inet/rcmd.c

   1 /*
   2  * Copyright (c) 1983, 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  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)rcmd.c      8.3 (Berkeley) 3/26/94";
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include <sys/param.h>
  39 #include <sys/socket.h>
  40 #include <sys/stat.h>
  41
  42 #include <netinet/in.h>
  43 #include <arpa/inet.h>
  44
  45 #include <alloca.h>
  46 #include <signal.h>
  47 #include <fcntl.h>
  48 #include <netdb.h>
  49 #include <unistd.h>
  50 #include <pwd.h>
  51 #include <errno.h>
  52 #include <stdio.h>
  53 #include <ctype.h>
  54 #include <string.h>
  55
  56
  57 int     __ivaliduser __P((FILE *, u_int32_t, const char *, const char *));
  58 static int __icheckhost __P((u_int32_t, char *));
  59
  60 int
  61 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
  62         char **ahost;
  63         u_short rport;
  64         const char *locuser, *remuser, *cmd;
  65         int *fd2p;
  66 {
  67         struct hostent hostbuf, *hp;
  68         size_t hstbuflen;
  69         char *tmphstbuf;
  70         struct sockaddr_in sin, from;
  71         fd_set reads;
  72         int32_t oldmask;
  73         pid_t pid;
  74         int s, lport, timo;
  75         char c;
  76         int herr;
  77         int save_errno;
  78
  79         pid = getpid();
  80
  81         hstbuflen = 1024;
  82         tmphstbuf = __alloca (hstbuflen);
  83         save_errno = errno;
  84
  85         while (__gethostbyname_r (*ahost, &hostbuf, tmphstbuf, hstbuflen,
  86                                   &hp, &herr) < 0)
  87           if (herr != NETDB_INTERNAL || errno != ERANGE)
  88             {
  89               __set_h_errno (herr);
  90               herror(*ahost);
  91               return -1;
  92             }
  93           else
  94             {
  95               /* Enlarge the buffer.  */
  96               hstbuflen *= 2;
  97               tmphstbuf = __alloca (hstbuflen);
  98               __set_errno (0);
  99             }
 100
 101         __set_errno (save_errno);
 102         *ahost = hp->h_name;
 103         oldmask = sigblock(sigmask(SIGURG));
 104         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
 105                 s = rresvport(&lport);
 106                 if (s < 0) {
 107                         if (errno == EAGAIN)
 108                                 (void)fprintf(stderr,
 109                                     _("rcmd: socket: All ports in use\n"));
 110                         else
 111                                 (void)fprintf(stderr, "rcmd: socket: %m\n");
 112                         sigsetmask(oldmask);
 113                         return -1;
 114                 }
 115                 fcntl(s, F_SETOWN, pid);
 116                 sin.sin_family = hp->h_addrtype;
 117                 bcopy(hp->h_addr_list[0], &sin.sin_addr,
 118                       MIN (sizeof (sin.sin_addr), hp->h_length));
 119                 sin.sin_port = rport;
 120                 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 121                         break;
 122                 (void)close(s);
 123                 if (errno == EADDRINUSE) {
 124                         lport--;
 125                         continue;
 126                 }
 127                 if (errno == ECONNREFUSED && timo <= 16) {
 128                         (void)sleep(timo);
 129                         timo *= 2;
 130                         continue;
 131                 }
 132                 if (hp->h_addr_list[1] != NULL) {
 133                         int oerrno = errno;
 134
 135                         (void)fprintf(stderr, _("connect to address %s: "),
 136                             inet_ntoa(sin.sin_addr));
 137                         __set_errno (oerrno);
 138                         perror(0);
 139                         hp->h_addr_list++;
 140                         bcopy(hp->h_addr_list[0], &sin.sin_addr,
 141                               MIN (sizeof (sin.sin_addr), hp->h_length));
 142                         (void)fprintf(stderr, _("Trying %s...\n"),
 143                             inet_ntoa(sin.sin_addr));
 144                         continue;
 145                 }
 146                 (void)fprintf(stderr, "%s: %m\n", hp->h_name);
 147                 sigsetmask(oldmask);
 148                 return -1;
 149         }
 150         lport--;
 151         if (fd2p == 0) {
 152                 write(s, "", 1);
 153                 lport = 0;
 154         } else {
 155                 char num[8];
 156                 int s2 = rresvport(&lport), s3;
 157                 size_t len = sizeof(from);
 158
 159                 if (s2 < 0)
 160                         goto bad;
 161                 listen(s2, 1);
 162                 (void)snprintf(num, sizeof(num), "%d", lport);
 163                 if (write(s, num, strlen(num)+1) != strlen(num)+1) {
 164                         (void)fprintf(stderr,
 165                             _("rcmd: write (setting up stderr): %m\n"));
 166                         (void)close(s2);
 167                         goto bad;
 168                 }
 169                 FD_ZERO(&reads);
 170                 FD_SET(s, &reads);
 171                 FD_SET(s2, &reads);
 172                 __set_errno (0);
 173                 if (select(1 + (s > s2 ? s : s2), &reads, 0, 0, 0) < 1 ||
 174                     !FD_ISSET(s2, &reads)) {
 175                         if (errno != 0)
 176                                 (void)fprintf(stderr,
 177                                   _("rcmd: select (setting up stderr): %m\n"));
 178                         else
 179                                 (void)fprintf(stderr,
 180                              _("select: protocol failure in circuit setup\n"));
 181                         (void)close(s2);
 182                         goto bad;
 183                 }
 184                 s3 = accept(s2, (struct sockaddr *)&from, &len);
 185                 (void)close(s2);
 186                 if (s3 < 0) {
 187                         (void)fprintf(stderr,
 188                             "rcmd: accept: %m\n");
 189                         lport = 0;
 190                         goto bad;
 191                 }
 192                 *fd2p = s3;
 193                 from.sin_port = ntohs((u_short)from.sin_port);
 194                 if (from.sin_family != AF_INET ||
 195                     from.sin_port >= IPPORT_RESERVED ||
 196                     from.sin_port < IPPORT_RESERVED / 2) {
 197                         (void)fprintf(stderr,
 198                             _("socket: protocol failure in circuit setup\n"));
 199                         goto bad2;
 200                 }
 201         }
 202         (void)write(s, locuser, strlen(locuser)+1);
 203         (void)write(s, remuser, strlen(remuser)+1);
 204         (void)write(s, cmd, strlen(cmd)+1);
 205         if (read(s, &c, 1) != 1) {
 206                 (void)fprintf(stderr,
 207                     "rcmd: %s: %m\n", *ahost);
 208                 goto bad2;
 209         }
 210         if (c != 0) {
 211                 while (read(s, &c, 1) == 1) {
 212                         (void)write(STDERR_FILENO, &c, 1);
 213                         if (c == '\n')
 214                                 break;
 215                 }
 216                 goto bad2;
 217         }
 218         sigsetmask(oldmask);
 219         return s;
 220 bad2:
 221         if (lport)
 222                 (void)close(*fd2p);
 223 bad:
 224         (void)close(s);
 225         sigsetmask(oldmask);
 226         return -1;
 227 }
 228
 229 int
 230 rresvport(alport)
 231         int *alport;
 232 {
 233         struct sockaddr_in sin;
 234         int s;
 235
 236         sin.sin_family = AF_INET;
 237         sin.sin_addr.s_addr = INADDR_ANY;
 238         s = socket(AF_INET, SOCK_STREAM, 0);
 239         if (s < 0)
 240                 return -1;
 241         for (;;) {
 242                 sin.sin_port = htons((u_short)*alport);
 243                 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 244                         return s;
 245                 if (errno != EADDRINUSE) {
 246                         (void)close(s);
 247                         return -1;
 248                 }
 249                 (*alport)--;
 250                 if (*alport == IPPORT_RESERVED/2) {
 251                         (void)close(s);
 252                         __set_errno (EAGAIN);           /* close */
 253                         return -1;
 254                 }
 255         }
 256 }
 257
 258 int     __check_rhosts_file = 1;
 259 char    *__rcmd_errstr;
 260
 261 int
 262 ruserok(rhost, superuser, ruser, luser)
 263         const char *rhost, *ruser, *luser;
 264         int superuser;
 265 {
 266         struct hostent hostbuf, *hp;
 267         size_t buflen;
 268         char *buffer;
 269         u_int32_t addr;
 270         char **ap;
 271         int herr;
 272         int save_errno;
 273
 274         buflen = 1024;
 275         buffer = __alloca (buflen);
 276         save_errno = errno;
 277
 278         while (__gethostbyname_r (rhost, &hostbuf, buffer, buflen, &hp, &herr)
 279                < 0)
 280           if (herr != NETDB_INTERNAL || errno != ERANGE)
 281             return -1;
 282           else
 283             {
 284               /* Enlarge the buffer.  */
 285               buflen *= 2;
 286               buffer = __alloca (buflen);
 287               __set_errno (0);
 288             }
 289
 290         __set_errno (save_errno);
 291
 292         for (ap = hp->h_addr_list; *ap; ++ap) {
 293                 bcopy(*ap, &addr, sizeof(addr));
 294                 if (iruserok(addr, superuser, ruser, luser) == 0)
 295                         return 0;
 296         }
 297         return -1;
 298 }
 299
 300 /*
 301  * New .rhosts strategy: We are passed an ip address. We spin through
 302  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 303  * has ip addresses, we don't have to trust a nameserver.  When it
 304  * contains hostnames, we spin through the list of addresses the nameserver
 305  * gives us and look for a match.
 306  *
 307  * Returns 0 if ok, -1 if not ok.
 308  */
 309 int
 310 iruserok(raddr, superuser, ruser, luser)
 311         u_int32_t raddr;
 312         int superuser;
 313         const char *ruser, *luser;
 314 {
 315         register char *cp;
 316         struct stat sbuf;
 317         struct passwd pwdbuf, *pwd;
 318         FILE *hostf;
 319         int first;
 320
 321         first = 1;
 322         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 323 again:
 324         if (hostf) {
 325                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 326                         (void)fclose(hostf);
 327                         return 0;
 328                 }
 329                 (void)fclose(hostf);
 330         }
 331         if (first == 1 && (__check_rhosts_file || superuser)) {
 332                 char *pbuf;
 333                 size_t dirlen;
 334                 size_t buflen = __sysconf (_SC_GETPW_R_SIZE_MAX);
 335                 char *buffer = __alloca (buflen);
 336
 337                 first = 0;
 338                 if (__getpwnam_r (luser, &pwdbuf, buffer, buflen, &pwd) < 0)
 339                         return -1;
 340
 341                 dirlen = strlen (pwd->pw_dir);
 342                 pbuf = alloca (dirlen + sizeof "/.rhosts");
 343                 memcpy (pbuf, pwd->pw_dir, dirlen);
 344                 memcpy (pbuf + dirlen, "/.rhosts", sizeof "/.rhosts");
 345
 346                 /*
 347                  * Change effective uid while opening .rhosts.  If root and
 348                  * reading an NFS mounted file system, can't read files that
 349                  * are protected read/write owner only.
 350                  */
 351                 if (__access (pbuf, R_OK) != 0)
 352                   hostf = NULL;
 353                 else
 354                   {
 355                     uid_t uid = geteuid ();
 356                     seteuid (pwd->pw_uid);
 357                     hostf = fopen (pbuf, "r");
 358                     seteuid (uid);
 359                   }
 360
 361                 if (hostf == NULL)
 362                         return -1;
 363                 /*
 364                  * If not a regular file, or is owned by someone other than
 365                  * user or root or if writeable by anyone but the owner, quit.
 366                  */
 367                 cp = NULL;
 368                 if (lstat(pbuf, &sbuf) < 0)
 369                         cp = _(".rhosts lstat failed");
 370                 else if (!S_ISREG(sbuf.st_mode))
 371                         cp = _(".rhosts not regular file");
 372                 else if (fstat(fileno(hostf), &sbuf) < 0)
 373                         cp = _(".rhosts fstat failed");
 374                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 375                         cp = _("bad .rhosts owner");
 376                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 377                         cp = _(".rhosts writeable by other than owner");
 378                 /* If there were any problems, quit. */
 379                 if (cp) {
 380                         __rcmd_errstr = cp;
 381                         (void)fclose(hostf);
 382                         return -1;
 383                 }
 384                 goto again;
 385         }
 386         return -1;
 387 }
 388
 389 /*
 390  * XXX
 391  * Don't make static, used by lpd(8).
 392  *
 393  * Returns 0 if ok, -1 if not ok.
 394  */
 395 int
 396 __ivaliduser(hostf, raddr, luser, ruser)
 397         FILE *hostf;
 398         u_int32_t raddr;
 399         const char *luser, *ruser;
 400 {
 401         register char *user, *p;
 402         int ch;
 403         char *buf = NULL;
 404         size_t bufsize = 0;
 405         ssize_t nread;
 406
 407         while ((nread = __getline (&buf, &bufsize, hostf)) > 0) {
 408                 buf[bufsize - 1] = '\0'; /* Make sure it's terminated.  */
 409                 p = buf;
 410                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 411                         *p = isupper(*p) ? tolower(*p) : *p;
 412                         p++;
 413                 }
 414                 if (*p == ' ' || *p == '\t') {
 415                         *p++ = '\0';
 416                         while (*p == ' ' || *p == '\t')
 417                                 p++;
 418                         user = p;
 419                         while (*p != '\n' && *p != ' ' &&
 420                             *p != '\t' && *p != '\0')
 421                                 p++;
 422                 } else
 423                         user = p;
 424                 *p = '\0';
 425                 if (__icheckhost(raddr, buf) &&
 426                     strcmp(ruser, *user ? user : luser) == 0) {
 427                         free (buf);
 428                         return 0;
 429                 }
 430         }
 431         free (buf);
 432         return -1;
 433 }
 434
 435 /*
 436  * Returns "true" if match, 0 if no match.
 437  */
 438 static int
 439 __icheckhost(raddr, lhost)
 440         u_int32_t raddr;
 441         register char *lhost;
 442 {
 443         struct hostent hostbuf, *hp;
 444         size_t buflen;
 445         char *buffer;
 446         register u_int32_t laddr;
 447         register char **pp;
 448         int herr;
 449         int save_errno;
 450
 451         /* Try for raw ip address first. */
 452         if (isdigit(*lhost) && (int32_t)(laddr = inet_addr(lhost)) != -1)
 453                 return raddr == laddr;
 454
 455         /* Better be a hostname. */
 456         buflen = 1024;
 457         buffer = __alloca (buflen);
 458         save_errno = errno;
 459
 460         while (__gethostbyname_r (lhost, &hostbuf, buffer, buflen, &hp, &herr)
 461                < 0)
 462           if (herr != NETDB_INTERNAL || errno != ERANGE)
 463             return 0;
 464           else
 465             {
 466               /* Enlarge the buffer.  */
 467               buflen *= 2;
 468               buffer = __alloca (buflen);
 469               __set_errno (0);
 470             }
 471
 472         __set_errno (save_errno);
 473
 474         /* Spin through ip addresses. */
 475         for (pp = hp->h_addr_list; *pp; ++pp)
 476                 if (!bcmp(&raddr, *pp, sizeof(u_int32_t)))
 477                         return 1;
 478
 479         /* No match. */
 480         return 0;
 481 }