2 * Copyright (c) 2015 Mark R V Murray
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer
10 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 * This is a skeleton for folks who wish to build a loadable module
30 * containing an alternative entropy-processing algorithm for random(4).
32 * The functions below should be completed with the appropriate code,
33 * and the nearby yarrow.c and fortuna.c may be consulted for examples
36 * The author is willing to provide reasonable help to those wishing to
37 * write such a module for themselves. Please use the markm@ FreeBSD
38 * email address, and ensure that you are developing this on a suitably
39 * supported branch (This is currently 11-CURRENT, and will be no
40 * older than 11-STABLE in the future).
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
46 #include <sys/param.h>
47 #include <sys/kernel.h>
49 #include <sys/malloc.h>
50 #include <sys/mutex.h>
51 #include <sys/random.h>
52 #include <sys/sysctl.h>
53 #include <sys/systm.h>
55 #include <machine/cpu.h>
57 #include <crypto/rijndael/rijndael-api-fst.h>
58 #include <crypto/sha2/sha256.h>
60 #include <dev/random/hash.h>
61 #include <dev/random/randomdev.h>
62 #include <dev/random/random_harvestq.h>
63 #include <dev/random/uint128.h>
64 #include <dev/random/other_algorithm.h>
66 static void random_other_pre_read(void);
67 static void random_other_read(uint8_t *, u_int);
68 static bool random_other_seeded(void);
69 static void random_other_process_event(struct harvest_event *);
70 static void random_other_init_alg(void *);
71 static void random_other_deinit_alg(void *);
74 * RANDOM_OTHER_NPOOLS is used when reading hardware random
75 * number sources to ensure that each pool gets one read sample
76 * per loop iteration. Yarrow has 2 such pools (FAST and SLOW),
77 * and fortuna has 32 (0-31). The RNG used prior to Yarrow and
78 * ported from Linux had just 1 pool.
80 #define RANDOM_OTHER_NPOOLS 1
82 struct random_algorithm random_alg_context = {
84 .ra_init_alg = random_other_init_alg,
85 .ra_deinit_alg = random_other_deinit_alg,
86 .ra_pre_read = random_other_pre_read,
87 .ra_read = random_other_read,
88 .ra_seeded = random_other_seeded,
89 .ra_event_processor = random_other_process_event,
90 .ra_poolcount = RANDOM_OTHER_NPOOLS,
93 /* Use a mutex to protect your reseed variables? */
94 static mtx_t other_mtx;
97 * void random_other_init_alg(void *unused __unused)
99 * Do algorithm-specific initialisation here.
102 random_other_init_alg(void *unused __unused)
105 RANDOM_RESEED_INIT_LOCK();
107 * Do set-up work here!
112 * void random_other_deinit_alg(void *unused __unused)
114 * Do algorithm-specific deinitialisation here.
117 random_other_deinit_alg(void *unused __unused)
121 * Do tear-down work here!
123 RANDOM_RESEED_DEINIT_LOCK();
127 * void random_other_pre_read(void)
129 * Do any pre-read preparation you need to. This will be called
130 * before >=1 calls to random_other_read() corresponding to one
133 * This routine will be called periodically while the generator is
134 * still blocked and a read is being attempted, giving you an
135 * opportunity to unblock.
138 random_other_pre_read(void)
141 RANDOM_RESEED_LOCK();
143 * Do pre-read housekeeping work here!
144 * You may use this as a chance to unblock the generator.
146 RANDOM_RESEED_UNLOCK();
150 * void random_other_read(uint8_t *buf, u_int count)
152 * Generate <count> bytes of output into <*buf>.
153 * You may use the fact that <count> will be a multiple of
154 * RANDOM_BLOCKSIZE for optimization purposes.
156 * This function will always be called with your generator
157 * unblocked and ready. If you are not ready to generate
158 * output here, then feel free to KASSERT() or panic().
161 random_other_read(uint8_t *buf, u_int count)
164 RANDOM_RESEED_LOCK();
166 * Do random-number generation work here!
168 RANDOM_RESEED_UNLOCK();
172 * bool random_other_seeded(void)
174 * Return true if your generator is ready to generate
175 * output, and false otherwise.
178 random_other_seeded(void)
183 * Find out if your generator is seeded here!
189 * void random_other_process_event(struct harvest_event *event)
191 * Process one stochastic event <*event> into your entropy
194 * The structure of the event may change, so it is easier to
195 * just grab the whole thing into your accumulation system.
196 * You may pick-and-choose bits, but please don't complain
197 * when/if these change.
200 random_other_process_event(struct harvest_event *event)
203 RANDOM_RESEED_LOCK();
205 * Do entropy accumulation work here!
206 * You may use this as a chance to unblock the generator.
208 RANDOM_RESEED_UNLOCK();