xref: /freebsd/lib/libc/rpc/key_call.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2009, Sun Microsystems, Inc.
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 are met:
9  * - Redistributions of source code must retain the above copyright notice,
10  *   this list of conditions and the following disclaimer.
11  * - Redistributions in binary form must reproduce the above copyright notice,
12  *   this list of conditions and the following disclaimer in the documentation
13  *   and/or other materials provided with the distribution.
14  * - Neither the name of Sun Microsystems, Inc. nor the names of its
15  *   contributors may be used to endorse or promote products derived
16  *   from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  */
30 /*
31  * Copyright (c) 1986-1991 by Sun Microsystems Inc.
32  */
33 
34 /*
35  * key_call.c, Interface to keyserver
36  *
37  * setsecretkey(key) - set your secret key
38  * encryptsessionkey(agent, deskey) - encrypt a session key to talk to agent
39  * decryptsessionkey(agent, deskey) - decrypt ditto
40  * gendeskey(deskey) - generate a secure des key
41  */
42 
43 #include "namespace.h"
44 #include "reentrant.h"
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <unistd.h>
48 #include <errno.h>
49 #include <rpc/rpc.h>
50 #include <rpc/auth.h>
51 #include <rpc/auth_unix.h>
52 #include <rpc/key_prot.h>
53 #include <string.h>
54 #include <netconfig.h>
55 #include <sys/utsname.h>
56 #include <stdlib.h>
57 #include <signal.h>
58 #include <sys/wait.h>
59 #include <sys/fcntl.h>
60 #include "un-namespace.h"
61 #include "mt_misc.h"
62 
63 
64 #define	KEY_TIMEOUT	5	/* per-try timeout in seconds */
65 #define	KEY_NRETRY	12	/* number of retries */
66 
67 #ifdef DEBUG
68 #define	debug(msg)	(void) fprintf(stderr, "%s\n", msg);
69 #else
70 #define	debug(msg)
71 #endif /* DEBUG */
72 
73 /*
74  * Hack to allow the keyserver to use AUTH_DES (for authenticated
75  * NIS+ calls, for example).  The only functions that get called
76  * are key_encryptsession_pk, key_decryptsession_pk, and key_gendes.
77  *
78  * The approach is to have the keyserver fill in pointers to local
79  * implementations of these functions, and to call those in key_call().
80  */
81 
82 cryptkeyres *(*__key_encryptsession_pk_LOCAL)(uid_t, void *arg) = 0;
83 cryptkeyres *(*__key_decryptsession_pk_LOCAL)(uid_t, void *arg) = 0;
84 des_block *(*__key_gendes_LOCAL)(uid_t, void *) = 0;
85 
86 static int key_call( u_long, xdrproc_t, void *, xdrproc_t, void *);
87 
88 int
89 key_setsecret(const char *secretkey)
90 {
91 	keystatus status;
92 
93 	if (!key_call((u_long) KEY_SET, (xdrproc_t)xdr_keybuf,
94 			(void *)secretkey,
95 			(xdrproc_t)xdr_keystatus, &status)) {
96 		return (-1);
97 	}
98 	if (status != KEY_SUCCESS) {
99 		debug("set status is nonzero");
100 		return (-1);
101 	}
102 	return (0);
103 }
104 
105 
106 /* key_secretkey_is_set() returns 1 if the keyserver has a secret key
107  * stored for the caller's effective uid; it returns 0 otherwise
108  *
109  * N.B.:  The KEY_NET_GET key call is undocumented.  Applications shouldn't
110  * be using it, because it allows them to get the user's secret key.
111  */
112 
113 int
114 key_secretkey_is_set(void)
115 {
116 	struct key_netstres 	kres;
117 
118 	memset((void*)&kres, 0, sizeof (kres));
119 	if (key_call((u_long) KEY_NET_GET, (xdrproc_t)xdr_void, NULL,
120 			(xdrproc_t)xdr_key_netstres, &kres) &&
121 	    (kres.status == KEY_SUCCESS) &&
122 	    (kres.key_netstres_u.knet.st_priv_key[0] != 0)) {
123 		/* avoid leaving secret key in memory */
124 		memset(kres.key_netstres_u.knet.st_priv_key, 0, HEXKEYBYTES);
125 		return (1);
126 	}
127 	return (0);
128 }
129 
130 int
131 key_encryptsession_pk(char *remotename, netobj *remotekey, des_block *deskey)
132 {
133 	cryptkeyarg2 arg;
134 	cryptkeyres res;
135 
136 	arg.remotename = remotename;
137 	arg.remotekey = *remotekey;
138 	arg.deskey = *deskey;
139 	if (!key_call((u_long)KEY_ENCRYPT_PK, (xdrproc_t)xdr_cryptkeyarg2, &arg,
140 			(xdrproc_t)xdr_cryptkeyres, &res)) {
141 		return (-1);
142 	}
143 	if (res.status != KEY_SUCCESS) {
144 		debug("encrypt status is nonzero");
145 		return (-1);
146 	}
147 	*deskey = res.cryptkeyres_u.deskey;
148 	return (0);
149 }
150 
151 int
152 key_decryptsession_pk(char *remotename, netobj *remotekey, des_block *deskey)
153 {
154 	cryptkeyarg2 arg;
155 	cryptkeyres res;
156 
157 	arg.remotename = remotename;
158 	arg.remotekey = *remotekey;
159 	arg.deskey = *deskey;
160 	if (!key_call((u_long)KEY_DECRYPT_PK, (xdrproc_t)xdr_cryptkeyarg2, &arg,
161 			(xdrproc_t)xdr_cryptkeyres, &res)) {
162 		return (-1);
163 	}
164 	if (res.status != KEY_SUCCESS) {
165 		debug("decrypt status is nonzero");
166 		return (-1);
167 	}
168 	*deskey = res.cryptkeyres_u.deskey;
169 	return (0);
170 }
171 
172 int
173 key_encryptsession(const char *remotename, des_block *deskey)
174 {
175 	cryptkeyarg arg;
176 	cryptkeyres res;
177 
178 	arg.remotename = (char *) remotename;
179 	arg.deskey = *deskey;
180 	if (!key_call((u_long)KEY_ENCRYPT, (xdrproc_t)xdr_cryptkeyarg, &arg,
181 			(xdrproc_t)xdr_cryptkeyres, &res)) {
182 		return (-1);
183 	}
184 	if (res.status != KEY_SUCCESS) {
185 		debug("encrypt status is nonzero");
186 		return (-1);
187 	}
188 	*deskey = res.cryptkeyres_u.deskey;
189 	return (0);
190 }
191 
192 int
193 key_decryptsession(const char *remotename, des_block *deskey)
194 {
195 	cryptkeyarg arg;
196 	cryptkeyres res;
197 
198 	arg.remotename = (char *) remotename;
199 	arg.deskey = *deskey;
200 	if (!key_call((u_long)KEY_DECRYPT, (xdrproc_t)xdr_cryptkeyarg, &arg,
201 			(xdrproc_t)xdr_cryptkeyres, &res)) {
202 		return (-1);
203 	}
204 	if (res.status != KEY_SUCCESS) {
205 		debug("decrypt status is nonzero");
206 		return (-1);
207 	}
208 	*deskey = res.cryptkeyres_u.deskey;
209 	return (0);
210 }
211 
212 int
213 key_gendes(des_block *key)
214 {
215 	if (!key_call((u_long)KEY_GEN, (xdrproc_t)xdr_void, NULL,
216 			(xdrproc_t)xdr_des_block, key)) {
217 		return (-1);
218 	}
219 	return (0);
220 }
221 
222 int
223 key_setnet(struct key_netstarg *arg)
224 {
225 	keystatus status;
226 
227 
228 	if (!key_call((u_long) KEY_NET_PUT, (xdrproc_t)xdr_key_netstarg, arg,
229 			(xdrproc_t)xdr_keystatus, &status)){
230 		return (-1);
231 	}
232 
233 	if (status != KEY_SUCCESS) {
234 		debug("key_setnet status is nonzero");
235 		return (-1);
236 	}
237 	return (1);
238 }
239 
240 
241 int
242 key_get_conv(char *pkey, des_block *deskey)
243 {
244 	cryptkeyres res;
245 
246 	if (!key_call((u_long) KEY_GET_CONV, (xdrproc_t)xdr_keybuf, pkey,
247 			(xdrproc_t)xdr_cryptkeyres, &res)) {
248 		return (-1);
249 	}
250 	if (res.status != KEY_SUCCESS) {
251 		debug("get_conv status is nonzero");
252 		return (-1);
253 	}
254 	*deskey = res.cryptkeyres_u.deskey;
255 	return (0);
256 }
257 
258 struct  key_call_private {
259 	CLIENT	*client;	/* Client handle */
260 	pid_t	pid;		/* process-id at moment of creation */
261 	uid_t	uid;		/* user-id at last authorization */
262 };
263 static struct key_call_private *key_call_private_main = NULL;
264 static thread_key_t key_call_key;
265 static once_t key_call_once = ONCE_INITIALIZER;
266 static int key_call_key_error;
267 
268 static void
269 key_call_destroy(void *vp)
270 {
271 	struct key_call_private *kcp = (struct key_call_private *)vp;
272 
273 	if (kcp) {
274 		if (kcp->client)
275 			clnt_destroy(kcp->client);
276 		free(kcp);
277 	}
278 }
279 
280 static void
281 key_call_init(void)
282 {
283 
284 	key_call_key_error = thr_keycreate(&key_call_key, key_call_destroy);
285 }
286 
287 /*
288  * Keep the handle cached.  This call may be made quite often.
289  */
290 static CLIENT *
291 getkeyserv_handle(int vers)
292 {
293 	void *localhandle;
294 	struct netconfig *nconf;
295 	struct netconfig *tpconf;
296 	struct key_call_private *kcp;
297 	struct timeval wait_time;
298 	struct utsname u;
299 	int main_thread;
300 	int fd;
301 
302 #define	TOTAL_TIMEOUT	30	/* total timeout talking to keyserver */
303 #define	TOTAL_TRIES	5	/* Number of tries */
304 
305 	if ((main_thread = thr_main())) {
306 		kcp = key_call_private_main;
307 	} else {
308 		if (thr_once(&key_call_once, key_call_init) != 0 ||
309 		    key_call_key_error != 0)
310 			return ((CLIENT *) NULL);
311 		kcp = (struct key_call_private *)thr_getspecific(key_call_key);
312 	}
313 	if (kcp == (struct key_call_private *)NULL) {
314 		kcp = (struct key_call_private *)malloc(sizeof (*kcp));
315 		if (kcp == (struct key_call_private *)NULL) {
316 			return ((CLIENT *) NULL);
317 		}
318                 if (main_thread)
319                         key_call_private_main = kcp;
320                 else
321                         thr_setspecific(key_call_key, (void *) kcp);
322 		kcp->client = NULL;
323 	}
324 
325 	/* if pid has changed, destroy client and rebuild */
326 	if (kcp->client != NULL && kcp->pid != getpid()) {
327 		clnt_destroy(kcp->client);
328 		kcp->client = NULL;
329 	}
330 
331 	if (kcp->client != NULL) {
332 		/* if uid has changed, build client handle again */
333 		if (kcp->uid != geteuid()) {
334 			kcp->uid = geteuid();
335 			auth_destroy(kcp->client->cl_auth);
336 			kcp->client->cl_auth =
337 				authsys_create("", kcp->uid, 0, 0, NULL);
338 			if (kcp->client->cl_auth == NULL) {
339 				clnt_destroy(kcp->client);
340 				kcp->client = NULL;
341 				return ((CLIENT *) NULL);
342 			}
343 		}
344 		/* Change the version number to the new one */
345 		clnt_control(kcp->client, CLSET_VERS, (void *)&vers);
346 		return (kcp->client);
347 	}
348 	if (!(localhandle = setnetconfig())) {
349 		return ((CLIENT *) NULL);
350 	}
351         tpconf = NULL;
352 #if defined(__FreeBSD__)
353 	if (uname(&u) == -1)
354 #else
355 #if defined(i386)
356 	if (_nuname(&u) == -1)
357 #elif defined(sparc)
358 	if (_uname(&u) == -1)
359 #else
360 #error Unknown architecture!
361 #endif
362 #endif
363 	{
364 		endnetconfig(localhandle);
365 		return ((CLIENT *) NULL);
366         }
367 	while ((nconf = getnetconfig(localhandle)) != NULL) {
368 		if (strcmp(nconf->nc_protofmly, NC_LOOPBACK) == 0) {
369 			/*
370 			 * We use COTS_ORD here so that the caller can
371 			 * find out immediately if the server is dead.
372 			 */
373 			if (nconf->nc_semantics == NC_TPI_COTS_ORD) {
374 				kcp->client = clnt_tp_create(u.nodename,
375 					KEY_PROG, vers, nconf);
376 				if (kcp->client)
377 					break;
378 			} else {
379 				tpconf = nconf;
380 			}
381 		}
382 	}
383 	if ((kcp->client == (CLIENT *) NULL) && (tpconf))
384 		/* Now, try the CLTS or COTS loopback transport */
385 		kcp->client = clnt_tp_create(u.nodename,
386 			KEY_PROG, vers, tpconf);
387 	endnetconfig(localhandle);
388 
389 	if (kcp->client == (CLIENT *) NULL) {
390 		return ((CLIENT *) NULL);
391         }
392 	kcp->uid = geteuid();
393 	kcp->pid = getpid();
394 	kcp->client->cl_auth = authsys_create("", kcp->uid, 0, 0, NULL);
395 	if (kcp->client->cl_auth == NULL) {
396 		clnt_destroy(kcp->client);
397 		kcp->client = NULL;
398 		return ((CLIENT *) NULL);
399 	}
400 
401 	wait_time.tv_sec = TOTAL_TIMEOUT/TOTAL_TRIES;
402 	wait_time.tv_usec = 0;
403 	(void) clnt_control(kcp->client, CLSET_RETRY_TIMEOUT,
404 		(char *)&wait_time);
405 	if (clnt_control(kcp->client, CLGET_FD, (char *)&fd))
406 		_fcntl(fd, F_SETFD, 1);	/* make it "close on exec" */
407 
408 	return (kcp->client);
409 }
410 
411 /* returns  0 on failure, 1 on success */
412 
413 static int
414 key_call(u_long proc, xdrproc_t xdr_arg, void *arg, xdrproc_t xdr_rslt,
415     void *rslt)
416 {
417 	CLIENT *clnt;
418 	struct timeval wait_time;
419 
420 	if (proc == KEY_ENCRYPT_PK && __key_encryptsession_pk_LOCAL) {
421 		cryptkeyres *res;
422 		res = (*__key_encryptsession_pk_LOCAL)(geteuid(), arg);
423 		*(cryptkeyres*)rslt = *res;
424 		return (1);
425 	} else if (proc == KEY_DECRYPT_PK && __key_decryptsession_pk_LOCAL) {
426 		cryptkeyres *res;
427 		res = (*__key_decryptsession_pk_LOCAL)(geteuid(), arg);
428 		*(cryptkeyres*)rslt = *res;
429 		return (1);
430 	} else if (proc == KEY_GEN && __key_gendes_LOCAL) {
431 		des_block *res;
432 		res = (*__key_gendes_LOCAL)(geteuid(), 0);
433 		*(des_block*)rslt = *res;
434 		return (1);
435 	}
436 
437 	if ((proc == KEY_ENCRYPT_PK) || (proc == KEY_DECRYPT_PK) ||
438 	    (proc == KEY_NET_GET) || (proc == KEY_NET_PUT) ||
439 	    (proc == KEY_GET_CONV))
440 		clnt = getkeyserv_handle(2); /* talk to version 2 */
441 	else
442 		clnt = getkeyserv_handle(1); /* talk to version 1 */
443 
444 	if (clnt == NULL) {
445 		return (0);
446 	}
447 
448 	wait_time.tv_sec = TOTAL_TIMEOUT;
449 	wait_time.tv_usec = 0;
450 
451 	if (clnt_call(clnt, proc, xdr_arg, arg, xdr_rslt, rslt,
452 		wait_time) == RPC_SUCCESS) {
453 		return (1);
454 	} else {
455 		return (0);
456 	}
457 }
458