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 <signal.h>
  46 #include <fcntl.h>
  47 #include <netdb.h>
  48 #include <unistd.h>
  49 #include <pwd.h>
  50 #include <errno.h>
  51 #include <stdio.h>
  52 #include <ctype.h>
  53 #include <string.h>
  54
  55 int     __ivaliduser __P((FILE *, u_long, const char *, const char *));
  56 static int __icheckhost __P((u_long, char *));
  57
  58 int
  59 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
  60         char **ahost;
  61         u_short rport;
  62         const char *locuser, *remuser, *cmd;
  63         int *fd2p;
  64 {
  65         struct hostent *hp;
  66         struct sockaddr_in sin, from;
  67         fd_set reads;
  68         long oldmask;
  69         pid_t pid;
  70         int s, lport, timo;
  71         char c;
  72
  73         pid = getpid();
  74         hp = gethostbyname(*ahost);
  75         if (hp == NULL) {
  76                 herror(*ahost);
  77                 return (-1);
  78         }
  79         *ahost = hp->h_name;
  80         oldmask = sigblock(sigmask(SIGURG));
  81         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
  82                 s = rresvport(&lport);
  83                 if (s < 0) {
  84                         if (errno == EAGAIN)
  85                                 (void)fprintf(stderr,
  86                                     _("rcmd: socket: All ports in use\n"));
  87                         else
  88                                 (void)fprintf(stderr, "rcmd: socket: %s\n",
  89                                     strerror(errno));
  90                         sigsetmask(oldmask);
  91                         return (-1);
  92                 }
  93                 fcntl(s, F_SETOWN, pid);
  94                 sin.sin_family = hp->h_addrtype;
  95                 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
  96                 sin.sin_port = rport;
  97                 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
  98                         break;
  99                 (void)close(s);
 100                 if (errno == EADDRINUSE) {
 101                         lport--;
 102                         continue;
 103                 }
 104                 if (errno == ECONNREFUSED && timo <= 16) {
 105                         (void)sleep(timo);
 106                         timo *= 2;
 107                         continue;
 108                 }
 109                 if (hp->h_addr_list[1] != NULL) {
 110                         int oerrno = errno;
 111
 112                         (void)fprintf(stderr, _("connect to address %s: "),
 113                             inet_ntoa(sin.sin_addr));
 114                         errno = oerrno;
 115                         perror(0);
 116                         hp->h_addr_list++;
 117                         bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
 118                         (void)fprintf(stderr, _("Trying %s...\n"),
 119                             inet_ntoa(sin.sin_addr));
 120                         continue;
 121                 }
 122                 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
 123                 sigsetmask(oldmask);
 124                 return (-1);
 125         }
 126         lport--;
 127         if (fd2p == 0) {
 128                 write(s, "", 1);
 129                 lport = 0;
 130         } else {
 131                 char num[8];
 132                 int s2 = rresvport(&lport), s3;
 133                 int len = sizeof(from);
 134
 135                 if (s2 < 0)
 136                         goto bad;
 137                 listen(s2, 1);
 138                 (void)snprintf(num, sizeof(num), "%d", lport);
 139                 if (write(s, num, strlen(num)+1) != strlen(num)+1) {
 140                         (void)fprintf(stderr,
 141                             _("rcmd: write (setting up stderr): %s\n"),
 142                             strerror(errno));
 143                         (void)close(s2);
 144                         goto bad;
 145                 }
 146                 FD_ZERO(&reads);
 147                 FD_SET(s, &reads);
 148                 FD_SET(s2, &reads);
 149                 errno = 0;
 150                 if (select(1 + (s > s2 ? s : s2), &reads, 0, 0, 0) < 1 ||
 151                     !FD_ISSET(s2, &reads)) {
 152                         if (errno != 0)
 153                                 (void)fprintf(stderr,
 154                                    _("rcmd: select (setting up stderr): %s\n"),
 155                                    strerror(errno));
 156                         else
 157                                 (void)fprintf(stderr,
 158                              _("select: protocol failure in circuit setup\n"));
 159                         (void)close(s2);
 160                         goto bad;
 161                 }
 162                 s3 = accept(s2, (struct sockaddr *)&from, &len);
 163                 (void)close(s2);
 164                 if (s3 < 0) {
 165                         (void)fprintf(stderr,
 166                             "rcmd: accept: %s\n", strerror(errno));
 167                         lport = 0;
 168                         goto bad;
 169                 }
 170                 *fd2p = s3;
 171                 from.sin_port = ntohs((u_short)from.sin_port);
 172                 if (from.sin_family != AF_INET ||
 173                     from.sin_port >= IPPORT_RESERVED ||
 174                     from.sin_port < IPPORT_RESERVED / 2) {
 175                         (void)fprintf(stderr,
 176                             _("socket: protocol failure in circuit setup.\n"));
 177                         goto bad2;
 178                 }
 179         }
 180         (void)write(s, locuser, strlen(locuser)+1);
 181         (void)write(s, remuser, strlen(remuser)+1);
 182         (void)write(s, cmd, strlen(cmd)+1);
 183         if (read(s, &c, 1) != 1) {
 184                 (void)fprintf(stderr,
 185                     "rcmd: %s: %s\n", *ahost, strerror(errno));
 186                 goto bad2;
 187         }
 188         if (c != 0) {
 189                 while (read(s, &c, 1) == 1) {
 190                         (void)write(STDERR_FILENO, &c, 1);
 191                         if (c == '\n')
 192                                 break;
 193                 }
 194                 goto bad2;
 195         }
 196         sigsetmask(oldmask);
 197         return (s);
 198 bad2:
 199         if (lport)
 200                 (void)close(*fd2p);
 201 bad:
 202         (void)close(s);
 203         sigsetmask(oldmask);
 204         return (-1);
 205 }
 206
 207 int
 208 rresvport(alport)
 209         int *alport;
 210 {
 211         struct sockaddr_in sin;
 212         int s;
 213
 214         sin.sin_family = AF_INET;
 215         sin.sin_addr.s_addr = INADDR_ANY;
 216         s = socket(AF_INET, SOCK_STREAM, 0);
 217         if (s < 0)
 218                 return (-1);
 219         for (;;) {
 220                 sin.sin_port = htons((u_short)*alport);
 221                 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 222                         return (s);
 223                 if (errno != EADDRINUSE) {
 224                         (void)close(s);
 225                         return (-1);
 226                 }
 227                 (*alport)--;
 228                 if (*alport == IPPORT_RESERVED/2) {
 229                         (void)close(s);
 230                         errno = EAGAIN;         /* close */
 231                         return (-1);
 232                 }
 233         }
 234 }
 235
 236 int     __check_rhosts_file = 1;
 237 char    *__rcmd_errstr;
 238
 239 int
 240 ruserok(rhost, superuser, ruser, luser)
 241         const char *rhost, *ruser, *luser;
 242         int superuser;
 243 {
 244         struct hostent *hp;
 245         u_long addr;
 246         char **ap;
 247
 248         if ((hp = gethostbyname(rhost)) == NULL)
 249                 return (-1);
 250         for (ap = hp->h_addr_list; *ap; ++ap) {
 251                 bcopy(*ap, &addr, sizeof(addr));
 252                 if (iruserok(addr, superuser, ruser, luser) == 0)
 253                         return (0);
 254         }
 255         return (-1);
 256 }
 257
 258 /*
 259  * New .rhosts strategy: We are passed an ip address. We spin through
 260  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 261  * has ip addresses, we don't have to trust a nameserver.  When it
 262  * contains hostnames, we spin through the list of addresses the nameserver
 263  * gives us and look for a match.
 264  *
 265  * Returns 0 if ok, -1 if not ok.
 266  */
 267 int
 268 iruserok(raddr, superuser, ruser, luser)
 269         u_long raddr;
 270         int superuser;
 271         const char *ruser, *luser;
 272 {
 273         register char *cp;
 274         struct stat sbuf;
 275         struct passwd *pwd;
 276         FILE *hostf;
 277         uid_t uid;
 278         int first;
 279
 280         first = 1;
 281         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 282 again:
 283         if (hostf) {
 284                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 285                         (void)fclose(hostf);
 286                         return (0);
 287                 }
 288                 (void)fclose(hostf);
 289         }
 290         if (first == 1 && (__check_rhosts_file || superuser)) {
 291                 char *pbuf;
 292                 size_t dirlen;
 293
 294                 first = 0;
 295                 if ((pwd = getpwnam(luser)) == NULL)
 296                         return (-1);
 297
 298                 dirlen = strlen (pwd->pw_dir);
 299                 pbuf = alloca (dirlen + sizeof "/.rhosts");
 300                 memcpy (pbuf, pwd->pw_dir, dirlen);
 301                 memcpy (pbuf + dirlen, "/.rhosts", sizeof "/.rhosts");
 302
 303                 /*
 304                  * Change effective uid while opening .rhosts.  If root and
 305                  * reading an NFS mounted file system, can't read files that
 306                  * are protected read/write owner only.
 307                  */
 308                 uid = geteuid();
 309                 (void)seteuid(pwd->pw_uid);
 310                 hostf = fopen(pbuf, "r");
 311                 (void)seteuid(uid);
 312
 313                 if (hostf == NULL)
 314                         return (-1);
 315                 /*
 316                  * If not a regular file, or is owned by someone other than
 317                  * user or root or if writeable by anyone but the owner, quit.
 318                  */
 319                 cp = NULL;
 320                 if (lstat(pbuf, &sbuf) < 0)
 321                         cp = _(".rhosts lstat failed");
 322                 else if (!S_ISREG(sbuf.st_mode))
 323                         cp = _(".rhosts not regular file");
 324                 else if (fstat(fileno(hostf), &sbuf) < 0)
 325                         cp = _(".rhosts fstat failed");
 326                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 327                         cp = _("bad .rhosts owner");
 328                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 329                         cp = _(".rhosts writeable by other than owner");
 330                 /* If there were any problems, quit. */
 331                 if (cp) {
 332                         __rcmd_errstr = cp;
 333                         (void)fclose(hostf);
 334                         return (-1);
 335                 }
 336                 goto again;
 337         }
 338         return (-1);
 339 }
 340
 341 /*
 342  * XXX
 343  * Don't make static, used by lpd(8).
 344  *
 345  * Returns 0 if ok, -1 if not ok.
 346  */
 347 int
 348 __ivaliduser(hostf, raddr, luser, ruser)
 349         FILE *hostf;
 350         u_long raddr;
 351         const char *luser, *ruser;
 352 {
 353         register char *user, *p;
 354         int ch;
 355         char *buf = NULL;
 356         size_t bufsize = 0;
 357         ssize_t nread;
 358
 359         while ((nread = getline (&buf, &bufsize, hostf)) > 0) {
 360                 buf[bufsize - 1] = '\0'; /* Make sure it's terminated.  */
 361                 p = buf;
 362                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 363                         *p = isupper(*p) ? tolower(*p) : *p;
 364                         p++;
 365                 }
 366                 if (*p == ' ' || *p == '\t') {
 367                         *p++ = '\0';
 368                         while (*p == ' ' || *p == '\t')
 369                                 p++;
 370                         user = p;
 371                         while (*p != '\n' && *p != ' ' &&
 372                             *p != '\t' && *p != '\0')
 373                                 p++;
 374                 } else
 375                         user = p;
 376                 *p = '\0';
 377                 if (__icheckhost(raddr, buf) &&
 378                     strcmp(ruser, *user ? user : luser) == 0) {
 379                         free (buf);
 380                         return (0);
 381                 }
 382         }
 383         free (buf);
 384         return (-1);
 385 }
 386
 387 /*
 388  * Returns "true" if match, 0 if no match.
 389  */
 390 static int
 391 __icheckhost(raddr, lhost)
 392         u_long raddr;
 393         register char *lhost;
 394 {
 395         register struct hostent *hp;
 396         register u_long laddr;
 397         register char **pp;
 398
 399         /* Try for raw ip address first. */
 400         if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1)
 401                 return (raddr == laddr);
 402
 403         /* Better be a hostname. */
 404         if ((hp = gethostbyname(lhost)) == NULL)
 405                 return (0);
 406
 407         /* Spin through ip addresses. */
 408         for (pp = hp->h_addr_list; *pp; ++pp)
 409                 if (!bcmp(&raddr, *pp, sizeof(u_long)))
 410                         return (1);
 411
 412         /* No match. */
 413         return (0);
 414 }