rndtest.c revision 284959 
1/*	$OpenBSD$	*/
2
3/*-
4 * Copyright (c) 2002 Jason L. Wright (jason@thought.net)
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 Jason L. Wright
18 * 4. The name of the author may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
25 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
26 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
27 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
29 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
30 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: head/sys/dev/rndtest/rndtest.c 284959 2015-06-30 17:00:45Z markm $");
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/bus.h>
40#include <sys/callout.h>
41#include <sys/kernel.h>
42#include <sys/malloc.h>
43#include <sys/module.h>
44#include <sys/random.h>
45#include <sys/sysctl.h>
46#include <machine/stdarg.h>
47
48#include <dev/rndtest/rndtest.h>
49
50static	void rndtest_test(struct rndtest_state *);
51static	void rndtest_timeout(void *);
52
53/* The tests themselves */
54static	int rndtest_monobit(struct rndtest_state *);
55static	int rndtest_runs(struct rndtest_state *);
56static	int rndtest_longruns(struct rndtest_state *);
57static	int rndtest_chi_4(struct rndtest_state *);
58
59static	int rndtest_runs_check(struct rndtest_state *, int, int *);
60static	void rndtest_runs_record(struct rndtest_state *, int, int *);
61
62static const struct rndtest_testfunc {
63	int (*test)(struct rndtest_state *);
64} rndtest_funcs[] = {
65	{ rndtest_monobit },
66	{ rndtest_runs },
67	{ rndtest_chi_4 },
68	{ rndtest_longruns },
69};
70
71#define	RNDTEST_NTESTS	(sizeof(rndtest_funcs)/sizeof(rndtest_funcs[0]))
72
73static SYSCTL_NODE(_kern, OID_AUTO, rndtest, CTLFLAG_RD, 0,
74	    "RNG test parameters");
75static	int rndtest_retest = 120;		/* interval in seconds */
76SYSCTL_INT(_kern_rndtest, OID_AUTO, retest, CTLFLAG_RW, &rndtest_retest,
77	    0, "retest interval (seconds)");
78static struct rndtest_stats rndstats;
79SYSCTL_STRUCT(_kern_rndtest, OID_AUTO, stats, CTLFLAG_RD, &rndstats,
80	    rndtest_stats, "RNG test statistics");
81static	int rndtest_verbose = 1;		/* report only failures */
82SYSCTL_INT(_kern_rndtest, OID_AUTO, verbose, CTLFLAG_RW, &rndtest_verbose,
83	    0, "display results on console");
84
85struct rndtest_state *
86rndtest_attach(device_t dev)
87{
88	struct rndtest_state *rsp;
89
90	rsp = malloc(sizeof (*rsp), M_DEVBUF, M_NOWAIT);
91	if (rsp != NULL) {
92		rsp->rs_begin = rsp->rs_buf;
93		rsp->rs_end = rsp->rs_buf + sizeof(rsp->rs_buf);
94		rsp->rs_current = rsp->rs_begin;
95		rsp->rs_discard = 1;
96		rsp->rs_collect = 1;
97		rsp->rs_parent = dev;
98#if __FreeBSD_version < 500000
99		callout_init(&rsp->rs_to);
100#else
101		callout_init(&rsp->rs_to, 1);
102#endif
103	} else
104		device_printf(dev, "rndtest_init: no memory for state block\n");
105	return (rsp);
106}
107
108void
109rndtest_detach(struct rndtest_state *rsp)
110{
111	callout_stop(&rsp->rs_to);
112	free(rsp, M_DEVBUF);
113}
114
115void
116rndtest_harvest(struct rndtest_state *rsp, void *buf, u_int len)
117{
118	size_t i;
119	/*
120	 * If enabled, collect data and run tests when we have enough.
121	 */
122	if (rsp->rs_collect) {
123		for (i = 0; i < len; i++) {
124			*rsp->rs_current = ((u_char *) buf)[i];
125			if (++rsp->rs_current == rsp->rs_end) {
126				rndtest_test(rsp);
127				rsp->rs_current = rsp->rs_begin;
128				/*
129				 * If tests passed, turn off collection and
130				 * schedule another test. Otherwise we keep
131				 * testing until the data looks ok.
132				 */
133				if (!rsp->rs_discard && rndtest_retest != 0) {
134					rsp->rs_collect = 0;
135					callout_reset(&rsp->rs_to,
136						hz * rndtest_retest,
137						rndtest_timeout, rsp);
138					break;
139				}
140			}
141		}
142	}
143	/*
144	 * Only stir entropy that passes muster into the pool.
145	 */
146	if (rsp->rs_discard)
147		rndstats.rst_discard += len;
148	else
149	/* MarkM: FIX!! Check that this does not swamp the harvester! */
150	random_harvest_queue(buf, len, len*NBBY/2, RANDOM_PURE_RNDTEST);
151}
152
153static void
154rndtest_test(struct rndtest_state *rsp)
155{
156	int i, rv = 0;
157
158	rndstats.rst_tests++;
159	for (i = 0; i < RNDTEST_NTESTS; i++)
160		rv |= (*rndtest_funcs[i].test)(rsp);
161	rsp->rs_discard = (rv != 0);
162}
163
164static void
165rndtest_report(struct rndtest_state *rsp, int failure, const char *fmt, ...)
166{
167	char buf[80];
168	va_list ap;
169
170	if (rndtest_verbose == 0)
171		return;
172	if (!failure && rndtest_verbose == 1)	/* don't report successes */
173		return;
174	va_start(ap, fmt);
175	vsnprintf(buf, sizeof (buf), fmt, ap);
176	va_end(ap);
177	device_printf(rsp->rs_parent, "rndtest: %s\n", buf);
178}
179
180#define	RNDTEST_MONOBIT_MINONES	9725
181#define	RNDTEST_MONOBIT_MAXONES	10275
182
183static int
184rndtest_monobit(struct rndtest_state *rsp)
185{
186	int i, ones = 0, j;
187	u_int8_t r;
188
189	for (i = 0; i < RNDTEST_NBYTES; i++) {
190		r = rsp->rs_buf[i];
191		for (j = 0; j < 8; j++, r <<= 1)
192			if (r & 0x80)
193				ones++;
194	}
195	if (ones > RNDTEST_MONOBIT_MINONES &&
196	    ones < RNDTEST_MONOBIT_MAXONES) {
197		if (rndtest_verbose > 1)
198			rndtest_report(rsp, 0, "monobit pass (%d < %d < %d)",
199			    RNDTEST_MONOBIT_MINONES, ones,
200			    RNDTEST_MONOBIT_MAXONES);
201		return (0);
202	} else {
203		if (rndtest_verbose)
204			rndtest_report(rsp, 1,
205			    "monobit failed (%d ones)", ones);
206		rndstats.rst_monobit++;
207		return (-1);
208	}
209}
210
211#define	RNDTEST_RUNS_NINTERVAL	6
212
213static const struct rndtest_runs_tabs {
214	u_int16_t min, max;
215} rndtest_runs_tab[] = {
216	{ 2343, 2657 },
217	{ 1135, 1365 },
218	{ 542, 708 },
219	{ 251, 373 },
220	{ 111, 201 },
221	{ 111, 201 },
222};
223
224static int
225rndtest_runs(struct rndtest_state *rsp)
226{
227	int i, j, ones, zeros, rv = 0;
228	int onei[RNDTEST_RUNS_NINTERVAL], zeroi[RNDTEST_RUNS_NINTERVAL];
229	u_int8_t c;
230
231	bzero(onei, sizeof(onei));
232	bzero(zeroi, sizeof(zeroi));
233	ones = zeros = 0;
234	for (i = 0; i < RNDTEST_NBYTES; i++) {
235		c = rsp->rs_buf[i];
236		for (j = 0; j < 8; j++, c <<= 1) {
237			if (c & 0x80) {
238				ones++;
239				rndtest_runs_record(rsp, zeros, zeroi);
240				zeros = 0;
241			} else {
242				zeros++;
243				rndtest_runs_record(rsp, ones, onei);
244				ones = 0;
245			}
246		}
247	}
248	rndtest_runs_record(rsp, ones, onei);
249	rndtest_runs_record(rsp, zeros, zeroi);
250
251	rv |= rndtest_runs_check(rsp, 0, zeroi);
252	rv |= rndtest_runs_check(rsp, 1, onei);
253
254	if (rv)
255		rndstats.rst_runs++;
256
257	return (rv);
258}
259
260static void
261rndtest_runs_record(struct rndtest_state *rsp, int len, int *intrv)
262{
263	if (len == 0)
264		return;
265	if (len > RNDTEST_RUNS_NINTERVAL)
266		len = RNDTEST_RUNS_NINTERVAL;
267	len -= 1;
268	intrv[len]++;
269}
270
271static int
272rndtest_runs_check(struct rndtest_state *rsp, int val, int *src)
273{
274	int i, rv = 0;
275
276	for (i = 0; i < RNDTEST_RUNS_NINTERVAL; i++) {
277		if (src[i] < rndtest_runs_tab[i].min ||
278		    src[i] > rndtest_runs_tab[i].max) {
279			rndtest_report(rsp, 1,
280			    "%s interval %d failed (%d, %d-%d)",
281			    val ? "ones" : "zeros",
282			    i + 1, src[i], rndtest_runs_tab[i].min,
283			    rndtest_runs_tab[i].max);
284			rv = -1;
285		} else {
286			rndtest_report(rsp, 0,
287			    "runs pass %s interval %d (%d < %d < %d)",
288			    val ? "ones" : "zeros",
289			    i + 1, rndtest_runs_tab[i].min, src[i],
290			    rndtest_runs_tab[i].max);
291		}
292	}
293	return (rv);
294}
295
296static int
297rndtest_longruns(struct rndtest_state *rsp)
298{
299	int i, j, ones = 0, zeros = 0, maxones = 0, maxzeros = 0;
300	u_int8_t c;
301
302	for (i = 0; i < RNDTEST_NBYTES; i++) {
303		c = rsp->rs_buf[i];
304		for (j = 0; j < 8; j++, c <<= 1) {
305			if (c & 0x80) {
306				zeros = 0;
307				ones++;
308				if (ones > maxones)
309					maxones = ones;
310			} else {
311				ones = 0;
312				zeros++;
313				if (zeros > maxzeros)
314					maxzeros = zeros;
315			}
316		}
317	}
318
319	if (maxones < 26 && maxzeros < 26) {
320		rndtest_report(rsp, 0, "longruns pass (%d ones, %d zeros)",
321			maxones, maxzeros);
322		return (0);
323	} else {
324		rndtest_report(rsp, 1, "longruns fail (%d ones, %d zeros)",
325			maxones, maxzeros);
326		rndstats.rst_longruns++;
327		return (-1);
328	}
329}
330
331/*
332 * chi^2 test over 4 bits: (this is called the poker test in FIPS 140-2,
333 * but it is really the chi^2 test over 4 bits (the poker test as described
334 * by Knuth vol 2 is something different, and I take him as authoritative
335 * on nomenclature over NIST).
336 */
337#define	RNDTEST_CHI4_K	16
338#define	RNDTEST_CHI4_K_MASK	(RNDTEST_CHI4_K - 1)
339
340/*
341 * The unnormalized values are used so that we don't have to worry about
342 * fractional precision.  The "real" value is found by:
343 *	(V - 1562500) * (16 / 5000) = Vn   (where V is the unnormalized value)
344 */
345#define	RNDTEST_CHI4_VMIN	1563181		/* 2.1792 */
346#define	RNDTEST_CHI4_VMAX	1576929		/* 46.1728 */
347
348static int
349rndtest_chi_4(struct rndtest_state *rsp)
350{
351	unsigned int freq[RNDTEST_CHI4_K], i, sum;
352
353	for (i = 0; i < RNDTEST_CHI4_K; i++)
354		freq[i] = 0;
355
356	/* Get number of occurrences of each 4 bit pattern */
357	for (i = 0; i < RNDTEST_NBYTES; i++) {
358		freq[(rsp->rs_buf[i] >> 4) & RNDTEST_CHI4_K_MASK]++;
359		freq[(rsp->rs_buf[i] >> 0) & RNDTEST_CHI4_K_MASK]++;
360	}
361
362	for (i = 0, sum = 0; i < RNDTEST_CHI4_K; i++)
363		sum += freq[i] * freq[i];
364
365	if (sum >= 1563181 && sum <= 1576929) {
366		rndtest_report(rsp, 0, "chi^2(4): pass (sum %u)", sum);
367		return (0);
368	} else {
369		rndtest_report(rsp, 1, "chi^2(4): failed (sum %u)", sum);
370		rndstats.rst_chi++;
371		return (-1);
372	}
373}
374
375static void
376rndtest_timeout(void *xrsp)
377{
378	struct rndtest_state *rsp = xrsp;
379
380	rsp->rs_collect = 1;
381}
382
383static int
384rndtest_modevent(module_t mod, int type, void *unused)
385{
386	switch (type) {
387	case MOD_LOAD:
388		return 0;
389	case MOD_UNLOAD:
390		return 0;
391	}
392	return EINVAL;
393}
394
395static moduledata_t rndtest_mod = {
396	"rndtest",
397	rndtest_modevent,
398	0
399};
400DECLARE_MODULE(rndtest, rndtest_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
401MODULE_VERSION(rndtest, 1);
402