5 Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
7 Copyright (C) 1997 - 2000 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
21 * Created: Sun Mar 9 00:09:18 1997
23 * This RNG is based on Secure Shell's random number generator.
25 /* XXX: Some operations block resulting slow initialization.
26 * XXX: I have some pending changes to make this better. */
30 * Revision 1.1.1.1 2000/06/27 11:36:55 priikone
31 * Importet from internal CVS/Added Log headers.
36 #include "silcincludes.h"
39 /* #define SILC_RNG_DEBUG */
42 SILC SilcRng State context.
44 This object is used by the random number generator to provide
45 variable points where the actual random number is fetched from
46 the random pool. This provides that the data is not fetched always
47 from the same point of the pool. Short description of the fields
53 The index for the random pool buffer. Lowest and current
56 SilcRngStateContext *next
58 Pointer to the next state. If this is the last state this
59 will point to the first state thus providing circular list.
62 typedef struct SilcRngStateContext {
65 struct SilcRngStateContext *next;
69 SILC Random Number Generator object.
71 This object holds random pool which is used to generate the random
72 numbers used by various routines needing cryptographically strong
73 random numbers. Following short descriptions of the fields.
77 The random pool. This buffer holds the random data. This is
78 frequently stirred thus providing ever changing randomnes.
82 Key used in stirring the random pool. The pool is encrypted
83 with SHA1 hash function in CFB (Cipher Feedback) mode.
85 SilcSilcRngState state
87 State object that is used to get the next position for the
88 random pool. This position is used to fetch data from pool
89 or to save the data to the pool. The state changes everytime
94 Hash object (SHA1) used to make the CFB encryption to the
95 random pool. This is allocated when RNG object is allocated and
96 free'd when RNG object is free'd.
99 typedef struct SilcRngObjectStruct {
100 unsigned char pool[SILC_RNG_POOLSIZE];
101 unsigned char key[64];
106 /* Allocates new RNG object. */
108 SilcRng silc_rng_alloc()
112 SILC_LOG_DEBUG(("Allocating new RNG object"));
114 new = silc_calloc(1, sizeof(*new));
116 SILC_LOG_ERROR(("Could not allocate new RNG object"));
120 memset(new->pool, 0, sizeof(new->pool));
121 memset(new->key, 0, sizeof(new->key));
123 silc_hash_alloc("sha1", &new->sha1);
128 /* Free's RNG object. */
130 void silc_rng_free(SilcRng rng)
133 memset(rng->pool, 0, sizeof(rng->pool));
134 memset(rng->key, 0, sizeof(rng->key));
135 silc_free(rng->sha1);
140 /* Initializes random number generator by getting noise from environment.
141 The environmental noise is our so called seed. One should not call
142 this function more than once. */
144 void silc_rng_init(SilcRng rng)
147 SilcRngState first, next;
151 SILC_LOG_DEBUG(("Initializing RNG object"));
153 /* Initialize the states for the RNG. */
154 rng->state = silc_malloc(sizeof(*rng->state));
157 rng->state->next = NULL;
159 for (i = SILC_RNG_STATE_NUM - 1; i >= 1; i--) {
160 next = silc_malloc(sizeof(*rng->state));
162 (i * (sizeof(rng->pool) / SILC_RNG_STATE_NUM));
164 (i * (sizeof(rng->pool) / SILC_RNG_STATE_NUM)) + 8;
166 next->pos = sizeof(rng->pool) -
167 ((i * (sizeof(rng->pool) / SILC_RNG_STATE_NUM))) + 8;
169 next->next = rng->state;
175 memset(rng->pool, 0, sizeof(rng->pool));
177 /* Get noise from various environmental sources */
178 silc_rng_get_soft_noise(rng);
179 silc_rng_get_medium_noise(rng);
180 silc_rng_get_hard_noise(rng);
183 /* This function gets 'soft' noise from environment. */
185 void silc_rng_get_soft_noise(SilcRng rng)
189 silc_rng_xor(rng, clock(), 0);
190 silc_rng_xor(rng, getpid(), 1);
191 silc_rng_xor(rng, getpgid(getpid() << 8), 2);
192 silc_rng_xor(rng, getpgid(getpid() << 8), 3);
193 silc_rng_xor(rng, getgid(), 4);
194 silc_rng_xor(rng, getpgrp(), 5);
195 silc_rng_xor(rng, getsid(getpid() << 16), 6);
196 silc_rng_xor(rng, times(&ptime), 7);
197 silc_rng_xor(rng, ptime.tms_utime, 8);
198 silc_rng_xor(rng, (ptime.tms_utime + ptime.tms_stime), 9);
199 silc_rng_xor(rng, (ptime.tms_stime + ptime.tms_cutime), 10);
200 silc_rng_xor(rng, (ptime.tms_utime + ptime.tms_stime), 11);
201 silc_rng_xor(rng, (ptime.tms_cutime ^ ptime.tms_stime), 12);
202 silc_rng_xor(rng, (ptime.tms_cutime ^ ptime.tms_cstime), 13);
203 silc_rng_xor(rng, (ptime.tms_utime ^ ptime.tms_stime), 14);
204 silc_rng_xor(rng, (ptime.tms_stime ^ ptime.tms_cutime), 15);
205 silc_rng_xor(rng, (ptime.tms_cutime + ptime.tms_stime), 16);
206 silc_rng_xor(rng, (ptime.tms_stime << 8), 17);
207 silc_rng_xor(rng, clock() << 4, 18);
208 silc_rng_xor(rng, getpgid(getpid() << 8), 19);
209 silc_rng_xor(rng, getpgrp(), 20);
210 silc_rng_xor(rng, getsid(getpid() << 16), 21);
211 silc_rng_xor(rng, times(&ptime), 22);
212 silc_rng_xor(rng, ptime.tms_utime, 23);
213 silc_rng_xor(rng, getpgrp(), 24);
215 /* Stir random pool */
216 silc_rng_stir_pool(rng);
219 /* This function gets noise from different commands */
221 void silc_rng_get_medium_noise(SilcRng rng)
223 silc_rng_exec_command(rng, "ps -lefaww 2> /dev/null");
224 silc_rng_exec_command(rng, "ls -afiln 2> /dev/null");
225 silc_rng_exec_command(rng, "ps -asww 2> /dev/null");
226 silc_rng_exec_command(rng, "ls -afiln /proc 2> /dev/null");
228 silc_rng_exec_command(rng, "ps -ef 2> /dev/null");
229 silc_rng_exec_command(rng, "ls -alin /dev 2> /dev/null");
233 /* This function gets 'hard' noise from environment. This tries to
234 get the noise from /dev/random if available. */
236 void silc_rng_get_hard_noise(SilcRng rng)
241 /* Get noise from /dev/random if available */
242 fd = open("/dev/random", O_RDONLY);
246 fcntl(fd, F_SETFL, O_NONBLOCK);
248 for (i = 0; i < 8; i++) {
249 len = read(fd, buf, sizeof(buf));
252 silc_rng_add_noise(rng, buf, len);
257 memset(buf, 0, sizeof(buf));
260 /* Execs command and gets noise from its output */
262 void silc_rng_exec_command(SilcRng rng, char *command)
270 fd = popen(command, "r");
274 /* Get data as much as we can get into the buffer */
275 for (i = 0; i < sizeof(buf); i++) {
287 /* Add the buffer into random pool */
288 silc_rng_add_noise(rng, buf, strlen(buf));
289 memset(buf, 0, sizeof(buf));
292 /* This function adds the contents of the buffer as noise into random
293 pool. After adding the noise the pool is stirred. */
295 void silc_rng_add_noise(SilcRng rng, unsigned char *buffer,
300 pos = silc_rng_get_position(rng);
302 /* Add the buffer one by one into the pool */
303 for(i = 0; i < len; i++, buffer++) {
304 if(pos >= SILC_RNG_POOLSIZE)
306 rng->pool[pos++] ^= *buffer;
309 /* Stir random pool */
310 silc_rng_stir_pool(rng);
313 /* XOR's data into the pool */
315 void silc_rng_xor(SilcRng rng, unsigned int val, unsigned int pos)
318 rng->pool[pos] ^= val + val;
321 /* This function stirs the random pool by encrypting buffer in CFB
322 (cipher feedback) mode with SHA1 algorithm. */
324 void silc_rng_stir_pool(SilcRng rng)
330 memcpy(iv, &rng->pool[SILC_RNG_POOLSIZE - 256], sizeof(iv));
333 for (i = 0; i < SILC_RNG_POOLSIZE; i += 5) {
334 rng->sha1->hash->transform(iv, rng->key);
335 iv[0] = rng->pool[i] ^= iv[0];
336 iv[1] = rng->pool[i + 1] ^= iv[1];
337 iv[2] = rng->pool[i + 2] ^= iv[2];
338 iv[3] = rng->pool[i + 3] ^= iv[3];
339 iv[4] = rng->pool[i + 4] ^= iv[4];
343 memcpy(rng->key, &rng->pool[silc_rng_get_position(rng)], sizeof(rng->key));
345 /* Second CFB pass */
346 for (i = 0; i < SILC_RNG_POOLSIZE; i += 5) {
347 rng->sha1->hash->transform(iv, rng->key);
348 iv[0] = rng->pool[i] ^= iv[0];
349 iv[1] = rng->pool[i + 1] ^= iv[1];
350 iv[2] = rng->pool[i + 2] ^= iv[2];
351 iv[3] = rng->pool[i + 3] ^= iv[3];
352 iv[4] = rng->pool[i + 4] ^= iv[4];
355 memset(iv, 0, sizeof(iv));
358 /* Returns next position where data is fetched from the pool or
361 unsigned int silc_rng_get_position(SilcRng rng)
366 next = rng->state->next;
368 pos = rng->state->pos++;
369 if ((next->low != 0 && pos >= next->low) || (pos >= SILC_RNG_POOLSIZE))
370 rng->state->pos = rng->state->low;
372 #ifdef SILC_RNG_DEBUG
373 fprintf(stderr, "state: %p: low: %d, pos: %d\n",
374 rng->state, rng->state->low, rng->state->pos);
382 /* returns random byte. Every two byte is from pools low or high state. */
384 unsigned char silc_rng_get_byte(SilcRng rng)
386 return rng->pool[silc_rng_get_position(rng)];
389 /* Returns 16 bit random number */
391 unsigned short silc_rng_get_rn16(SilcRng rng)
396 rn[0] = silc_rng_get_byte(rng);
397 rn[1] = silc_rng_get_byte(rng);
398 SILC_GET16_MSB(num, rn);
403 /* Returns 32 bit random number */
405 unsigned int silc_rng_get_rn32(SilcRng rng)
410 rn[0] = silc_rng_get_byte(rng);
411 rn[1] = silc_rng_get_byte(rng);
412 rn[2] = silc_rng_get_byte(rng);
413 rn[3] = silc_rng_get_byte(rng);
414 SILC_GET32_MSB(num, rn);
419 /* Returns random number string. Returned string is in HEX format. */
421 unsigned char *silc_rng_get_rn_string(SilcRng rng, unsigned int len)
424 unsigned char *string;
426 string = silc_calloc((len * 2 + 1), sizeof(unsigned char));
430 for (i = 0; i < len; i++)
431 sprintf(string + 2 * i, "%02x", silc_rng_get_byte(rng));