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1␊
2#include "libsaio.h"␊
3␊
4/*␊
5 * License for L15_Swap, L15_InitState, L_SCHEDULE, L15_KSA, L15_Discard, L15, L15_Byte␊
6 *␊
7 * Copyright (c) 2004, 2005, 2006 Robin J Carey. 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 * without modification, immediately at the beginning of the file.␊
15 * 2. The name of the author may not be used to endorse or promote products␊
16 * derived from this software without specific prior written permission.␊
17 *␊
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND␊
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE␊
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE␊
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR␊
22 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL␊
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS␊
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)␊
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT␊
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY␊
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF␊
28 * SUCH DAMAGE.␊
29 *␊
30 * $DragonFly: src/sys/kern/kern_nrandom.c,v 1.7 2008/08/01 04:42:30 dillon Exp $␊
31 */␊
32␊
33/*␊
34 * IMPORTANT NOTE: LByteType must be exactly 8-bits in size or this software␊
35 * will not function correctly.␊
36 */␊
37typedef unsigned char LByteType;␊
38#define L15_STATE_SIZE 256␊
39static LByteType L15_x, L15_y;␊
40static LByteType L15_start_x;␊
41static LByteType L15_state[L15_STATE_SIZE];␊
42␊
43/*␊
44 * PRIVATE FUNCS:␊
45 */␊
46static void L15(const LByteType * const key, const size_t keyLen);␊
47static void L15_Swap(const LByteType pos1, const LByteType pos2);␊
48static void L15_InitState(void);␊
49static void L15_KSA(const LByteType * const key,␊
50 const size_t keyLen);␊
51static void L15_Discard(const LByteType numCalls);␊
52/*␊
53 * PUBLIC INTERFACE:␊
54 */␊
55static LByteType L15_Byte(void);␊
56 ␊
57static __inline void␊
58L15_Swap(const LByteType pos1, const LByteType pos2)␊
59{␊
60␉const LByteType save1 = L15_state[pos1];␊
61␉␊
62␉L15_state[pos1] = L15_state[pos2];␊
63␉L15_state[pos2] = save1; ␊
64}␊
65␊
66static void␊
67L15_InitState (void)␊
68{␊
69␉size_t i;␊
70␉for (i = 0; i < L15_STATE_SIZE; ++i)␊
71␉␉L15_state[i] = i; ␊
72}␊
73␊
74#define L_SCHEDULE(xx) \␊
75 \␊
76for (i = 0; i < L15_STATE_SIZE; ++i) { \␊
77 L15_Swap(i, (stateIndex += (L15_state[i] + (xx)))); \␊
78}␊
79␊
80static void␊
81L15_KSA (const LByteType * const key, const size_t keyLen)␊
82{␊
83 size_t i, keyIndex;␊
84 LByteType stateIndex = 0;␊
85␊
86 L_SCHEDULE(keyLen);␊
87 for (keyIndex = 0; keyIndex < keyLen; ++keyIndex) {␊
88 L_SCHEDULE(key[keyIndex]);␊
89 }␊
90}␊
91 ␊
92static void␊
93L15_Discard(const LByteType numCalls)␊
94{␊
95 LByteType i;␊
96 for (i = 0; i < numCalls; ++i) {␊
97 (void)L15_Byte();␊
98 }␊
99}␊
100 ␊
101/*␊
102 * PUBLIC INTERFACE:␊
103 */␊
104static void␊
105L15(const LByteType * const key, const size_t keyLen)␊
106{␊
107 L15_x = L15_start_x = 0;␊
108 L15_y = L15_STATE_SIZE - 1;␊
109 L15_InitState();␊
110 L15_KSA(key, keyLen);␊
111 L15_Discard(L15_Byte());␊
112}␊
113␊
114static LByteType␊
115L15_Byte(void)␊
116{␊
117␉LByteType z;␊
118␉␊
119␉L15_Swap(L15_state[L15_x], L15_y);␊
120␉z = (L15_state [L15_x++] + L15_state[L15_y--]);␊
121␉if (L15_x == L15_start_x) {␊
122␉␉--L15_y;␊
123␉}␊
124␉return (L15_state[z]); ␊
125}␊
126␊
127␊
128␊
129/*-␊
130 * THE BEER-WARE LICENSE␊
131 *␊
132 * <dan@FreeBSD.ORG> wrote this file. As long as you retain this notice you␊
133 * can do whatever you want with this stuff. If we meet some day, and you␊
134 * think this stuff is worth it, you can buy me a beer in return.␊
135 *␊
136 * Dan Moschuk␊
137 *␊
138 * $FreeBSD: src/sys/libkern/arc4random.c,v 1.3.2.2 2001/09/17 07:06:50 silby Exp $␊
139 */␊
140␊
141␊
142#define␉ARC4_MAXRUNS 16384␊
143#define␉ARC4_RESEED_SECONDS 300 * 18␊
144#define␉ARC4_KEYBYTES 32 /* 256 bit key */␊
145␊
146static u_int8_t arc4_i, arc4_j;␊
147static int arc4_initialized = 0;␊
148static int arc4_numruns = 0;␊
149static u_int8_t arc4_sbox[256];␊
150static u_int32_t arc4_tv_nextreseed;␊
151␊
152static u_int8_t arc4_randbyte(void);␊
153␊
154static __inline void␊
155arc4_swap(u_int8_t *a, u_int8_t *b)␊
156{␊
157␉u_int8_t c;␊
158␉␊
159␉c = *a;␊
160␉*a = *b;␊
161␉*b = c;␊
162}␉␊
163␊
164/*␊
165 * Stir our S-box.␊
166 */␊
167static void␊
168arc4_randomstir (void)␊
169{␊
170␉u_int8_t key[256];␊
171␉int r, n;␊
172␉␊
173␉/*␊
174␉ * XXX read_random() returns unsafe numbers if the entropy␊
175␉ * device is not loaded -- MarkM.␊
176␉ */␊
177␉ ␊
178␉{␉␉␊
179␉␉for (r = 0; r < ARC4_KEYBYTES; ++r)␊
180␉␉␉((u_char *)key)[r] = L15_Byte();␊
181␉}␊
182␊
183␉/* If r == 0 || -1, just use what was on the stack. */␊
184␉if (r > 0)␊
185␉{␊
186␉␉for (n = r; n < sizeof(key); n++)␊
187␉␉␉key[n] = key[n % r];␊
188␉}␊
189␉␊
190␉for (n = 0; n < 256; n++)␊
191␉{␊
192␉␉arc4_j = (arc4_j + arc4_sbox[n] + key[n]) % 256;␊
193␉␉arc4_swap(&arc4_sbox[n], &arc4_sbox[arc4_j]);␊
194␉}␊
195␉arc4_i = arc4_j = 0;␊
196␉␊
197␉/* Reset for next reseed cycle. */␊
198␉arc4_tv_nextreseed = time18();␊
199␉arc4_tv_nextreseed += ARC4_RESEED_SECONDS;␊
200␉arc4_numruns = 0;␊
201}␊
202␊
203/*␊
204 * Initialize our S-box to its beginning defaults.␊
205 */␊
206static void␊
207arc4_init(void)␊
208{␊
209␉int n;␊
210␉␊
211␉u_int32_t now = time18();␊
212␉L15((const LByteType *)&now, sizeof(u_int32_t));␊
213␉␊
214␉arc4_i = arc4_j = 0;␊
215␉for (n = 0; n < 256; n++)␊
216␉␉arc4_sbox[n] = (u_int8_t) n;␊
217␉␊
218␉arc4_randomstir();␊
219␉arc4_initialized = 1;␊
220␉␊
221␉/*␊
222␉ * Throw away the first N words of output, as suggested in the␊
223␉ * paper "Weaknesses in the Key Scheduling Algorithm of RC4"␊
224␉ * by Fluher, Mantin, and Shamir. (N = 256 in our case.)␊
225␉ */␊
226␉for (n = 0; n < 256*4; n++)␊
227␉␉arc4_randbyte();␊
228}␊
229␊
230/*␊
231 * Generate a random byte.␊
232 */␊
233static u_int8_t␊
234arc4_randbyte(void)␊
235{␊
236␉u_int8_t arc4_t;␊
237␉␊
238␉arc4_i = (arc4_i + 1) % 256;␊
239␉arc4_j = (arc4_j + arc4_sbox[arc4_i]) % 256;␊
240␉␊
241␉arc4_swap(&arc4_sbox[arc4_i], &arc4_sbox[arc4_j]);␊
242␉␊
243␉arc4_t = (arc4_sbox[arc4_i] + arc4_sbox[arc4_j]) % 256;␊
244␉return arc4_sbox[arc4_t];␊
245}␊
246␊
247void␊
248arc4rand(void *ptr, u_int len, int reseed)␊
249{␊
250␉u_char *p;␊
251␉u_int32_t tv_now;␊
252␉␊
253␉/* Initialize array if needed. */␊
254␉if (!arc4_initialized)␊
255␉␉arc4_init();␊
256␉␊
257␉tv_now = time18();␊
258␊
259␉if (reseed || ␊
260␉␉(arc4_numruns > ARC4_MAXRUNS) ||␊
261␉␉(tv_now > arc4_tv_nextreseed))␊
262␉␉arc4_randomstir();␊
263␉␊
264␉arc4_numruns += len;␊
265␉p = ptr;␊
266␉while (len--)␊
267␉␉*p++ = arc4_randbyte();␊
268}␊
269␊
270uint32_t␊
271arc4random(void)␊
272{␊
273␉uint32_t ret;␊
274␉␊
275␉arc4rand(&ret, sizeof ret, 0);␊
276␉return ret; ␊
277}␊
278

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