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("$FreeBSD$");
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
50 static void rndtest_test(struct rndtest_state *);
51 static void rndtest_timeout(void *);
52
53 /* The tests themselves */
54 static int rndtest_monobit(struct rndtest_state *);
55 static int rndtest_runs(struct rndtest_state *);
56 static int rndtest_longruns(struct rndtest_state *);
57 static int rndtest_chi_4(struct rndtest_state *);
58
59 static int rndtest_runs_check(struct rndtest_state *, int, int *);
60 static void rndtest_runs_record(struct rndtest_state *, int, int *);
61
62 static 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 nitems(rndtest_funcs)
72
73 static SYSCTL_NODE(_kern, OID_AUTO, rndtest, CTLFLAG_RD, 0,
74 "RNG test parameters");
75 static int rndtest_retest = 120; /* interval in seconds */
76 SYSCTL_INT(_kern_rndtest, OID_AUTO, retest, CTLFLAG_RW, &rndtest_retest,
77 0, "retest interval (seconds)");
78 static struct rndtest_stats rndstats;
79 SYSCTL_STRUCT(_kern_rndtest, OID_AUTO, stats, CTLFLAG_RD, &rndstats,
80 rndtest_stats, "RNG test statistics");
81 static int rndtest_verbose = 1; /* report only failures */
82 SYSCTL_INT(_kern_rndtest, OID_AUTO, verbose, CTLFLAG_RW, &rndtest_verbose,
83 0, "display results on console");
84
85 struct rndtest_state *
rndtest_attach(device_t dev)86 rndtest_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
108 void
rndtest_detach(struct rndtest_state * rsp)109 rndtest_detach(struct rndtest_state *rsp)
110 {
111 callout_stop(&rsp->rs_to);
112 free(rsp, M_DEVBUF);
113 }
114
115 void
rndtest_harvest(struct rndtest_state * rsp,void * buf,u_int len)116 rndtest_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
153 static void
rndtest_test(struct rndtest_state * rsp)154 rndtest_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
164 static void
rndtest_report(struct rndtest_state * rsp,int failure,const char * fmt,...)165 rndtest_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
183 static int
rndtest_monobit(struct rndtest_state * rsp)184 rndtest_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
213 static 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
224 static int
rndtest_runs(struct rndtest_state * rsp)225 rndtest_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
260 static void
rndtest_runs_record(struct rndtest_state * rsp,int len,int * intrv)261 rndtest_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
271 static int
rndtest_runs_check(struct rndtest_state * rsp,int val,int * src)272 rndtest_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
296 static int
rndtest_longruns(struct rndtest_state * rsp)297 rndtest_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
348 static int
rndtest_chi_4(struct rndtest_state * rsp)349 rndtest_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
375 static void
rndtest_timeout(void * xrsp)376 rndtest_timeout(void *xrsp)
377 {
378 struct rndtest_state *rsp = xrsp;
379
380 rsp->rs_collect = 1;
381 }
382
383 static int
rndtest_modevent(module_t mod,int type,void * unused)384 rndtest_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
395 static moduledata_t rndtest_mod = {
396 "rndtest",
397 rndtest_modevent,
398 0
399 };
400 DECLARE_MODULE(rndtest, rndtest_mod, SI_SUB_DRIVERS, SI_ORDER_ANY);
401 MODULE_VERSION(rndtest, 1);
402