xref: /freebsd/sys/dev/rndtest/rndtest.c (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
1 /*	$OpenBSD$	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-4-Clause
5  *
6  * Copyright (c) 2002 Jason L. Wright (jason@thought.net)
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by Jason L. Wright
20  * 4. The name of the author may not be used to endorse or promote products
21  *    derived from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
25  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
27  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
28  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
29  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
31  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
32  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33  * POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/bus.h>
42 #include <sys/callout.h>
43 #include <sys/kernel.h>
44 #include <sys/malloc.h>
45 #include <sys/module.h>
46 #include <sys/random.h>
47 #include <sys/sysctl.h>
48 #include <machine/stdarg.h>
49 
50 #include <dev/rndtest/rndtest.h>
51 
52 static	void rndtest_test(struct rndtest_state *);
53 static	void rndtest_timeout(void *);
54 
55 /* The tests themselves */
56 static	int rndtest_monobit(struct rndtest_state *);
57 static	int rndtest_runs(struct rndtest_state *);
58 static	int rndtest_longruns(struct rndtest_state *);
59 static	int rndtest_chi_4(struct rndtest_state *);
60 
61 static	int rndtest_runs_check(struct rndtest_state *, int, int *);
62 static	void rndtest_runs_record(struct rndtest_state *, int, int *);
63 
64 static const struct rndtest_testfunc {
65 	int (*test)(struct rndtest_state *);
66 } rndtest_funcs[] = {
67 	{ rndtest_monobit },
68 	{ rndtest_runs },
69 	{ rndtest_chi_4 },
70 	{ rndtest_longruns },
71 };
72 
73 #define	RNDTEST_NTESTS	nitems(rndtest_funcs)
74 
75 static SYSCTL_NODE(_kern, OID_AUTO, rndtest, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
76     "RNG test parameters");
77 static	int rndtest_retest = 120;		/* interval in seconds */
78 SYSCTL_INT(_kern_rndtest, OID_AUTO, retest, CTLFLAG_RW, &rndtest_retest,
79 	    0, "retest interval (seconds)");
80 static struct rndtest_stats rndstats;
81 SYSCTL_STRUCT(_kern_rndtest, OID_AUTO, stats, CTLFLAG_RD, &rndstats,
82 	    rndtest_stats, "RNG test statistics");
83 static	int rndtest_verbose = 1;		/* report only failures */
84 SYSCTL_INT(_kern_rndtest, OID_AUTO, verbose, CTLFLAG_RW, &rndtest_verbose,
85 	    0, "display results on console");
86 
87 struct rndtest_state *
88 rndtest_attach(device_t dev)
89 {
90 	struct rndtest_state *rsp;
91 
92 	rsp = malloc(sizeof (*rsp), M_DEVBUF, M_NOWAIT);
93 	if (rsp != NULL) {
94 		rsp->rs_begin = rsp->rs_buf;
95 		rsp->rs_end = rsp->rs_buf + sizeof(rsp->rs_buf);
96 		rsp->rs_current = rsp->rs_begin;
97 		rsp->rs_discard = 1;
98 		rsp->rs_collect = 1;
99 		rsp->rs_parent = dev;
100 		callout_init(&rsp->rs_to, 1);
101 	} else
102 		device_printf(dev, "rndtest_init: no memory for state block\n");
103 	return (rsp);
104 }
105 
106 void
107 rndtest_detach(struct rndtest_state *rsp)
108 {
109 	callout_stop(&rsp->rs_to);
110 	free(rsp, M_DEVBUF);
111 }
112 
113 void
114 rndtest_harvest(struct rndtest_state *rsp, void *buf, u_int len)
115 {
116 	size_t i;
117 	/*
118 	 * If enabled, collect data and run tests when we have enough.
119 	 */
120 	if (rsp->rs_collect) {
121 		for (i = 0; i < len; i++) {
122 			*rsp->rs_current = ((u_char *) buf)[i];
123 			if (++rsp->rs_current == rsp->rs_end) {
124 				rndtest_test(rsp);
125 				rsp->rs_current = rsp->rs_begin;
126 				/*
127 				 * If tests passed, turn off collection and
128 				 * schedule another test. Otherwise we keep
129 				 * testing until the data looks ok.
130 				 */
131 				if (!rsp->rs_discard && rndtest_retest != 0) {
132 					rsp->rs_collect = 0;
133 					callout_reset(&rsp->rs_to,
134 						hz * rndtest_retest,
135 						rndtest_timeout, rsp);
136 					break;
137 				}
138 			}
139 		}
140 	}
141 	/*
142 	 * Only stir entropy that passes muster into the pool.
143 	 */
144 	if (rsp->rs_discard)
145 		rndstats.rst_discard += len;
146 	else
147 	/* MarkM: FIX!! Check that this does not swamp the harvester! */
148 	random_harvest_queue(buf, len, RANDOM_PURE_RNDTEST);
149 }
150 
151 static void
152 rndtest_test(struct rndtest_state *rsp)
153 {
154 	int i, rv = 0;
155 
156 	rndstats.rst_tests++;
157 	for (i = 0; i < RNDTEST_NTESTS; i++)
158 		rv |= (*rndtest_funcs[i].test)(rsp);
159 	rsp->rs_discard = (rv != 0);
160 }
161 
162 static void
163 rndtest_report(struct rndtest_state *rsp, int failure, const char *fmt, ...)
164 {
165 	char buf[80];
166 	va_list ap;
167 
168 	if (rndtest_verbose == 0)
169 		return;
170 	if (!failure && rndtest_verbose == 1)	/* don't report successes */
171 		return;
172 	va_start(ap, fmt);
173 	vsnprintf(buf, sizeof (buf), fmt, ap);
174 	va_end(ap);
175 	device_printf(rsp->rs_parent, "rndtest: %s\n", buf);
176 }
177 
178 #define	RNDTEST_MONOBIT_MINONES	9725
179 #define	RNDTEST_MONOBIT_MAXONES	10275
180 
181 static int
182 rndtest_monobit(struct rndtest_state *rsp)
183 {
184 	int i, ones = 0, j;
185 	u_int8_t r;
186 
187 	for (i = 0; i < RNDTEST_NBYTES; i++) {
188 		r = rsp->rs_buf[i];
189 		for (j = 0; j < 8; j++, r <<= 1)
190 			if (r & 0x80)
191 				ones++;
192 	}
193 	if (ones > RNDTEST_MONOBIT_MINONES &&
194 	    ones < RNDTEST_MONOBIT_MAXONES) {
195 		if (rndtest_verbose > 1)
196 			rndtest_report(rsp, 0, "monobit pass (%d < %d < %d)",
197 			    RNDTEST_MONOBIT_MINONES, ones,
198 			    RNDTEST_MONOBIT_MAXONES);
199 		return (0);
200 	} else {
201 		if (rndtest_verbose)
202 			rndtest_report(rsp, 1,
203 			    "monobit failed (%d ones)", ones);
204 		rndstats.rst_monobit++;
205 		return (-1);
206 	}
207 }
208 
209 #define	RNDTEST_RUNS_NINTERVAL	6
210 
211 static const struct rndtest_runs_tabs {
212 	u_int16_t min, max;
213 } rndtest_runs_tab[] = {
214 	{ 2343, 2657 },
215 	{ 1135, 1365 },
216 	{ 542, 708 },
217 	{ 251, 373 },
218 	{ 111, 201 },
219 	{ 111, 201 },
220 };
221 
222 static int
223 rndtest_runs(struct rndtest_state *rsp)
224 {
225 	int i, j, ones, zeros, rv = 0;
226 	int onei[RNDTEST_RUNS_NINTERVAL], zeroi[RNDTEST_RUNS_NINTERVAL];
227 	u_int8_t c;
228 
229 	bzero(onei, sizeof(onei));
230 	bzero(zeroi, sizeof(zeroi));
231 	ones = zeros = 0;
232 	for (i = 0; i < RNDTEST_NBYTES; i++) {
233 		c = rsp->rs_buf[i];
234 		for (j = 0; j < 8; j++, c <<= 1) {
235 			if (c & 0x80) {
236 				ones++;
237 				rndtest_runs_record(rsp, zeros, zeroi);
238 				zeros = 0;
239 			} else {
240 				zeros++;
241 				rndtest_runs_record(rsp, ones, onei);
242 				ones = 0;
243 			}
244 		}
245 	}
246 	rndtest_runs_record(rsp, ones, onei);
247 	rndtest_runs_record(rsp, zeros, zeroi);
248 
249 	rv |= rndtest_runs_check(rsp, 0, zeroi);
250 	rv |= rndtest_runs_check(rsp, 1, onei);
251 
252 	if (rv)
253 		rndstats.rst_runs++;
254 
255 	return (rv);
256 }
257 
258 static void
259 rndtest_runs_record(struct rndtest_state *rsp, int len, int *intrv)
260 {
261 	if (len == 0)
262 		return;
263 	if (len > RNDTEST_RUNS_NINTERVAL)
264 		len = RNDTEST_RUNS_NINTERVAL;
265 	len -= 1;
266 	intrv[len]++;
267 }
268 
269 static int
270 rndtest_runs_check(struct rndtest_state *rsp, int val, int *src)
271 {
272 	int i, rv = 0;
273 
274 	for (i = 0; i < RNDTEST_RUNS_NINTERVAL; i++) {
275 		if (src[i] < rndtest_runs_tab[i].min ||
276 		    src[i] > rndtest_runs_tab[i].max) {
277 			rndtest_report(rsp, 1,
278 			    "%s interval %d failed (%d, %d-%d)",
279 			    val ? "ones" : "zeros",
280 			    i + 1, src[i], rndtest_runs_tab[i].min,
281 			    rndtest_runs_tab[i].max);
282 			rv = -1;
283 		} else {
284 			rndtest_report(rsp, 0,
285 			    "runs pass %s interval %d (%d < %d < %d)",
286 			    val ? "ones" : "zeros",
287 			    i + 1, rndtest_runs_tab[i].min, src[i],
288 			    rndtest_runs_tab[i].max);
289 		}
290 	}
291 	return (rv);
292 }
293 
294 static int
295 rndtest_longruns(struct rndtest_state *rsp)
296 {
297 	int i, j, ones = 0, zeros = 0, maxones = 0, maxzeros = 0;
298 	u_int8_t c;
299 
300 	for (i = 0; i < RNDTEST_NBYTES; i++) {
301 		c = rsp->rs_buf[i];
302 		for (j = 0; j < 8; j++, c <<= 1) {
303 			if (c & 0x80) {
304 				zeros = 0;
305 				ones++;
306 				if (ones > maxones)
307 					maxones = ones;
308 			} else {
309 				ones = 0;
310 				zeros++;
311 				if (zeros > maxzeros)
312 					maxzeros = zeros;
313 			}
314 		}
315 	}
316 
317 	if (maxones < 26 && maxzeros < 26) {
318 		rndtest_report(rsp, 0, "longruns pass (%d ones, %d zeros)",
319 			maxones, maxzeros);
320 		return (0);
321 	} else {
322 		rndtest_report(rsp, 1, "longruns fail (%d ones, %d zeros)",
323 			maxones, maxzeros);
324 		rndstats.rst_longruns++;
325 		return (-1);
326 	}
327 }
328 
329 /*
330  * chi^2 test over 4 bits: (this is called the poker test in FIPS 140-2,
331  * but it is really the chi^2 test over 4 bits (the poker test as described
332  * by Knuth vol 2 is something different, and I take him as authoritative
333  * on nomenclature over NIST).
334  */
335 #define	RNDTEST_CHI4_K	16
336 #define	RNDTEST_CHI4_K_MASK	(RNDTEST_CHI4_K - 1)
337 
338 /*
339  * The unnormalized values are used so that we don't have to worry about
340  * fractional precision.  The "real" value is found by:
341  *	(V - 1562500) * (16 / 5000) = Vn   (where V is the unnormalized value)
342  */
343 #define	RNDTEST_CHI4_VMIN	1563181		/* 2.1792 */
344 #define	RNDTEST_CHI4_VMAX	1576929		/* 46.1728 */
345 
346 static int
347 rndtest_chi_4(struct rndtest_state *rsp)
348 {
349 	unsigned int freq[RNDTEST_CHI4_K], i, sum;
350 
351 	for (i = 0; i < RNDTEST_CHI4_K; i++)
352 		freq[i] = 0;
353 
354 	/* Get number of occurrences of each 4 bit pattern */
355 	for (i = 0; i < RNDTEST_NBYTES; i++) {
356 		freq[(rsp->rs_buf[i] >> 4) & RNDTEST_CHI4_K_MASK]++;
357 		freq[(rsp->rs_buf[i] >> 0) & RNDTEST_CHI4_K_MASK]++;
358 	}
359 
360 	for (i = 0, sum = 0; i < RNDTEST_CHI4_K; i++)
361 		sum += freq[i] * freq[i];
362 
363 	if (sum >= 1563181 && sum <= 1576929) {
364 		rndtest_report(rsp, 0, "chi^2(4): pass (sum %u)", sum);
365 		return (0);
366 	} else {
367 		rndtest_report(rsp, 1, "chi^2(4): failed (sum %u)", sum);
368 		rndstats.rst_chi++;
369 		return (-1);
370 	}
371 }
372 
373 static void
374 rndtest_timeout(void *xrsp)
375 {
376 	struct rndtest_state *rsp = xrsp;
377 
378 	rsp->rs_collect = 1;
379 }
380 
381 static int
382 rndtest_modevent(module_t mod, int type, void *unused)
383 {
384 	switch (type) {
385 	case MOD_LOAD:
386 		return 0;
387 	case MOD_UNLOAD:
388 		return 0;
389 	}
390 	return EINVAL;
391 }
392 
393 static moduledata_t rndtest_mod = {
394 	"rndtest",
395 	rndtest_modevent,
396 	0
397 };
398 DECLARE_MODULE(rndtest, rndtest_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
399 MODULE_VERSION(rndtest, 1);
400