1 /*-
2 * Copyright (c) 2015-2018 Mark R V Murray
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.
25 *
26 */
27
28 /*-
29 * This is a skeleton for folks who wish to build a loadable module
30 * containing an alternative entropy-processing algorithm for random(4).
31 *
32 * The functions below should be completed with the appropriate code,
33 * and the nearby fortuna.c may be consulted for examples of working code.
34 *
35 * The author is willing to provide reasonable help to those wishing to
36 * write such a module for themselves. Please use the markm@ FreeBSD
37 * email address, and ensure that you are developing this on a suitably
38 * supported branch (This is currently 12-CURRENT, and may be no
39 * older than 12-STABLE in the future).
40 */
41
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44
45 #include <sys/limits.h>
46
47 #ifdef _KERNEL
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/lock.h>
51 #include <sys/malloc.h>
52 #include <sys/mutex.h>
53 #include <sys/random.h>
54 #include <sys/sysctl.h>
55 #include <sys/systm.h>
56
57 #include <machine/cpu.h>
58
59 #include <crypto/rijndael/rijndael-api-fst.h>
60 #include <crypto/sha2/sha256.h>
61
62 #include <dev/random/hash.h>
63 #include <dev/random/randomdev.h>
64 #include <dev/random/random_harvestq.h>
65 #include <dev/random/uint128.h>
66 #include <dev/random/other_algorithm.h>
67 #else /* !_KERNEL */
68 #include <inttypes.h>
69 #include <stdbool.h>
70 #include <stdio.h>
71 #include <stdlib.h>
72 #include <string.h>
73 #include <threads.h>
74
75 #include "unit_test.h"
76
77 #include <crypto/rijndael/rijndael-api-fst.h>
78 #include <crypto/sha2/sha256.h>
79
80 #include <dev/random/hash.h>
81 #include <dev/random/randomdev.h>
82 #include <dev/random/uint128.h>
83 #include <dev/random/other_algorithm.h>
84 #endif /* _KERNEL */
85
86 static void random_other_pre_read(void);
87 static void random_other_read(uint8_t *, size_t);
88 static bool random_other_seeded(void);
89 static void random_other_process_event(struct harvest_event *);
90
91 /*
92 * RANDOM_OTHER_NPOOLS is used when reading hardware random
93 * number sources to ensure that each pool gets one read sample
94 * per loop iteration. Fortuna has 32 (0-31).
95 */
96 #define RANDOM_OTHER_NPOOLS 1
97
98 #ifdef RANDOM_LOADABLE
99 static
100 #endif
101 const struct random_algorithm random_alg_context = {
102 .ra_ident = "other",
103 .ra_pre_read = random_other_pre_read,
104 .ra_read = random_other_read,
105 .ra_seeded = random_other_seeded,
106 .ra_event_processor = random_other_process_event,
107 .ra_poolcount = RANDOM_OTHER_NPOOLS,
108 };
109
110 /* Use a mutex to protect your reseed variables? */
111 static mtx_t other_mtx;
112
113 /*
114 * Do algorithm-specific initialisation here.
115 */
116 static void
117 random_other_init_alg(void *unused __unused)
118 {
119
120 #ifdef RANDOM_LOADABLE
121 p_random_alg_context = &random_alg_context;
122 #endif
123
124 RANDOM_RESEED_INIT_LOCK();
125 }
126 SYSINIT(random_alg, SI_SUB_RANDOM, SI_ORDER_SECOND, random_other_init_alg,
127 NULL);
128
129 /*
130 * void random_other_pre_read(void)
131 *
132 * Do any pre-read preparation you need to. This will be called
133 * before >=1 calls to random_other_read() corresponding to one
134 * read(2).
135 *
136 * This routine will be called periodically while the generator is
137 * still blocked and a read is being attempted, giving you an
138 * opportunity to unblock.
139 */
140 static void
141 random_other_pre_read(void)
142 {
143
144 RANDOM_RESEED_LOCK();
145 /*
146 * Do pre-read housekeeping work here!
147 * You may use this as a chance to unblock the generator.
148 */
149 RANDOM_RESEED_UNLOCK();
150 }
151
152 /*
153 * void random_other_read(uint8_t *buf, size_t count)
154 *
155 * Generate <count> bytes of output into <*buf>.
156 * You may NOT use the fact that <count> will be a multiple of
157 * RANDOM_BLOCKSIZE for optimization purposes.
158 *
159 * This function will always be called with your generator
160 * unblocked and ready. If you are not ready to generate
161 * output here, then feel free to KASSERT() or panic().
162 */
163 static void
164 random_other_read(uint8_t *buf, size_t count)
165 {
166
167 RANDOM_RESEED_LOCK();
168 /*
169 * Do random-number generation work here!
170 */
171 RANDOM_RESEED_UNLOCK();
172 }
173
174 /*
175 * bool random_other_seeded(void)
176 *
177 * Return true if your generator is ready to generate
178 * output, and false otherwise.
179 */
180 static bool
181 random_other_seeded(void)
182 {
183 bool seeded = false;
184
185 /*
186 * Find out if your generator is seeded here!
187 */
188 return (seeded);
189 }
190
191 /*
192 * void random_other_process_event(struct harvest_event *event)
193 *
194 * Process one stochastic event <*event> into your entropy
195 * processor.
196 *
197 * The structure of the event may change, so it is easier to
198 * just grab the whole thing into your accumulation system.
199 * You may pick-and-choose bits, but please don't complain
200 * when/if these change.
201 */
202 static void
203 random_other_process_event(struct harvest_event *event)
204 {
205
206 RANDOM_RESEED_LOCK();
207 /*
208 * Do entropy accumulation work here!
209 * You may use this as a chance to unblock the generator.
210 */
211 RANDOM_RESEED_UNLOCK();
212 }
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