inet/rcmd.c

   1 /*
   2  * Copyright (C) 1998 WIDE Project.
   3  * 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  * 3. Neither the name of the project nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29 /*
  30  * Copyright (c) 1983, 1993, 1994
  31  *      The Regents of the University of California.  All rights reserved.
  32  *
  33  * Redistribution and use in source and binary forms, with or without
  34  * modification, are permitted provided that the following conditions
  35  * are met:
  36  * 1. Redistributions of source code must retain the above copyright
  37  *    notice, this list of conditions and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58 #if defined(LIBC_SCCS) && !defined(lint)
  59 static char sccsid[] = "@(#)rcmd.c      8.3 (Berkeley) 3/26/94";
  60 #endif /* LIBC_SCCS and not lint */
  61
  62 #include <sys/param.h>
  63 #include <sys/poll.h>
  64 #include <sys/socket.h>
  65 #include <sys/stat.h>
  66
  67 #include <netinet/in.h>
  68 #include <arpa/inet.h>
  69
  70 #include <alloca.h>
  71 #include <signal.h>
  72 #include <fcntl.h>
  73 #include <netdb.h>
  74 #include <unistd.h>
  75 #include <pwd.h>
  76 #include <errno.h>
  77 #include <stdio.h>
  78 #include <ctype.h>
  79 #include <string.h>
  80 #include <libintl.h>
  81 #include <stdlib.h>
  82
  83
  84 int __ivaliduser (FILE *, u_int32_t, const char *, const char *);
  85 static int __validuser2_sa (FILE *, struct sockaddr *, size_t,
  86                             const char *, const char *, const char *);
  87 static int ruserok2_sa (struct sockaddr *ra, size_t ralen,
  88                         int superuser, const char *ruser,
  89                         const char *luser, const char *rhost);
  90 static int ruserok_sa (struct sockaddr *ra, size_t ralen,
  91                         int superuser, const char *ruser,
  92                         const char *luser);
  93 int iruserok_af (const void *raddr, int superuser, const char *ruser,
  94                  const char *luser, sa_family_t af);
  95 int iruserok (u_int32_t raddr, int superuser, const char *ruser,
  96               const char *luser);
  97
  98 static char ahostbuf[NI_MAXHOST];
  99
 100 int
 101 rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
 102         char **ahost;
 103         u_short rport;
 104         const char *locuser, *remuser, *cmd;
 105         int *fd2p;
 106         sa_family_t af;
 107 {
 108         char paddr[INET6_ADDRSTRLEN];
 109         struct addrinfo hints, *res, *ai;
 110         struct sockaddr_storage from;
 111         struct pollfd pfd[2];
 112         int32_t oldmask;
 113         pid_t pid;
 114         int s, lport, timo, error;
 115         char c;
 116         int refused;
 117         char num[8];
 118         ssize_t n;
 119
 120         if (af != AF_INET && af != AF_INET6)
 121           {
 122             __set_errno (EAFNOSUPPORT);
 123             return -1;
 124           }
 125
 126         pid = __getpid();
 127
 128         memset(&hints, '\0', sizeof(hints));
 129         hints.ai_flags = AI_CANONNAME;
 130         hints.ai_family = af;
 131         hints.ai_socktype = SOCK_STREAM;
 132         (void)snprintf(num, sizeof(num), "%d", ntohs(rport));
 133         error = getaddrinfo(*ahost, num, &hints, &res);
 134         if (error) {
 135             fprintf(stderr, "rcmd: getaddrinfo: %s\n",
 136                     gai_strerror(error));
 137                 return (-1);
 138         }
 139
 140         pfd[0].events = POLLIN;
 141         pfd[1].events = POLLIN;
 142
 143         if (res->ai_canonname){
 144                 strncpy(ahostbuf, res->ai_canonname, sizeof(ahostbuf));
 145                 ahostbuf[sizeof(ahostbuf)-1] = '\0';
 146                 *ahost = ahostbuf;
 147         }
 148         else
 149                 *ahost = NULL;
 150         ai = res;
 151         refused = 0;
 152         oldmask = __sigblock(sigmask(SIGURG));
 153         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
 154                 s = rresvport_af(&lport, ai->ai_family);
 155                 if (s < 0) {
 156                         if (errno == EAGAIN)
 157                                 fprintf(stderr,
 158                                         _("rcmd: socket: All ports in use\n"));
 159                         else
 160                                 fprintf(stderr, "rcmd: socket: %m\n");
 161                         __sigsetmask(oldmask);
 162                         freeaddrinfo(res);
 163                         return -1;
 164                 }
 165                 __fcntl(s, F_SETOWN, pid);
 166                 if (__connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
 167                         break;
 168                 (void)__close(s);
 169                 if (errno == EADDRINUSE) {
 170                         lport--;
 171                         continue;
 172                 }
 173                 if (errno == ECONNREFUSED)
 174                         refused = 1;
 175                 if (ai->ai_next != NULL) {
 176                         int oerrno = errno;
 177
 178                         getnameinfo(ai->ai_addr, ai->ai_addrlen,
 179                                     paddr, sizeof(paddr),
 180                                     NULL, 0,
 181                                     NI_NUMERICHOST);
 182                         fprintf(stderr, "connect to address %s: ", paddr);
 183                         __set_errno (oerrno);
 184                         perror(0);
 185                         ai = ai->ai_next;
 186                         getnameinfo(ai->ai_addr, ai->ai_addrlen,
 187                                     paddr, sizeof(paddr),
 188                                     NULL, 0,
 189                                     NI_NUMERICHOST);
 190                         fprintf(stderr, "Trying %s...\n", paddr);
 191                         continue;
 192                 }
 193                 if (refused && timo <= 16) {
 194                         (void)sleep(timo);
 195                         timo *= 2;
 196                         ai = res;
 197                         refused = 0;
 198                         continue;
 199                 }
 200                 freeaddrinfo(res);
 201                 (void)fprintf(stderr, "%s: %s\n", *ahost, strerror(errno));
 202                 __sigsetmask(oldmask);
 203                 return -1;
 204         }
 205         lport--;
 206         if (fd2p == 0) {
 207                 __write(s, "", 1);
 208                 lport = 0;
 209         } else {
 210                 char num[8];
 211                 int s2 = rresvport_af(&lport, ai->ai_family), s3;
 212                 size_t len = ai->ai_addrlen;
 213
 214                 if (s2 < 0)
 215                         goto bad;
 216                 listen(s2, 1);
 217                 (void)__snprintf(num, sizeof(num), "%d", lport);
 218                 if (__write(s, num, strlen(num)+1) != strlen(num)+1) {
 219                         (void)fprintf(stderr,
 220                             _("rcmd: write (setting up stderr): %m\n"));
 221                         (void)__close(s2);
 222                         goto bad;
 223                 }
 224                 pfd[0].fd = s;
 225                 pfd[1].fd = s2;
 226                 __set_errno (0);
 227                 if (__poll (pfd, 2, -1) < 1 || (pfd[1].revents & POLLIN) == 0){
 228                         if (errno != 0)
 229                                 (void)fprintf(stderr,
 230                                   _("rcmd: poll (setting up stderr): %m\n"));
 231                         else
 232                                 (void)fprintf(stderr,
 233                              _("poll: protocol failure in circuit setup\n"));
 234                         (void)__close(s2);
 235                         goto bad;
 236                 }
 237                 s3 = accept(s2, (struct sockaddr *)&from, &len);
 238                 switch (from.__ss_family) {
 239                 case AF_INET:
 240                         rport = ntohs(((struct sockaddr_in *)&from)->sin_port);
 241                         break;
 242                 case AF_INET6:
 243                         rport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port);
 244                         break;
 245                 default:
 246                         rport = 0;
 247                         break;
 248                 }
 249                 (void)__close(s2);
 250                 if (s3 < 0) {
 251                         (void)fprintf(stderr,
 252                             "rcmd: accept: %m\n");
 253                         lport = 0;
 254                         goto bad;
 255                 }
 256                 *fd2p = s3;
 257
 258                 if (rport >= IPPORT_RESERVED || rport < IPPORT_RESERVED / 2){
 259                         (void)fprintf(stderr,
 260                         _("socket: protocol failure in circuit setup\n"));
 261                         goto bad2;
 262                 }
 263         }
 264         (void)__write(s, locuser, strlen(locuser)+1);
 265         (void)__write(s, remuser, strlen(remuser)+1);
 266         (void)__write(s, cmd, strlen(cmd)+1);
 267         n = __read(s, &c, 1);
 268         if (n != 1) {
 269                 if (n == 0)
 270                         (void)fprintf(stderr, _("rcmd: %s: short read"),
 271                                       *ahost);
 272                 else
 273                         (void)fprintf(stderr, "rcmd: %s: %m\n", *ahost);
 274                 goto bad2;
 275         }
 276         if (c != 0) {
 277                 while (__read(s, &c, 1) == 1) {
 278                         (void)__write(STDERR_FILENO, &c, 1);
 279                         if (c == '\n')
 280                                 break;
 281                 }
 282                 goto bad2;
 283         }
 284         __sigsetmask(oldmask);
 285         freeaddrinfo(res);
 286         return s;
 287 bad2:
 288         if (lport)
 289                 (void)__close(*fd2p);
 290 bad:
 291         (void)__close(s);
 292         __sigsetmask(oldmask);
 293         freeaddrinfo(res);
 294         return -1;
 295 }
 296
 297 int
 298 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
 299         char **ahost;
 300         u_short rport;
 301         const char *locuser, *remuser, *cmd;
 302         int *fd2p;
 303 {
 304   return rcmd_af (ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
 305 }
 306
 307 int
 308 rresvport_af(alport, family)
 309         int *alport;
 310         sa_family_t family;
 311 {
 312         struct sockaddr_storage ss;
 313         int s;
 314         size_t len;
 315         uint16_t *sport;
 316
 317         switch(family){
 318         case AF_INET:
 319                 len = sizeof(struct sockaddr_in);
 320                 sport = &((struct sockaddr_in *)&ss)->sin_port;
 321                 break;
 322         case AF_INET6:
 323                 len = sizeof(struct sockaddr_in6);
 324                 sport = &((struct sockaddr_in6 *)&ss)->sin6_port;
 325                 break;
 326         default:
 327                 __set_errno (EAFNOSUPPORT);
 328                 return -1;
 329         }
 330         s = socket(family, SOCK_STREAM, 0);
 331         if (s < 0)
 332                 return -1;
 333
 334         memset (&ss, '\0', sizeof(ss));
 335 #ifdef SALEN
 336         ss.__ss_len = len;
 337 #endif
 338         ss.__ss_family = family;
 339
 340         for (;;) {
 341                 *sport = htons((uint16_t) *alport);
 342                 if (bind(s, (struct sockaddr *)&ss, len) >= 0)
 343                         return s;
 344                 if (errno != EADDRINUSE) {
 345                         (void)__close(s);
 346                         return -1;
 347                 }
 348                 (*alport)--;
 349                 if (*alport == IPPORT_RESERVED/2)
 350                         break;
 351         }
 352         (void)__close(s);
 353         __set_errno (EAGAIN);
 354         return -1;
 355 }
 356
 357 int
 358 rresvport(alport)
 359         int *alport;
 360 {
 361         return rresvport_af(alport, AF_INET);
 362 }
 363
 364 int     __check_rhosts_file = 1;
 365 char    *__rcmd_errstr;
 366
 367 int
 368 ruserok_af(rhost, superuser, ruser, luser, af)
 369         const char *rhost, *ruser, *luser;
 370         int superuser;
 371         sa_family_t af;
 372 {
 373         struct addrinfo hints, *res, *res0;
 374         int gai;
 375         int ret;
 376
 377         memset (&hints, '\0', sizeof(hints));
 378         hints.ai_family = af;
 379         gai = getaddrinfo(rhost, NULL, &hints, &res0);
 380         if (gai)
 381                 return -1;
 382         ret = -1;
 383         for (res=res0; res; res=res->ai_next)
 384                 if (ruserok2_sa(res->ai_addr, res->ai_addrlen,
 385                                 superuser, ruser, luser, rhost) == 0){
 386                         ret = 0;
 387                         break;
 388                 }
 389         freeaddrinfo(res0);
 390         return (ret);
 391 }
 392 int
 393 ruserok(rhost, superuser, ruser, luser)
 394         const char *rhost, *ruser, *luser;
 395         int superuser;
 396 {
 397         return ruserok_af(rhost, superuser, ruser, luser, AF_INET);
 398 }
 399
 400 /* Extremely paranoid file open function. */
 401 static FILE *
 402 iruserfopen (const char *file, uid_t okuser)
 403 {
 404   struct stat st;
 405   char *cp = NULL;
 406   FILE *res = NULL;
 407
 408   /* If not a regular file, if owned by someone other than user or
 409      root, if writeable by anyone but the owner, or if hardlinked
 410      anywhere, quit.  */
 411   cp = NULL;
 412   if (__lxstat (_STAT_VER, file, &st))
 413     cp = _("lstat failed");
 414   else if (!S_ISREG (st.st_mode))
 415     cp = _("not regular file");
 416   else
 417     {
 418       res = fopen (file, "r");
 419       if (!res)
 420         cp = _("cannot open");
 421       else if (__fxstat (_STAT_VER, fileno (res), &st) < 0)
 422         cp = _("fstat failed");
 423       else if (st.st_uid && st.st_uid != okuser)
 424         cp = _("bad owner");
 425       else if (st.st_mode & (S_IWGRP|S_IWOTH))
 426         cp = _("writeable by other than owner");
 427       else if (st.st_nlink > 1)
 428         cp = _("hard linked somewhere");
 429     }
 430
 431   /* If there were any problems, quit.  */
 432   if (cp != NULL)
 433     {
 434       __rcmd_errstr = cp;
 435       if (res)
 436         fclose (res);
 437       return NULL;
 438     }
 439
 440   return res;
 441 }
 442
 443 /*
 444  * New .rhosts strategy: We are passed an ip address. We spin through
 445  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 446  * has ip addresses, we don't have to trust a nameserver.  When it
 447  * contains hostnames, we spin through the list of addresses the nameserver
 448  * gives us and look for a match.
 449  *
 450  * Returns 0 if ok, -1 if not ok.
 451  */
 452 static int
 453 ruserok2_sa (ra, ralen, superuser, ruser, luser, rhost)
 454      struct sockaddr *ra;
 455      size_t ralen;
 456      int superuser;
 457      const char *ruser, *luser, *rhost;
 458 {
 459   FILE *hostf = NULL;
 460   int isbad = -1;
 461
 462   if (!superuser)
 463     hostf = iruserfopen (_PATH_HEQUIV, 0);
 464
 465   if (hostf)
 466     {
 467       isbad = __validuser2_sa (hostf, ra, ralen, luser, ruser, rhost);
 468       fclose (hostf);
 469
 470       if (!isbad)
 471         return 0;
 472     }
 473
 474   if (__check_rhosts_file || superuser)
 475     {
 476       char *pbuf;
 477       struct passwd pwdbuf, *pwd;
 478       size_t dirlen;
 479       size_t buflen = __sysconf (_SC_GETPW_R_SIZE_MAX);
 480       char *buffer = __alloca (buflen);
 481       uid_t uid;
 482
 483       if (__getpwnam_r (luser, &pwdbuf, buffer, buflen, &pwd) != 0
 484           || pwd == NULL)
 485         return -1;
 486
 487       dirlen = strlen (pwd->pw_dir);
 488       pbuf = alloca (dirlen + sizeof "/.rhosts");
 489       __mempcpy (__mempcpy (pbuf, pwd->pw_dir, dirlen),
 490                  "/.rhosts", sizeof "/.rhosts");
 491
 492        /* Change effective uid while reading .rhosts.  If root and
 493           reading an NFS mounted file system, can't read files that
 494           are protected read/write owner only.  */
 495        uid = __geteuid ();
 496        seteuid (pwd->pw_uid);
 497        hostf = iruserfopen (pbuf, pwd->pw_uid);
 498
 499        if (hostf != NULL)
 500          {
 501            isbad = __validuser2_sa (hostf, ra, ralen, luser, ruser, rhost);
 502            fclose (hostf);
 503          }
 504
 505        seteuid (uid);
 506        return isbad;
 507     }
 508   return -1;
 509 }
 510 /*
 511  * ruserok_sa() is now discussed on ipng, so
 512  * currently disabled for external use
 513  */
 514 static int ruserok_sa(ra, ralen, superuser, ruser, luser)
 515      struct sockaddr *ra;
 516      size_t ralen;
 517      int superuser;
 518      const char *ruser, *luser;
 519 {
 520   return ruserok2_sa(ra, ralen, superuser, ruser, luser, "-");
 521 }
 522
 523 /* This is the exported version.  */
 524 int
 525 iruserok_af (raddr, superuser, ruser, luser, af)
 526      const void *raddr;
 527      int superuser;
 528      const char *ruser, *luser;
 529      sa_family_t af;
 530 {
 531   struct sockaddr_storage ra;
 532   size_t ralen;
 533
 534   memset (&ra, '\0', sizeof(ra));
 535   switch (af){
 536   case AF_INET:
 537     ((struct sockaddr_in *)&ra)->sin_family = AF_INET;
 538     memcpy (&(((struct sockaddr_in *)&ra)->sin_addr), raddr,
 539             sizeof(struct in_addr));
 540     ralen = sizeof(struct sockaddr_in);
 541     break;
 542   case AF_INET6:
 543     ((struct sockaddr_in6 *)&ra)->sin6_family = AF_INET6;
 544     memcpy (&(((struct sockaddr_in6 *)&ra)->sin6_addr), raddr,
 545             sizeof(struct in6_addr));
 546     ralen = sizeof(struct sockaddr_in6);
 547     break;
 548   default:
 549     return 0;
 550   }
 551   return ruserok_sa ((struct sockaddr *)&ra, ralen, superuser, ruser, luser);
 552 }
 553 int
 554 iruserok (raddr, superuser, ruser, luser)
 555      u_int32_t raddr;
 556      int superuser;
 557      const char *ruser, *luser;
 558 {
 559   return iruserok_af (&raddr, superuser, ruser, luser, AF_INET);
 560 }
 561
 562 /*
 563  * XXX
 564  * Don't make static, used by lpd(8).
 565  *
 566  * This function is not used anymore. It is only present because lpd(8)
 567  * calls it (!?!). We simply call __invaliduser2() with an illegal rhost
 568  * argument. This means that netgroups won't work in .rhost/hosts.equiv
 569  * files. If you want lpd to work with netgroups, fix lpd to use ruserok()
 570  * or PAM.
 571  * Returns 0 if ok, -1 if not ok.
 572  */
 573 int
 574 __ivaliduser(hostf, raddr, luser, ruser)
 575         FILE *hostf;
 576         u_int32_t raddr;
 577         const char *luser, *ruser;
 578 {
 579         struct sockaddr_in ra;
 580         memset(&ra, '\0', sizeof(ra));
 581         ra.sin_family = AF_INET;
 582         ra.sin_addr.s_addr = raddr;
 583         return __validuser2_sa(hostf, (struct sockaddr *)&ra, sizeof(ra),
 584                                luser, ruser, "-");
 585 }
 586
 587
 588 /* Returns 1 on positive match, 0 on no match, -1 on negative match.  */
 589 static int
 590 internal_function
 591 __checkhost_sa (struct sockaddr *ra, size_t ralen, char *lhost,
 592                 const char *rhost)
 593 {
 594         struct addrinfo hints, *res0, *res;
 595         char raddr[INET6_ADDRSTRLEN];
 596         int match;
 597         int negate=1;    /* Multiply return with this to get -1 instead of 1 */
 598
 599         /* Check nis netgroup.  */
 600         if (strncmp ("+@", lhost, 2) == 0)
 601                 return innetgr (&lhost[2], rhost, NULL, NULL);
 602
 603         if (strncmp ("-@", lhost, 2) == 0)
 604                 return -innetgr (&lhost[2], rhost, NULL, NULL);
 605
 606         /* -host */
 607         if (strncmp ("-", lhost,1) == 0) {
 608                 negate = -1;
 609                 lhost++;
 610         } else if (strcmp ("+",lhost) == 0) {
 611                 return 1;                    /* asking for trouble, but ok.. */
 612         }
 613
 614         /* Try for raw ip address first. */
 615         /* XXX */
 616         if (getnameinfo(ra, ralen,
 617                         raddr, sizeof(raddr), NULL, 0,
 618                         NI_NUMERICHOST) == 0)
 619                 return negate * (strcmp(raddr, lhost) == 0);
 620
 621         /* Better be a hostname. */
 622         match = 0;
 623         memset(&hints, '\0', sizeof(hints));
 624         hints.ai_family = ra->sa_family;
 625         if (getaddrinfo(lhost, NULL, &hints, &res0) == 0){
 626                 /* Spin through ip addresses. */
 627                 for (res = res0; res; res = res->ai_next)
 628                   {
 629                     if (res->ai_family == ra->sa_family
 630                         && !memcmp(res->ai_addr, ra, res->ai_addrlen))
 631                       {
 632                         match = 1;
 633                         break;
 634                       }
 635                   }
 636                 freeaddrinfo (res0);
 637         }
 638         return negate * match;
 639 }
 640
 641 /* Returns 1 on positive match, 0 on no match, -1 on negative match.  */
 642 static int
 643 internal_function
 644 __icheckuser (const char *luser, const char *ruser)
 645 {
 646     /*
 647       luser is user entry from .rhosts/hosts.equiv file
 648       ruser is user id on remote host
 649       */
 650
 651     /* [-+]@netgroup */
 652     if (strncmp ("+@", luser, 2) == 0)
 653         return innetgr (&luser[2], NULL, ruser, NULL);
 654
 655     if (strncmp ("-@", luser,2) == 0)
 656         return -innetgr (&luser[2], NULL, ruser, NULL);
 657
 658     /* -user */
 659     if (strncmp ("-", luser, 1) == 0)
 660         return -(strcmp (&luser[1], ruser) == 0);
 661
 662     /* + */
 663     if (strcmp ("+", luser) == 0)
 664         return 1;
 665
 666     /* simple string match */
 667     return strcmp (ruser, luser) == 0;
 668 }
 669
 670 /*
 671  * Returns 1 for blank lines (or only comment lines) and 0 otherwise
 672  */
 673 static int
 674 __isempty (char *p)
 675 {
 676     while (*p && isspace (*p)) {
 677         ++p;
 678     }
 679
 680     return (*p == '\0' || *p == '#') ? 1 : 0 ;
 681 }
 682
 683 /*
 684  * Returns 0 if positive match, -1 if _not_ ok.
 685  */
 686 static int
 687 __validuser2_sa(hostf, ra, ralen, luser, ruser, rhost)
 688         FILE *hostf;
 689         struct sockaddr *ra;
 690         size_t ralen;
 691         const char *luser, *ruser, *rhost;
 692 {
 693     register const char *user;
 694     register char *p;
 695     int hcheck, ucheck;
 696     char *buf = NULL;
 697     size_t bufsize = 0;
 698     int retval = -1;
 699
 700     while (__getline (&buf, &bufsize, hostf) > 0) {
 701         buf[bufsize - 1] = '\0'; /* Make sure it's terminated.  */
 702         p = buf;
 703
 704         /* Skip empty or comment lines */
 705         if (__isempty (p)) {
 706             continue;
 707         }
 708
 709         /* Skip lines that are too long. */
 710         if (strchr (p, '\n') == NULL) {
 711             int ch = getc_unlocked (hostf);
 712
 713             while (ch != '\n' && ch != EOF)
 714                 ch = getc_unlocked (hostf);
 715             continue;
 716         }
 717
 718         for (;*p && !isspace(*p); ++p) {
 719             *p = _tolower (*p);
 720         }
 721
 722         /* Next we want to find the permitted name for the remote user.  */
 723         if (*p == ' ' || *p == '\t') {
 724             /* <nul> terminate hostname and skip spaces */
 725             for (*p++='\0'; *p && isspace (*p); ++p);
 726
 727             user = p;                   /* this is the user's name */
 728             while (*p && !isspace (*p))
 729                 ++p;                    /* find end of user's name */
 730         } else
 731             user = p;
 732
 733         *p = '\0';              /* <nul> terminate username (+host?) */
 734
 735         /* buf -> host(?) ; user -> username(?) */
 736
 737         /* First check host part */
 738         hcheck = __checkhost_sa (ra, ralen, buf, rhost);
 739
 740         if (hcheck < 0)
 741             break;
 742
 743         if (hcheck) {
 744             /* Then check user part */
 745             if (! (*user))
 746                 user = luser;
 747
 748             ucheck = __icheckuser (user, ruser);
 749
 750             /* Positive 'host user' match? */
 751             if (ucheck > 0) {
 752                 retval = 0;
 753                 break;
 754             }
 755
 756             /* Negative 'host -user' match? */
 757             if (ucheck < 0)
 758                 break;
 759
 760             /* Neither, go on looking for match */
 761         }
 762     }
 763
 764     if (buf != NULL)
 765       free (buf);
 766
 767     return retval;
 768 }