xref: /titanic_41/usr/src/cmd/cmd-inet/common/kcmd.c (revision cb6207858a9fcc2feaee22e626912fba281ac969)
1 /*
2  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 #pragma ident	"%Z%%M%	%I%	%E% SMI"
7 
8 /*
9  * Copyright (c) 1983 Regents of the University of California.
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms are permitted
13  * provided that the above copyright notice and this paragraph are
14  * duplicated in all such forms and that any documentation,
15  * advertising materials, and other materials related to such
16  * distribution and use acknowledge that the software was developed
17  * by the University of California, Berkeley.  The name of the
18  * University may not be used to endorse or promote products derived
19  * from this software without specific prior written permission.
20  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
22  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
23  */
24 
25 /* derived from @(#)rcmd.c	5.17 (Berkeley) 6/27/88 */
26 
27 #include <unistd.h>
28 #include <stdlib.h>
29 #include <stdio.h>
30 #include <ctype.h>
31 #include <string.h>
32 #include <pwd.h>
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <fcntl.h>
36 
37 #include <signal.h>
38 #include <sys/file.h>
39 #include <sys/socket.h>
40 #include <sys/stat.h>
41 
42 #include <netinet/in.h>
43 #include <arpa/inet.h>
44 #include <netdb.h>
45 #include <locale.h>
46 #include <syslog.h>
47 
48 #include <errno.h>
49 #include <com_err.h>
50 #include <k5-int.h>
51 #include <kcmd.h>
52 
53 static char *default_service = "host";
54 
55 #define	KCMD_BUFSIZ	102400
56 #define	KCMD8_BUFSIZ	(4096 - 256)
57 /*
58  * For compatibility with earlier versions of Solaris and other OS
59  * (kerborized rsh uses 4KB of RSH_BUFSIZE)- 256 to make sure
60  * there is room
61  */
62 static int deswrite_compat(int, char *, int, int);
63 
64 #define	KCMD_KEYUSAGE	1026
65 
66 static char storage[KCMD_BUFSIZ];
67 static int nstored = 0;
68 static int MAXSIZE = (KCMD_BUFSIZ + 8);
69 static char *store_ptr = storage;
70 static krb5_data desinbuf, desoutbuf;
71 
72 static boolean_t encrypt_flag = B_FALSE;
73 static krb5_context kcmd_context;
74 
75 /* XXX Overloaded: use_ivecs!=0 -> new protocol, inband signalling, etc.  */
76 static boolean_t use_ivecs = B_FALSE;
77 static krb5_data encivec_i[2], encivec_o[2];
78 static krb5_keyusage enc_keyusage_i[2], enc_keyusage_o[2];
79 static krb5_enctype final_enctype;
80 static krb5_keyblock *skey;
81 
82 /* ARGSUSED */
83 int
84 kcmd(int *sock, char **ahost, ushort_t rport,
85 	char *locuser, char *remuser,
86 	char *cmd, int *fd2p, char *service, char *realm,
87 	krb5_context bsd_context, krb5_auth_context *authconp,
88 	krb5_creds **cred, krb5_int32 *seqno, krb5_int32 *server_seqno,
89 	krb5_flags authopts,
90 	int anyport, enum kcmd_proto *protonump)
91 {
92 	int s = -1;
93 	sigset_t oldmask, urgmask;
94 	struct sockaddr_in sin;
95 	struct sockaddr_storage from;
96 	krb5_creds *get_cred = NULL;
97 	krb5_creds *ret_cred = NULL;
98 	char c;
99 	struct hostent *hp;
100 	int rc;
101 	char *host_save = NULL;
102 	krb5_error_code status;
103 	krb5_ap_rep_enc_part *rep_ret;
104 	krb5_error	*error = 0;
105 	krb5_ccache cc;
106 	krb5_data outbuf;
107 	krb5_flags options = authopts;
108 	krb5_auth_context auth_context = NULL;
109 	char *cksumbuf;
110 	krb5_data cksumdat;
111 	int bsize = 0;
112 	char *kcmd_version;
113 	enum kcmd_proto protonum = *protonump;
114 
115 	bsize = strlen(cmd) + strlen(remuser) + 64;
116 	if ((cksumbuf = malloc(bsize)) == 0) {
117 		(void) fprintf(stderr, gettext("Unable to allocate"
118 					    " memory for checksum buffer.\n"));
119 		return (-1);
120 	}
121 	(void) snprintf(cksumbuf, bsize, "%u:", ntohs(rport));
122 	if (strlcat(cksumbuf, cmd, bsize) >= bsize) {
123 		(void) fprintf(stderr, gettext("cmd buffer too long.\n"));
124 		free(cksumbuf);
125 		return (-1);
126 	}
127 	if (strlcat(cksumbuf, remuser, bsize) >= bsize) {
128 		(void) fprintf(stderr, gettext("remuser too long.\n"));
129 		free(cksumbuf);
130 		return (-1);
131 	}
132 	cksumdat.data = cksumbuf;
133 	cksumdat.length = strlen(cksumbuf);
134 
135 	hp = gethostbyname(*ahost);
136 	if (hp == 0) {
137 		(void) fprintf(stderr,
138 			    gettext("%s: unknown host\n"), *ahost);
139 		return (-1);
140 	}
141 
142 	if ((host_save = (char *)strdup(hp->h_name)) == NULL) {
143 		(void) fprintf(stderr, gettext("kcmd: no memory\n"));
144 		return (-1);
145 	}
146 
147 	/* If no service is given set to the default service */
148 	if (!service) service = default_service;
149 
150 	if (!(get_cred = (krb5_creds *)calloc(1, sizeof (krb5_creds)))) {
151 		(void) fprintf(stderr, gettext("kcmd: no memory\n"));
152 		return (-1);
153 	}
154 	(void) sigemptyset(&urgmask);
155 	(void) sigaddset(&urgmask, SIGURG);
156 	(void) sigprocmask(SIG_BLOCK, &urgmask, &oldmask);
157 
158 	status = krb5_sname_to_principal(bsd_context, host_save, service,
159 					KRB5_NT_SRV_HST, &get_cred->server);
160 	if (status) {
161 		(void) fprintf(stderr,
162 			    gettext("kcmd: "
163 				    "krb5_sname_to_principal failed: %s\n"),
164 			    error_message(status));
165 		status = -1;
166 		goto bad;
167 	}
168 
169 	if (realm && *realm) {
170 		(void) krb5_xfree(
171 			krb5_princ_realm(bsd_context, get_cred->server)->data);
172 		krb5_princ_set_realm_length(bsd_context, get_cred->server,
173 					strlen(realm));
174 		krb5_princ_set_realm_data(bsd_context, get_cred->server,
175 						strdup(realm));
176 	}
177 
178 	s = socket(AF_INET, SOCK_STREAM, 0);
179 	if (s < 0) {
180 		perror(gettext("Error creating socket"));
181 		status = -1;
182 		goto bad;
183 	}
184 	/*
185 	 * Kerberos only supports IPv4 addresses for now.
186 	 */
187 	if (hp->h_addrtype == AF_INET) {
188 		sin.sin_family = hp->h_addrtype;
189 		(void) memcpy((void *)&sin.sin_addr,
190 			    hp->h_addr, hp->h_length);
191 		sin.sin_port = rport;
192 	} else {
193 		syslog(LOG_ERR, "Address type %d not supported for "
194 		    "Kerberos", hp->h_addrtype);
195 		status = -1;
196 		goto bad;
197 	}
198 
199 	if (connect(s, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
200 		perror(host_save);
201 		status = -1;
202 		goto bad;
203 	}
204 
205 	if (fd2p == 0) {
206 		(void) write(s, "", 1);
207 	} else {
208 		char num[16];
209 		int s2;
210 		int s3;
211 		struct sockaddr_storage sname;
212 		struct sockaddr_in *sp;
213 		int len = sizeof (struct sockaddr_storage);
214 
215 		s2 = socket(AF_INET, SOCK_STREAM, 0);
216 		if (s2 < 0) {
217 			status = -1;
218 			goto bad;
219 		}
220 		(void) memset((char *)&sin, 0, sizeof (sin));
221 		sin.sin_family = AF_INET;
222 		sin.sin_addr.s_addr = INADDR_ANY;
223 		sin.sin_port = 0;
224 
225 		if (bind(s2, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
226 			perror(gettext("error binding socket"));
227 			(void) close(s2);
228 			status = -1;
229 			goto bad;
230 		}
231 		if (getsockname(s2, (struct sockaddr *)&sname, &len) < 0) {
232 			perror(gettext("getsockname error"));
233 			(void) close(s2);
234 			status = -1;
235 			goto bad;
236 		}
237 		sp = (struct sockaddr_in *)&sname;
238 		(void) listen(s2, 1);
239 		(void) snprintf(num, sizeof (num), "%d",
240 			    htons((ushort_t)sp->sin_port));
241 		if (write(s, num, strlen(num)+1) != strlen(num)+1) {
242 			perror(gettext("write: error setting up stderr"));
243 			(void) close(s2);
244 			status = -1;
245 			goto bad;
246 		}
247 
248 		s3 = accept(s2, (struct sockaddr *)&from, &len);
249 		(void) close(s2);
250 		if (s3 < 0) {
251 			perror(gettext("accept"));
252 			status = -1;
253 			goto bad;
254 		}
255 		*fd2p = s3;
256 		if (SOCK_FAMILY(from) == AF_INET) {
257 			if (!anyport && SOCK_PORT(from) >= IPPORT_RESERVED) {
258 				(void) fprintf(stderr,
259 				    gettext("socket: protocol "
260 					    "failure in circuit setup.\n"));
261 				status = -1;
262 				goto bad2;
263 			}
264 		} else {
265 			(void) fprintf(stderr,
266 				    gettext("Kerberos does not support "
267 					    "address type %d\n"),
268 				    SOCK_FAMILY(from));
269 			status = -1;
270 			goto bad2;
271 		}
272 	}
273 
274 	if (status = krb5_cc_default(bsd_context, &cc))
275 		goto bad2;
276 
277 	status = krb5_cc_get_principal(bsd_context, cc, &get_cred->client);
278 	if (status) {
279 		(void) krb5_cc_close(bsd_context, cc);
280 		goto bad2;
281 	}
282 
283 	/* Get ticket from credentials cache or kdc */
284 	status = krb5_get_credentials(bsd_context, 0, cc, get_cred, &ret_cred);
285 	(void) krb5_cc_close(bsd_context, cc);
286 	if (status) goto bad2;
287 
288 	/* Reset internal flags; these should not be sent. */
289 	authopts &= (~OPTS_FORWARD_CREDS);
290 	authopts &= (~OPTS_FORWARDABLE_CREDS);
291 
292 	if ((status = krb5_auth_con_init(bsd_context, &auth_context)))
293 		goto bad2;
294 
295 	if ((status = krb5_auth_con_setflags(bsd_context, auth_context,
296 					KRB5_AUTH_CONTEXT_RET_TIME)))
297 		goto bad2;
298 
299 	/* Only need local address for mk_cred() to send to krlogind */
300 	if ((status = krb5_auth_con_genaddrs(bsd_context, auth_context, s,
301 			KRB5_AUTH_CONTEXT_GENERATE_LOCAL_FULL_ADDR)))
302 		goto bad2;
303 
304 	if (protonum == KCMD_PROTOCOL_COMPAT_HACK) {
305 		krb5_boolean is_des;
306 		status = krb5_c_enctype_compare(bsd_context,
307 						ENCTYPE_DES_CBC_CRC,
308 						ret_cred->keyblock.enctype,
309 						&is_des);
310 		if (status)
311 			goto bad2;
312 		protonum = is_des ? KCMD_OLD_PROTOCOL : KCMD_NEW_PROTOCOL;
313 	}
314 
315 	switch (protonum) {
316 	case KCMD_NEW_PROTOCOL:
317 		authopts |= AP_OPTS_USE_SUBKEY;
318 		kcmd_version = "KCMDV0.2";
319 		break;
320 	case KCMD_OLD_PROTOCOL:
321 		kcmd_version = "KCMDV0.1";
322 		break;
323 	default:
324 		status = -1;
325 		goto bad2;
326 	}
327 
328 	/*
329 	 * Call the Kerberos library routine to obtain an authenticator,
330 	 * pass it over the socket to the server, and obtain mutual
331 	 * authentication.
332 	 */
333 	status = krb5_sendauth(bsd_context, &auth_context, (krb5_pointer) &s,
334 			kcmd_version, ret_cred->client, ret_cred->server,
335 			authopts, &cksumdat, ret_cred, 0, &error,
336 			&rep_ret, NULL);
337 	krb5_xfree(cksumdat.data);
338 	if (status) {
339 		(void) fprintf(stderr, gettext("Couldn't authenticate"
340 					    " to server: %s\n"),
341 			    error_message(status));
342 		if (error) {
343 			(void) fprintf(stderr, gettext("Server returned error"
344 						" code %d (%s)\n"),
345 				error->error,
346 				error_message(ERROR_TABLE_BASE_krb5 +
347 					    error->error));
348 			if (error->text.length)
349 				(void) fprintf(stderr,
350 					    gettext("Error text"
351 						    " sent from server: %s\n"),
352 					    error->text.data);
353 		}
354 		if (error) {
355 			krb5_free_error(bsd_context, error);
356 			error = 0;
357 		}
358 		goto bad2;
359 	}
360 	if (rep_ret && server_seqno) {
361 		*server_seqno = rep_ret->seq_number;
362 		krb5_free_ap_rep_enc_part(bsd_context, rep_ret);
363 	}
364 
365 	(void) write(s, remuser, strlen(remuser)+1);
366 	(void) write(s, cmd, strlen(cmd)+1);
367 	if (locuser)
368 		(void) write(s, locuser, strlen(locuser)+1);
369 	else
370 		(void) write(s, "", 1);
371 
372 	if (options & OPTS_FORWARD_CREDS) {   /* Forward credentials */
373 		if (status = krb5_fwd_tgt_creds(bsd_context, auth_context,
374 					host_save,
375 					ret_cred->client, ret_cred->server,
376 					0, options & OPTS_FORWARDABLE_CREDS,
377 					&outbuf)) {
378 			(void) fprintf(stderr,
379 				    gettext("kcmd: Error getting"
380 					    " forwarded creds\n"));
381 			goto bad2;
382 		}
383 		/* Send forwarded credentials */
384 		if (status = krb5_write_message(bsd_context, (krb5_pointer)&s,
385 						&outbuf))
386 			goto bad2;
387 	} else { /* Dummy write to signal no forwarding */
388 		outbuf.length = 0;
389 		if (status = krb5_write_message(bsd_context,
390 						(krb5_pointer)&s, &outbuf))
391 			goto bad2;
392 	}
393 
394 	if ((rc = read(s, &c, 1)) != 1) {
395 		if (rc == -1) {
396 			perror(*ahost);
397 		} else {
398 			(void) fprintf(stderr, gettext("kcmd: bad connection "
399 					"with remote host\n"));
400 		}
401 		status = -1;
402 		goto bad2;
403 	}
404 	if (c != 0) {
405 		while (read(s, &c, 1) == 1) {
406 			(void) write(2, &c, 1);
407 			if (c == '\n')
408 				break;
409 		}
410 		status = -1;
411 		goto bad2;
412 	}
413 	(void) sigprocmask(SIG_SETMASK, &oldmask, (sigset_t *)0);
414 	*sock = s;
415 
416 	/* pass back credentials if wanted */
417 	if (cred) krb5_copy_creds(bsd_context, ret_cred, cred);
418 		krb5_free_creds(bsd_context, ret_cred);
419 	/*
420 	 * Initialize *authconp to auth_context, so
421 	 * that the clients can make use of it
422 	 */
423 	*authconp = auth_context;
424 
425 	return (0);
426 bad2:
427 	if (fd2p != NULL)
428 		(void) close(*fd2p);
429 bad:
430 	if (s > 0)
431 		(void) close(s);
432 	if (get_cred)
433 		krb5_free_creds(bsd_context, get_cred);
434 	if (ret_cred)
435 		krb5_free_creds(bsd_context, ret_cred);
436 	if (host_save)
437 		free(host_save);
438 	(void) sigprocmask(SIG_SETMASK, &oldmask, (sigset_t *)0);
439 	return (status);
440 }
441 
442 /*
443  * Strsave was a routine in the version 4 krb library: we put it here
444  * for compatablilty with version 5 krb library, since kcmd.o is linked
445  * into all programs.
446  */
447 
448 char *
449 strsave(char *sp)
450 {
451 	char *ret;
452 
453 	if ((ret = (char *)strdup(sp)) == NULL) {
454 		(void) fprintf(stderr, gettext("no memory for saving args\n"));
455 		exit(1);
456 	}
457 	return (ret);
458 }
459 
460 /*
461  * Decode, decrypt and store the forwarded creds in the local ccache.
462  */
463 krb5_error_code
464 rd_and_store_for_creds(krb5_context context,
465 		    krb5_auth_context auth_context,
466 		    krb5_data *inbuf,
467 		    krb5_ticket *ticket,
468 		    char *lusername,
469 		    krb5_ccache *ccache)
470 {
471 	krb5_creds ** creds;
472 	krb5_error_code retval;
473 	char ccname[64];
474 	struct passwd *pwd;
475 	uid_t uid;
476 
477 	*ccache = NULL;
478 	if (!(pwd = (struct passwd *)getpwnam(lusername)))
479 		return (ENOENT);
480 
481 	uid = getuid();
482 	if (seteuid(pwd->pw_uid))
483 		return (-1);
484 
485 	if ((retval =
486 		krb5_rd_cred(context, auth_context, inbuf, &creds, NULL)) != 0)
487 		return (retval);
488 
489 	(void) snprintf(ccname, sizeof (ccname),
490 			"FILE:/tmp/krb5cc_%ld", pwd->pw_uid);
491 
492 	if ((retval = krb5_cc_resolve(context, ccname, ccache)) != 0)
493 		goto cleanup;
494 
495 	if ((retval = krb5_cc_initialize(context, *ccache,
496 					ticket->enc_part2->client)) != 0)
497 		goto cleanup;
498 
499 	if ((retval = krb5_cc_store_cred(context, *ccache, *creds)) != 0)
500 		goto cleanup;
501 
502 	if ((retval = krb5_cc_close(context, *ccache)) != 0)
503 		goto cleanup;
504 
505 cleanup:
506 	(void) seteuid(uid);
507 	krb5_free_creds(context, *creds);
508 	return (retval);
509 }
510 
511 /*
512  * This routine is to initialize the desinbuf, desoutbuf and the session key
513  * structures to carry out desread()'s and deswrite()'s successfully
514  */
515 void
516 init_encrypt(int enc, krb5_context ctxt, enum kcmd_proto protonum,
517 	krb5_data *inbuf, krb5_data *outbuf,
518 	int amclient, krb5_encrypt_block *block)
519 {
520 	krb5_error_code statuscode;
521 	size_t blocksize;
522 	int i;
523 	krb5_error_code ret;
524 
525 	kcmd_context = ctxt;
526 
527 	if (enc > 0) {
528 		desinbuf.data = inbuf->data;
529 		desoutbuf.data = outbuf->data + 4;
530 		desinbuf.length = inbuf->length;
531 		desoutbuf.length = outbuf->length + 4;
532 		encrypt_flag = B_TRUE;
533 	} else {
534 		encrypt_flag = B_FALSE;
535 		return;
536 	}
537 
538 	skey = block->key;
539 	final_enctype = skey->enctype;
540 
541 	enc_keyusage_i[0] = KCMD_KEYUSAGE;
542 	enc_keyusage_i[1] = KCMD_KEYUSAGE;
543 	enc_keyusage_o[0] = KCMD_KEYUSAGE;
544 	enc_keyusage_o[1] = KCMD_KEYUSAGE;
545 
546 	if (protonum == KCMD_OLD_PROTOCOL) {
547 		use_ivecs = B_FALSE;
548 		return;
549 	}
550 
551 	use_ivecs = B_TRUE;
552 	switch (skey->enctype) {
553 	/*
554 	 * For the DES-based enctypes and the 3DES enctype we
555 	 * want to use a non-zero  IV because that's what we did.
556 	 * In the future we use different keyusage for each
557 	 * channel and direction and a fresh cipher state.
558 	 */
559 	case ENCTYPE_DES_CBC_CRC:
560 	case ENCTYPE_DES_CBC_MD4:
561 	case ENCTYPE_DES_CBC_MD5:
562 	case ENCTYPE_DES3_CBC_SHA1:
563 		statuscode = krb5_c_block_size(kcmd_context, final_enctype,
564 				&blocksize);
565 		if (statuscode) {
566 			/* XXX what do I do? */
567 			abort();
568 		}
569 
570 		encivec_i[0].length = encivec_i[1].length =
571 		encivec_o[0].length = encivec_o[1].length = blocksize;
572 
573 		if ((encivec_i[0].data = malloc(encivec_i[0].length * 4))
574 			== NULL) {
575 			/* XXX what do I do? */
576 			abort();
577 		}
578 		encivec_i[1].data = encivec_i[0].data + encivec_i[0].length;
579 		encivec_o[0].data = encivec_i[1].data + encivec_i[0].length;
580 		encivec_o[1].data = encivec_o[0].data + encivec_i[0].length;
581 
582 		/* is there a better way to initialize this? */
583 		(void) memset(encivec_i[0].data, amclient, blocksize);
584 		(void) memset(encivec_o[0].data, 1 - amclient, blocksize);
585 		(void) memset(encivec_i[1].data, 2 | amclient, blocksize);
586 		(void) memset(encivec_o[1].data, 2 | (1 - amclient), blocksize);
587 		break;
588 	default:
589 		if (amclient) {
590 			enc_keyusage_i[0] = 1028;
591 			enc_keyusage_i[1] = 1030;
592 			enc_keyusage_o[0] = 1032;
593 			enc_keyusage_o[1] = 1034;
594 		} else { /* amclient */
595 			enc_keyusage_i[0] = 1032;
596 			enc_keyusage_i[1] = 1034;
597 			enc_keyusage_o[0] = 1028;
598 			enc_keyusage_o[1] = 1030;
599 		}
600 		for (i = 0; i < 2; i++) {
601 			ret = krb5_c_init_state(ctxt,
602 				skey, enc_keyusage_i[i],
603 				&encivec_i[i]);
604 			if (ret)
605 				goto fail;
606 			ret = krb5_c_init_state(ctxt,
607 				skey, enc_keyusage_o[i],
608 				&encivec_o[i]);
609 			if (ret)
610 				goto fail;
611 		}
612 		break;
613 	}
614 	return;
615 fail:
616 	abort();
617 }
618 
619 int
620 desread(int fd, char *buf, int len, int secondary)
621 {
622 	int nreturned = 0;
623 	long net_len, rd_len;
624 	int cc;
625 	size_t ret = 0;
626 	unsigned char len_buf[4];
627 	krb5_enc_data inputd;
628 	krb5_data outputd;
629 
630 	if (!encrypt_flag)
631 		return (read(fd, buf, len));
632 
633 	/*
634 	 * If there is stored data from a previous read,
635 	 * put it into the output buffer and return it now.
636 	 */
637 	if (nstored >= len) {
638 		(void) memcpy(buf, store_ptr, len);
639 		store_ptr += len;
640 		nstored -= len;
641 		return (len);
642 	} else if (nstored) {
643 		(void) memcpy(buf, store_ptr, nstored);
644 		nreturned += nstored;
645 		buf += nstored;
646 		len -= nstored;
647 		nstored = 0;
648 	}
649 
650 	if ((cc = krb5_net_read(kcmd_context, fd, (char *)len_buf, 4)) != 4) {
651 		if ((cc < 0) && ((errno == EWOULDBLOCK) || (errno == EAGAIN)))
652 			return (cc);
653 		/* XXX can't read enough, pipe must have closed */
654 		return (0);
655 	}
656 	rd_len = ((len_buf[0] << 24) | (len_buf[1] << 16) |
657 		    (len_buf[2] << 8) | len_buf[3]);
658 
659 	if (krb5_c_encrypt_length(kcmd_context, final_enctype,
660 				use_ivecs ? (size_t)rd_len + 4 : (size_t)rd_len,
661 				&ret))
662 		net_len = ((size_t)-1);
663 	else
664 		net_len = ret;
665 
666 	if ((net_len <= 0) || (net_len > desinbuf.length)) {
667 		/*
668 		 * preposterous length; assume out-of-sync; only recourse
669 		 * is to close connection, so return 0
670 		 */
671 		(void) fprintf(stderr, gettext("Read size problem.\n"));
672 		return (0);
673 	}
674 
675 	if ((cc = krb5_net_read(kcmd_context, fd, desinbuf.data, net_len))
676 	    != net_len) {
677 		/* pipe must have closed, return 0 */
678 		(void) fprintf(stderr,
679 			    gettext("Read error: length received %d "
680 				    "!= expected %d.\n"),
681 			    cc, net_len);
682 		return (0);
683 	}
684 
685 	/*
686 	 * Decrypt information
687 	 */
688 	inputd.enctype = ENCTYPE_UNKNOWN;
689 	inputd.ciphertext.length = net_len;
690 	inputd.ciphertext.data = (krb5_pointer)desinbuf.data;
691 
692 	outputd.length = sizeof (storage);
693 	outputd.data = (krb5_pointer)storage;
694 
695 	/*
696 	 * data is decrypted into the "storage" buffer, which
697 	 * had better be large enough!
698 	 */
699 	cc = krb5_c_decrypt(kcmd_context, skey,
700 				enc_keyusage_i[secondary],
701 				use_ivecs ? encivec_i + secondary : 0,
702 				&inputd, &outputd);
703 	if (cc) {
704 		(void) fprintf(stderr, gettext("Cannot decrypt data "
705 			"from network\n"));
706 		return (0);
707 	}
708 
709 	store_ptr = storage;
710 	nstored = rd_len;
711 	if (use_ivecs == B_TRUE) {
712 		int rd_len2;
713 		rd_len2 = storage[0] & 0xff;
714 		rd_len2 <<= 8; rd_len2 |= storage[1] & 0xff;
715 		rd_len2 <<= 8; rd_len2 |= storage[2] & 0xff;
716 		rd_len2 <<= 8; rd_len2 |= storage[3] & 0xff;
717 		if (rd_len2 != rd_len) {
718 			/* cleartext length trashed? */
719 			errno = EIO;
720 			return (-1);
721 		}
722 		store_ptr += 4;
723 	}
724 	/*
725 	 * Copy only as much data as the input buffer will allow.
726 	 * The rest is kept in the 'storage' pointer for the next
727 	 * read.
728 	 */
729 	if (nstored > len) {
730 		(void) memcpy(buf, store_ptr, len);
731 		nreturned += len;
732 		store_ptr += len;
733 		nstored -= len;
734 	} else {
735 		(void) memcpy(buf, store_ptr, nstored);
736 		nreturned += nstored;
737 		nstored = 0;
738 	}
739 
740 	return (nreturned);
741 }
742 int
743 deswrite(int fd, char *buf, int len, int secondary)
744 {
745 	int bytes_written;
746 	int r;
747 	int outlen;
748 	char *p;
749 	if (!encrypt_flag)
750 		return (write(fd, buf, len));
751 
752 	bytes_written = 0;
753 	while (len > 0) {
754 		p = buf + bytes_written;
755 		if (len > KCMD8_BUFSIZ)
756 			outlen = KCMD8_BUFSIZ;
757 		else
758 			outlen = len;
759 		r = deswrite_compat(fd, p, outlen, secondary);
760 		if (r == -1)
761 			return (r);
762 		bytes_written += r;
763 		len -= r;
764 	}
765 	return (bytes_written);
766 }
767 static int
768 deswrite_compat(int fd, char *buf, int len, int secondary)
769 {
770 	int cc;
771 	size_t ret = 0;
772 	krb5_data inputd;
773 	krb5_enc_data outputd;
774 	char tmpbuf[KCMD_BUFSIZ + 8];
775 	char encrbuf[KCMD_BUFSIZ + 8];
776 	unsigned char *len_buf = (unsigned char *)tmpbuf;
777 
778 	if (use_ivecs == B_TRUE) {
779 		unsigned char *lenbuf2 = (unsigned char *)tmpbuf;
780 		if (len + 4 > sizeof (tmpbuf))
781 			abort();
782 		lenbuf2[0] = (len & 0xff000000) >> 24;
783 		lenbuf2[1] = (len & 0xff0000) >> 16;
784 		lenbuf2[2] = (len & 0xff00) >> 8;
785 		lenbuf2[3] = (len & 0xff);
786 		(void) memcpy(tmpbuf + 4, buf, len);
787 
788 		inputd.data = (krb5_pointer)tmpbuf;
789 		inputd.length = len + 4;
790 	} else {
791 		inputd.data = (krb5_pointer)buf;
792 		inputd.length = len;
793 	}
794 
795 	desoutbuf.data = encrbuf;
796 
797 	if (krb5_c_encrypt_length(kcmd_context, final_enctype,
798 			use_ivecs ? (size_t)len + 4 : (size_t)len, &ret)) {
799 		desoutbuf.length = ((size_t)-1);
800 		goto err;
801 	} else {
802 		desoutbuf.length = ret;
803 	}
804 
805 	if (desoutbuf.length > MAXSIZE) {
806 		(void) fprintf(stderr, gettext("Write size problem.\n"));
807 		return (-1);
808 	}
809 
810 	/*
811 	 * Encrypt information
812 	 */
813 	outputd.ciphertext.length = desoutbuf.length;
814 	outputd.ciphertext.data = (krb5_pointer)desoutbuf.data;
815 
816 	cc = krb5_c_encrypt(kcmd_context, skey,
817 			enc_keyusage_o[secondary],
818 			use_ivecs ? encivec_o + secondary : 0,
819 			&inputd, &outputd);
820 
821 	if (cc) {
822 err:
823 		(void) fprintf(stderr, gettext("Write encrypt problem.\n"));
824 		return (-1);
825 	}
826 
827 	len_buf[0] = (len & 0xff000000) >> 24;
828 	len_buf[1] = (len & 0xff0000) >> 16;
829 	len_buf[2] = (len & 0xff00) >> 8;
830 	len_buf[3] = (len & 0xff);
831 	(void) write(fd, len_buf, 4);
832 
833 	if (write(fd, desoutbuf.data, desoutbuf.length) != desoutbuf.length) {
834 		(void) fprintf(stderr, gettext("Could not write "
835 			"out all data.\n"));
836 		return (-1);
837 	} else {
838 		return (len);
839 	}
840 }
841