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1.7 ! tholo 1: /* $OpenBSD: rsh.c,v 1.6 1996/07/24 17:31:08 deraadt Exp $ */
1.4 deraadt 2:
1.1 deraadt 3: /*-
4: * Copyright (c) 1983, 1990 The Regents of the University of California.
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: * 3. All advertising materials mentioning features or use of this software
16: * must display the following acknowledgement:
17: * This product includes software developed by the University of
18: * California, Berkeley and its contributors.
19: * 4. Neither the name of the University nor the names of its contributors
20: * may be used to endorse or promote products derived from this software
21: * without specific prior written permission.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33: * SUCH DAMAGE.
34: */
35:
36: #ifndef lint
37: char copyright[] =
38: "@(#) Copyright (c) 1983, 1990 The Regents of the University of California.\n\
39: All rights reserved.\n";
40: #endif /* not lint */
41:
42: #ifndef lint
43: /*static char sccsid[] = "from: @(#)rsh.c 5.24 (Berkeley) 7/1/91";*/
1.7 ! tholo 44: static char rcsid[] = "$OpenBSD: rsh.c,v 1.6 1996/07/24 17:31:08 deraadt Exp $";
1.1 deraadt 45: #endif /* not lint */
46:
47: #include <sys/types.h>
48: #include <sys/socket.h>
49: #include <sys/ioctl.h>
50: #include <sys/file.h>
51:
52: #include <netinet/in.h>
53: #include <netdb.h>
54:
55: #include <pwd.h>
56: #include <signal.h>
57: #include <stdio.h>
58: #include <errno.h>
59: #include <string.h>
1.7 ! tholo 60: #if __STDC__
! 61: #include <stdarg.h>
! 62: #else
1.1 deraadt 63: #include <varargs.h>
1.7 ! tholo 64: #endif
1.1 deraadt 65: #include "pathnames.h"
66:
67: #ifdef KERBEROS
68: #include <kerberosIV/des.h>
69: #include <kerberosIV/krb.h>
70:
71: CREDENTIALS cred;
72: Key_schedule schedule;
73: int use_kerberos = 1, doencrypt;
74: char dst_realm_buf[REALM_SZ], *dest_realm;
1.7 ! tholo 75:
! 76: void warning __P((const char *, ...));
1.1 deraadt 77: #endif
78:
79: /*
80: * rsh - remote shell
81: */
82: extern int errno;
83: int rfd2;
84:
85: main(argc, argv)
86: int argc;
87: char **argv;
88: {
89: extern char *optarg;
90: extern int optind;
91: struct passwd *pw;
92: struct servent *sp;
93: long omask;
94: int argoff, asrsh, ch, dflag, nflag, one, pid, rem, uid;
95: register char *p;
96: char *args, *host, *user, *copyargs();
97: void sendsig();
98:
99: argoff = asrsh = dflag = nflag = 0;
100: one = 1;
101: host = user = NULL;
102:
103: /* if called as something other than "rsh", use it as the host name */
104: if (p = rindex(argv[0], '/'))
105: ++p;
106: else
107: p = argv[0];
108: if (strcmp(p, "rsh"))
109: host = p;
110: else
111: asrsh = 1;
112:
113: /* handle "rsh host flags" */
114: if (!host && argc > 2 && argv[1][0] != '-') {
115: host = argv[1];
116: argoff = 1;
117: }
118:
119: #ifdef KERBEROS
120: #define OPTIONS "8KLdek:l:nwx"
121: #else
122: #define OPTIONS "8KLdel:nw"
123: #endif
124: while ((ch = getopt(argc - argoff, argv + argoff, OPTIONS)) != EOF)
125: switch(ch) {
126: case 'K':
127: #ifdef KERBEROS
128: use_kerberos = 0;
129: #endif
130: break;
131: case 'L': /* -8Lew are ignored to allow rlogin aliases */
132: case 'e':
133: case 'w':
134: case '8':
135: break;
136: case 'd':
137: dflag = 1;
138: break;
139: case 'l':
140: user = optarg;
141: break;
142: #ifdef KERBEROS
143: case 'k':
144: dest_realm = dst_realm_buf;
145: strncpy(dest_realm, optarg, REALM_SZ);
146: break;
147: #endif
148: case 'n':
149: nflag = 1;
150: break;
151: #ifdef KERBEROS
152: case 'x':
153: doencrypt = 1;
1.3 tholo 154: desrw_set_key(&cred.session, schedule);
1.1 deraadt 155: break;
156: #endif
157: case '?':
158: default:
159: usage();
160: }
161: optind += argoff;
162:
163: /* if haven't gotten a host yet, do so */
164: if (!host && !(host = argv[optind++]))
165: usage();
166:
167: /* if no further arguments, must have been called as rlogin. */
168: if (!argv[optind]) {
169: if (asrsh)
170: *argv = "rlogin";
1.6 deraadt 171: setuid(getuid());
1.1 deraadt 172: execv(_PATH_RLOGIN, argv);
173: (void)fprintf(stderr, "rsh: can't exec %s.\n", _PATH_RLOGIN);
174: exit(1);
175: }
176:
177: argc -= optind;
178: argv += optind;
179:
180: if (!(pw = getpwuid(uid = getuid()))) {
181: (void)fprintf(stderr, "rsh: unknown user id.\n");
182: exit(1);
183: }
184: if (!user)
185: user = pw->pw_name;
186:
187: #ifdef KERBEROS
188: /* -x turns off -n */
189: if (doencrypt)
190: nflag = 0;
191: #endif
192:
193: args = copyargs(argv);
194:
195: sp = NULL;
196: #ifdef KERBEROS
197: if (use_kerberos) {
198: sp = getservbyname((doencrypt ? "ekshell" : "kshell"), "tcp");
199: if (sp == NULL) {
200: use_kerberos = 0;
201: warning("can't get entry for %s/tcp service",
202: doencrypt ? "ekshell" : "kshell");
203: }
204: }
205: #endif
206: if (sp == NULL)
207: sp = getservbyname("shell", "tcp");
208: if (sp == NULL) {
209: (void)fprintf(stderr, "rsh: shell/tcp: unknown service.\n");
210: exit(1);
211: }
212:
213: #ifdef KERBEROS
214: try_connect:
215: if (use_kerberos) {
216: rem = KSUCCESS;
217: errno = 0;
218: if (dest_realm == NULL)
219: dest_realm = krb_realmofhost(host);
220:
221: if (doencrypt)
222: rem = krcmd_mutual(&host, sp->s_port, user, args,
223: &rfd2, dest_realm, &cred, schedule);
224: else
225: rem = krcmd(&host, sp->s_port, user, args, &rfd2,
226: dest_realm);
227: if (rem < 0) {
228: use_kerberos = 0;
229: sp = getservbyname("shell", "tcp");
230: if (sp == NULL) {
231: (void)fprintf(stderr,
232: "rsh: unknown service shell/tcp.\n");
233: exit(1);
234: }
235: if (errno == ECONNREFUSED)
236: warning("remote host doesn't support Kerberos");
237: if (errno == ENOENT)
238: warning("can't provide Kerberos auth data");
239: goto try_connect;
240: }
241: } else {
242: if (doencrypt) {
243: (void)fprintf(stderr,
244: "rsh: the -x flag requires Kerberos authentication.\n");
245: exit(1);
246: }
247: rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
248: }
249: #else
250: rem = rcmd(&host, sp->s_port, pw->pw_name, user, args, &rfd2);
251: #endif
252:
253: if (rem < 0)
254: exit(1);
255:
256: if (rfd2 < 0) {
257: (void)fprintf(stderr, "rsh: can't establish stderr.\n");
258: exit(1);
259: }
260: if (dflag) {
261: if (setsockopt(rem, SOL_SOCKET, SO_DEBUG, &one,
262: sizeof(one)) < 0)
263: (void)fprintf(stderr, "rsh: setsockopt: %s.\n",
264: strerror(errno));
265: if (setsockopt(rfd2, SOL_SOCKET, SO_DEBUG, &one,
266: sizeof(one)) < 0)
267: (void)fprintf(stderr, "rsh: setsockopt: %s.\n",
268: strerror(errno));
269: }
270:
271: (void)setuid(uid);
272: omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGTERM));
273: if (signal(SIGINT, SIG_IGN) != SIG_IGN)
274: (void)signal(SIGINT, sendsig);
275: if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
276: (void)signal(SIGQUIT, sendsig);
277: if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
278: (void)signal(SIGTERM, sendsig);
279:
280: if (!nflag) {
281: pid = fork();
282: if (pid < 0) {
283: (void)fprintf(stderr,
284: "rsh: fork: %s.\n", strerror(errno));
285: exit(1);
286: }
287: }
288:
289: #ifdef KERBEROS
290: if (!doencrypt)
291: #endif
292: {
293: (void)ioctl(rfd2, FIONBIO, &one);
294: (void)ioctl(rem, FIONBIO, &one);
295: }
296:
297: talk(nflag, omask, pid, rem);
298:
299: if (!nflag)
300: (void)kill(pid, SIGKILL);
301: exit(0);
302: }
303:
304: talk(nflag, omask, pid, rem)
305: int nflag, pid;
306: long omask;
307: register int rem;
308: {
309: register int cc, wc;
310: register char *bp;
311: int readfrom, ready, rembits;
312: char buf[BUFSIZ];
313:
314: if (!nflag && pid == 0) {
315: (void)close(rfd2);
316:
317: reread: errno = 0;
318: if ((cc = read(0, buf, sizeof buf)) <= 0)
319: goto done;
320: bp = buf;
321:
322: rewrite: rembits = 1 << rem;
323: if (select(16, 0, &rembits, 0, 0) < 0) {
324: if (errno != EINTR) {
325: (void)fprintf(stderr,
326: "rsh: select: %s.\n", strerror(errno));
327: exit(1);
328: }
329: goto rewrite;
330: }
331: if ((rembits & (1 << rem)) == 0)
332: goto rewrite;
333: #ifdef KERBEROS
334: if (doencrypt)
335: wc = des_write(rem, bp, cc);
336: else
337: #endif
338: wc = write(rem, bp, cc);
339: if (wc < 0) {
340: if (errno == EWOULDBLOCK)
341: goto rewrite;
342: goto done;
343: }
344: bp += wc;
345: cc -= wc;
346: if (cc == 0)
347: goto reread;
348: goto rewrite;
349: done:
350: (void)shutdown(rem, 1);
351: exit(0);
352: }
353:
354: (void)sigsetmask(omask);
355: readfrom = (1 << rfd2) | (1 << rem);
356: do {
357: ready = readfrom;
358: if (select(16, &ready, 0, 0, 0) < 0) {
359: if (errno != EINTR) {
360: (void)fprintf(stderr,
361: "rsh: select: %s.\n", strerror(errno));
362: exit(1);
363: }
364: continue;
365: }
366: if (ready & (1 << rfd2)) {
367: errno = 0;
368: #ifdef KERBEROS
369: if (doencrypt)
370: cc = des_read(rfd2, buf, sizeof buf);
371: else
372: #endif
373: cc = read(rfd2, buf, sizeof buf);
374: if (cc <= 0) {
375: if (errno != EWOULDBLOCK)
376: readfrom &= ~(1 << rfd2);
377: } else
378: (void)write(2, buf, cc);
379: }
380: if (ready & (1 << rem)) {
381: errno = 0;
382: #ifdef KERBEROS
383: if (doencrypt)
384: cc = des_read(rem, buf, sizeof buf);
385: else
386: #endif
387: cc = read(rem, buf, sizeof buf);
388: if (cc <= 0) {
389: if (errno != EWOULDBLOCK)
390: readfrom &= ~(1 << rem);
391: } else
392: (void)write(1, buf, cc);
393: }
394: } while (readfrom);
395: }
396:
397: void
398: sendsig(signo)
399: char signo;
400: {
401: #ifdef KERBEROS
402: if (doencrypt)
403: (void)des_write(rfd2, &signo, 1);
404: else
405: #endif
406: (void)write(rfd2, &signo, 1);
407: }
408:
409: #ifdef KERBEROS
410: /* VARARGS */
1.7 ! tholo 411: void
! 412: #if __STDC__
! 413: warning(const char *fmt, ...)
! 414: #else
1.1 deraadt 415: warning(va_alist)
416: va_dcl
1.7 ! tholo 417: #endif
1.1 deraadt 418: {
419: va_list ap;
1.7 ! tholo 420: #if !__STDC__
1.1 deraadt 421: char *fmt;
1.7 ! tholo 422: #endif
! 423: char myrealm[REALM_SZ];
1.1 deraadt 424:
1.7 ! tholo 425: if (krb_get_lrealm(myrealm, 0) != KSUCCESS)
! 426: return;
1.1 deraadt 427: (void)fprintf(stderr, "rsh: warning, using standard rsh: ");
1.7 ! tholo 428: #if __STDC__
! 429: va_start(ap, fmt);
! 430: #else
1.1 deraadt 431: va_start(ap);
432: fmt = va_arg(ap, char *);
1.7 ! tholo 433: #endif
1.1 deraadt 434: vfprintf(stderr, fmt, ap);
435: va_end(ap);
436: (void)fprintf(stderr, ".\n");
437: }
438: #endif
439:
440: char *
441: copyargs(argv)
442: char **argv;
443: {
444: register int cc;
445: register char **ap, *p;
446: char *args, *malloc();
447:
448: cc = 0;
449: for (ap = argv; *ap; ++ap)
450: cc += strlen(*ap) + 1;
451: if (!(args = malloc((u_int)cc))) {
452: (void)fprintf(stderr, "rsh: %s.\n", strerror(ENOMEM));
453: exit(1);
454: }
455: for (p = args, ap = argv; *ap; ++ap) {
456: (void)strcpy(p, *ap);
457: for (p = strcpy(p, *ap); *p; ++p);
458: if (ap[1])
459: *p++ = ' ';
460: }
461: return(args);
462: }
463:
464: usage()
465: {
466: (void)fprintf(stderr,
467: "usage: rsh [-nd%s]%s[-l login] host [command]\n",
468: #ifdef KERBEROS
469: "x", " [-k realm] ");
470: #else
471: "", " ");
472: #endif
473: exit(1);
474: }