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"
33 extern pid_t getsid (pid_t __pid);
37 extern pid_t getpgid (pid_t __pid);
42 /*#define SILC_RNG_DEBUG*/
44 /* Number of states to fetch data from pool. */
45 #define SILC_RNG_STATE_NUM 4
47 /* Byte size of the random data pool. */
48 #define SILC_RNG_POOLSIZE 1024
50 static uint32 silc_rng_get_position(SilcRng rng);
51 static void silc_rng_stir_pool(SilcRng rng);
52 static void silc_rng_xor(SilcRng rng, uint32 val, unsigned int pos);
53 static void silc_rng_exec_command(SilcRng rng, char *command);
54 static void silc_rng_get_hard_noise(SilcRng rng);
55 static void silc_rng_get_medium_noise(SilcRng rng);
56 static void silc_rng_get_soft_noise(SilcRng rng);
59 SILC SilcRng State context.
61 This object is used by the random number generator to provide
62 variable points where the actual random number is fetched from
63 the random pool. This provides that the data is not fetched always
64 from the same point of the pool. Short description of the fields
70 The index for the random pool buffer. Lowest and current
73 SilcRngStateContext *next
75 Pointer to the next state. If this is the last state this
76 will point to the first state thus providing circular list.
79 typedef struct SilcRngStateContext {
82 struct SilcRngStateContext *next;
86 SILC Random Number Generator object.
88 This object holds random pool which is used to generate the random
89 numbers used by various routines needing cryptographically strong
90 random numbers. Following short descriptions of the fields.
94 The random pool. This buffer holds the random data. This is
95 frequently stirred thus providing ever changing randomnes.
99 Key used in stirring the random pool. The pool is encrypted
100 with SHA1 hash function in CFB (Cipher Feedback) mode.
102 SilcSilcRngState state
104 State object that is used to get the next position for the
105 random pool. This position is used to fetch data from pool
106 or to save the data to the pool. The state changes everytime
111 Hash object (SHA1) used to make the CFB encryption to the
112 random pool. This is allocated when RNG object is allocated and
113 free'd when RNG object is free'd.
117 Threshhold to indicate when it is required to acquire more
118 noise from the environment. More soft noise is acquired after
119 64 bits of output and hard noise every 160 bits of output.
122 typedef struct SilcRngObjectStruct {
123 unsigned char pool[SILC_RNG_POOLSIZE];
124 unsigned char key[64];
132 /* Allocates new RNG object. */
134 SilcRng silc_rng_alloc()
138 SILC_LOG_DEBUG(("Allocating new RNG object"));
140 new = silc_calloc(1, sizeof(*new));
141 new->fd_devurandom = -1;
143 memset(new->pool, 0, sizeof(new->pool));
144 memset(new->key, 0, sizeof(new->key));
146 silc_hash_alloc("sha1", &new->sha1);
148 new->devrandom = strdup("/dev/random");
153 /* Free's RNG object. */
155 void silc_rng_free(SilcRng rng)
158 memset(rng->pool, 0, sizeof(rng->pool));
159 memset(rng->key, 0, sizeof(rng->key));
160 silc_hash_free(rng->sha1);
161 silc_free(rng->devrandom);
163 if (rng->fd_devurandom != -1)
164 close(rng->fd_devurandom);
170 /* Initializes random number generator by getting noise from environment.
171 The environmental noise is our so called seed. One should not call
172 this function more than once. */
174 void silc_rng_init(SilcRng rng)
177 SilcRngState first, next;
181 SILC_LOG_DEBUG(("Initializing RNG object"));
183 /* Initialize the states for the RNG. */
184 rng->state = silc_calloc(1, sizeof(*rng->state));
187 rng->state->next = NULL;
189 for (i = SILC_RNG_STATE_NUM - 1; i >= 1; i--) {
190 next = silc_calloc(1, sizeof(*rng->state));
192 (i * (sizeof(rng->pool) / SILC_RNG_STATE_NUM));
194 (i * (sizeof(rng->pool) / SILC_RNG_STATE_NUM)) + 8;
195 next->next = rng->state;
201 memset(rng->pool, 0, sizeof(rng->pool));
203 /* Get noise from various environmental sources */
204 silc_rng_get_soft_noise(rng);
205 silc_rng_get_medium_noise(rng);
206 silc_rng_get_hard_noise(rng);
207 silc_rng_get_soft_noise(rng);
208 silc_free(rng->devrandom);
209 rng->devrandom = strdup("/dev/urandom");
212 /* This function gets 'soft' noise from environment. */
214 static void silc_rng_get_soft_noise(SilcRng rng)
221 pos = silc_rng_get_position(rng);
223 silc_rng_xor(rng, clock(), 0);
226 silc_rng_xor(rng, getpid(), 1);
228 silc_rng_xor(rng, getpgid(getpid()) << 8, 2);
229 silc_rng_xor(rng, getpgid(getpid()) << 8, 3);
231 silc_rng_xor(rng, getgid(), 4);
234 silc_rng_xor(rng, getpgrp(), 5);
237 silc_rng_xor(rng, getsid(getpid()) << 16, 6);
239 silc_rng_xor(rng, times(&ptime), 7);
240 silc_rng_xor(rng, ptime.tms_utime, 8);
241 silc_rng_xor(rng, (ptime.tms_utime + ptime.tms_stime), pos++);
242 silc_rng_xor(rng, (ptime.tms_stime + ptime.tms_cutime), pos++);
243 silc_rng_xor(rng, (ptime.tms_utime + ptime.tms_stime), pos++);
244 silc_rng_xor(rng, (ptime.tms_cutime ^ ptime.tms_stime), pos++);
245 silc_rng_xor(rng, (ptime.tms_cutime ^ ptime.tms_cstime), pos++);
246 silc_rng_xor(rng, (ptime.tms_utime ^ ptime.tms_stime), pos++);
247 silc_rng_xor(rng, (ptime.tms_stime ^ ptime.tms_cutime), pos++);
248 silc_rng_xor(rng, (ptime.tms_cutime + ptime.tms_stime), pos++);
249 silc_rng_xor(rng, (ptime.tms_stime << 8), pos++);
251 silc_rng_xor(rng, clock() << 4, pos++);
254 silc_rng_xor(rng, getpgid(getpid()) << 8, pos++);
257 silc_rng_xor(rng, getpgrp(), pos++);
260 silc_rng_xor(rng, getsid(getpid()) << 16, pos++);
262 silc_rng_xor(rng, times(&ptime), pos++);
263 silc_rng_xor(rng, ptime.tms_utime, pos++);
265 silc_rng_xor(rng, getpgrp(), pos++);
269 #ifdef SILC_RNG_DEBUG
270 SILC_LOG_HEXDUMP(("pool"), rng->pool, sizeof(rng->pool));
273 /* Stir random pool */
274 silc_rng_stir_pool(rng);
277 /* This function gets noise from different commands */
279 static void silc_rng_get_medium_noise(SilcRng rng)
281 silc_rng_exec_command(rng, "ps -leaww 2> /dev/null");
282 silc_rng_exec_command(rng, "ls -afiln ~ 2> /dev/null");
283 silc_rng_exec_command(rng, "ls -afiln /proc 2> /dev/null");
284 silc_rng_exec_command(rng, "ps -axww 2> /dev/null");
286 #ifdef SILC_RNG_DEBUG
287 SILC_LOG_HEXDUMP(("pool"), rng->pool, sizeof(rng->pool));
291 /* This function gets 'hard' noise from environment. This tries to
292 get the noise from /dev/random if available. */
294 static void silc_rng_get_hard_noise(SilcRng rng)
297 unsigned char buf[32];
300 /* Get noise from /dev/[u]random if available */
301 fd = open(rng->devrandom, O_RDONLY);
305 fcntl(fd, F_SETFL, O_NONBLOCK);
307 for (i = 0; i < 2; i++) {
308 len = read(fd, buf, sizeof(buf));
311 silc_rng_add_noise(rng, buf, len);
314 #ifdef SILC_RNG_DEBUG
315 SILC_LOG_HEXDUMP(("pool"), rng->pool, sizeof(rng->pool));
320 memset(buf, 0, sizeof(buf));
324 /* Execs command and gets noise from its output */
326 static void silc_rng_exec_command(SilcRng rng, char *command)
329 unsigned char buf[1024];
335 fd = popen(command, "r");
339 /* Get data as much as we can get into the buffer */
340 for (i = 0; i < sizeof(buf); i++) {
352 /* Add the buffer into random pool */
353 silc_rng_add_noise(rng, buf, i);
354 memset(buf, 0, sizeof(buf));
358 /* This function adds the contents of the buffer as noise into random
359 pool. After adding the noise the pool is stirred. */
361 void silc_rng_add_noise(SilcRng rng, unsigned char *buffer, uint32 len)
365 pos = silc_rng_get_position(rng);
367 /* Add the buffer one by one into the pool */
368 for(i = 0; i < len; i++, buffer++) {
369 if(pos >= SILC_RNG_POOLSIZE)
371 rng->pool[pos++] ^= *buffer;
374 /* Stir random pool */
375 silc_rng_stir_pool(rng);
378 /* XOR's data into the pool */
380 static void silc_rng_xor(SilcRng rng, uint32 val, unsigned int pos)
383 rng->pool[pos] ^= val + val;
386 /* This function stirs the random pool by encrypting buffer in CFB
387 (cipher feedback) mode with SHA1 algorithm. */
389 static void silc_rng_stir_pool(SilcRng rng)
395 memcpy(iv, &rng->pool[16], sizeof(iv));
398 for (i = 0; i < SILC_RNG_POOLSIZE; i += 5) {
399 rng->sha1->hash->transform(iv, rng->key);
400 iv[0] = rng->pool[i] ^= iv[0];
401 iv[1] = rng->pool[i + 1] ^= iv[1];
402 iv[2] = rng->pool[i + 2] ^= iv[2];
403 iv[3] = rng->pool[i + 3] ^= iv[3];
404 iv[4] = rng->pool[i + 4] ^= iv[4];
408 memcpy(rng->key, &rng->pool[silc_rng_get_position(rng)], sizeof(rng->key));
410 /* Second CFB pass */
411 for (i = 0; i < SILC_RNG_POOLSIZE; i += 5) {
412 rng->sha1->hash->transform(iv, rng->key);
413 iv[0] = rng->pool[i] ^= iv[0];
414 iv[1] = rng->pool[i + 1] ^= iv[1];
415 iv[2] = rng->pool[i + 2] ^= iv[2];
416 iv[3] = rng->pool[i + 3] ^= iv[3];
417 iv[4] = rng->pool[i + 4] ^= iv[4];
420 memset(iv, 0, sizeof(iv));
423 /* Returns next position where data is fetched from the pool or
426 static uint32 silc_rng_get_position(SilcRng rng)
431 next = rng->state->next;
433 pos = rng->state->pos++;
434 if ((next->low != 0 && pos >= next->low) || (pos >= SILC_RNG_POOLSIZE))
435 rng->state->pos = rng->state->low;
437 #ifdef SILC_RNG_DEBUG
438 fprintf(stderr, "state: %p: low: %lu, pos: %lu\n",
439 rng->state, rng->state->low, rng->state->pos);
447 /* Returns random byte. */
449 unsigned char silc_rng_get_byte(SilcRng rng)
453 /* Get more soft noise after 64 bits threshhold */
454 if (rng->threshhold >= 8)
455 silc_rng_get_soft_noise(rng);
457 /* Get hard noise after 160 bits threshhold, zero the threshhold. */
458 if (rng->threshhold >= 20) {
460 silc_rng_get_hard_noise(rng);
463 return rng->pool[silc_rng_get_position(rng)];
466 /* Returns 16 bit random number */
468 uint16 silc_rng_get_rn16(SilcRng rng)
473 rn[0] = silc_rng_get_byte(rng);
474 rn[1] = silc_rng_get_byte(rng);
475 SILC_GET16_MSB(num, rn);
480 /* Returns 32 bit random number */
482 uint32 silc_rng_get_rn32(SilcRng rng)
487 rn[0] = silc_rng_get_byte(rng);
488 rn[1] = silc_rng_get_byte(rng);
489 rn[2] = silc_rng_get_byte(rng);
490 rn[3] = silc_rng_get_byte(rng);
491 SILC_GET32_MSB(num, rn);
496 /* Returns random number string. Returned string is in HEX format. */
498 unsigned char *silc_rng_get_rn_string(SilcRng rng, uint32 len)
501 unsigned char *string;
503 string = silc_calloc((len * 2 + 1), sizeof(unsigned char));
505 for (i = 0; i < len; i++)
506 sprintf(string + 2 * i, "%02x", silc_rng_get_byte(rng));
511 /* Returns random number binary data. */
513 unsigned char *silc_rng_get_rn_data(SilcRng rng, uint32 len)
518 data = silc_calloc(len + 1, sizeof(*data));
520 for (i = 0; i < len; i++)
521 data[i] = silc_rng_get_byte(rng);
526 /* Global RNG. This is global RNG that application can initialize so
527 that any part of code anywhere can use RNG without having to allocate
528 new RNG object everytime. If this is not initialized then these routines
529 will fail. Note: currently in SILC applications always initialize this. */
531 SilcRng global_rng = NULL;
533 /* Initialize global RNG. If `rng' is provided it is set as the global
534 RNG object (it can be allocated by the application for example). */
536 int silc_rng_global_init(SilcRng rng)
541 global_rng = silc_rng_alloc();
546 /* Uninitialize global RNG */
548 int silc_rng_global_uninit()
551 silc_rng_free(global_rng);
558 /* These are analogous to the functions above. */
560 unsigned char silc_rng_global_get_byte()
562 return global_rng ? silc_rng_get_byte(global_rng) : 0;
565 /* Return random byte as fast as possible. Reads from /dev/urandom if
566 available. If not then return from normal RNG (not so fast). */
568 unsigned char silc_rng_global_get_byte_fast()
571 unsigned char buf[1];
576 if (global_rng->fd_devurandom == -1) {
577 global_rng->fd_devurandom = open("/dev/urandom", O_RDONLY);
579 return silc_rng_global_get_byte();
580 fcntl(global_rng->fd_devurandom, F_SETFL, O_NONBLOCK);
583 if (read(global_rng->fd_devurandom, buf, sizeof(buf)) < 0)
584 return silc_rng_global_get_byte();
588 return silc_rng_global_get_byte();
592 uint16 silc_rng_global_get_rn16()
594 return global_rng ? silc_rng_get_rn16(global_rng) : 0;
597 uint32 silc_rng_global_get_rn32()
599 return global_rng ? silc_rng_get_rn32(global_rng) : 0;
602 unsigned char *silc_rng_global_get_rn_string(uint32 len)
604 return global_rng ? silc_rng_get_rn_string(global_rng, len) : NULL;
607 unsigned char *silc_rng_global_get_rn_data(uint32 len)
609 return global_rng ? silc_rng_get_rn_data(global_rng, len) : NULL;
612 void silc_rng_global_add_noise(unsigned char *buffer, uint32 len)
615 silc_rng_add_noise(global_rng, buffer, len);