rndtest.c revision 314667 
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: stable/10/sys/dev/rndtest/rndtest.c 314667 2017-03-04 13:03:31Z avg $");
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#if __FreeBSD_version < 500000
150		/* XXX verify buffer is word aligned */
151		u_int32_t *p = buf;
152		for (len /= sizeof (u_int32_t); len; len--)
153			add_true_randomness(*p++);
154#else
155		random_harvest(buf, len, len*NBBY/2, RANDOM_PURE_RNDTEST);
156#endif
157	}
158}
159
160static void
161rndtest_test(struct rndtest_state *rsp)
162{
163	int i, rv = 0;
164
165	rndstats.rst_tests++;
166	for (i = 0; i < RNDTEST_NTESTS; i++)
167		rv |= (*rndtest_funcs[i].test)(rsp);
168	rsp->rs_discard = (rv != 0);
169}
170
171static void
172rndtest_report(struct rndtest_state *rsp, int failure, const char *fmt, ...)
173{
174	char buf[80];
175	va_list ap;
176
177	if (rndtest_verbose == 0)
178		return;
179	if (!failure && rndtest_verbose == 1)	/* don't report successes */
180		return;
181	va_start(ap, fmt);
182	vsnprintf(buf, sizeof (buf), fmt, ap);
183	va_end(ap);
184	device_printf(rsp->rs_parent, "rndtest: %s\n", buf);
185}
186
187#define	RNDTEST_MONOBIT_MINONES	9725
188#define	RNDTEST_MONOBIT_MAXONES	10275
189
190static int
191rndtest_monobit(struct rndtest_state *rsp)
192{
193	int i, ones = 0, j;
194	u_int8_t r;
195
196	for (i = 0; i < RNDTEST_NBYTES; i++) {
197		r = rsp->rs_buf[i];
198		for (j = 0; j < 8; j++, r <<= 1)
199			if (r & 0x80)
200				ones++;
201	}
202	if (ones > RNDTEST_MONOBIT_MINONES &&
203	    ones < RNDTEST_MONOBIT_MAXONES) {
204		if (rndtest_verbose > 1)
205			rndtest_report(rsp, 0, "monobit pass (%d < %d < %d)",
206			    RNDTEST_MONOBIT_MINONES, ones,
207			    RNDTEST_MONOBIT_MAXONES);
208		return (0);
209	} else {
210		if (rndtest_verbose)
211			rndtest_report(rsp, 1,
212			    "monobit failed (%d ones)", ones);
213		rndstats.rst_monobit++;
214		return (-1);
215	}
216}
217
218#define	RNDTEST_RUNS_NINTERVAL	6
219
220static const struct rndtest_runs_tabs {
221	u_int16_t min, max;
222} rndtest_runs_tab[] = {
223	{ 2343, 2657 },
224	{ 1135, 1365 },
225	{ 542, 708 },
226	{ 251, 373 },
227	{ 111, 201 },
228	{ 111, 201 },
229};
230
231static int
232rndtest_runs(struct rndtest_state *rsp)
233{
234	int i, j, ones, zeros, rv = 0;
235	int onei[RNDTEST_RUNS_NINTERVAL], zeroi[RNDTEST_RUNS_NINTERVAL];
236	u_int8_t c;
237
238	bzero(onei, sizeof(onei));
239	bzero(zeroi, sizeof(zeroi));
240	ones = zeros = 0;
241	for (i = 0; i < RNDTEST_NBYTES; i++) {
242		c = rsp->rs_buf[i];
243		for (j = 0; j < 8; j++, c <<= 1) {
244			if (c & 0x80) {
245				ones++;
246				rndtest_runs_record(rsp, zeros, zeroi);
247				zeros = 0;
248			} else {
249				zeros++;
250				rndtest_runs_record(rsp, ones, onei);
251				ones = 0;
252			}
253		}
254	}
255	rndtest_runs_record(rsp, ones, onei);
256	rndtest_runs_record(rsp, zeros, zeroi);
257
258	rv |= rndtest_runs_check(rsp, 0, zeroi);
259	rv |= rndtest_runs_check(rsp, 1, onei);
260
261	if (rv)
262		rndstats.rst_runs++;
263
264	return (rv);
265}
266
267static void
268rndtest_runs_record(struct rndtest_state *rsp, int len, int *intrv)
269{
270	if (len == 0)
271		return;
272	if (len > RNDTEST_RUNS_NINTERVAL)
273		len = RNDTEST_RUNS_NINTERVAL;
274	len -= 1;
275	intrv[len]++;
276}
277
278static int
279rndtest_runs_check(struct rndtest_state *rsp, int val, int *src)
280{
281	int i, rv = 0;
282
283	for (i = 0; i < RNDTEST_RUNS_NINTERVAL; i++) {
284		if (src[i] < rndtest_runs_tab[i].min ||
285		    src[i] > rndtest_runs_tab[i].max) {
286			rndtest_report(rsp, 1,
287			    "%s interval %d failed (%d, %d-%d)",
288			    val ? "ones" : "zeros",
289			    i + 1, src[i], rndtest_runs_tab[i].min,
290			    rndtest_runs_tab[i].max);
291			rv = -1;
292		} else {
293			rndtest_report(rsp, 0,
294			    "runs pass %s interval %d (%d < %d < %d)",
295			    val ? "ones" : "zeros",
296			    i + 1, rndtest_runs_tab[i].min, src[i],
297			    rndtest_runs_tab[i].max);
298		}
299	}
300	return (rv);
301}
302
303static int
304rndtest_longruns(struct rndtest_state *rsp)
305{
306	int i, j, ones = 0, zeros = 0, maxones = 0, maxzeros = 0;
307	u_int8_t c;
308
309	for (i = 0; i < RNDTEST_NBYTES; i++) {
310		c = rsp->rs_buf[i];
311		for (j = 0; j < 8; j++, c <<= 1) {
312			if (c & 0x80) {
313				zeros = 0;
314				ones++;
315				if (ones > maxones)
316					maxones = ones;
317			} else {
318				ones = 0;
319				zeros++;
320				if (zeros > maxzeros)
321					maxzeros = zeros;
322			}
323		}
324	}
325
326	if (maxones < 26 && maxzeros < 26) {
327		rndtest_report(rsp, 0, "longruns pass (%d ones, %d zeros)",
328			maxones, maxzeros);
329		return (0);
330	} else {
331		rndtest_report(rsp, 1, "longruns fail (%d ones, %d zeros)",
332			maxones, maxzeros);
333		rndstats.rst_longruns++;
334		return (-1);
335	}
336}
337
338/*
339 * chi^2 test over 4 bits: (this is called the poker test in FIPS 140-2,
340 * but it is really the chi^2 test over 4 bits (the poker test as described
341 * by Knuth vol 2 is something different, and I take him as authoritative
342 * on nomenclature over NIST).
343 */
344#define	RNDTEST_CHI4_K	16
345#define	RNDTEST_CHI4_K_MASK	(RNDTEST_CHI4_K - 1)
346
347/*
348 * The unnormalized values are used so that we don't have to worry about
349 * fractional precision.  The "real" value is found by:
350 *	(V - 1562500) * (16 / 5000) = Vn   (where V is the unnormalized value)
351 */
352#define	RNDTEST_CHI4_VMIN	1563181		/* 2.1792 */
353#define	RNDTEST_CHI4_VMAX	1576929		/* 46.1728 */
354
355static int
356rndtest_chi_4(struct rndtest_state *rsp)
357{
358	unsigned int freq[RNDTEST_CHI4_K], i, sum;
359
360	for (i = 0; i < RNDTEST_CHI4_K; i++)
361		freq[i] = 0;
362
363	/* Get number of occurrences of each 4 bit pattern */
364	for (i = 0; i < RNDTEST_NBYTES; i++) {
365		freq[(rsp->rs_buf[i] >> 4) & RNDTEST_CHI4_K_MASK]++;
366		freq[(rsp->rs_buf[i] >> 0) & RNDTEST_CHI4_K_MASK]++;
367	}
368
369	for (i = 0, sum = 0; i < RNDTEST_CHI4_K; i++)
370		sum += freq[i] * freq[i];
371
372	if (sum >= 1563181 && sum <= 1576929) {
373		rndtest_report(rsp, 0, "chi^2(4): pass (sum %u)", sum);
374		return (0);
375	} else {
376		rndtest_report(rsp, 1, "chi^2(4): failed (sum %u)", sum);
377		rndstats.rst_chi++;
378		return (-1);
379	}
380}
381
382static void
383rndtest_timeout(void *xrsp)
384{
385	struct rndtest_state *rsp = xrsp;
386
387	rsp->rs_collect = 1;
388}
389
390static int
391rndtest_modevent(module_t mod, int type, void *unused)
392{
393	switch (type) {
394	case MOD_LOAD:
395		return 0;
396	case MOD_UNLOAD:
397		return 0;
398	}
399	return EINVAL;
400}
401
402static moduledata_t rndtest_mod = {
403	"rndtest",
404	rndtest_modevent,
405	0
406};
407DECLARE_MODULE(rndtest, rndtest_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
408MODULE_VERSION(rndtest, 1);
409