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