gen/rcmd.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1983, 1993, 1994
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55 #if defined(LIBC_SCCS) && !defined(lint)
  56 static char sccsid[] = "@(#)rcmd.c      8.3 (Berkeley) 3/26/94";
  57 #endif /* LIBC_SCCS and not lint */
  58
  59 #include <sys/param.h>
  60 #include <sys/socket.h>
  61 #include <sys/stat.h>
  62
  63 #include <netinet/in.h>
  64 #include <arpa/inet.h>
  65
  66 #include <signal.h>
  67 #include <fcntl.h>
  68 #include <netdb.h>
  69 #include <unistd.h>
  70 #include <pwd.h>
  71 #include <errno.h>
  72 #include <stdio.h>
  73 #include <ctype.h>
  74 #include <string.h>
  75
  76 int     __ivaliduser __P((FILE *, u_long, const char *, const char *));
  77 static int __icheckhost __P((u_long, char *));
  78
  79 int
  80 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
  81         char **ahost;
  82         u_short rport;
  83         const char *locuser, *remuser, *cmd;
  84         int *fd2p;
  85 {
  86         struct hostent *hp;
  87         struct sockaddr_in sin, from;
  88         fd_set reads;
  89         long oldmask;
  90         pid_t pid;
  91         int s, lport, timo;
  92         char c;
  93
  94         pid = getpid();
  95         hp = gethostbyname(*ahost);
  96         if (hp == NULL) {
  97                 herror(*ahost);
  98                 return (-1);
  99         }
 100         *ahost = hp->h_name;
 101         oldmask = sigblock(sigmask(SIGURG));
 102         for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
 103                 s = rresvport(&lport);
 104                 if (s < 0) {
 105                         if (errno == EAGAIN)
 106                                 (void)fprintf(stderr,
 107                                     "rcmd: socket: All ports in use\n");
 108                         else
 109                                 (void)fprintf(stderr, "rcmd: socket: %s\n",
 110                                     strerror(errno));
 111                         sigsetmask(oldmask);
 112                         return (-1);
 113                 }
 114                 fcntl(s, F_SETOWN, pid);
 115                 sin.sin_family = hp->h_addrtype;
 116                 bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
 117                 sin.sin_port = rport;
 118                 if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 119                         break;
 120                 (void)close(s);
 121                 if (errno == EADDRINUSE) {
 122                         lport--;
 123                         continue;
 124                 }
 125                 if (errno == ECONNREFUSED && timo <= 16) {
 126                         (void)sleep(timo);
 127                         timo *= 2;
 128                         continue;
 129                 }
 130                 if (hp->h_addr_list[1] != NULL) {
 131                         int oerrno = errno;
 132
 133                         (void)fprintf(stderr, "connect to address %s: ",
 134                             inet_ntoa(sin.sin_addr));
 135                         errno = oerrno;
 136                         perror(0);
 137                         hp->h_addr_list++;
 138                         bcopy(hp->h_addr_list[0], &sin.sin_addr, hp->h_length);
 139                         (void)fprintf(stderr, "Trying %s...\n",
 140                             inet_ntoa(sin.sin_addr));
 141                         continue;
 142                 }
 143                 (void)fprintf(stderr, "%s: %s\n", hp->h_name, strerror(errno));
 144                 sigsetmask(oldmask);
 145                 return (-1);
 146         }
 147         lport--;
 148         if (fd2p == 0) {
 149                 write(s, "", 1);
 150                 lport = 0;
 151         } else {
 152                 char num[8];
 153                 int s2 = rresvport(&lport), s3;
 154                 int len = sizeof(from);
 155
 156                 if (s2 < 0)
 157                         goto bad;
 158                 listen(s2, 1);
 159                 (void)snprintf(num, sizeof(num), "%d", lport);
 160                 if (write(s, num, strlen(num)+1) != strlen(num)+1) {
 161                         (void)fprintf(stderr,
 162                             "rcmd: write (setting up stderr): %s\n",
 163                             strerror(errno));
 164                         (void)close(s2);
 165                         goto bad;
 166                 }
 167                 FD_ZERO(&reads);
 168                 FD_SET(s, &reads);
 169                 FD_SET(s2, &reads);
 170                 errno = 0;
 171                 if (select(32, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)) {
 172                         if (errno != 0)
 173                                 (void)fprintf(stderr,
 174                                     "rcmd: select (setting up stderr): %s\n",
 175                                     strerror(errno));
 176                         else
 177                                 (void)fprintf(stderr,
 178                                 "select: protocol failure in circuit setup\n");
 179                         (void)close(s2);
 180                         goto bad;
 181                 }
 182                 s3 = accept(s2, (struct sockaddr *)&from, &len);
 183                 (void)close(s2);
 184                 if (s3 < 0) {
 185                         (void)fprintf(stderr,
 186                             "rcmd: accept: %s\n", strerror(errno));
 187                         lport = 0;
 188                         goto bad;
 189                 }
 190                 *fd2p = s3;
 191                 from.sin_port = ntohs((u_short)from.sin_port);
 192                 if (from.sin_family != AF_INET ||
 193                     from.sin_port >= IPPORT_RESERVED ||
 194                     from.sin_port < IPPORT_RESERVED / 2) {
 195                         (void)fprintf(stderr,
 196                             "socket: protocol failure in circuit setup.\n");
 197                         goto bad2;
 198                 }
 199         }
 200         (void)write(s, locuser, strlen(locuser)+1);
 201         (void)write(s, remuser, strlen(remuser)+1);
 202         (void)write(s, cmd, strlen(cmd)+1);
 203         if (read(s, &c, 1) != 1) {
 204                 (void)fprintf(stderr,
 205                     "rcmd: %s: %s\n", *ahost, strerror(errno));
 206                 goto bad2;
 207         }
 208         if (c != 0) {
 209                 while (read(s, &c, 1) == 1) {
 210                         (void)write(STDERR_FILENO, &c, 1);
 211                         if (c == '\n')
 212                                 break;
 213                 }
 214                 goto bad2;
 215         }
 216         sigsetmask(oldmask);
 217         return (s);
 218 bad2:
 219         if (lport)
 220                 (void)close(*fd2p);
 221 bad:
 222         (void)close(s);
 223         sigsetmask(oldmask);
 224         return (-1);
 225 }
 226
 227 int
 228 rresvport(alport)
 229         int *alport;
 230 {
 231         struct sockaddr_in sin;
 232         int s;
 233
 234         sin.sin_family = AF_INET;
 235         sin.sin_addr.s_addr = INADDR_ANY;
 236         s = socket(AF_INET, SOCK_STREAM, 0);
 237         if (s < 0)
 238                 return (-1);
 239         for (;;) {
 240                 sin.sin_port = htons((u_short)*alport);
 241                 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
 242                         return (s);
 243                 if (errno != EADDRINUSE) {
 244                         (void)close(s);
 245                         return (-1);
 246                 }
 247                 (*alport)--;
 248                 if (*alport == IPPORT_RESERVED/2) {
 249                         (void)close(s);
 250                         errno = EAGAIN;         /* close */
 251                         return (-1);
 252                 }
 253         }
 254 }
 255
 256 int     __check_rhosts_file = 1;
 257 char    *__rcmd_errstr;
 258
 259 int
 260 ruserok(rhost, superuser, ruser, luser)
 261         const char *rhost, *ruser, *luser;
 262         int superuser;
 263 {
 264         struct hostent *hp;
 265         u_long addr;
 266         char **ap;
 267
 268         if ((hp = gethostbyname(rhost)) == NULL)
 269                 return (-1);
 270         for (ap = hp->h_addr_list; *ap; ++ap) {
 271                 bcopy(*ap, &addr, sizeof(addr));
 272                 if (iruserok(addr, superuser, ruser, luser) == 0)
 273                         return (0);
 274         }
 275         return (-1);
 276 }
 277
 278 /*
 279  * New .rhosts strategy: We are passed an ip address. We spin through
 280  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 281  * has ip addresses, we don't have to trust a nameserver.  When it
 282  * contains hostnames, we spin through the list of addresses the nameserver
 283  * gives us and look for a match.
 284  *
 285  * Returns 0 if ok, -1 if not ok.
 286  */
 287 int
 288 iruserok(raddr, superuser, ruser, luser)
 289         u_long raddr;
 290         int superuser;
 291         const char *ruser, *luser;
 292 {
 293         register char *cp;
 294         struct stat sbuf;
 295         struct passwd *pwd;
 296         FILE *hostf;
 297         uid_t uid;
 298         int first;
 299         char pbuf[MAXPATHLEN];
 300
 301         first = 1;
 302         hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
 303 again:
 304         if (hostf) {
 305                 if (__ivaliduser(hostf, raddr, luser, ruser) == 0) {
 306                         (void)fclose(hostf);
 307                         return (0);
 308                 }
 309                 (void)fclose(hostf);
 310         }
 311         if (first == 1 && (__check_rhosts_file || superuser)) {
 312                 first = 0;
 313                 if ((pwd = getpwnam(luser)) == NULL)
 314                         return (-1);
 315                 (void)strcpy(pbuf, pwd->pw_dir);
 316                 (void)strcat(pbuf, "/.rhosts");
 317
 318                 /*
 319                  * Change effective uid while opening .rhosts.  If root and
 320                  * reading an NFS mounted file system, can't read files that
 321                  * are protected read/write owner only.
 322                  */
 323                 uid = geteuid();
 324                 (void)seteuid(pwd->pw_uid);
 325                 hostf = fopen(pbuf, "r");
 326                 (void)seteuid(uid);
 327
 328                 if (hostf == NULL)
 329                         return (-1);
 330                 /*
 331                  * If not a regular file, or is owned by someone other than
 332                  * user or root or if writeable by anyone but the owner, quit.
 333                  */
 334                 cp = NULL;
 335                 if (lstat(pbuf, &sbuf) < 0)
 336                         cp = ".rhosts lstat failed";
 337                 else if (!S_ISREG(sbuf.st_mode))
 338                         cp = ".rhosts not regular file";
 339                 else if (fstat(fileno(hostf), &sbuf) < 0)
 340                         cp = ".rhosts fstat failed";
 341                 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
 342                         cp = "bad .rhosts owner";
 343                 else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
 344                         cp = ".rhosts writeable by other than owner";
 345                 /* If there were any problems, quit. */
 346                 if (cp) {
 347                         __rcmd_errstr = cp;
 348                         (void)fclose(hostf);
 349                         return (-1);
 350                 }
 351                 goto again;
 352         }
 353         return (-1);
 354 }
 355
 356 /*
 357  * XXX
 358  * Don't make static, used by lpd(8).
 359  *
 360  * Returns 0 if ok, -1 if not ok.
 361  */
 362 int
 363 __ivaliduser(hostf, raddr, luser, ruser)
 364         FILE *hostf;
 365         u_long raddr;
 366         const char *luser, *ruser;
 367 {
 368         register char *user, *p;
 369         int ch;
 370         char buf[MAXHOSTNAMELEN + 128];         /* host + login */
 371
 372         while (fgets(buf, sizeof(buf), hostf)) {
 373                 p = buf;
 374                 /* Skip lines that are too long. */
 375                 if (strchr(p, '\n') == NULL) {
 376                         while ((ch = getc(hostf)) != '\n' && ch != EOF);
 377                         continue;
 378                 }
 379                 while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
 380                         *p = isupper(*p) ? tolower(*p) : *p;
 381                         p++;
 382                 }
 383                 if (*p == ' ' || *p == '\t') {
 384                         *p++ = '\0';
 385                         while (*p == ' ' || *p == '\t')
 386                                 p++;
 387                         user = p;
 388                         while (*p != '\n' && *p != ' ' &&
 389                             *p != '\t' && *p != '\0')
 390                                 p++;
 391                 } else
 392                         user = p;
 393                 *p = '\0';
 394                 if (__icheckhost(raddr, buf) &&
 395                     strcmp(ruser, *user ? user : luser) == 0) {
 396                         return (0);
 397                 }
 398         }
 399         return (-1);
 400 }
 401
 402 /*
 403  * Returns "true" if match, 0 if no match.
 404  */
 405 static int
 406 __icheckhost(raddr, lhost)
 407         u_long raddr;
 408         register char *lhost;
 409 {
 410         register struct hostent *hp;
 411         register u_long laddr;
 412         register char **pp;
 413
 414         /* Try for raw ip address first. */
 415         if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1)
 416                 return (raddr == laddr);
 417
 418         /* Better be a hostname. */
 419         if ((hp = gethostbyname(lhost)) == NULL)
 420                 return (0);
 421
 422         /* Spin through ip addresses. */
 423         for (pp = hp->h_addr_list; *pp; ++pp)
 424                 if (!bcmp(&raddr, *pp, sizeof(u_long)))
 425                         return (1);
 426
 427         /* No match. */
 428         return (0);
 429 }