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 #include <sys/limits.h>
44
45 #ifdef _KERNEL
46 #include <sys/param.h>
47 #include <sys/kernel.h>
48 #include <sys/lock.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>
54
55 #include <machine/cpu.h>
56
57 #include <crypto/rijndael/rijndael-api-fst.h>
58 #include <crypto/sha2/sha256.h>
59
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>
65 #else /* !_KERNEL */
66 #include <inttypes.h>
67 #include <stdbool.h>
68 #include <stdio.h>
69 #include <stdlib.h>
70 #include <string.h>
71 #include <threads.h>
72
73 #include "unit_test.h"
74
75 #include <crypto/rijndael/rijndael-api-fst.h>
76 #include <crypto/sha2/sha256.h>
77
78 #include <dev/random/hash.h>
79 #include <dev/random/randomdev.h>
80 #include <dev/random/uint128.h>
81 #include <dev/random/other_algorithm.h>
82 #endif /* _KERNEL */
83
84 static void random_other_pre_read(void);
85 static void random_other_read(uint8_t *, size_t);
86 static bool random_other_seeded(void);
87 static void random_other_process_event(struct harvest_event *);
88
89 /*
90 * RANDOM_OTHER_NPOOLS is used when reading hardware random
91 * number sources to ensure that each pool gets one read sample
92 * per loop iteration. Fortuna has 32 (0-31).
93 */
94 #define RANDOM_OTHER_NPOOLS 1
95
96 #ifdef RANDOM_LOADABLE
97 static
98 #endif
99 const struct random_algorithm random_alg_context = {
100 .ra_ident = "other",
101 .ra_pre_read = random_other_pre_read,
102 .ra_read = random_other_read,
103 .ra_seeded = random_other_seeded,
104 .ra_event_processor = random_other_process_event,
105 .ra_poolcount = RANDOM_OTHER_NPOOLS,
106 };
107
108 /* Use a mutex to protect your reseed variables? */
109 static mtx_t other_mtx;
110
111 /*
112 * Do algorithm-specific initialisation here.
113 */
114 static void
random_other_init_alg(void * unused __unused)115 random_other_init_alg(void *unused __unused)
116 {
117
118 #ifdef RANDOM_LOADABLE
119 p_random_alg_context = &random_alg_context;
120 #endif
121
122 RANDOM_RESEED_INIT_LOCK();
123 }
124 SYSINIT(random_alg, SI_SUB_RANDOM, SI_ORDER_SECOND, random_other_init_alg,
125 NULL);
126
127 /*
128 * void random_other_pre_read(void)
129 *
130 * Do any pre-read preparation you need to. This will be called
131 * before >=1 calls to random_other_read() corresponding to one
132 * read(2).
133 *
134 * This routine will be called periodically while the generator is
135 * still blocked and a read is being attempted, giving you an
136 * opportunity to unblock.
137 */
138 static void
random_other_pre_read(void)139 random_other_pre_read(void)
140 {
141
142 RANDOM_RESEED_LOCK();
143 /*
144 * Do pre-read housekeeping work here!
145 * You may use this as a chance to unblock the generator.
146 */
147 RANDOM_RESEED_UNLOCK();
148 }
149
150 /*
151 * void random_other_read(uint8_t *buf, size_t count)
152 *
153 * Generate <count> bytes of output into <*buf>.
154 * You may NOT use the fact that <count> will be a multiple of
155 * RANDOM_BLOCKSIZE for optimization purposes.
156 *
157 * This function will always be called with your generator
158 * unblocked and ready. If you are not ready to generate
159 * output here, then feel free to KASSERT() or panic().
160 */
161 static void
random_other_read(uint8_t * buf,size_t count)162 random_other_read(uint8_t *buf, size_t count)
163 {
164
165 RANDOM_RESEED_LOCK();
166 /*
167 * Do random-number generation work here!
168 */
169 RANDOM_RESEED_UNLOCK();
170 }
171
172 /*
173 * bool random_other_seeded(void)
174 *
175 * Return true if your generator is ready to generate
176 * output, and false otherwise.
177 */
178 static bool
random_other_seeded(void)179 random_other_seeded(void)
180 {
181 bool seeded = false;
182
183 /*
184 * Find out if your generator is seeded here!
185 */
186 return (seeded);
187 }
188
189 /*
190 * void random_other_process_event(struct harvest_event *event)
191 *
192 * Process one stochastic event <*event> into your entropy
193 * processor.
194 *
195 * The structure of the event may change, so it is easier to
196 * just grab the whole thing into your accumulation system.
197 * You may pick-and-choose bits, but please don't complain
198 * when/if these change.
199 */
200 static void
random_other_process_event(struct harvest_event * event)201 random_other_process_event(struct harvest_event *event)
202 {
203
204 RANDOM_RESEED_LOCK();
205 /*
206 * Do entropy accumulation work here!
207 * You may use this as a chance to unblock the generator.
208 */
209 RANDOM_RESEED_UNLOCK();
210 }
211