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
52static	void rndtest_test(struct rndtest_state *);
53static	void rndtest_timeout(void *);
54
55/* The tests themselves */
56static	int rndtest_monobit(struct rndtest_state *);
57static	int rndtest_runs(struct rndtest_state *);
58static	int rndtest_longruns(struct rndtest_state *);
59static	int rndtest_chi_4(struct rndtest_state *);
60
61static	int rndtest_runs_check(struct rndtest_state *, int, int *);
62static	void rndtest_runs_record(struct rndtest_state *, int, int *);
63
64static 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
75static SYSCTL_NODE(_kern, OID_AUTO, rndtest, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
76    "RNG test parameters");
77static	int rndtest_retest = 120;		/* interval in seconds */
78SYSCTL_INT(_kern_rndtest, OID_AUTO, retest, CTLFLAG_RW, &rndtest_retest,
79	    0, "retest interval (seconds)");
80static struct rndtest_stats rndstats;
81SYSCTL_STRUCT(_kern_rndtest, OID_AUTO, stats, CTLFLAG_RD, &rndstats,
82	    rndtest_stats, "RNG test statistics");
83static	int rndtest_verbose = 1;		/* report only failures */
84SYSCTL_INT(_kern_rndtest, OID_AUTO, verbose, CTLFLAG_RW, &rndtest_verbose,
85	    0, "display results on console");
86
87struct rndtest_state *
88rndtest_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
106void
107rndtest_detach(struct rndtest_state *rsp)
108{
109	callout_stop(&rsp->rs_to);
110	free(rsp, M_DEVBUF);
111}
112
113void
114rndtest_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
151static void
152rndtest_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
162static void
163rndtest_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
181static int
182rndtest_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
211static 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
222static int
223rndtest_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
258static void
259rndtest_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
269static int
270rndtest_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
294static int
295rndtest_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
346static int
347rndtest_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
373static void
374rndtest_timeout(void *xrsp)
375{
376	struct rndtest_state *rsp = xrsp;
377
378	rsp->rs_collect = 1;
379}
380
381static int
382rndtest_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
393static moduledata_t rndtest_mod = {
394	"rndtest",
395	rndtest_modevent,
396	0
397};
398DECLARE_MODULE(rndtest, rndtest_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
399MODULE_VERSION(rndtest, 1);
400