gen/rcmd.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1983, 1993, 1994
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58 #if defined(LIBC_SCCS) && !defined(lint)
  59 static char sccsid[] = "@(#)rcmd.c      8.3 (Berkeley) 3/26/94";
  60 #endif /* LIBC_SCCS and not lint */
  61
  62 #include <sys/param.h>
  63 #include <sys/socket.h>
  64 #include <sys/stat.h>
  65
  66 #include <netinet/in.h>
  67 #include <arpa/inet.h>
  68
  69 #include <signal.h>
  70 #include <fcntl.h>
  71 #include <netdb.h>
  72 #include <unistd.h>
  73 #include <pwd.h>
  74 #include <errno.h>
  75 #include <stdio.h>
  76 #include <ctype.h>
  77 #include <string.h>
  78
  79 int     __ivaliduser __P((FILE *, u_long, const char *, const char *));
  80 static int __icheckhost __P((u_long, char *));
  81
  82 int
  83 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
  84         char **ahost;
  85         u_short rport;
  86         const char *locuser, *remuser, *cmd;
  87         int *fd2p;
  88 {
  89         struct hostent *hp;
  90         struct sockaddr_in sin, from;
  91         fd_set reads;
  92         long oldmask;
  93         pid_t pid;
  94         int s, lport, timo;
  95         char c;
  96
  97         pid = getpid();
  98         hp = gethostbyname(*ahost);
  99         if (hp == NULL) {
 100                 herror(*ahost);
 101                 return (-1);
 102         }
 103         *ahost = hp->h_name;
 104         oldmask = sigblock(sigmask(SIGURG));
 105         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
 106                 s = rresvport(&lport);
 107                 if (s < 0) {
 108                         if (errno == EAGAIN)
 109                                 (void)fprintf(stderr,
 110                                     "rcmd: socket: All ports in use\n");
 111                         else
 112                                 (void)fprintf(stderr, "rcmd: socket: %s\n",
 113                                     strerror(errno));
 114                         sigsetmask(oldmask);
 115                         return (-1);
 116                 }
 117                 fcntl(s, F_SETOWN, pid);
 118                 sin.sin_family = hp->h_addrtype;
 119                 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
 120                 sin.sin_port = rport;
 121                 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 122                         break;
 123                 (void)close(s);
 124                 if (errno == EADDRINUSE) {
 125                         lport--;
 126                         continue;
 127                 }
 128                 if (errno == ECONNREFUSED && timo <= 16) {
 129                         (void)sleep(timo);
 130                         timo *= 2;
 131                         continue;
 132                 }
 133                 if (hp->h_addr_list[1] != NULL) {
 134                         int oerrno = errno;
 135
 136                         (void)fprintf(stderr, "connect to address %s: ",
 137                             inet_ntoa(sin.sin_addr));
 138                         errno = oerrno;
 139                         perror(0);
 140                         hp->h_addr_list++;
 141                         bcopy(hp->h_addr_list[0], &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: %s\n", hp->h_name, strerror(errno));
 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                 int 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): %s\n",
 166                             strerror(errno));
 167                         (void)close(s2);
 168                         goto bad;
 169                 }
 170                 FD_ZERO(&reads);
 171                 FD_SET(s, &reads);
 172                 FD_SET(s2, &reads);
 173                 errno = 0;
 174                 if (select(32, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)) {
 175                         if (errno != 0)
 176                                 (void)fprintf(stderr,
 177                                     "rcmd: select (setting up stderr): %s\n",
 178                                     strerror(errno));
 179                         else
 180                                 (void)fprintf(stderr,
 181                                 "select: protocol failure in circuit setup\n");
 182                         (void)close(s2);
 183                         goto bad;
 184                 }
 185                 s3 = accept(s2, (struct sockaddr *)&from, &len);
 186                 (void)close(s2);
 187                 if (s3 < 0) {
 188                         (void)fprintf(stderr,
 189                             "rcmd: accept: %s\n", strerror(errno));
 190                         lport = 0;
 191                         goto bad;
 192                 }
 193                 *fd2p = s3;
 194                 from.sin_port = ntohs((u_short)from.sin_port);
 195                 if (from.sin_family != AF_INET ||
 196                     from.sin_port >= IPPORT_RESERVED ||
 197                     from.sin_port < IPPORT_RESERVED / 2) {
 198                         (void)fprintf(stderr,
 199                             "socket: protocol failure in circuit setup.\n");
 200                         goto bad2;
 201                 }
 202         }
 203         (void)write(s, locuser, strlen(locuser)+1);
 204         (void)write(s, remuser, strlen(remuser)+1);
 205         (void)write(s, cmd, strlen(cmd)+1);
 206         if (read(s, &c, 1) != 1) {
 207                 (void)fprintf(stderr,
 208                     "rcmd: %s: %s\n", *ahost, strerror(errno));
 209                 goto bad2;
 210         }
 211         if (c != 0) {
 212                 while (read(s, &c, 1) == 1) {
 213                         (void)write(STDERR_FILENO, &c, 1);
 214                         if (c == '\n')
 215                                 break;
 216                 }
 217                 goto bad2;
 218         }
 219         sigsetmask(oldmask);
 220         return (s);
 221 bad2:
 222         if (lport)
 223                 (void)close(*fd2p);
 224 bad:
 225         (void)close(s);
 226         sigsetmask(oldmask);
 227         return (-1);
 228 }
 229
 230 int
 231 rresvport(alport)
 232         int *alport;
 233 {
 234         struct sockaddr_in sin;
 235         int s;
 236
 237         sin.sin_family = AF_INET;
 238         sin.sin_addr.s_addr = INADDR_ANY;
 239         s = socket(AF_INET, SOCK_STREAM, 0);
 240         if (s < 0)
 241                 return (-1);
 242         for (;;) {
 243                 sin.sin_port = htons((u_short)*alport);
 244                 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 245                         return (s);
 246                 if (errno != EADDRINUSE) {
 247                         (void)close(s);
 248                         return (-1);
 249                 }
 250                 (*alport)--;
 251                 if (*alport == IPPORT_RESERVED/2) {
 252                         (void)close(s);
 253                         errno = EAGAIN;         /* close */
 254                         return (-1);
 255                 }
 256         }
 257 }
 258
 259 int     __check_rhosts_file = 1;
 260 char    *__rcmd_errstr;
 261
 262 int
 263 ruserok(rhost, superuser, ruser, luser)
 264         const char *rhost, *ruser, *luser;
 265         int superuser;
 266 {
 267         struct hostent *hp;
 268         u_long addr;
 269         char **ap;
 270
 271         if ((hp = gethostbyname(rhost)) == NULL)
 272                 return (-1);
 273         for (ap = hp->h_addr_list; *ap; ++ap) {
 274                 bcopy(*ap, &addr, sizeof(addr));
 275                 if (iruserok(addr, superuser, ruser, luser) == 0)
 276                         return (0);
 277         }
 278         return (-1);
 279 }
 280
 281 /*
 282  * New .rhosts strategy: We are passed an ip address. We spin through
 283  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 284  * has ip addresses, we don't have to trust a nameserver.  When it
 285  * contains hostnames, we spin through the list of addresses the nameserver
 286  * gives us and look for a match.
 287  *
 288  * Returns 0 if ok, -1 if not ok.
 289  */
 290 int
 291 iruserok(raddr, superuser, ruser, luser)
 292         u_long raddr;
 293         int superuser;
 294         const char *ruser, *luser;
 295 {
 296         register char *cp;
 297         struct stat sbuf;
 298         struct passwd *pwd;
 299         FILE *hostf;
 300         uid_t uid;
 301         int first;
 302         char pbuf[MAXPATHLEN];
 303
 304         first = 1;
 305         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 306 again:
 307         if (hostf) {
 308                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 309                         (void)fclose(hostf);
 310                         return (0);
 311                 }
 312                 (void)fclose(hostf);
 313         }
 314         if (first == 1 && (__check_rhosts_file || superuser)) {
 315                 first = 0;
 316                 if ((pwd = getpwnam(luser)) == NULL)
 317                         return (-1);
 318                 (void)strcpy(pbuf, pwd->pw_dir);
 319                 (void)strcat(pbuf, "/.rhosts");
 320
 321                 /*
 322                  * Change effective uid while opening .rhosts.  If root and
 323                  * reading an NFS mounted file system, can't read files that
 324                  * are protected read/write owner only.
 325                  */
 326                 uid = geteuid();
 327                 (void)seteuid(pwd->pw_uid);
 328                 hostf = fopen(pbuf, "r");
 329                 (void)seteuid(uid);
 330
 331                 if (hostf == NULL)
 332                         return (-1);
 333                 /*
 334                  * If not a regular file, or is owned by someone other than
 335                  * user or root or if writeable by anyone but the owner, quit.
 336                  */
 337                 cp = NULL;
 338                 if (lstat(pbuf, &sbuf) < 0)
 339                         cp = ".rhosts lstat failed";
 340                 else if (!S_ISREG(sbuf.st_mode))
 341                         cp = ".rhosts not regular file";
 342                 else if (fstat(fileno(hostf), &sbuf) < 0)
 343                         cp = ".rhosts fstat failed";
 344                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 345                         cp = "bad .rhosts owner";
 346                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 347                         cp = ".rhosts writeable by other than owner";
 348                 /* If there were any problems, quit. */
 349                 if (cp) {
 350                         __rcmd_errstr = cp;
 351                         (void)fclose(hostf);
 352                         return (-1);
 353                 }
 354                 goto again;
 355         }
 356         return (-1);
 357 }
 358
 359 /*
 360  * XXX
 361  * Don't make static, used by lpd(8).
 362  *
 363  * Returns 0 if ok, -1 if not ok.
 364  */
 365 int
 366 __ivaliduser(hostf, raddr, luser, ruser)
 367         FILE *hostf;
 368         u_long raddr;
 369         const char *luser, *ruser;
 370 {
 371         register char *user, *p;
 372         int ch;
 373         char buf[MAXHOSTNAMELEN + 128];         /* host + login */
 374
 375         while (fgets(buf, sizeof(buf), hostf)) {
 376                 p = buf;
 377                 /* Skip lines that are too long. */
 378                 if (strchr(p, '\n') == NULL) {
 379                         while ((ch = getc(hostf)) != '\n' && ch != EOF);
 380                         continue;
 381                 }
 382                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 383                         *p = isupper(*p) ? tolower(*p) : *p;
 384                         p++;
 385                 }
 386                 if (*p == ' ' || *p == '\t') {
 387                         *p++ = '\0';
 388                         while (*p == ' ' || *p == '\t')
 389                                 p++;
 390                         user = p;
 391                         while (*p != '\n' && *p != ' ' &&
 392                             *p != '\t' && *p != '\0')
 393                                 p++;
 394                 } else
 395                         user = p;
 396                 *p = '\0';
 397                 if (__icheckhost(raddr, buf) &&
 398                     strcmp(ruser, *user ? user : luser) == 0) {
 399                         return (0);
 400                 }
 401         }
 402         return (-1);
 403 }
 404
 405 /*
 406  * Returns "true" if match, 0 if no match.
 407  */
 408 static int
 409 __icheckhost(raddr, lhost)
 410         u_long raddr;
 411         register char *lhost;
 412 {
 413         register struct hostent *hp;
 414         register u_long laddr;
 415         register char **pp;
 416
 417         /* Try for raw ip address first. */
 418         if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1)
 419                 return (raddr == laddr);
 420
 421         /* Better be a hostname. */
 422         if ((hp = gethostbyname(lhost)) == NULL)
 423                 return (0);
 424
 425         /* Spin through ip addresses. */
 426         for (pp = hp->h_addr_list; *pp; ++pp)
 427                 if (!bcmp(&raddr, *pp, sizeof(u_long)))
 428                         return (1);
 429
 430         /* No match. */
 431         return (0);
 432 }