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
  56 int     __ivaliduser __P((FILE *, u_int32_t, const char *, const char *));
  57 static int __icheckhost __P((u_int32_t, char *));
  58
  59 int
  60 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
  61         char **ahost;
  62         u_short rport;
  63         const char *locuser, *remuser, *cmd;
  64         int *fd2p;
  65 {
  66         struct hostent *hp;
  67         struct sockaddr_in sin, from;
  68         fd_set reads;
  69         int32_t oldmask;
  70         pid_t pid;
  71         int s, lport, timo;
  72         char c;
  73
  74         pid = getpid();
  75         hp = gethostbyname(*ahost);
  76         if (hp == NULL) {
  77                 herror(*ahost);
  78                 return (-1);
  79         }
  80         *ahost = hp->h_name;
  81         oldmask = sigblock(sigmask(SIGURG));
  82         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
  83                 s = rresvport(&lport);
  84                 if (s < 0) {
  85                         if (errno == EAGAIN)
  86                                 (void)fprintf(stderr,
  87                                     _("rcmd: socket: All ports in use\n"));
  88                         else
  89                                 (void)fprintf(stderr, "rcmd: socket: %s\n",
  90                                     strerror(errno));
  91                         sigsetmask(oldmask);
  92                         return (-1);
  93                 }
  94                 fcntl(s, F_SETOWN, pid);
  95                 sin.sin_family = hp->h_addrtype;
  96                 bcopy(hp->h_addr_list[0], &sin.sin_addr,
  97                       MIN (sizeof (sin.sin_addr), hp->h_length));
  98                 sin.sin_port = rport;
  99                 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 100                         break;
 101                 (void)close(s);
 102                 if (errno == EADDRINUSE) {
 103                         lport--;
 104                         continue;
 105                 }
 106                 if (errno == ECONNREFUSED && timo <= 16) {
 107                         (void)sleep(timo);
 108                         timo *= 2;
 109                         continue;
 110                 }
 111                 if (hp->h_addr_list[1] != NULL) {
 112                         int oerrno = errno;
 113
 114                         (void)fprintf(stderr, _("connect to address %s: "),
 115                             inet_ntoa(sin.sin_addr));
 116                         __set_errno (oerrno);
 117                         perror(0);
 118                         hp->h_addr_list++;
 119                         bcopy(hp->h_addr_list[0], &sin.sin_addr,
 120                               MIN (sizeof (sin.sin_addr), hp->h_length));
 121                         (void)fprintf(stderr, _("Trying %s...\n"),
 122                             inet_ntoa(sin.sin_addr));
 123                         continue;
 124                 }
 125                 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
 126                 sigsetmask(oldmask);
 127                 return (-1);
 128         }
 129         lport--;
 130         if (fd2p == 0) {
 131                 write(s, "", 1);
 132                 lport = 0;
 133         } else {
 134                 char num[8];
 135                 int s2 = rresvport(&lport), s3;
 136                 int len = sizeof(from);
 137
 138                 if (s2 < 0)
 139                         goto bad;
 140                 listen(s2, 1);
 141                 (void)snprintf(num, sizeof(num), "%d", lport);
 142                 if (write(s, num, strlen(num)+1) != strlen(num)+1) {
 143                         (void)fprintf(stderr,
 144                             _("rcmd: write (setting up stderr): %s\n"),
 145                             strerror(errno));
 146                         (void)close(s2);
 147                         goto bad;
 148                 }
 149                 FD_ZERO(&reads);
 150                 FD_SET(s, &reads);
 151                 FD_SET(s2, &reads);
 152                 __set_errno (0);
 153                 if (select(1 + (s > s2 ? s : s2), &reads, 0, 0, 0) < 1 ||
 154                     !FD_ISSET(s2, &reads)) {
 155                         if (errno != 0)
 156                                 (void)fprintf(stderr,
 157                                    _("rcmd: select (setting up stderr): %s\n"),
 158                                    strerror(errno));
 159                         else
 160                                 (void)fprintf(stderr,
 161                              _("select: protocol failure in circuit setup\n"));
 162                         (void)close(s2);
 163                         goto bad;
 164                 }
 165                 s3 = accept(s2, (struct sockaddr *)&from, &len);
 166                 (void)close(s2);
 167                 if (s3 < 0) {
 168                         (void)fprintf(stderr,
 169                             "rcmd: accept: %s\n", strerror(errno));
 170                         lport = 0;
 171                         goto bad;
 172                 }
 173                 *fd2p = s3;
 174                 from.sin_port = ntohs((u_short)from.sin_port);
 175                 if (from.sin_family != AF_INET ||
 176                     from.sin_port >= IPPORT_RESERVED ||
 177                     from.sin_port < IPPORT_RESERVED / 2) {
 178                         (void)fprintf(stderr,
 179                             _("socket: protocol failure in circuit setup\n"));
 180                         goto bad2;
 181                 }
 182         }
 183         (void)write(s, locuser, strlen(locuser)+1);
 184         (void)write(s, remuser, strlen(remuser)+1);
 185         (void)write(s, cmd, strlen(cmd)+1);
 186         if (read(s, &c, 1) != 1) {
 187                 (void)fprintf(stderr,
 188                     "rcmd: %s: %s\n", *ahost, strerror(errno));
 189                 goto bad2;
 190         }
 191         if (c != 0) {
 192                 while (read(s, &c, 1) == 1) {
 193                         (void)write(STDERR_FILENO, &c, 1);
 194                         if (c == '\n')
 195                                 break;
 196                 }
 197                 goto bad2;
 198         }
 199         sigsetmask(oldmask);
 200         return (s);
 201 bad2:
 202         if (lport)
 203                 (void)close(*fd2p);
 204 bad:
 205         (void)close(s);
 206         sigsetmask(oldmask);
 207         return (-1);
 208 }
 209
 210 int
 211 rresvport(alport)
 212         int *alport;
 213 {
 214         struct sockaddr_in sin;
 215         int s;
 216
 217         sin.sin_family = AF_INET;
 218         sin.sin_addr.s_addr = INADDR_ANY;
 219         s = socket(AF_INET, SOCK_STREAM, 0);
 220         if (s < 0)
 221                 return (-1);
 222         for (;;) {
 223                 sin.sin_port = htons((u_short)*alport);
 224                 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 225                         return (s);
 226                 if (errno != EADDRINUSE) {
 227                         (void)close(s);
 228                         return (-1);
 229                 }
 230                 (*alport)--;
 231                 if (*alport == IPPORT_RESERVED/2) {
 232                         (void)close(s);
 233                         __set_errno (EAGAIN);           /* close */
 234                         return (-1);
 235                 }
 236         }
 237 }
 238
 239 int     __check_rhosts_file = 1;
 240 char    *__rcmd_errstr;
 241
 242 int
 243 ruserok(rhost, superuser, ruser, luser)
 244         const char *rhost, *ruser, *luser;
 245         int superuser;
 246 {
 247         struct hostent *hp;
 248         u_int32_t addr;
 249         char **ap;
 250
 251         if ((hp = gethostbyname(rhost)) == NULL)
 252                 return (-1);
 253         for (ap = hp->h_addr_list; *ap; ++ap) {
 254                 bcopy(*ap, &addr, sizeof(addr));
 255                 if (iruserok(addr, superuser, ruser, luser) == 0)
 256                         return (0);
 257         }
 258         return (-1);
 259 }
 260
 261 /*
 262  * New .rhosts strategy: We are passed an ip address. We spin through
 263  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 264  * has ip addresses, we don't have to trust a nameserver.  When it
 265  * contains hostnames, we spin through the list of addresses the nameserver
 266  * gives us and look for a match.
 267  *
 268  * Returns 0 if ok, -1 if not ok.
 269  */
 270 int
 271 iruserok(raddr, superuser, ruser, luser)
 272         u_int32_t raddr;
 273         int superuser;
 274         const char *ruser, *luser;
 275 {
 276         register char *cp;
 277         struct stat sbuf;
 278         struct passwd *pwd;
 279         FILE *hostf;
 280         uid_t uid;
 281         int first;
 282
 283         first = 1;
 284         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 285 again:
 286         if (hostf) {
 287                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 288                         (void)fclose(hostf);
 289                         return (0);
 290                 }
 291                 (void)fclose(hostf);
 292         }
 293         if (first == 1 && (__check_rhosts_file || superuser)) {
 294                 char *pbuf;
 295                 size_t dirlen;
 296
 297                 first = 0;
 298                 if ((pwd = getpwnam(luser)) == NULL)
 299                         return (-1);
 300
 301                 dirlen = strlen (pwd->pw_dir);
 302                 pbuf = alloca (dirlen + sizeof "/.rhosts");
 303                 memcpy (pbuf, pwd->pw_dir, dirlen);
 304                 memcpy (pbuf + dirlen, "/.rhosts", sizeof "/.rhosts");
 305
 306                 /*
 307                  * Change effective uid while opening .rhosts.  If root and
 308                  * reading an NFS mounted file system, can't read files that
 309                  * are protected read/write owner only.
 310                  */
 311                 uid = geteuid();
 312                 (void)seteuid(pwd->pw_uid);
 313                 hostf = fopen(pbuf, "r");
 314                 (void)seteuid(uid);
 315
 316                 if (hostf == NULL)
 317                         return (-1);
 318                 /*
 319                  * If not a regular file, or is owned by someone other than
 320                  * user or root or if writeable by anyone but the owner, quit.
 321                  */
 322                 cp = NULL;
 323                 if (lstat(pbuf, &sbuf) < 0)
 324                         cp = _(".rhosts lstat failed");
 325                 else if (!S_ISREG(sbuf.st_mode))
 326                         cp = _(".rhosts not regular file");
 327                 else if (fstat(fileno(hostf), &sbuf) < 0)
 328                         cp = _(".rhosts fstat failed");
 329                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 330                         cp = _("bad .rhosts owner");
 331                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 332                         cp = _(".rhosts writeable by other than owner");
 333                 /* If there were any problems, quit. */
 334                 if (cp) {
 335                         __rcmd_errstr = cp;
 336                         (void)fclose(hostf);
 337                         return (-1);
 338                 }
 339                 goto again;
 340         }
 341         return (-1);
 342 }
 343
 344 /*
 345  * XXX
 346  * Don't make static, used by lpd(8).
 347  *
 348  * Returns 0 if ok, -1 if not ok.
 349  */
 350 int
 351 __ivaliduser(hostf, raddr, luser, ruser)
 352         FILE *hostf;
 353         u_int32_t raddr;
 354         const char *luser, *ruser;
 355 {
 356         register char *user, *p;
 357         int ch;
 358         char *buf = NULL;
 359         size_t bufsize = 0;
 360         ssize_t nread;
 361
 362         while ((nread = getline (&buf, &bufsize, hostf)) > 0) {
 363                 buf[bufsize - 1] = '\0'; /* Make sure it's terminated.  */
 364                 p = buf;
 365                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 366                         *p = isupper(*p) ? tolower(*p) : *p;
 367                         p++;
 368                 }
 369                 if (*p == ' ' || *p == '\t') {
 370                         *p++ = '\0';
 371                         while (*p == ' ' || *p == '\t')
 372                                 p++;
 373                         user = p;
 374                         while (*p != '\n' && *p != ' ' &&
 375                             *p != '\t' && *p != '\0')
 376                                 p++;
 377                 } else
 378                         user = p;
 379                 *p = '\0';
 380                 if (__icheckhost(raddr, buf) &&
 381                     strcmp(ruser, *user ? user : luser) == 0) {
 382                         free (buf);
 383                         return (0);
 384                 }
 385         }
 386         free (buf);
 387         return (-1);
 388 }
 389
 390 /*
 391  * Returns "true" if match, 0 if no match.
 392  */
 393 static int
 394 __icheckhost(raddr, lhost)
 395         u_int32_t raddr;
 396         register char *lhost;
 397 {
 398         register struct hostent *hp;
 399         register u_int32_t laddr;
 400         register char **pp;
 401
 402         /* Try for raw ip address first. */
 403         if (isdigit(*lhost) && (int32_t)(laddr = inet_addr(lhost)) != -1)
 404                 return (raddr == laddr);
 405
 406         /* Better be a hostname. */
 407         if ((hp = gethostbyname(lhost)) == NULL)
 408                 return (0);
 409
 410         /* Spin through ip addresses. */
 411         for (pp = hp->h_addr_list; *pp; ++pp)
 412                 if (!bcmp(&raddr, *pp, sizeof(u_int32_t)))
 413                         return (1);
 414
 415         /* No match. */
 416         return (0);
 417 }