5 Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
7 Copyright (C) 1997 - 2001 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.
22 * Created: Sun Mar 9 00:09:18 1997
24 * The original RNG was based on Secure Shell's random number generator
25 * by Tatu Ylönen and was used as reference when programming this RNG.
26 * This RNG has been rewritten twice since the creation.
29 #include "silcincludes.h"
32 /*#define SILC_RNG_DEBUG*/
34 /* Number of states to fetch data from pool. */
35 #define SILC_RNG_STATE_NUM 4
37 /* Byte size of the random data pool. */
38 #define SILC_RNG_POOLSIZE 1024
40 static uint32 silc_rng_get_position(SilcRng rng);
41 static void silc_rng_stir_pool(SilcRng rng);
42 static void silc_rng_xor(SilcRng rng, uint32 val, unsigned int pos);
43 static void silc_rng_exec_command(SilcRng rng, char *command);
44 static void silc_rng_get_hard_noise(SilcRng rng);
45 static void silc_rng_get_medium_noise(SilcRng rng);
46 static void silc_rng_get_soft_noise(SilcRng rng);
49 SILC SilcRng State context.
51 This object is used by the random number generator to provide
52 variable points where the actual random number is fetched from
53 the random pool. This provides that the data is not fetched always
54 from the same point of the pool. Short description of the fields
60 The index for the random pool buffer. Lowest and current
63 SilcRngStateContext *next
65 Pointer to the next state. If this is the last state this
66 will point to the first state thus providing circular list.
69 typedef struct SilcRngStateContext {
72 struct SilcRngStateContext *next;
76 SILC Random Number Generator object.
78 This object holds random pool which is used to generate the random
79 numbers used by various routines needing cryptographically strong
80 random numbers. Following short descriptions of the fields.
84 The random pool. This buffer holds the random data. This is
85 frequently stirred thus providing ever changing randomnes.
89 Key used in stirring the random pool. The pool is encrypted
90 with SHA1 hash function in CFB (Cipher Feedback) mode.
92 SilcSilcRngState state
94 State object that is used to get the next position for the
95 random pool. This position is used to fetch data from pool
96 or to save the data to the pool. The state changes everytime
101 Hash object (SHA1) used to make the CFB encryption to the
102 random pool. This is allocated when RNG object is allocated and
103 free'd when RNG object is free'd.
107 Threshhold to indicate when it is required to acquire more
108 noise from the environment. More soft noise is acquired after
109 64 bits of output and hard noise every 160 bits of output.
112 typedef struct SilcRngObjectStruct {
113 unsigned char pool[SILC_RNG_POOLSIZE];
114 unsigned char key[64];
120 /* Allocates new RNG object. */
122 SilcRng silc_rng_alloc()
126 SILC_LOG_DEBUG(("Allocating new RNG object"));
128 new = silc_calloc(1, sizeof(*new));
130 memset(new->pool, 0, sizeof(new->pool));
131 memset(new->key, 0, sizeof(new->key));
133 silc_hash_alloc("sha1", &new->sha1);
138 /* Free's RNG object. */
140 void silc_rng_free(SilcRng rng)
143 memset(rng->pool, 0, sizeof(rng->pool));
144 memset(rng->key, 0, sizeof(rng->key));
145 silc_free(rng->sha1);
150 /* Initializes random number generator by getting noise from environment.
151 The environmental noise is our so called seed. One should not call
152 this function more than once. */
154 void silc_rng_init(SilcRng rng)
157 SilcRngState first, next;
161 SILC_LOG_DEBUG(("Initializing RNG object"));
163 /* Initialize the states for the RNG. */
164 rng->state = silc_calloc(1, sizeof(*rng->state));
167 rng->state->next = NULL;
169 for (i = SILC_RNG_STATE_NUM - 1; i >= 1; i--) {
170 next = silc_calloc(1, sizeof(*rng->state));
172 (i * (sizeof(rng->pool) / SILC_RNG_STATE_NUM));
174 (i * (sizeof(rng->pool) / SILC_RNG_STATE_NUM)) + 8;
175 next->next = rng->state;
181 memset(rng->pool, 0, sizeof(rng->pool));
183 /* Get noise from various environmental sources */
184 silc_rng_get_soft_noise(rng);
185 silc_rng_get_medium_noise(rng);
186 silc_rng_get_hard_noise(rng);
187 silc_rng_get_soft_noise(rng);
190 /* This function gets 'soft' noise from environment. */
192 static void silc_rng_get_soft_noise(SilcRng rng)
199 pos = silc_rng_get_position(rng);
201 silc_rng_xor(rng, clock(), 0);
204 silc_rng_xor(rng, getpid(), 1);
206 silc_rng_xor(rng, getpgid(getpid() << 8), 2);
207 silc_rng_xor(rng, getpgid(getpid() << 8), 3);
209 silc_rng_xor(rng, getgid(), 4);
212 silc_rng_xor(rng, getpgrp(), 5);
215 silc_rng_xor(rng, getsid(getpid() << 16), 6);
217 silc_rng_xor(rng, times(&ptime), 7);
218 silc_rng_xor(rng, ptime.tms_utime, 8);
219 silc_rng_xor(rng, (ptime.tms_utime + ptime.tms_stime), pos++);
220 silc_rng_xor(rng, (ptime.tms_stime + ptime.tms_cutime), pos++);
221 silc_rng_xor(rng, (ptime.tms_utime + ptime.tms_stime), pos++);
222 silc_rng_xor(rng, (ptime.tms_cutime ^ ptime.tms_stime), pos++);
223 silc_rng_xor(rng, (ptime.tms_cutime ^ ptime.tms_cstime), pos++);
224 silc_rng_xor(rng, (ptime.tms_utime ^ ptime.tms_stime), pos++);
225 silc_rng_xor(rng, (ptime.tms_stime ^ ptime.tms_cutime), pos++);
226 silc_rng_xor(rng, (ptime.tms_cutime + ptime.tms_stime), pos++);
227 silc_rng_xor(rng, (ptime.tms_stime << 8), pos++);
229 silc_rng_xor(rng, clock() << 4, pos++);
232 silc_rng_xor(rng, getpgid(getpid() << 8), pos++);
235 silc_rng_xor(rng, getpgrp(), pos++);
238 silc_rng_xor(rng, getsid(getpid() << 16), pos++);
240 silc_rng_xor(rng, times(&ptime), pos++);
241 silc_rng_xor(rng, ptime.tms_utime, pos++);
243 silc_rng_xor(rng, getpgrp(), pos++);
247 #ifdef SILC_RNG_DEBUG
248 SILC_LOG_HEXDUMP(("pool"), rng->pool, sizeof(rng->pool));
251 /* Stir random pool */
252 silc_rng_stir_pool(rng);
255 /* This function gets noise from different commands */
257 static void silc_rng_get_medium_noise(SilcRng rng)
259 silc_rng_exec_command(rng, "ps -leaww 2> /dev/null");
260 silc_rng_exec_command(rng, "ls -afiln ~ 2> /dev/null");
261 silc_rng_exec_command(rng, "ls -afiln /proc 2> /dev/null");
262 silc_rng_exec_command(rng, "ps -axww 2> /dev/null");
264 #ifdef SILC_RNG_DEBUG
265 SILC_LOG_HEXDUMP(("pool"), rng->pool, sizeof(rng->pool));
269 /* This function gets 'hard' noise from environment. This tries to
270 get the noise from /dev/random if available. */
272 static void silc_rng_get_hard_noise(SilcRng rng)
278 /* Get noise from /dev/random if available */
279 fd = open("/dev/random", O_RDONLY);
283 fcntl(fd, F_SETFL, O_NONBLOCK);
285 for (i = 0; i < 2; i++) {
286 len = read(fd, buf, sizeof(buf));
289 silc_rng_add_noise(rng, buf, len);
292 #ifdef SILC_RNG_DEBUG
293 SILC_LOG_HEXDUMP(("pool"), rng->pool, sizeof(rng->pool));
298 memset(buf, 0, sizeof(buf));
302 /* Execs command and gets noise from its output */
304 static void silc_rng_exec_command(SilcRng rng, char *command)
312 fd = popen(command, "r");
316 /* Get data as much as we can get into the buffer */
317 for (i = 0; i < sizeof(buf); i++) {
329 /* Add the buffer into random pool */
330 silc_rng_add_noise(rng, buf, strlen(buf));
331 memset(buf, 0, sizeof(buf));
334 /* This function adds the contents of the buffer as noise into random
335 pool. After adding the noise the pool is stirred. */
337 void silc_rng_add_noise(SilcRng rng, unsigned char *buffer, uint32 len)
341 pos = silc_rng_get_position(rng);
343 /* Add the buffer one by one into the pool */
344 for(i = 0; i < len; i++, buffer++) {
345 if(pos >= SILC_RNG_POOLSIZE)
347 rng->pool[pos++] ^= *buffer;
350 /* Stir random pool */
351 silc_rng_stir_pool(rng);
354 /* XOR's data into the pool */
356 static void silc_rng_xor(SilcRng rng, uint32 val, unsigned int pos)
359 rng->pool[pos] ^= val + val;
362 /* This function stirs the random pool by encrypting buffer in CFB
363 (cipher feedback) mode with SHA1 algorithm. */
365 static void silc_rng_stir_pool(SilcRng rng)
371 memcpy(iv, &rng->pool[SILC_RNG_POOLSIZE - 256], sizeof(iv));
374 for (i = 0; i < SILC_RNG_POOLSIZE; i += 5) {
375 rng->sha1->hash->transform(iv, rng->key);
376 iv[0] = rng->pool[i] ^= iv[0];
377 iv[1] = rng->pool[i + 1] ^= iv[1];
378 iv[2] = rng->pool[i + 2] ^= iv[2];
379 iv[3] = rng->pool[i + 3] ^= iv[3];
380 iv[4] = rng->pool[i + 4] ^= iv[4];
384 memcpy(rng->key, &rng->pool[silc_rng_get_position(rng)], sizeof(rng->key));
386 /* Second CFB pass */
387 for (i = 0; i < SILC_RNG_POOLSIZE; i += 5) {
388 rng->sha1->hash->transform(iv, rng->key);
389 iv[0] = rng->pool[i] ^= iv[0];
390 iv[1] = rng->pool[i + 1] ^= iv[1];
391 iv[2] = rng->pool[i + 2] ^= iv[2];
392 iv[3] = rng->pool[i + 3] ^= iv[3];
393 iv[4] = rng->pool[i + 4] ^= iv[4];
396 memset(iv, 0, sizeof(iv));
399 /* Returns next position where data is fetched from the pool or
402 static uint32 silc_rng_get_position(SilcRng rng)
407 next = rng->state->next;
409 pos = rng->state->pos++;
410 if ((next->low != 0 && pos >= next->low) || (pos >= SILC_RNG_POOLSIZE))
411 rng->state->pos = rng->state->low;
413 #ifdef SILC_RNG_DEBUG
414 fprintf(stderr, "state: %p: low: %lu, pos: %lu\n",
415 rng->state, rng->state->low, rng->state->pos);
423 /* Returns random byte. */
425 unsigned char silc_rng_get_byte(SilcRng rng)
429 /* Get more soft noise after 64 bits threshhold */
430 if (rng->threshhold >= 8)
431 silc_rng_get_soft_noise(rng);
433 /* Get hard noise after 160 bits threshhold, zero the threshhold. */
434 if (rng->threshhold >= 20) {
436 silc_rng_get_hard_noise(rng);
439 return rng->pool[silc_rng_get_position(rng)];
442 /* Returns 16 bit random number */
444 uint16 silc_rng_get_rn16(SilcRng rng)
449 rn[0] = silc_rng_get_byte(rng);
450 rn[1] = silc_rng_get_byte(rng);
451 SILC_GET16_MSB(num, rn);
456 /* Returns 32 bit random number */
458 uint32 silc_rng_get_rn32(SilcRng rng)
463 rn[0] = silc_rng_get_byte(rng);
464 rn[1] = silc_rng_get_byte(rng);
465 rn[2] = silc_rng_get_byte(rng);
466 rn[3] = silc_rng_get_byte(rng);
467 SILC_GET32_MSB(num, rn);
472 /* Returns random number string. Returned string is in HEX format. */
474 unsigned char *silc_rng_get_rn_string(SilcRng rng, uint32 len)
477 unsigned char *string;
479 string = silc_calloc((len * 2 + 1), sizeof(unsigned char));
481 for (i = 0; i < len; i++)
482 sprintf(string + 2 * i, "%02x", silc_rng_get_byte(rng));
487 /* Returns random number binary data. */
489 unsigned char *silc_rng_get_rn_data(SilcRng rng, uint32 len)
494 data = silc_calloc(len + 1, sizeof(*data));
496 for (i = 0; i < len; i++)
497 data[i] = silc_rng_get_byte(rng);
502 /* Global RNG. This is global RNG that application can initialize so
503 that any part of code anywhere can use RNG without having to allocate
504 new RNG object everytime. If this is not initialized then these routines
505 will fail. Note: currently in SILC applications always initialize this. */
507 SilcRng global_rng = NULL;
509 /* Initialize global RNG. If `rng' is provided it is set as the global
510 RNG object (it can be allocated by the application for example). */
512 int silc_rng_global_init(SilcRng rng)
517 global_rng = silc_rng_alloc();
522 /* Uninitialize global RNG */
524 int silc_rng_global_uninit()
527 silc_rng_free(global_rng);
534 /* These are analogous to the functions above. */
536 unsigned char silc_rng_global_get_byte()
538 return global_rng ? silc_rng_get_byte(global_rng) : 0;
541 uint16 silc_rng_global_get_rn16()
543 return global_rng ? silc_rng_get_rn16(global_rng) : 0;
546 uint32 silc_rng_global_get_rn32()
548 return global_rng ? silc_rng_get_rn32(global_rng) : 0;
551 unsigned char *silc_rng_global_get_rn_string(uint32 len)
553 return global_rng ? silc_rng_get_rn_string(global_rng, len) : NULL;
556 unsigned char *silc_rng_global_get_rn_data(uint32 len)
558 return global_rng ? silc_rng_get_rn_data(global_rng, len) : NULL;
561 void silc_rng_global_add_noise(unsigned char *buffer, uint32 len)
564 silc_rng_add_noise(global_rng, buffer, len);