin4[1] = *(struct sockaddr_in *)&ss[1];
 532                 sin4[1].sin_port = htons(fport);
 533                 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
 534                                  sizeof(sin4)) == -1)
 535                         getcredfail = errno;
 536                 break;
 537 #ifdef INET6
 538         case AF_INET6:
 539                 sin6[0] = *(struct sockaddr_in6 *)&ss[0];
 540                 sin6[0].sin6_port = htons(lport);
 541                 sin6[1] = *(struct sockaddr_in6 *)&ss[1];
 542                 sin6[1].sin6_port = htons(fport);
 543                 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
 544                                  sizeof(sin6)) == -1)
 545                         getcredfail = errno;
 546                 break;
 547 #endif
 548         default: /* should not reach here */
 549                 getcredfail = EAFNOSUPPORT;
 550                 break;
 551         }
 552         if (getcredfail != 0) {
 553                 if (*idbuf == '\0')
 554                         iderror(lport, fport, s,
 555                             getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
 556                 goto printit;
 557         }
 558
 559         /* Look up the pw to get the username and home directory*/
 560         errno = 0;
 561         pw = getpwuid(uc.cr_uid);
 562         if (pw == NULL)
 563                 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
 564
 565         if (iflag)
 566                 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
 567         else
 568                 strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
 569
 570         /*
 571          * If enabled, we check for a file named ".noident" in the user's
 572          * home directory. If found, we return HIDDEN-USER.
 573          */
 574         if (nflag) {
 575                 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
 576                         iderror(lport, fport, s, ID_UNKNOWN);
 577                 if (lstat(p, &sb) == 0) {
 578                         free(p);
 579                         iderror(lport, fport, s, ID_HIDDEN);
 580                 }
 581                 free(p);
 582         }
 583
 584         /*
 585          * Here, if enabled, we read a user's ".fakeid" file in their
 586          * home directory. It consists of a line containing the name
 587          * they want.
 588          */
 589         if (fflag) {
 590                 int fakeid_fd;
 591
 592                 /*
 593                  * Here we set ourself to effectively be the user, so we don't
 594                  * open any files we have no permission to open, especially
 595                  * symbolic links to sensitive root-owned files or devices.
 596                  */
 597                 if (initgroups(pw->pw_name, pw->pw_gid) == -1)
 598                         iderror(lport, fport, s, ID_UNKNOWN);
 599                 if (seteuid(pw->pw_uid) == -1)
 600                         iderror(lport, fport, s, ID_UNKNOWN);
 601                 /*
 602                  * We can't stat() here since that would be a race
 603                  * condition.
 604                  * Therefore, we open the file we have permissions to open
 605                  * and if it's not a regular file, we close it and end up
 606                  * returning the user's real username.
 607                  */
 608                 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
 609                         iderror(lport, fport, s, ID_UNKNOWN);
 610                 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
 611                 free(p);
 612                 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
 613                     !S_ISREG(sb.st_mode))
 614                         goto fakeid_fail;
 615
 616                 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
 617                         goto fakeid_fail;
 618                 buf[ssize] = '\0';
 619
 620                 /*
 621                  * Usually, the file will have the desired identity
 622                  * in the form "identity\n". Allow for leading white
 623                  * space and trailing white space/end of line.
 624                  */
 625                 p = buf;
 626                 p += strspn(p, " \t");
 627                 p[strcspn(p, " \t\r\n")] = '\0';
 628                 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
 629                         p[MAXLOGNAME - 1] = '\0';
 630
 631                 /*
 632                  * If the name is a zero-length string or matches it
 633                  * the id or name of another user (unless permitted by -F)
 634                  * then it is invalid.
 635                  */
 636                 if (*p == '\0')
 637                         goto fakeid_fail;
 638                 if (!Fflag) {
 639                         if (iflag) {
 640                                 if (p[strspn(p, "0123456789")] == '\0' &&
 641                                     getpwuid(atoi(p)) != NULL)
 642                                         goto fakeid_fail;
 643                         } else {
 644                                 if (getpwnam(p) != NULL)
 645                                         goto fakeid_fail;
 646                         }
 647                 }
 648
 649                 strlcpy(idbuf, p, sizeof(idbuf));
 650
 651 fakeid_fail:
 652                 if (fakeid_fd != -1)
 653                         close(fakeid_fd);
 654         }
 655
 656 printit:
 657         /* Finally, we make and send the reply. */
 658         if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
 659             idbuf) == -1) {
 660                 syslog(LOG_ERR, "asprintf: %m");
 661                 exit(EX_OSERR);
 662         }
 663         send(s, p, strlen(p), MSG_EOF);
 664         free(p);
 665
 666         exit(0);
 667 }
 668
 669 /*
 670  * RFC738 Time Server.
 671  * Return a machine readable date and time, in the form of the
 672  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
 673  * returns the number of seconds since midnight, Jan 1, 1970,
 674  * we must add 2208988800 seconds to this figure to make up for
 675  * some seventy years Bell Labs was asleep.
 676  */
 677
 678 unsigned long
 679 machtime(void)
 680 {
 681         struct timeval tv;
 682
 683         if (gettimeofday(&tv, (struct timezone *)NULL) < 0) {
 684                 if (debug)
 685                         warnx("unable to get time of day");
 686                 return (0L);
 687         }
 688 #define OFFSET ((u_long)25567 * 24*60*60)
 689         return (htonl((long)(tv.tv_sec + OFFSET)));
 690 #undef OFFSET
 691 }
 692
 693 /* ARGSUSED */
 694 void
 695 machtime_dg(int s, struct servtab *sep)
 696 {
 697         unsigned long result;
 698         struct sockaddr_storage ss;
 699         socklen_t size;
 700
 701         size = sizeof(ss);
 702         if (recvfrom(s, (char *)&result, sizeof(result), 0,
 703                      (struct sockaddr *)&ss, &size) < 0)
 704                 return;
 705
 706         if (check_loop((struct sockaddr *)&ss, sep))
 707                 return;
 708
 709         result = machtime();
 710         sendto(s, (char *) &result, sizeof(result), 0,
 711                       (struct sockaddr *)&ss, size);
 712 }
 713
 714 /* ARGSUSED */
 715 void
 716 machtime_stream(int s, struct servtab *sep __unused)
 717 {
 718         unsigned long result;
 719
 720         result = machtime();
 721         send(s, (char *) &result, sizeof(result), MSG_EOF);
 722 }
 723
 724 /*
 725  * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
 726  * services based on the service name sent.
 727  *
 728  *  Based on TCPMUX.C by Mark K. Lottor November 1988
 729  *  sri-nic::ps:<mkl>tcpmux.c
 730  */
 731
 732 #define MAX_SERV_LEN    (256+2)         /* 2 bytes for \r\n */
 733 #define strwrite(fd, buf)       write(fd, buf, sizeof(buf)-1)
 734
 735 static int              /* # of characters upto \r,\n or \0 */
 736 getline(int fd, char *buf, int len)
 737 {
 738         int count = 0, n;
 739         struct sigaction sa;
 740
 741         sa.sa_flags = 0;
 742         sigemptyset(&sa.sa_mask);
 743         sa.sa_handler = SIG_DFL;
 744         sigaction(SIGALRM, &sa, (struct sigaction *)0);
 745         do {
 746                 alarm(10);
 747                 n = read(fd, buf, len-count);
 748                 alarm(0);
 749                 if (n == 0)
 750                         return (count);
 751                 if (n < 0)
 752                         return (-1);
 753                 while (--n >= 0) {
 754                         if (*buf == '\r' || *buf == '\n' || *buf == '\0')
 755                                 return (count);
 756                         count++;
 757                         buf++;
 758                 }
 759         } while (count < len);
 760         return (count);
 761 }
 762
 763 struct servtab *
 764 tcpmux(int s)
 765 {
 766         struct servtab *sep;
 767         char service[MAX_SERV_LEN+1];
 768         int len;
 769
 770         /* Get requested service name */
 771         if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
 772                 strwrite(s, "-Error reading service name\r\n");
 773                 return (NULL);
 774         }
 775         service[len] = '\0';
 776
 777         if (debug)
 778                 warnx("tcpmux: someone wants %s", service);
 779
 780         /*
 781          * Help is a required command, and lists available services,
 782          * one per line.
 783          */
 784         if (!strcasecmp(service, "help")) {
 785                 for (sep = servtab; sep; sep = sep->se_next) {
 786                         if (!ISMUX(sep))
 787                                 continue;
 788                         write(s,sep->se_service,strlen(sep->se_service));
 789                         strwrite(s, "\r\n");
 790                 }
 791                 return (NULL);
 792         }
 793
 794         /* Try matching a service in inetd.conf with the request */
 795         for (sep = servtab; sep; sep = sep->se_next) {
 796                 if (!ISMUX(sep))
 797                         continue;
 798                 if (!strcasecmp(service, sep->se_service)) {
 799                         if (ISMUXPLUS(sep)) {
 800                                 strwrite(s, "+Go\r\n");
 801                         }
 802                         return (sep);
 803                 }
 804         }
 805         strwrite(s, "-Service not available\r\n");
 806         return (NULL);
 807 }