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