yarrow.c revision 107789
162053Smarkm/*- 262765Smarkm * Copyright (c) 2000 Mark R V Murray 362053Smarkm * All rights reserved. 462053Smarkm * 562053Smarkm * Redistribution and use in source and binary forms, with or without 662053Smarkm * modification, are permitted provided that the following conditions 762053Smarkm * are met: 862053Smarkm * 1. Redistributions of source code must retain the above copyright 962053Smarkm * notice, this list of conditions and the following disclaimer 1062053Smarkm * in this position and unchanged. 1162053Smarkm * 2. Redistributions in binary form must reproduce the above copyright 1262053Smarkm * notice, this list of conditions and the following disclaimer in the 1362053Smarkm * documentation and/or other materials provided with the distribution. 1462053Smarkm * 1562053Smarkm * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1662053Smarkm * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1762053Smarkm * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 1862053Smarkm * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 1962053Smarkm * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 2062053Smarkm * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2162053Smarkm * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2262053Smarkm * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2362053Smarkm * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2462053Smarkm * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2562053Smarkm * 2662053Smarkm * $FreeBSD: head/sys/dev/random/yarrow.c 107789 2002-12-12 17:38:45Z markm $ 2762053Smarkm */ 2862053Smarkm 2962053Smarkm#include <sys/param.h> 3062053Smarkm#include <sys/systm.h> 3165686Smarkm#include <sys/kernel.h> 3274914Sjhb#include <sys/lock.h> 3367365Sjhb#include <sys/mutex.h> 3462053Smarkm#include <sys/random.h> 3574072Smarkm#include <sys/sysctl.h> 3669168Smarkm 3774072Smarkm#include <crypto/rijndael/rijndael.h> 38100082Smarkm#include <crypto/sha2/sha2.h> 3969168Smarkm 4067112Smarkm#include <dev/random/hash.h> 4174072Smarkm#include <dev/random/randomdev.h> 4267112Smarkm#include <dev/random/yarrow.h> 4362053Smarkm 4462765Smarkm/* #define DEBUG */ 4562053Smarkm 4674072SmarkmRANDOM_CHECK_UINT(gengateinterval, 4, 64); 4774072SmarkmRANDOM_CHECK_UINT(bins, 2, 16); 4874072SmarkmRANDOM_CHECK_UINT(fastthresh, BLOCKSIZE/4, BLOCKSIZE); 4974072SmarkmRANDOM_CHECK_UINT(slowthresh, BLOCKSIZE/4, BLOCKSIZE); 5074072SmarkmRANDOM_CHECK_UINT(slowoverthresh, 1, 5); 5174072Smarkm 5289170Smsmith/* Structure holding the entropy state */ 5389170Smsmithstatic struct random_state random_state; 5489170Smsmith 5574072SmarkmSYSCTL_NODE(_kern_random, OID_AUTO, yarrow, CTLFLAG_RW, 0, "Yarrow Parameters"); 5674072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, gengateinterval, 5774072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.gengateinterval, 10, 5874072Smarkm random_check_uint_gengateinterval, "I", "Generator Gate Interval"); 5974072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, bins, 6074072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.bins, 10, 6174072Smarkm random_check_uint_bins, "I", "Execution time tuner"); 6274072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, fastthresh, 6374072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.pool[0].thresh, (3*BLOCKSIZE)/4, 6474072Smarkm random_check_uint_fastthresh, "I", "Fast reseed threshold"); 6574072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, slowthresh, 6674072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.pool[1].thresh, BLOCKSIZE, 6774072Smarkm random_check_uint_slowthresh, "I", "Slow reseed threshold"); 6874072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, slowoverthresh, 6974072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.slowoverthresh, 2, 7074072Smarkm random_check_uint_slowoverthresh, "I", "Slow over-threshold reseed"); 7174072Smarkm 7262765Smarkmstatic void generator_gate(void); 7374072Smarkmstatic void reseed(u_int); 7462053Smarkm 7565686Smarkm/* The reseed thread mutex */ 7665856Sjhbstatic struct mtx random_reseed_mtx; 7762765Smarkm 7874072Smarkm/* Process a single stochastic event off the harvest queue */ 7974072Smarkmvoid 8074072Smarkmrandom_process_event(struct harvest *event) 8162765Smarkm{ 8291600Smarkm u_int pl, overthreshhold[2]; 8365686Smarkm struct source *source; 8491600Smarkm enum esource src; 8565686Smarkm 8674072Smarkm /* Unpack the event into the appropriate source accumulator */ 8774072Smarkm pl = random_state.which; 8874072Smarkm source = &random_state.pool[pl].source[event->source]; 8974072Smarkm yarrow_hash_iterate(&random_state.pool[pl].hash, event->entropy, 9074072Smarkm sizeof(event->entropy)); 9174072Smarkm yarrow_hash_iterate(&random_state.pool[pl].hash, &event->somecounter, 9274072Smarkm sizeof(event->somecounter)); 9374072Smarkm source->frac += event->frac; 9474072Smarkm source->bits += event->bits + source->frac/1024; 9574072Smarkm source->frac %= 1024; 9665686Smarkm 9774072Smarkm /* Count the over-threshold sources in each pool */ 9874072Smarkm for (pl = 0; pl < 2; pl++) { 9974072Smarkm overthreshhold[pl] = 0; 10091600Smarkm for (src = RANDOM_START; src < ENTROPYSOURCE; src++) { 10174072Smarkm if (random_state.pool[pl].source[src].bits 10274072Smarkm > random_state.pool[pl].thresh) 10374072Smarkm overthreshhold[pl]++; 10465686Smarkm } 10574072Smarkm } 10665686Smarkm 10774072Smarkm /* if any fast source over threshhold, reseed */ 10874072Smarkm if (overthreshhold[FAST]) 10974072Smarkm reseed(FAST); 11065686Smarkm 11174072Smarkm /* if enough slow sources are over threshhold, reseed */ 11274072Smarkm if (overthreshhold[SLOW] >= random_state.slowoverthresh) 11374072Smarkm reseed(SLOW); 11465686Smarkm 11574072Smarkm /* Invert the fast/slow pool selector bit */ 11674072Smarkm random_state.which = !random_state.which; 11762765Smarkm} 11862765Smarkm 11974072Smarkmvoid 12062765Smarkmrandom_init(void) 12162053Smarkm{ 12274072Smarkm int i; 12365686Smarkm 12472364Smarkm /* Yarrow parameters. Do not adjust these unless you have 12572364Smarkm * have a very good clue about what they do! 12672364Smarkm */ 12762765Smarkm random_state.gengateinterval = 10; 12862765Smarkm random_state.bins = 10; 12974072Smarkm random_state.pool[0].thresh = (3*BLOCKSIZE)/4; 13074072Smarkm random_state.pool[1].thresh = BLOCKSIZE; 13162765Smarkm random_state.slowoverthresh = 2; 13262765Smarkm random_state.which = FAST; 13365686Smarkm 13474072Smarkm /* Initialise the fast and slow entropy pools */ 13574072Smarkm for (i = 0; i < 2; i++) 13674072Smarkm yarrow_hash_init(&random_state.pool[i].hash); 13765686Smarkm 13874072Smarkm /* Clear the counter */ 13974072Smarkm for (i = 0; i < 4; i++) 14074072Smarkm random_state.counter[i] = 0; 14169526Smarkm 14274072Smarkm /* Set up a lock for the reseed process */ 14393818Sjhb mtx_init(&random_reseed_mtx, "random reseed", NULL, MTX_DEF); 14462053Smarkm} 14562053Smarkm 14662053Smarkmvoid 14762765Smarkmrandom_deinit(void) 14862053Smarkm{ 14965686Smarkm mtx_destroy(&random_reseed_mtx); 15062765Smarkm} 15162765Smarkm 15262765Smarkmstatic void 15374072Smarkmreseed(u_int fastslow) 15462765Smarkm{ 15565686Smarkm /* Interrupt-context stack is a limited resource; make large 15665686Smarkm * structures static. 15763771Smarkm */ 15865686Smarkm static u_char v[TIMEBIN][KEYSIZE]; /* v[i] */ 15965686Smarkm static struct yarrowhash context; 16065686Smarkm u_char hash[KEYSIZE]; /* h' */ 16165686Smarkm u_char temp[KEYSIZE]; 16291600Smarkm u_int i; 16391600Smarkm enum esource j; 16462053Smarkm 16562765Smarkm#ifdef DEBUG 16662765Smarkm printf("Reseed type %d\n", fastslow); 16762765Smarkm#endif 16862765Smarkm 16965686Smarkm /* The reseed task must not be jumped on */ 17072200Sbmilekic mtx_lock(&random_reseed_mtx); 17165686Smarkm 17262053Smarkm /* 1. Hash the accumulated entropy into v[0] */ 17362053Smarkm 17474072Smarkm yarrow_hash_init(&context); 17565686Smarkm /* Feed the slow pool hash in if slow */ 17665686Smarkm if (fastslow == SLOW) 17765686Smarkm yarrow_hash_iterate(&context, 17874072Smarkm &random_state.pool[SLOW].hash, 17974072Smarkm sizeof(struct yarrowhash)); 18065686Smarkm yarrow_hash_iterate(&context, 18165686Smarkm &random_state.pool[FAST].hash, sizeof(struct yarrowhash)); 18274072Smarkm yarrow_hash_finish(&context, v[0]); 18362765Smarkm 18463771Smarkm /* 2. Compute hash values for all v. _Supposed_ to be computationally 18563771Smarkm * intensive. 18663771Smarkm */ 18762053Smarkm 18862765Smarkm if (random_state.bins > TIMEBIN) 18962765Smarkm random_state.bins = TIMEBIN; 19062765Smarkm for (i = 1; i < random_state.bins; i++) { 19174072Smarkm yarrow_hash_init(&context); 19274072Smarkm /* v[i] #= h(v[i - 1]) */ 19365686Smarkm yarrow_hash_iterate(&context, v[i - 1], KEYSIZE); 19462765Smarkm /* v[i] #= h(v[0]) */ 19565686Smarkm yarrow_hash_iterate(&context, v[0], KEYSIZE); 19662765Smarkm /* v[i] #= h(i) */ 19774072Smarkm yarrow_hash_iterate(&context, &i, sizeof(u_int)); 19865686Smarkm /* Return the hashval */ 19965686Smarkm yarrow_hash_finish(&context, v[i]); 20062053Smarkm } 20162053Smarkm 20265686Smarkm /* 3. Compute a new key; h' is the identity function here; 20365686Smarkm * it is not being ignored! 20465686Smarkm */ 20562053Smarkm 20674072Smarkm yarrow_hash_init(&context); 20765686Smarkm yarrow_hash_iterate(&context, &random_state.key, KEYSIZE); 20865686Smarkm for (i = 1; i < random_state.bins; i++) 20965686Smarkm yarrow_hash_iterate(&context, &v[i], KEYSIZE); 21065686Smarkm yarrow_hash_finish(&context, temp); 21174072Smarkm yarrow_encrypt_init(&random_state.key, temp); 21262053Smarkm 21362053Smarkm /* 4. Recompute the counter */ 21462053Smarkm 21574072Smarkm for (i = 0; i < 4; i++) 21674072Smarkm random_state.counter[i] = 0; 21774072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, temp); 21874072Smarkm memcpy(random_state.counter, temp, sizeof(random_state.counter)); 21962053Smarkm 22062765Smarkm /* 5. Reset entropy estimate accumulators to zero */ 22162053Smarkm 22262765Smarkm for (i = 0; i <= fastslow; i++) { 22391600Smarkm for (j = RANDOM_START; j < ENTROPYSOURCE; j++) { 22474072Smarkm random_state.pool[i].source[j].bits = 0; 22574072Smarkm random_state.pool[i].source[j].frac = 0; 22662765Smarkm } 22762765Smarkm } 22862053Smarkm 22962053Smarkm /* 6. Wipe memory of intermediate values */ 23062053Smarkm 23165686Smarkm memset((void *)v, 0, sizeof(v)); 23265686Smarkm memset((void *)temp, 0, sizeof(temp)); 23365686Smarkm memset((void *)hash, 0, sizeof(hash)); 23462053Smarkm 23565686Smarkm /* 7. Dump to seed file */ 23665686Smarkm /* XXX Not done here yet */ 23762053Smarkm 23865686Smarkm /* Release the reseed mutex */ 23972200Sbmilekic mtx_unlock(&random_reseed_mtx); 24065686Smarkm 24165686Smarkm#ifdef DEBUG 24265686Smarkm printf("Reseed finish\n"); 24365686Smarkm#endif 24465686Smarkm 24574072Smarkm /* Unblock the device if it was blocked due to being unseeded */ 24674072Smarkm random_unblock(); 24762053Smarkm} 24862053Smarkm 249100082Smarkm/* Internal function to return processed entropy from the PRNG */ 25091600Smarkmint 25191600Smarkmread_random_real(void *buf, int count) 25262053Smarkm{ 25362053Smarkm static int cur = 0; 25462053Smarkm static int gate = 1; 25574908Smarkm static u_char genval[KEYSIZE]; 256107789Smarkm size_t tomove; 25791600Smarkm int i; 25891600Smarkm int retval; 25962053Smarkm 26062875Smarkm /* The reseed task must not be jumped on */ 26172200Sbmilekic mtx_lock(&random_reseed_mtx); 26262875Smarkm 26362053Smarkm if (gate) { 26462053Smarkm generator_gate(); 26562765Smarkm random_state.outputblocks = 0; 26662053Smarkm gate = 0; 26762053Smarkm } 26891600Smarkm if (count > 0 && (size_t)count >= sizeof(random_state.counter)) { 26962053Smarkm retval = 0; 27091600Smarkm for (i = 0; i < count; i += (int)sizeof(random_state.counter)) { 27174072Smarkm random_state.counter[0]++; 27274072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 27374908Smarkm genval); 274107789Smarkm tomove = min(count - i, sizeof(random_state.counter)); 275107789Smarkm memcpy((char *)buf + i, genval, tomove); 27674072Smarkm if (++random_state.outputblocks >= 27774072Smarkm random_state.gengateinterval) { 27862053Smarkm generator_gate(); 27962765Smarkm random_state.outputblocks = 0; 28062053Smarkm } 281107789Smarkm retval += (int)tomove; 28262053Smarkm } 28362053Smarkm } 28462053Smarkm else { 28562053Smarkm if (!cur) { 28674072Smarkm random_state.counter[0]++; 28774072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 28874908Smarkm genval); 28991600Smarkm memcpy(buf, genval, (size_t)count); 29091600Smarkm cur = (int)sizeof(random_state.counter) - count; 29174072Smarkm if (++random_state.outputblocks >= 29274072Smarkm random_state.gengateinterval) { 29362053Smarkm generator_gate(); 29462765Smarkm random_state.outputblocks = 0; 29562053Smarkm } 29662053Smarkm retval = count; 29762053Smarkm } 29862053Smarkm else { 29962053Smarkm retval = cur < count ? cur : count; 30091600Smarkm memcpy(buf, 30191600Smarkm &genval[(int)sizeof(random_state.counter) - cur], 30291600Smarkm (size_t)retval); 30362053Smarkm cur -= retval; 30462053Smarkm } 30562053Smarkm } 30672200Sbmilekic mtx_unlock(&random_reseed_mtx); 30762053Smarkm return retval; 30862053Smarkm} 30962053Smarkm 31062765Smarkmstatic void 31162053Smarkmgenerator_gate(void) 31262053Smarkm{ 31374072Smarkm u_int i; 31465686Smarkm u_char temp[KEYSIZE]; 31562053Smarkm 31662765Smarkm#ifdef DEBUG 31762875Smarkm printf("Generator gate\n"); 31862765Smarkm#endif 31962875Smarkm 32062765Smarkm for (i = 0; i < KEYSIZE; i += sizeof(random_state.counter)) { 32174072Smarkm random_state.counter[0]++; 32274072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 32374072Smarkm &(temp[i])); 32462053Smarkm } 32562053Smarkm 32674072Smarkm yarrow_encrypt_init(&random_state.key, temp); 32765686Smarkm memset((void *)temp, 0, KEYSIZE); 32862875Smarkm 32965686Smarkm#ifdef DEBUG 33065686Smarkm printf("Generator gate finish\n"); 33165686Smarkm#endif 33262053Smarkm} 33362765Smarkm 33469172Smarkm/* Helper routine to perform explicit reseeds */ 33569172Smarkmvoid 33669172Smarkmrandom_reseed(void) 33769172Smarkm{ 338100082Smarkm reseed(SLOW); 33969172Smarkm} 340