1 /*	$NetBSD: rand.c,v 1.1.1.1 2011/04/13 18:14:50 elric Exp $	*/
2 
3 /*
4  * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
5  * (Royal Institute of Technology, Stockholm, Sweden).
6  * All rights reserved.
7  *
8  * Portions Copyright (c) 2009 Apple Inc. All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  *
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  *
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * 3. Neither the name of the Institute nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 
38 #include <config.h>
39 
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <rand.h>
43 #include <randi.h>
44 
45 #include <krb5/roken.h>
46 
47 #ifndef O_BINARY
48 #define O_BINARY 0
49 #endif
50 
51 #ifdef _WIN32
52 #include<shlobj.h>
53 #endif
54 
55 /**
56  * @page page_rand RAND - random number
57  *
58  * See the library functions here: @ref hcrypto_rand
59  */
60 
61 const static RAND_METHOD *selected_meth = NULL;
62 static ENGINE *selected_engine = NULL;
63 
64 static void
65 init_method(void)
66 {
67     if (selected_meth != NULL)
68 	return;
69 #if defined(_WIN32)
70     selected_meth = &hc_rand_w32crypto_method;
71 #elif defined(__APPLE__)
72     selected_meth = &hc_rand_unix_method;
73 #else
74     selected_meth = &hc_rand_fortuna_method;
75 #endif
76 }
77 
78 /**
79  * Seed that random number generator. Secret material can securely be
80  * feed into the function, they will never be returned.
81  *
82  * @param indata seed data
83  * @param size length seed data
84  *
85  * @ingroup hcrypto_rand
86  */
87 
88 void
89 RAND_seed(const void *indata, size_t size)
90 {
91     init_method();
92     (*selected_meth->seed)(indata, size);
93 }
94 
95 /**
96  * Get a random block from the random generator, can be used for key material.
97  *
98  * @param outdata random data
99  * @param size length random data
100  *
101  * @return 1 on success, 0 on failure.
102  *
103  * @ingroup hcrypto_rand
104  */
105 int
106 RAND_bytes(void *outdata, size_t size)
107 {
108     if (size == 0)
109 	return 1;
110     init_method();
111     return (*selected_meth->bytes)(outdata, size);
112 }
113 
114 /**
115  * Reset and free memory used by the random generator.
116  *
117  * @ingroup hcrypto_rand
118  */
119 
120 void
121 RAND_cleanup(void)
122 {
123     const RAND_METHOD *meth = selected_meth;
124     ENGINE *engine = selected_engine;
125 
126     selected_meth = NULL;
127     selected_engine = NULL;
128 
129     if (meth)
130 	(*meth->cleanup)();
131     if (engine)
132 	ENGINE_finish(engine);
133 }
134 
135 /**
136  * Seed that random number generator. Secret material can securely be
137  * feed into the function, they will never be returned.
138  *
139  * @param indata the input data.
140  * @param size size of in data.
141  * @param entropi entropi in data.
142  *
143  *
144  * @ingroup hcrypto_rand
145  */
146 
147 void
148 RAND_add(const void *indata, size_t size, double entropi)
149 {
150     init_method();
151     (*selected_meth->add)(indata, size, entropi);
152 }
153 
154 /**
155  * Get a random block from the random generator, should NOT be used for key material.
156  *
157  * @param outdata random data
158  * @param size length random data
159  *
160  * @return 1 on success, 0 on failure.
161  *
162  * @ingroup hcrypto_rand
163  */
164 
165 int
166 RAND_pseudo_bytes(void *outdata, size_t size)
167 {
168     init_method();
169     return (*selected_meth->pseudorand)(outdata, size);
170 }
171 
172 /**
173  * Return status of the random generator
174  *
175  * @return 1 if the random generator can deliver random data.
176  *
177  * @ingroup hcrypto_rand
178  */
179 
180 int
181 RAND_status(void)
182 {
183     init_method();
184     return (*selected_meth->status)();
185 }
186 
187 /**
188  * Set the default random method.
189  *
190  * @param meth set the new default method.
191  *
192  * @return 1 on success.
193  *
194  * @ingroup hcrypto_rand
195  */
196 
197 int
198 RAND_set_rand_method(const RAND_METHOD *meth)
199 {
200     const RAND_METHOD *old = selected_meth;
201     selected_meth = meth;
202     if (old)
203 	(*old->cleanup)();
204     if (selected_engine) {
205 	ENGINE_finish(selected_engine);
206 	selected_engine = NULL;
207     }
208     return 1;
209 }
210 
211 /**
212  * Get the default random method.
213  *
214  * @ingroup hcrypto_rand
215  */
216 
217 const RAND_METHOD *
218 RAND_get_rand_method(void)
219 {
220     init_method();
221     return selected_meth;
222 }
223 
224 /**
225  * Set the default random method from engine.
226  *
227  * @param engine use engine, if NULL is passed it, old method and engine is cleared.
228  *
229  * @return 1 on success, 0 on failure.
230  *
231  * @ingroup hcrypto_rand
232  */
233 
234 int
235 RAND_set_rand_engine(ENGINE *engine)
236 {
237     const RAND_METHOD *meth, *old = selected_meth;
238 
239     if (engine) {
240 	ENGINE_up_ref(engine);
241 	meth = ENGINE_get_RAND(engine);
242 	if (meth == NULL) {
243 	    ENGINE_finish(engine);
244 	    return 0;
245 	}
246     } else {
247 	meth = NULL;
248     }
249 
250     if (old)
251 	(*old->cleanup)();
252 
253     if (selected_engine)
254 	ENGINE_finish(selected_engine);
255 
256     selected_engine = engine;
257     selected_meth = meth;
258 
259     return 1;
260 }
261 
262 #define RAND_FILE_SIZE 1024
263 
264 /**
265  * Load a a file and feed it into RAND_seed().
266  *
267  * @param filename name of file to read.
268  * @param size minimum size to read.
269  *
270  * @ingroup hcrypto_rand
271  */
272 
273 int
274 RAND_load_file(const char *filename, size_t size)
275 {
276     unsigned char buf[128];
277     size_t len;
278     ssize_t slen;
279     int fd;
280 
281     fd = open(filename, O_RDONLY | O_BINARY, 0600);
282     if (fd < 0)
283 	return 0;
284     rk_cloexec(fd);
285     len = 0;
286     while(len < size) {
287 	slen = read(fd, buf, sizeof(buf));
288 	if (slen <= 0)
289 	    break;
290 	RAND_seed(buf, slen);
291 	len += slen;
292     }
293     close(fd);
294 
295     return len ? 1 : 0;
296 }
297 
298 /**
299  * Write of random numbers to a file to store for later initiation with RAND_load_file().
300  *
301  * @param filename name of file to write.
302  *
303  * @return 1 on success and non-one on failure.
304  * @ingroup hcrypto_rand
305  */
306 
307 int
308 RAND_write_file(const char *filename)
309 {
310     unsigned char buf[128];
311     size_t len;
312     int res = 0, fd;
313 
314     fd = open(filename, O_WRONLY | O_CREAT | O_BINARY, 0600);
315     if (fd < 0)
316 	return 0;
317     rk_cloexec(fd);
318 
319     len = 0;
320     while(len < RAND_FILE_SIZE) {
321 	res = RAND_bytes(buf, sizeof(buf));
322 	if (res != 1)
323 	    break;
324 	if (write(fd, buf, sizeof(buf)) != sizeof(buf)) {
325 	    res = 0;
326 	    break;
327 	}
328 	len += sizeof(buf);
329     }
330 
331     close(fd);
332 
333     return res;
334 }
335 
336 /**
337  * Return the default random state filename for a user to use for
338  * RAND_load_file(), and RAND_write_file().
339  *
340  * @param filename buffer to hold file name.
341  * @param size size of buffer filename.
342  *
343  * @return the buffer filename or NULL on failure.
344  *
345  * @ingroup hcrypto_rand
346  */
347 
348 const char *
349 RAND_file_name(char *filename, size_t size)
350 {
351     const char *e = NULL;
352     int pathp = 0, ret;
353 
354     if (!issuid()) {
355 	e = getenv("RANDFILE");
356 	if (e == NULL)
357 	    e = getenv("HOME");
358 	if (e)
359 	    pathp = 1;
360     }
361 
362 #ifndef _WIN32
363     /*
364      * Here we really want to call getpwuid(getuid()) but this will
365      * cause recursive lookups if the nss library uses
366      * gssapi/krb5/hcrypto to authenticate to the ldap servers.
367      *
368      * So at least return the unix /dev/random if we have one
369      */
370     if (e == NULL) {
371 	int fd;
372 
373 	fd = _hc_unix_device_fd(O_RDONLY, &e);
374 	if (fd >= 0)
375 	    close(fd);
376     }
377 #else  /* Win32 */
378 
379     if (e == NULL) {
380 	char profile[MAX_PATH];
381 
382 	if (SHGetFolderPath(NULL, CSIDL_LOCAL_APPDATA, NULL,
383 			    SHGFP_TYPE_CURRENT, profile) == S_OK) {
384 	    ret = snprintf(filename, size, "%s\\.rnd", profile);
385 
386 	    if (ret > 0 && ret < size)
387 		return filename;
388 	}
389     }
390 
391 #endif
392 
393     if (e == NULL)
394 	return NULL;
395 
396     if (pathp)
397 	ret = snprintf(filename, size, "%s/.rnd", e);
398     else
399 	ret = snprintf(filename, size, "%s", e);
400 
401     if (ret <= 0 || ret >= size)
402 	return NULL;
403 
404     return filename;
405 }
406