1 /* $OpenBSD$ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-4-Clause
5 *
6 * Copyright (c) 2002 Jason L. Wright ([email protected])
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, 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 *
rndtest_attach(device_t dev)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 #if __FreeBSD_version < 500000
101 callout_init(&rsp->rs_to);
102 #else
103 callout_init(&rsp->rs_to, 1);
104 #endif
105 } else
106 device_printf(dev, "rndtest_init: no memory for state block\n");
107 return (rsp);
108 }
109
110 void
rndtest_detach(struct rndtest_state * rsp)111 rndtest_detach(struct rndtest_state *rsp)
112 {
113 callout_stop(&rsp->rs_to);
114 free(rsp, M_DEVBUF);
115 }
116
117 void
rndtest_harvest(struct rndtest_state * rsp,void * buf,u_int len)118 rndtest_harvest(struct rndtest_state *rsp, void *buf, u_int len)
119 {
120 size_t i;
121 /*
122 * If enabled, collect data and run tests when we have enough.
123 */
124 if (rsp->rs_collect) {
125 for (i = 0; i < len; i++) {
126 *rsp->rs_current = ((u_char *) buf)[i];
127 if (++rsp->rs_current == rsp->rs_end) {
128 rndtest_test(rsp);
129 rsp->rs_current = rsp->rs_begin;
130 /*
131 * If tests passed, turn off collection and
132 * schedule another test. Otherwise we keep
133 * testing until the data looks ok.
134 */
135 if (!rsp->rs_discard && rndtest_retest != 0) {
136 rsp->rs_collect = 0;
137 callout_reset(&rsp->rs_to,
138 hz * rndtest_retest,
139 rndtest_timeout, rsp);
140 break;
141 }
142 }
143 }
144 }
145 /*
146 * Only stir entropy that passes muster into the pool.
147 */
148 if (rsp->rs_discard)
149 rndstats.rst_discard += len;
150 else
151 /* MarkM: FIX!! Check that this does not swamp the harvester! */
152 random_harvest_queue(buf, len, RANDOM_PURE_RNDTEST);
153 }
154
155 static void
rndtest_test(struct rndtest_state * rsp)156 rndtest_test(struct rndtest_state *rsp)
157 {
158 int i, rv = 0;
159
160 rndstats.rst_tests++;
161 for (i = 0; i < RNDTEST_NTESTS; i++)
162 rv |= (*rndtest_funcs[i].test)(rsp);
163 rsp->rs_discard = (rv != 0);
164 }
165
166 static void
rndtest_report(struct rndtest_state * rsp,int failure,const char * fmt,...)167 rndtest_report(struct rndtest_state *rsp, int failure, const char *fmt, ...)
168 {
169 char buf[80];
170 va_list ap;
171
172 if (rndtest_verbose == 0)
173 return;
174 if (!failure && rndtest_verbose == 1) /* don't report successes */
175 return;
176 va_start(ap, fmt);
177 vsnprintf(buf, sizeof (buf), fmt, ap);
178 va_end(ap);
179 device_printf(rsp->rs_parent, "rndtest: %s\n", buf);
180 }
181
182 #define RNDTEST_MONOBIT_MINONES 9725
183 #define RNDTEST_MONOBIT_MAXONES 10275
184
185 static int
rndtest_monobit(struct rndtest_state * rsp)186 rndtest_monobit(struct rndtest_state *rsp)
187 {
188 int i, ones = 0, j;
189 u_int8_t r;
190
191 for (i = 0; i < RNDTEST_NBYTES; i++) {
192 r = rsp->rs_buf[i];
193 for (j = 0; j < 8; j++, r <<= 1)
194 if (r & 0x80)
195 ones++;
196 }
197 if (ones > RNDTEST_MONOBIT_MINONES &&
198 ones < RNDTEST_MONOBIT_MAXONES) {
199 if (rndtest_verbose > 1)
200 rndtest_report(rsp, 0, "monobit pass (%d < %d < %d)",
201 RNDTEST_MONOBIT_MINONES, ones,
202 RNDTEST_MONOBIT_MAXONES);
203 return (0);
204 } else {
205 if (rndtest_verbose)
206 rndtest_report(rsp, 1,
207 "monobit failed (%d ones)", ones);
208 rndstats.rst_monobit++;
209 return (-1);
210 }
211 }
212
213 #define RNDTEST_RUNS_NINTERVAL 6
214
215 static const struct rndtest_runs_tabs {
216 u_int16_t min, max;
217 } rndtest_runs_tab[] = {
218 { 2343, 2657 },
219 { 1135, 1365 },
220 { 542, 708 },
221 { 251, 373 },
222 { 111, 201 },
223 { 111, 201 },
224 };
225
226 static int
rndtest_runs(struct rndtest_state * rsp)227 rndtest_runs(struct rndtest_state *rsp)
228 {
229 int i, j, ones, zeros, rv = 0;
230 int onei[RNDTEST_RUNS_NINTERVAL], zeroi[RNDTEST_RUNS_NINTERVAL];
231 u_int8_t c;
232
233 bzero(onei, sizeof(onei));
234 bzero(zeroi, sizeof(zeroi));
235 ones = zeros = 0;
236 for (i = 0; i < RNDTEST_NBYTES; i++) {
237 c = rsp->rs_buf[i];
238 for (j = 0; j < 8; j++, c <<= 1) {
239 if (c & 0x80) {
240 ones++;
241 rndtest_runs_record(rsp, zeros, zeroi);
242 zeros = 0;
243 } else {
244 zeros++;
245 rndtest_runs_record(rsp, ones, onei);
246 ones = 0;
247 }
248 }
249 }
250 rndtest_runs_record(rsp, ones, onei);
251 rndtest_runs_record(rsp, zeros, zeroi);
252
253 rv |= rndtest_runs_check(rsp, 0, zeroi);
254 rv |= rndtest_runs_check(rsp, 1, onei);
255
256 if (rv)
257 rndstats.rst_runs++;
258
259 return (rv);
260 }
261
262 static void
rndtest_runs_record(struct rndtest_state * rsp,int len,int * intrv)263 rndtest_runs_record(struct rndtest_state *rsp, int len, int *intrv)
264 {
265 if (len == 0)
266 return;
267 if (len > RNDTEST_RUNS_NINTERVAL)
268 len = RNDTEST_RUNS_NINTERVAL;
269 len -= 1;
270 intrv[len]++;
271 }
272
273 static int
rndtest_runs_check(struct rndtest_state * rsp,int val,int * src)274 rndtest_runs_check(struct rndtest_state *rsp, int val, int *src)
275 {
276 int i, rv = 0;
277
278 for (i = 0; i < RNDTEST_RUNS_NINTERVAL; i++) {
279 if (src[i] < rndtest_runs_tab[i].min ||
280 src[i] > rndtest_runs_tab[i].max) {
281 rndtest_report(rsp, 1,
282 "%s interval %d failed (%d, %d-%d)",
283 val ? "ones" : "zeros",
284 i + 1, src[i], rndtest_runs_tab[i].min,
285 rndtest_runs_tab[i].max);
286 rv = -1;
287 } else {
288 rndtest_report(rsp, 0,
289 "runs pass %s interval %d (%d < %d < %d)",
290 val ? "ones" : "zeros",
291 i + 1, rndtest_runs_tab[i].min, src[i],
292 rndtest_runs_tab[i].max);
293 }
294 }
295 return (rv);
296 }
297
298 static int
rndtest_longruns(struct rndtest_state * rsp)299 rndtest_longruns(struct rndtest_state *rsp)
300 {
301 int i, j, ones = 0, zeros = 0, maxones = 0, maxzeros = 0;
302 u_int8_t c;
303
304 for (i = 0; i < RNDTEST_NBYTES; i++) {
305 c = rsp->rs_buf[i];
306 for (j = 0; j < 8; j++, c <<= 1) {
307 if (c & 0x80) {
308 zeros = 0;
309 ones++;
310 if (ones > maxones)
311 maxones = ones;
312 } else {
313 ones = 0;
314 zeros++;
315 if (zeros > maxzeros)
316 maxzeros = zeros;
317 }
318 }
319 }
320
321 if (maxones < 26 && maxzeros < 26) {
322 rndtest_report(rsp, 0, "longruns pass (%d ones, %d zeros)",
323 maxones, maxzeros);
324 return (0);
325 } else {
326 rndtest_report(rsp, 1, "longruns fail (%d ones, %d zeros)",
327 maxones, maxzeros);
328 rndstats.rst_longruns++;
329 return (-1);
330 }
331 }
332
333 /*
334 * chi^2 test over 4 bits: (this is called the poker test in FIPS 140-2,
335 * but it is really the chi^2 test over 4 bits (the poker test as described
336 * by Knuth vol 2 is something different, and I take him as authoritative
337 * on nomenclature over NIST).
338 */
339 #define RNDTEST_CHI4_K 16
340 #define RNDTEST_CHI4_K_MASK (RNDTEST_CHI4_K - 1)
341
342 /*
343 * The unnormalized values are used so that we don't have to worry about
344 * fractional precision. The "real" value is found by:
345 * (V - 1562500) * (16 / 5000) = Vn (where V is the unnormalized value)
346 */
347 #define RNDTEST_CHI4_VMIN 1563181 /* 2.1792 */
348 #define RNDTEST_CHI4_VMAX 1576929 /* 46.1728 */
349
350 static int
rndtest_chi_4(struct rndtest_state * rsp)351 rndtest_chi_4(struct rndtest_state *rsp)
352 {
353 unsigned int freq[RNDTEST_CHI4_K], i, sum;
354
355 for (i = 0; i < RNDTEST_CHI4_K; i++)
356 freq[i] = 0;
357
358 /* Get number of occurrences of each 4 bit pattern */
359 for (i = 0; i < RNDTEST_NBYTES; i++) {
360 freq[(rsp->rs_buf[i] >> 4) & RNDTEST_CHI4_K_MASK]++;
361 freq[(rsp->rs_buf[i] >> 0) & RNDTEST_CHI4_K_MASK]++;
362 }
363
364 for (i = 0, sum = 0; i < RNDTEST_CHI4_K; i++)
365 sum += freq[i] * freq[i];
366
367 if (sum >= 1563181 && sum <= 1576929) {
368 rndtest_report(rsp, 0, "chi^2(4): pass (sum %u)", sum);
369 return (0);
370 } else {
371 rndtest_report(rsp, 1, "chi^2(4): failed (sum %u)", sum);
372 rndstats.rst_chi++;
373 return (-1);
374 }
375 }
376
377 static void
rndtest_timeout(void * xrsp)378 rndtest_timeout(void *xrsp)
379 {
380 struct rndtest_state *rsp = xrsp;
381
382 rsp->rs_collect = 1;
383 }
384
385 static int
rndtest_modevent(module_t mod,int type,void * unused)386 rndtest_modevent(module_t mod, int type, void *unused)
387 {
388 switch (type) {
389 case MOD_LOAD:
390 return 0;
391 case MOD_UNLOAD:
392 return 0;
393 }
394 return EINVAL;
395 }
396
397 static moduledata_t rndtest_mod = {
398 "rndtest",
399 rndtest_modevent,
400 0
401 };
402 DECLARE_MODULE(rndtest, rndtest_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
403 MODULE_VERSION(rndtest, 1);
404