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 #include <sys/param.h>
  59 #include <sys/poll.h>
  60 #include <sys/socket.h>
  61 #include <sys/stat.h>
  62
  63 #include <netinet/in.h>
  64 #include <arpa/inet.h>
  65
  66 #include <alloca.h>
  67 #include <signal.h>
  68 #include <fcntl.h>
  69 #include <netdb.h>
  70 #include <unistd.h>
  71 #include <pwd.h>
  72 #include <errno.h>
  73 #include <stdio.h>
  74 #include <stdio_ext.h>
  75 #include <ctype.h>
  76 #include <string.h>
  77 #include <libintl.h>
  78 #include <stdlib.h>
  79 #include <wchar.h>
  80 #include <sys/uio.h>
  81
  82
  83 int __ivaliduser (FILE *, u_int32_t, const char *, const char *);
  84 static int __validuser2_sa (FILE *, struct sockaddr *, size_t,
  85                             const char *, const char *, const char *);
  86 static int ruserok2_sa (struct sockaddr *ra, size_t ralen,
  87                         int superuser, const char *ruser,
  88                         const char *luser, const char *rhost);
  89 static int ruserok_sa (struct sockaddr *ra, size_t ralen,
  90                         int superuser, const char *ruser,
  91                         const char *luser);
  92 int iruserok_af (const void *raddr, int superuser, const char *ruser,
  93                  const char *luser, sa_family_t af);
  94 int iruserok (u_int32_t raddr, int superuser, const char *ruser,
  95               const char *luser);
  96
  97 libc_hidden_proto (iruserok_af)
  98
  99 libc_freeres_ptr(static char *ahostbuf);
 100
 101 int
 102 rcmd_af (char **ahost, u_short rport, const char *locuser, const char *remuser,
 103          const char *cmd, int *fd2p, sa_family_t af)
 104 {
 105         char paddr[INET6_ADDRSTRLEN];
 106         struct addrinfo hints, *res, *ai;
 107         union
 108         {
 109                 struct sockaddr sa;
 110                 struct sockaddr_storage ss;
 111                 struct sockaddr_in sin;
 112                 struct sockaddr_in6 sin6;
 113         } from;
 114         struct pollfd pfd[2];
 115         int32_t oldmask;
 116         pid_t pid;
 117         int s, lport, timo, error;
 118         char c;
 119         int refused;
 120         char num[8];
 121         ssize_t n;
 122
 123         if (af != AF_INET && af != AF_INET6 && af != AF_UNSPEC)
 124           {
 125             __set_errno (EAFNOSUPPORT);
 126             return -1;
 127           }
 128
 129         pid = __getpid();
 130
 131         memset(&hints, '\0', sizeof(hints));
 132         hints.ai_flags = AI_CANONNAME;
 133         hints.ai_family = af;
 134         hints.ai_socktype = SOCK_STREAM;
 135         (void)__snprintf(num, sizeof(num), "%d", ntohs(rport));
 136         error = getaddrinfo(*ahost, num, &hints, &res);
 137         if (error) {
 138                 if (error == EAI_NONAME && *ahost != NULL)
 139                         __fxprintf(NULL, "%s: Unknown host\n", *ahost);
 140                 else
 141                         __fxprintf(NULL, "rcmd: getaddrinfo: %s\n",
 142                                    gai_strerror(error));
 143
 144                 return -1;
 145         }
 146
 147         pfd[0].events = POLLIN;
 148         pfd[1].events = POLLIN;
 149
 150         if (res->ai_canonname){
 151                 free (ahostbuf);
 152                 ahostbuf = strdup (res->ai_canonname);
 153                 if (ahostbuf == NULL) {
 154                         __fxprintf(NULL, "%s",
 155                                    _("rcmd: Cannot allocate memory\n"));
 156                         return -1;
 157                 }
 158                 *ahost = ahostbuf;
 159         } else
 160                 *ahost = NULL;
 161         ai = res;
 162         refused = 0;
 163         oldmask = __sigblock(sigmask(SIGURG));
 164         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
 165                 char errbuf[200];
 166
 167                 s = rresvport_af(&lport, ai->ai_family);
 168                 if (s < 0) {
 169                         if (errno == EAGAIN)
 170                                 __fxprintf(NULL, "%s", _("\
 171 rcmd: socket: All ports in use\n"));
 172                         else
 173                                 __fxprintf(NULL, "rcmd: socket: %m\n");
 174
 175                         __sigsetmask(oldmask);
 176                         freeaddrinfo(res);
 177                         return -1;
 178                 }
 179                 __fcntl(s, F_SETOWN, pid);
 180                 if (__connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
 181                         break;
 182                 (void)__close(s);
 183                 if (errno == EADDRINUSE) {
 184                         lport--;
 185                         continue;
 186                 }
 187                 if (errno == ECONNREFUSED)
 188                         refused = 1;
 189                 if (ai->ai_next != NULL) {
 190                         int oerrno = errno;
 191                         char *buf = NULL;
 192
 193                         getnameinfo(ai->ai_addr, ai->ai_addrlen,
 194                                     paddr, sizeof(paddr),
 195                                     NULL, 0,
 196                                     NI_NUMERICHOST);
 197
 198                         if (__asprintf (&buf, _("connect to address %s: "),
 199                                         paddr) >= 0)
 200                           {
 201                             __fxprintf(NULL, "%s", buf);
 202                             free (buf);
 203                           }
 204                         __set_errno (oerrno);
 205                         perror(0);
 206                         ai = ai->ai_next;
 207                         getnameinfo(ai->ai_addr, ai->ai_addrlen,
 208                                     paddr, sizeof(paddr),
 209                                     NULL, 0,
 210                                     NI_NUMERICHOST);
 211                         if (__asprintf (&buf, _("Trying %s...\n"), paddr) >= 0)
 212                           {
 213                             __fxprintf (NULL, "%s", buf);
 214                             free (buf);
 215                           }
 216                         continue;
 217                 }
 218                 if (refused && timo <= 16) {
 219                         (void)__sleep(timo);
 220                         timo *= 2;
 221                         ai = res;
 222                         refused = 0;
 223                         continue;
 224                 }
 225                 freeaddrinfo(res);
 226                 (void)__fxprintf(NULL, "%s: %s\n", *ahost,
 227                                  __strerror_r(errno, errbuf, sizeof (errbuf)));
 228                 __sigsetmask(oldmask);
 229                 return -1;
 230         }
 231         lport--;
 232         if (fd2p == 0) {
 233                 __write(s, "", 1);
 234                 lport = 0;
 235         } else {
 236                 char num[8];
 237                 int s2 = rresvport_af(&lport, ai->ai_family), s3;
 238                 socklen_t len = ai->ai_addrlen;
 239
 240                 if (s2 < 0)
 241                         goto bad;
 242                 __listen(s2, 1);
 243                 (void)__snprintf(num, sizeof(num), "%d", lport);
 244                 if (__write(s, num, strlen(num)+1) != (ssize_t)strlen(num)+1) {
 245                         char *buf = NULL;
 246
 247                         if (__asprintf (&buf, _("\
 248 rcmd: write (setting up stderr): %m\n")) >= 0)
 249                           {
 250                             __fxprintf(NULL, "%s", buf);
 251                             free (buf);
 252                           }
 253                         (void)__close(s2);
 254                         goto bad;
 255                 }
 256                 pfd[0].fd = s;
 257                 pfd[1].fd = s2;
 258                 __set_errno (0);
 259                 if (__poll (pfd, 2, -1) < 1 || (pfd[1].revents & POLLIN) == 0){
 260                         char *buf = NULL;
 261
 262                         if ((errno != 0
 263                              && __asprintf(&buf, _("\
 264 rcmd: poll (setting up stderr): %m\n")) >= 0)
 265                             || (errno == 0
 266                                 && __asprintf(&buf, _("\
 267 poll: protocol failure in circuit setup\n")) >= 0))
 268                           {
 269                             __fxprintf (NULL, "%s", buf);
 270                             free  (buf);
 271                           }
 272                         (void)__close(s2);
 273                         goto bad;
 274                 }
 275                 s3 = TEMP_FAILURE_RETRY (accept(s2, &from.sa, &len));
 276                 switch (from.sa.sa_family) {
 277                 case AF_INET:
 278                         rport = ntohs(from.sin.sin_port);
 279                         break;
 280                 case AF_INET6:
 281                         rport = ntohs(from.sin6.sin6_port);
 282                         break;
 283                 default:
 284                         rport = 0;
 285                         break;
 286                 }
 287                 (void)__close(s2);
 288                 if (s3 < 0) {
 289                         (void)__fxprintf(NULL, "rcmd: accept: %m\n");
 290                         lport = 0;
 291                         goto bad;
 292                 }
 293                 *fd2p = s3;
 294
 295                 if (rport >= IPPORT_RESERVED || rport < IPPORT_RESERVED / 2){
 296                         char *buf = NULL;
 297
 298                         if (__asprintf(&buf, _("\
 299 socket: protocol failure in circuit setup\n")) >= 0)
 300                           {
 301                             __fxprintf (NULL, "%s", buf);
 302                             free (buf);
 303                           }
 304                         goto bad2;
 305                 }
 306         }
 307         struct iovec iov[3] =
 308           {
 309             [0] = { .iov_base = (void *) locuser,
 310                     .iov_len = strlen (locuser) + 1 },
 311             [1] = { .iov_base = (void *) remuser,
 312                     .iov_len = strlen (remuser) + 1 },
 313             [2] = { .iov_base = (void *) cmd,
 314                     .iov_len = strlen (cmd) + 1 }
 315           };
 316         (void) TEMP_FAILURE_RETRY (__writev (s, iov, 3));
 317         n = TEMP_FAILURE_RETRY (__read(s, &c, 1));
 318         if (n != 1) {
 319                 char *buf = NULL;
 320
 321                 if ((n == 0
 322                      && __asprintf(&buf, _("rcmd: %s: short read"),
 323                                    *ahost) >= 0)
 324                     || (n != 0
 325                         && __asprintf(&buf, "rcmd: %s: %m\n", *ahost) >= 0))
 326                   {
 327                     __fxprintf (NULL, "%s", buf);
 328                     free (buf);
 329                   }
 330                 goto bad2;
 331         }
 332         if (c != 0) {
 333                 while (__read(s, &c, 1) == 1) {
 334                         (void)__write(STDERR_FILENO, &c, 1);
 335                         if (c == '\n')
 336                                 break;
 337                 }
 338                 goto bad2;
 339         }
 340         __sigsetmask(oldmask);
 341         freeaddrinfo(res);
 342         return s;
 343 bad2:
 344         if (lport)
 345                 (void)__close(*fd2p);
 346 bad:
 347         (void)__close(s);
 348         __sigsetmask(oldmask);
 349         freeaddrinfo(res);
 350         return -1;
 351 }
 352 libc_hidden_def (rcmd_af)
 353
 354 int
 355 rcmd (char **ahost, u_short rport, const char *locuser, const char *remuser,
 356       const char *cmd, int *fd2p)
 357 {
 358   return rcmd_af (ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
 359 }
 360
 361 int
 362 rresvport_af (int *alport, sa_family_t family)
 363 {
 364         union {
 365                 struct sockaddr generic;
 366                 struct sockaddr_in in;
 367                 struct sockaddr_in6 in6;
 368         } ss;
 369         int s;
 370         size_t len;
 371         uint16_t *sport;
 372
 373         switch(family){
 374         case AF_INET:
 375                 len = sizeof(struct sockaddr_in);
 376                 sport = &ss.in.sin_port;
 377                 break;
 378         case AF_INET6:
 379                 len = sizeof(struct sockaddr_in6);
 380                 sport = &ss.in6.sin6_port;
 381                 break;
 382         default:
 383                 __set_errno (EAFNOSUPPORT);
 384                 return -1;
 385         }
 386         s = __socket(family, SOCK_STREAM, 0);
 387         if (s < 0)
 388                 return -1;
 389
 390         memset (&ss, '\0', sizeof(ss));
 391 #ifdef SALEN
 392         ss.generic.__ss_len = len;
 393 #endif
 394         ss.generic.sa_family = family;
 395
 396         /* Ignore invalid values.  */
 397         if (*alport < IPPORT_RESERVED / 2)
 398                 *alport = IPPORT_RESERVED / 2;
 399         else if (*alport >= IPPORT_RESERVED)
 400                 *alport = IPPORT_RESERVED - 1;
 401
 402         int start = *alport;
 403         do {
 404                 *sport = htons((uint16_t) *alport);
 405                 if (__bind(s, &ss.generic, len) >= 0)
 406                         return s;
 407                 if (errno != EADDRINUSE) {
 408                         (void)__close(s);
 409                         return -1;
 410                 }
 411                 if ((*alport)-- == IPPORT_RESERVED/2)
 412                         *alport = IPPORT_RESERVED - 1;
 413         } while (*alport != start);
 414         (void)__close(s);
 415         __set_errno (EAGAIN);
 416         return -1;
 417 }
 418 libc_hidden_def (rresvport_af)
 419
 420 int
 421 rresvport (int *alport)
 422 {
 423         return rresvport_af(alport, AF_INET);
 424 }
 425
 426 int     __check_rhosts_file = 1;
 427 char    *__rcmd_errstr;
 428
 429 int
 430 ruserok_af (const char *rhost, int superuser, const char *ruser,
 431             const char *luser, sa_family_t af)
 432 {
 433         struct addrinfo hints, *res, *res0;
 434         int gai;
 435         int ret;
 436
 437         memset (&hints, '\0', sizeof(hints));
 438         hints.ai_family = af;
 439         gai = getaddrinfo(rhost, NULL, &hints, &res0);
 440         if (gai)
 441                 return -1;
 442         ret = -1;
 443         for (res=res0; res; res=res->ai_next)
 444                 if (ruserok2_sa(res->ai_addr, res->ai_addrlen,
 445                                 superuser, ruser, luser, rhost) == 0){
 446                         ret = 0;
 447                         break;
 448                 }
 449         freeaddrinfo(res0);
 450         return (ret);
 451 }
 452 libc_hidden_def (ruserok_af)
 453
 454 int
 455 ruserok (const char *rhost, int superuser, const char *ruser,
 456          const char *luser)
 457 {
 458         return ruserok_af(rhost, superuser, ruser, luser, AF_INET);
 459 }
 460
 461 /* Extremely paranoid file open function. */
 462 static FILE *
 463 iruserfopen (const char *file, uid_t okuser)
 464 {
 465   struct stat64 st;
 466   char *cp = NULL;
 467   FILE *res = NULL;
 468
 469   /* If not a regular file, if owned by someone other than user or
 470      root, if writeable by anyone but the owner, or if hardlinked
 471      anywhere, quit.  */
 472   if (__lxstat64 (_STAT_VER, file, &st))
 473     cp = _("lstat failed");
 474   else if (!S_ISREG (st.st_mode))
 475     cp = _("not regular file");
 476   else
 477     {
 478       res = fopen (file, "rce");
 479       if (!res)
 480         cp = _("cannot open");
 481       else if (__fxstat64 (_STAT_VER, fileno (res), &st) < 0)
 482         cp = _("fstat failed");
 483       else if (st.st_uid && st.st_uid != okuser)
 484         cp = _("bad owner");
 485       else if (st.st_mode & (S_IWGRP|S_IWOTH))
 486         cp = _("writeable by other than owner");
 487       else if (st.st_nlink > 1)
 488         cp = _("hard linked somewhere");
 489     }
 490
 491   /* If there were any problems, quit.  */
 492   if (cp != NULL)
 493     {
 494       __rcmd_errstr = cp;
 495       if (res)
 496         fclose (res);
 497       return NULL;
 498     }
 499
 500   /* No threads use this stream.  */
 501   __fsetlocking (res, FSETLOCKING_BYCALLER);
 502
 503   return res;
 504 }
 505
 506 /*
 507  * New .rhosts strategy: We are passed an ip address. We spin through
 508  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 509  * has ip addresses, we don't have to trust a nameserver.  When it
 510  * contains hostnames, we spin through the list of addresses the nameserver
 511  * gives us and look for a match.
 512  *
 513  * Returns 0 if ok, -1 if not ok.
 514  */
 515 static int
 516 ruserok2_sa (struct sockaddr *ra, size_t ralen, int superuser,
 517              const char *ruser, const char *luser, const char *rhost)
 518 {
 519   FILE *hostf = NULL;
 520   int isbad = -1;
 521
 522   if (!superuser)
 523     hostf = iruserfopen (_PATH_HEQUIV, 0);
 524
 525   if (hostf)
 526     {
 527       isbad = __validuser2_sa (hostf, ra, ralen, luser, ruser, rhost);
 528       fclose (hostf);
 529
 530       if (!isbad)
 531         return 0;
 532     }
 533
 534   if (__check_rhosts_file || superuser)
 535     {
 536       char *pbuf;
 537       struct passwd pwdbuf, *pwd;
 538       size_t dirlen;
 539       size_t buflen = __sysconf (_SC_GETPW_R_SIZE_MAX);
 540       char *buffer = __alloca (buflen);
 541       uid_t uid;
 542
 543       if (__getpwnam_r (luser, &pwdbuf, buffer, buflen, &pwd) != 0
 544           || pwd == NULL)
 545         return -1;
 546
 547       dirlen = strlen (pwd->pw_dir);
 548       pbuf = alloca (dirlen + sizeof "/.rhosts");
 549       __mempcpy (__mempcpy (pbuf, pwd->pw_dir, dirlen),
 550                  "/.rhosts", sizeof "/.rhosts");
 551
 552        /* Change effective uid while reading .rhosts.  If root and
 553           reading an NFS mounted file system, can't read files that
 554           are protected read/write owner only.  */
 555        uid = __geteuid ();
 556        seteuid (pwd->pw_uid);
 557        hostf = iruserfopen (pbuf, pwd->pw_uid);
 558
 559        if (hostf != NULL)
 560          {
 561            isbad = __validuser2_sa (hostf, ra, ralen, luser, ruser, rhost);
 562            fclose (hostf);
 563          }
 564
 565        seteuid (uid);
 566        return isbad;
 567     }
 568   return -1;
 569 }
 570 /*
 571  * ruserok_sa() is now discussed on ipng, so
 572  * currently disabled for external use
 573  */
 574 static int
 575 ruserok_sa (struct sockaddr *ra, size_t ralen, int superuser,
 576             const char *ruser, const char *luser)
 577 {
 578   return ruserok2_sa(ra, ralen, superuser, ruser, luser, "-");
 579 }
 580
 581 /* This is the exported version.  */
 582 int
 583 iruserok_af (const void *raddr, int superuser, const char *ruser,
 584              const char *luser, sa_family_t af)
 585 {
 586   union {
 587     struct sockaddr generic;
 588     struct sockaddr_in in;
 589     struct sockaddr_in6 in6;
 590   } ra;
 591   size_t ralen;
 592
 593   memset (&ra, '\0', sizeof(ra));
 594   switch (af){
 595   case AF_INET:
 596     ra.in.sin_family = AF_INET;
 597     memcpy (&ra.in.sin_addr, raddr, sizeof(struct in_addr));
 598     ralen = sizeof(struct sockaddr_in);
 599     break;
 600   case AF_INET6:
 601     ra.in6.sin6_family = AF_INET6;
 602     memcpy (&ra.in6.sin6_addr, raddr, sizeof(struct in6_addr));
 603     ralen = sizeof(struct sockaddr_in6);
 604     break;
 605   default:
 606     return 0;
 607   }
 608   return ruserok_sa (&ra.generic, ralen, superuser, ruser, luser);
 609 }
 610 libc_hidden_def (iruserok_af)
 611
 612 int
 613 iruserok (u_int32_t raddr, int superuser, const char *ruser, const char *luser)
 614 {
 615   return iruserok_af (&raddr, superuser, ruser, luser, AF_INET);
 616 }
 617
 618 /*
 619  * XXX
 620  * Don't make static, used by lpd(8).
 621  *
 622  * This function is not used anymore. It is only present because lpd(8)
 623  * calls it (!?!). We simply call __invaliduser2() with an illegal rhost
 624  * argument. This means that netgroups won't work in .rhost/hosts.equiv
 625  * files. If you want lpd to work with netgroups, fix lpd to use ruserok()
 626  * or PAM.
 627  * Returns 0 if ok, -1 if not ok.
 628  */
 629 int
 630 __ivaliduser (FILE *hostf, u_int32_t raddr, const char *luser,
 631               const char *ruser)
 632 {
 633         struct sockaddr_in ra;
 634         memset(&ra, '\0', sizeof(ra));
 635         ra.sin_family = AF_INET;
 636         ra.sin_addr.s_addr = raddr;
 637         return __validuser2_sa(hostf, (struct sockaddr *)&ra, sizeof(ra),
 638                                luser, ruser, "-");
 639 }
 640
 641
 642 /* Returns 1 on positive match, 0 on no match, -1 on negative match.  */
 643 static int
 644 internal_function
 645 __checkhost_sa (struct sockaddr *ra, size_t ralen, char *lhost,
 646                 const char *rhost)
 647 {
 648         struct addrinfo hints, *res0, *res;
 649         char raddr[INET6_ADDRSTRLEN];
 650         int match;
 651         int negate=1;    /* Multiply return with this to get -1 instead of 1 */
 652
 653         /* Check nis netgroup.  */
 654         if (strncmp ("+@", lhost, 2) == 0)
 655                 return innetgr (&lhost[2], rhost, NULL, NULL);
 656
 657         if (strncmp ("-@", lhost, 2) == 0)
 658                 return -innetgr (&lhost[2], rhost, NULL, NULL);
 659
 660         /* -host */
 661         if (strncmp ("-", lhost,1) == 0) {
 662                 negate = -1;
 663                 lhost++;
 664         } else if (strcmp ("+",lhost) == 0) {
 665                 return 1;                    /* asking for trouble, but ok.. */
 666         }
 667
 668         /* Try for raw ip address first. */
 669         /* XXX */
 670         if (getnameinfo(ra, ralen,
 671                         raddr, sizeof(raddr), NULL, 0,
 672                         NI_NUMERICHOST) == 0
 673             && strcmp(raddr, lhost) == 0)
 674                 return negate;
 675
 676         /* Better be a hostname. */
 677         match = 0;
 678         memset(&hints, '\0', sizeof(hints));
 679         hints.ai_family = ra->sa_family;
 680         if (getaddrinfo(lhost, NULL, &hints, &res0) == 0){
 681                 /* Spin through ip addresses. */
 682                 for (res = res0; res; res = res->ai_next)
 683                   {
 684                     if (res->ai_family == ra->sa_family
 685                         && !memcmp(res->ai_addr, ra, res->ai_addrlen))
 686                       {
 687                         match = 1;
 688                         break;
 689                       }
 690                   }
 691                 freeaddrinfo (res0);
 692         }
 693         return negate * match;
 694 }
 695
 696 /* Returns 1 on positive match, 0 on no match, -1 on negative match.  */
 697 static int
 698 internal_function
 699 __icheckuser (const char *luser, const char *ruser)
 700 {
 701     /*
 702       luser is user entry from .rhosts/hosts.equiv file
 703       ruser is user id on remote host
 704       */
 705
 706     /* [-+]@netgroup */
 707     if (strncmp ("+@", luser, 2) == 0)
 708         return innetgr (&luser[2], NULL, ruser, NULL);
 709
 710     if (strncmp ("-@", luser,2) == 0)
 711         return -innetgr (&luser[2], NULL, ruser, NULL);
 712
 713     /* -user */
 714     if (strncmp ("-", luser, 1) == 0)
 715         return -(strcmp (&luser[1], ruser) == 0);
 716
 717     /* + */
 718     if (strcmp ("+", luser) == 0)
 719         return 1;
 720
 721     /* simple string match */
 722     return strcmp (ruser, luser) == 0;
 723 }
 724
 725 /*
 726  * Returns 1 for blank lines (or only comment lines) and 0 otherwise
 727  */
 728 static int
 729 __isempty (char *p)
 730 {
 731     while (*p && isspace (*p)) {
 732         ++p;
 733     }
 734
 735     return (*p == '\0' || *p == '#') ? 1 : 0 ;
 736 }
 737
 738 /*
 739  * Returns 0 if positive match, -1 if _not_ ok.
 740  */
 741 static int
 742 __validuser2_sa (FILE *hostf, struct sockaddr *ra, size_t ralen,
 743                  const char *luser, const char *ruser, const char *rhost)
 744 {
 745     const char *user;
 746     char *p;
 747     int hcheck, ucheck;
 748     char *buf = NULL;
 749     size_t bufsize = 0;
 750     int retval = -1;
 751
 752     while (__getline (&buf, &bufsize, hostf) > 0) {
 753         buf[bufsize - 1] = '\0'; /* Make sure it's terminated.  */
 754         p = buf;
 755
 756         /* Skip empty or comment lines */
 757         if (__isempty (p)) {
 758             continue;
 759         }
 760
 761         for (;*p && !isspace(*p); ++p) {
 762             *p = _tolower (*p);
 763         }
 764
 765         /* Next we want to find the permitted name for the remote user.  */
 766         if (*p == ' ' || *p == '\t') {
 767             /* <nul> terminate hostname and skip spaces */
 768             for (*p++='\0'; *p && isspace (*p); ++p);
 769
 770             user = p;                   /* this is the user's name */
 771             while (*p && !isspace (*p))
 772                 ++p;                    /* find end of user's name */
 773         } else
 774             user = p;
 775
 776         *p = '\0';              /* <nul> terminate username (+host?) */
 777
 778         /* buf -> host(?) ; user -> username(?) */
 779         if (*buf == '\0')
 780           break;
 781         if (*user == '\0')
 782           user = luser;
 783
 784         /* First check the user part.  In a naive implementation we
 785            would check the host part first, then the user.  However,
 786            if we check the user first and reject the entry we will
 787            have saved doing any host lookups to normalize the comparison
 788            and that likely saves several DNS queries.  Therefore we
 789            check the user first.  */
 790         ucheck = __icheckuser (user, ruser);
 791
 792         /* Either we found the user, or we didn't and this is a
 793            negative host check.  We must do the negative host lookup
 794            in order to preserve the semantics of stopping on this line
 795            before processing others.  */
 796         if (ucheck != 0 || *buf == '-') {
 797
 798             /* Next check host part.  */
 799             hcheck = __checkhost_sa (ra, ralen, buf, rhost);
 800
 801             /* Negative '-host user(?)' match?  */
 802             if (hcheck < 0)
 803                 break;
 804
 805             /* Positive 'host user' match?  */
 806             if (hcheck > 0 && ucheck > 0) {
 807                 retval = 0;
 808                 break;
 809             }
 810
 811             /* Negative 'host -user' match?  */
 812             if (hcheck > 0 && ucheck < 0)
 813               break;
 814
 815             /* Neither, go on looking for match.  */
 816         }
 817     }
 818
 819     free (buf);
 820
 821     return retval;
 822 }