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 *)) internal_function;
  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
  78         pid = getpid();
  79
  80         hstbuflen = 1024;
  81         tmphstbuf = __alloca (hstbuflen);
  82         while (__gethostbyname_r (*ahost, &hostbuf, tmphstbuf, hstbuflen,
  83                                   &hp, &herr) < 0)
  84           if (herr != NETDB_INTERNAL || errno != ERANGE)
  85             {
  86               __set_h_errno (herr);
  87               herror(*ahost);
  88               return -1;
  89             }
  90           else
  91             {
  92               /* Enlarge the buffer.  */
  93               hstbuflen *= 2;
  94               tmphstbuf = __alloca (hstbuflen);
  95             }
  96
  97         *ahost = hp->h_name;
  98         oldmask = sigblock(sigmask(SIGURG));
  99         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
 100                 s = rresvport(&lport);
 101                 if (s < 0) {
 102                         if (errno == EAGAIN)
 103                                 (void)fprintf(stderr,
 104                                     _("rcmd: socket: All ports in use\n"));
 105                         else
 106                                 (void)fprintf(stderr, "rcmd: socket: %m\n");
 107                         sigsetmask(oldmask);
 108                         return -1;
 109                 }
 110                 fcntl(s, F_SETOWN, pid);
 111                 sin.sin_family = hp->h_addrtype;
 112                 bcopy(hp->h_addr_list[0], &sin.sin_addr,
 113                       MIN (sizeof (sin.sin_addr), hp->h_length));
 114                 sin.sin_port = rport;
 115                 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 116                         break;
 117                 (void)close(s);
 118                 if (errno == EADDRINUSE) {
 119                         lport--;
 120                         continue;
 121                 }
 122                 if (errno == ECONNREFUSED && timo <= 16) {
 123                         (void)sleep(timo);
 124                         timo *= 2;
 125                         continue;
 126                 }
 127                 if (hp->h_addr_list[1] != NULL) {
 128                         int oerrno = errno;
 129
 130                         (void)fprintf(stderr, _("connect to address %s: "),
 131                             inet_ntoa(sin.sin_addr));
 132                         __set_errno (oerrno);
 133                         perror(0);
 134                         hp->h_addr_list++;
 135                         bcopy(hp->h_addr_list[0], &sin.sin_addr,
 136                               MIN (sizeof (sin.sin_addr), hp->h_length));
 137                         (void)fprintf(stderr, _("Trying %s...\n"),
 138                             inet_ntoa(sin.sin_addr));
 139                         continue;
 140                 }
 141                 (void)fprintf(stderr, "%s: %m\n", hp->h_name);
 142                 sigsetmask(oldmask);
 143                 return -1;
 144         }
 145         lport--;
 146         if (fd2p == 0) {
 147                 write(s, "", 1);
 148                 lport = 0;
 149         } else {
 150                 char num[8];
 151                 int s2 = rresvport(&lport), s3;
 152                 size_t len = sizeof(from);
 153
 154                 if (s2 < 0)
 155                         goto bad;
 156                 listen(s2, 1);
 157                 (void)snprintf(num, sizeof(num), "%d", lport);
 158                 if (write(s, num, strlen(num)+1) != strlen(num)+1) {
 159                         (void)fprintf(stderr,
 160                             _("rcmd: write (setting up stderr): %m\n"));
 161                         (void)close(s2);
 162                         goto bad;
 163                 }
 164                 FD_ZERO(&reads);
 165                 FD_SET(s, &reads);
 166                 FD_SET(s2, &reads);
 167                 __set_errno (0);
 168                 if (select(1 + (s > s2 ? s : s2), &reads, 0, 0, 0) < 1 ||
 169                     !FD_ISSET(s2, &reads)) {
 170                         if (errno != 0)
 171                                 (void)fprintf(stderr,
 172                                   _("rcmd: select (setting up stderr): %m\n"));
 173                         else
 174                                 (void)fprintf(stderr,
 175                              _("select: protocol failure in circuit setup\n"));
 176                         (void)close(s2);
 177                         goto bad;
 178                 }
 179                 s3 = accept(s2, (struct sockaddr *)&from, &len);
 180                 (void)close(s2);
 181                 if (s3 < 0) {
 182                         (void)fprintf(stderr,
 183                             "rcmd: accept: %m\n");
 184                         lport = 0;
 185                         goto bad;
 186                 }
 187                 *fd2p = s3;
 188                 from.sin_port = ntohs((u_short)from.sin_port);
 189                 if (from.sin_family != AF_INET ||
 190                     from.sin_port >= IPPORT_RESERVED ||
 191                     from.sin_port < IPPORT_RESERVED / 2) {
 192                         (void)fprintf(stderr,
 193                             _("socket: protocol failure in circuit setup\n"));
 194                         goto bad2;
 195                 }
 196         }
 197         (void)write(s, locuser, strlen(locuser)+1);
 198         (void)write(s, remuser, strlen(remuser)+1);
 199         (void)write(s, cmd, strlen(cmd)+1);
 200         if (read(s, &c, 1) != 1) {
 201                 (void)fprintf(stderr,
 202                     "rcmd: %s: %m\n", *ahost);
 203                 goto bad2;
 204         }
 205         if (c != 0) {
 206                 while (read(s, &c, 1) == 1) {
 207                         (void)write(STDERR_FILENO, &c, 1);
 208                         if (c == '\n')
 209                                 break;
 210                 }
 211                 goto bad2;
 212         }
 213         sigsetmask(oldmask);
 214         return s;
 215 bad2:
 216         if (lport)
 217                 (void)close(*fd2p);
 218 bad:
 219         (void)close(s);
 220         sigsetmask(oldmask);
 221         return -1;
 222 }
 223
 224 int
 225 rresvport(alport)
 226         int *alport;
 227 {
 228         struct sockaddr_in sin;
 229         int s;
 230
 231         sin.sin_family = AF_INET;
 232         sin.sin_addr.s_addr = INADDR_ANY;
 233         s = socket(AF_INET, SOCK_STREAM, 0);
 234         if (s < 0)
 235                 return -1;
 236         for (;;) {
 237                 sin.sin_port = htons((u_short)*alport);
 238                 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 239                         return s;
 240                 if (errno != EADDRINUSE) {
 241                         (void)close(s);
 242                         return -1;
 243                 }
 244                 (*alport)--;
 245                 if (*alport == IPPORT_RESERVED/2) {
 246                         (void)close(s);
 247                         __set_errno (EAGAIN);           /* close */
 248                         return -1;
 249                 }
 250         }
 251 }
 252
 253 int     __check_rhosts_file = 1;
 254 char    *__rcmd_errstr;
 255
 256 int
 257 ruserok(rhost, superuser, ruser, luser)
 258         const char *rhost, *ruser, *luser;
 259         int superuser;
 260 {
 261         struct hostent hostbuf, *hp;
 262         size_t buflen;
 263         char *buffer;
 264         u_int32_t addr;
 265         char **ap;
 266         int herr;
 267
 268         buflen = 1024;
 269         buffer = __alloca (buflen);
 270
 271         while (__gethostbyname_r (rhost, &hostbuf, buffer, buflen, &hp, &herr)
 272                < 0)
 273           if (herr != NETDB_INTERNAL || errno != ERANGE)
 274             return -1;
 275           else
 276             {
 277               /* Enlarge the buffer.  */
 278               buflen *= 2;
 279               buffer = __alloca (buflen);
 280             }
 281
 282         for (ap = hp->h_addr_list; *ap; ++ap) {
 283                 bcopy(*ap, &addr, sizeof(addr));
 284                 if (iruserok(addr, superuser, ruser, luser) == 0)
 285                         return 0;
 286         }
 287         return -1;
 288 }
 289
 290 /*
 291  * New .rhosts strategy: We are passed an ip address. We spin through
 292  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 293  * has ip addresses, we don't have to trust a nameserver.  When it
 294  * contains hostnames, we spin through the list of addresses the nameserver
 295  * gives us and look for a match.
 296  *
 297  * Returns 0 if ok, -1 if not ok.
 298  */
 299 int
 300 iruserok(raddr, superuser, ruser, luser)
 301         u_int32_t raddr;
 302         int superuser;
 303         const char *ruser, *luser;
 304 {
 305         register char *cp;
 306         struct stat sbuf;
 307         struct passwd pwdbuf, *pwd;
 308         FILE *hostf;
 309         int first;
 310
 311         first = 1;
 312         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 313 again:
 314         if (hostf) {
 315                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 316                         (void)fclose(hostf);
 317                         return 0;
 318                 }
 319                 (void)fclose(hostf);
 320         }
 321         if (first == 1 && (__check_rhosts_file || superuser)) {
 322                 char *pbuf;
 323                 size_t dirlen;
 324                 size_t buflen = __sysconf (_SC_GETPW_R_SIZE_MAX);
 325                 char *buffer = __alloca (buflen);
 326
 327                 first = 0;
 328                 if (__getpwnam_r (luser, &pwdbuf, buffer, buflen, &pwd) < 0)
 329                         return -1;
 330
 331                 dirlen = strlen (pwd->pw_dir);
 332                 pbuf = alloca (dirlen + sizeof "/.rhosts");
 333                 memcpy (pbuf, pwd->pw_dir, dirlen);
 334                 memcpy (pbuf + dirlen, "/.rhosts", sizeof "/.rhosts");
 335
 336                 /*
 337                  * Change effective uid while opening .rhosts.  If root and
 338                  * reading an NFS mounted file system, can't read files that
 339                  * are protected read/write owner only.
 340                  */
 341                 if (__access (pbuf, R_OK) != 0)
 342                   hostf = NULL;
 343                 else
 344                   {
 345                     uid_t uid = geteuid ();
 346                     seteuid (pwd->pw_uid);
 347                     hostf = fopen (pbuf, "r");
 348                     seteuid (uid);
 349                   }
 350
 351                 if (hostf == NULL)
 352                         return -1;
 353                 /*
 354                  * If not a regular file, or is owned by someone other than
 355                  * user or root or if writeable by anyone but the owner, quit.
 356                  */
 357                 cp = NULL;
 358                 if (lstat(pbuf, &sbuf) < 0)
 359                         cp = _(".rhosts lstat failed");
 360                 else if (!S_ISREG(sbuf.st_mode))
 361                         cp = _(".rhosts not regular file");
 362                 else if (fstat(fileno(hostf), &sbuf) < 0)
 363                         cp = _(".rhosts fstat failed");
 364                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 365                         cp = _("bad .rhosts owner");
 366                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 367                         cp = _(".rhosts writeable by other than owner");
 368                 /* If there were any problems, quit. */
 369                 if (cp) {
 370                         __rcmd_errstr = cp;
 371                         (void)fclose(hostf);
 372                         return -1;
 373                 }
 374                 goto again;
 375         }
 376         return -1;
 377 }
 378
 379 /*
 380  * XXX
 381  * Don't make static, used by lpd(8).
 382  *
 383  * Returns 0 if ok, -1 if not ok.
 384  */
 385 int
 386 __ivaliduser(hostf, raddr, luser, ruser)
 387         FILE *hostf;
 388         u_int32_t raddr;
 389         const char *luser, *ruser;
 390 {
 391         register char *user, *p;
 392         int ch;
 393         char *buf = NULL;
 394         size_t bufsize = 0;
 395         ssize_t nread;
 396
 397         while ((nread = __getline (&buf, &bufsize, hostf)) > 0) {
 398                 buf[bufsize - 1] = '\0'; /* Make sure it's terminated.  */
 399                 p = buf;
 400                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 401                         *p = isupper(*p) ? tolower(*p) : *p;
 402                         p++;
 403                 }
 404                 if (*p == ' ' || *p == '\t') {
 405                         *p++ = '\0';
 406                         while (*p == ' ' || *p == '\t')
 407                                 p++;
 408                         user = p;
 409                         while (*p != '\n' && *p != ' ' &&
 410                             *p != '\t' && *p != '\0')
 411                                 p++;
 412                 } else
 413                         user = p;
 414                 *p = '\0';
 415                 if (__icheckhost(raddr, buf) &&
 416                     strcmp(ruser, *user ? user : luser) == 0) {
 417                         free (buf);
 418                         return 0;
 419                 }
 420         }
 421         free (buf);
 422         return -1;
 423 }
 424
 425 /*
 426  * Returns "true" if match, 0 if no match.
 427  */
 428 static int
 429 internal_function
 430 __icheckhost(raddr, lhost)
 431         u_int32_t raddr;
 432         register char *lhost;
 433 {
 434         struct hostent hostbuf, *hp;
 435         size_t buflen;
 436         char *buffer;
 437         register u_int32_t laddr;
 438         register char **pp;
 439         int herr;
 440
 441         /* Try for raw ip address first. */
 442         if (isdigit(*lhost) && (int32_t)(laddr = inet_addr(lhost)) != -1)
 443                 return raddr == laddr;
 444
 445         /* Better be a hostname. */
 446         buflen = 1024;
 447         buffer = __alloca (buflen);
 448         while (__gethostbyname_r (lhost, &hostbuf, buffer, buflen, &hp, &herr)
 449                < 0)
 450           if (herr != NETDB_INTERNAL || errno != ERANGE)
 451             return 0;
 452           else
 453             {
 454               /* Enlarge the buffer.  */
 455               buflen *= 2;
 456               buffer = __alloca (buflen);
 457             }
 458
 459         /* Spin through ip addresses. */
 460         for (pp = hp->h_addr_list; *pp; ++pp)
 461                 if (!bcmp(&raddr, *pp, sizeof(u_int32_t)))
 462                         return 1;
 463
 464         /* No match. */
 465         return 0;
 466 }