yarrow.c revision 91600
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 91600 2002-03-03 19:44:22Z 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> 3869168Smarkm 3967112Smarkm#include <dev/random/hash.h> 4074072Smarkm#include <dev/random/randomdev.h> 4167112Smarkm#include <dev/random/yarrow.h> 4262053Smarkm 4362765Smarkm/* #define DEBUG */ 4462053Smarkm 4574072SmarkmRANDOM_CHECK_UINT(gengateinterval, 4, 64); 4674072SmarkmRANDOM_CHECK_UINT(bins, 2, 16); 4774072SmarkmRANDOM_CHECK_UINT(fastthresh, BLOCKSIZE/4, BLOCKSIZE); 4874072SmarkmRANDOM_CHECK_UINT(slowthresh, BLOCKSIZE/4, BLOCKSIZE); 4974072SmarkmRANDOM_CHECK_UINT(slowoverthresh, 1, 5); 5074072Smarkm 5189170Smsmith/* Structure holding the entropy state */ 5289170Smsmithstatic struct random_state random_state; 5389170Smsmith 5474072SmarkmSYSCTL_NODE(_kern_random, OID_AUTO, yarrow, CTLFLAG_RW, 0, "Yarrow Parameters"); 5574072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, gengateinterval, 5674072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.gengateinterval, 10, 5774072Smarkm random_check_uint_gengateinterval, "I", "Generator Gate Interval"); 5874072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, bins, 5974072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.bins, 10, 6074072Smarkm random_check_uint_bins, "I", "Execution time tuner"); 6174072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, fastthresh, 6274072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.pool[0].thresh, (3*BLOCKSIZE)/4, 6374072Smarkm random_check_uint_fastthresh, "I", "Fast reseed threshold"); 6474072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, slowthresh, 6574072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.pool[1].thresh, BLOCKSIZE, 6674072Smarkm random_check_uint_slowthresh, "I", "Slow reseed threshold"); 6774072SmarkmSYSCTL_PROC(_kern_random_yarrow, OID_AUTO, slowoverthresh, 6874072Smarkm CTLTYPE_INT|CTLFLAG_RW, &random_state.slowoverthresh, 2, 6974072Smarkm random_check_uint_slowoverthresh, "I", "Slow over-threshold reseed"); 7074072Smarkm 7162765Smarkmstatic void generator_gate(void); 7274072Smarkmstatic void reseed(u_int); 7362053Smarkm 7465686Smarkm/* The reseed thread mutex */ 7565856Sjhbstatic struct mtx random_reseed_mtx; 7662765Smarkm 7774072Smarkm/* Process a single stochastic event off the harvest queue */ 7874072Smarkmvoid 7974072Smarkmrandom_process_event(struct harvest *event) 8062765Smarkm{ 8191600Smarkm u_int pl, overthreshhold[2]; 8265686Smarkm struct source *source; 8391600Smarkm enum esource src; 8465686Smarkm 8574072Smarkm /* Unpack the event into the appropriate source accumulator */ 8674072Smarkm pl = random_state.which; 8774072Smarkm source = &random_state.pool[pl].source[event->source]; 8874072Smarkm yarrow_hash_iterate(&random_state.pool[pl].hash, event->entropy, 8974072Smarkm sizeof(event->entropy)); 9074072Smarkm yarrow_hash_iterate(&random_state.pool[pl].hash, &event->somecounter, 9174072Smarkm sizeof(event->somecounter)); 9274072Smarkm source->frac += event->frac; 9374072Smarkm source->bits += event->bits + source->frac/1024; 9474072Smarkm source->frac %= 1024; 9565686Smarkm 9674072Smarkm /* Count the over-threshold sources in each pool */ 9774072Smarkm for (pl = 0; pl < 2; pl++) { 9874072Smarkm overthreshhold[pl] = 0; 9991600Smarkm for (src = RANDOM_START; src < ENTROPYSOURCE; src++) { 10074072Smarkm if (random_state.pool[pl].source[src].bits 10174072Smarkm > random_state.pool[pl].thresh) 10274072Smarkm overthreshhold[pl]++; 10365686Smarkm } 10474072Smarkm } 10565686Smarkm 10674072Smarkm /* if any fast source over threshhold, reseed */ 10774072Smarkm if (overthreshhold[FAST]) 10874072Smarkm reseed(FAST); 10965686Smarkm 11074072Smarkm /* if enough slow sources are over threshhold, reseed */ 11174072Smarkm if (overthreshhold[SLOW] >= random_state.slowoverthresh) 11274072Smarkm reseed(SLOW); 11365686Smarkm 11474072Smarkm /* Invert the fast/slow pool selector bit */ 11574072Smarkm random_state.which = !random_state.which; 11662765Smarkm} 11762765Smarkm 11874072Smarkmvoid 11962765Smarkmrandom_init(void) 12062053Smarkm{ 12174072Smarkm int i; 12265686Smarkm 12372364Smarkm /* Yarrow parameters. Do not adjust these unless you have 12472364Smarkm * have a very good clue about what they do! 12572364Smarkm */ 12662765Smarkm random_state.gengateinterval = 10; 12762765Smarkm random_state.bins = 10; 12874072Smarkm random_state.pool[0].thresh = (3*BLOCKSIZE)/4; 12974072Smarkm random_state.pool[1].thresh = BLOCKSIZE; 13062765Smarkm random_state.slowoverthresh = 2; 13162765Smarkm random_state.which = FAST; 13265686Smarkm 13374072Smarkm /* Initialise the fast and slow entropy pools */ 13474072Smarkm for (i = 0; i < 2; i++) 13574072Smarkm yarrow_hash_init(&random_state.pool[i].hash); 13665686Smarkm 13774072Smarkm /* Clear the counter */ 13874072Smarkm for (i = 0; i < 4; i++) 13974072Smarkm random_state.counter[i] = 0; 14069526Smarkm 14174072Smarkm /* Set up a lock for the reseed process */ 14274072Smarkm mtx_init(&random_reseed_mtx, "random reseed", MTX_DEF); 14362053Smarkm} 14462053Smarkm 14562053Smarkmvoid 14662765Smarkmrandom_deinit(void) 14762053Smarkm{ 14865686Smarkm mtx_destroy(&random_reseed_mtx); 14962765Smarkm} 15062765Smarkm 15162765Smarkmstatic void 15274072Smarkmreseed(u_int fastslow) 15362765Smarkm{ 15465686Smarkm /* Interrupt-context stack is a limited resource; make large 15565686Smarkm * structures static. 15663771Smarkm */ 15765686Smarkm static u_char v[TIMEBIN][KEYSIZE]; /* v[i] */ 15865686Smarkm static struct yarrowhash context; 15965686Smarkm u_char hash[KEYSIZE]; /* h' */ 16065686Smarkm u_char temp[KEYSIZE]; 16191600Smarkm u_int i; 16291600Smarkm enum esource j; 16362053Smarkm 16462765Smarkm#ifdef DEBUG 16572200Sbmilekic mtx_lock(&Giant); 16662765Smarkm printf("Reseed type %d\n", fastslow); 16772200Sbmilekic mtx_unlock(&Giant); 16862765Smarkm#endif 16962765Smarkm 17065686Smarkm /* The reseed task must not be jumped on */ 17172200Sbmilekic mtx_lock(&random_reseed_mtx); 17265686Smarkm 17362053Smarkm /* 1. Hash the accumulated entropy into v[0] */ 17462053Smarkm 17574072Smarkm yarrow_hash_init(&context); 17665686Smarkm /* Feed the slow pool hash in if slow */ 17765686Smarkm if (fastslow == SLOW) 17865686Smarkm yarrow_hash_iterate(&context, 17974072Smarkm &random_state.pool[SLOW].hash, 18074072Smarkm sizeof(struct yarrowhash)); 18165686Smarkm yarrow_hash_iterate(&context, 18265686Smarkm &random_state.pool[FAST].hash, sizeof(struct yarrowhash)); 18374072Smarkm yarrow_hash_finish(&context, v[0]); 18462765Smarkm 18563771Smarkm /* 2. Compute hash values for all v. _Supposed_ to be computationally 18663771Smarkm * intensive. 18763771Smarkm */ 18862053Smarkm 18962765Smarkm if (random_state.bins > TIMEBIN) 19062765Smarkm random_state.bins = TIMEBIN; 19162765Smarkm for (i = 1; i < random_state.bins; i++) { 19274072Smarkm yarrow_hash_init(&context); 19374072Smarkm /* v[i] #= h(v[i - 1]) */ 19465686Smarkm yarrow_hash_iterate(&context, v[i - 1], KEYSIZE); 19562765Smarkm /* v[i] #= h(v[0]) */ 19665686Smarkm yarrow_hash_iterate(&context, v[0], KEYSIZE); 19762765Smarkm /* v[i] #= h(i) */ 19874072Smarkm yarrow_hash_iterate(&context, &i, sizeof(u_int)); 19965686Smarkm /* Return the hashval */ 20065686Smarkm yarrow_hash_finish(&context, v[i]); 20162053Smarkm } 20262053Smarkm 20365686Smarkm /* 3. Compute a new key; h' is the identity function here; 20465686Smarkm * it is not being ignored! 20565686Smarkm */ 20662053Smarkm 20774072Smarkm yarrow_hash_init(&context); 20865686Smarkm yarrow_hash_iterate(&context, &random_state.key, KEYSIZE); 20965686Smarkm for (i = 1; i < random_state.bins; i++) 21065686Smarkm yarrow_hash_iterate(&context, &v[i], KEYSIZE); 21165686Smarkm yarrow_hash_finish(&context, temp); 21274072Smarkm yarrow_encrypt_init(&random_state.key, temp); 21362053Smarkm 21462053Smarkm /* 4. Recompute the counter */ 21562053Smarkm 21674072Smarkm for (i = 0; i < 4; i++) 21774072Smarkm random_state.counter[i] = 0; 21874072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, temp); 21974072Smarkm memcpy(random_state.counter, temp, sizeof(random_state.counter)); 22062053Smarkm 22162765Smarkm /* 5. Reset entropy estimate accumulators to zero */ 22262053Smarkm 22362765Smarkm for (i = 0; i <= fastslow; i++) { 22491600Smarkm for (j = RANDOM_START; j < ENTROPYSOURCE; j++) { 22574072Smarkm random_state.pool[i].source[j].bits = 0; 22674072Smarkm random_state.pool[i].source[j].frac = 0; 22762765Smarkm } 22862765Smarkm } 22962053Smarkm 23062053Smarkm /* 6. Wipe memory of intermediate values */ 23162053Smarkm 23265686Smarkm memset((void *)v, 0, sizeof(v)); 23365686Smarkm memset((void *)temp, 0, sizeof(temp)); 23465686Smarkm memset((void *)hash, 0, sizeof(hash)); 23562053Smarkm 23665686Smarkm /* 7. Dump to seed file */ 23765686Smarkm /* XXX Not done here yet */ 23862053Smarkm 23965686Smarkm /* Release the reseed mutex */ 24072200Sbmilekic mtx_unlock(&random_reseed_mtx); 24165686Smarkm 24265686Smarkm#ifdef DEBUG 24372200Sbmilekic mtx_lock(&Giant); 24465686Smarkm printf("Reseed finish\n"); 24572200Sbmilekic mtx_unlock(&Giant); 24665686Smarkm#endif 24765686Smarkm 24874072Smarkm /* Unblock the device if it was blocked due to being unseeded */ 24974072Smarkm random_unblock(); 25062053Smarkm} 25162053Smarkm 25274072Smarkm/* Internal function to do return processed entropy from the 25374072Smarkm * Yarrow PRNG 25474072Smarkm */ 25591600Smarkmint 25691600Smarkmread_random_real(void *buf, int count) 25762053Smarkm{ 25862053Smarkm static int cur = 0; 25962053Smarkm static int gate = 1; 26074908Smarkm static u_char genval[KEYSIZE]; 26191600Smarkm int i; 26291600Smarkm int retval; 26362053Smarkm 26462875Smarkm /* The reseed task must not be jumped on */ 26572200Sbmilekic mtx_lock(&random_reseed_mtx); 26662875Smarkm 26762053Smarkm if (gate) { 26862053Smarkm generator_gate(); 26962765Smarkm random_state.outputblocks = 0; 27062053Smarkm gate = 0; 27162053Smarkm } 27291600Smarkm if (count > 0 && (size_t)count >= sizeof(random_state.counter)) { 27362053Smarkm retval = 0; 27491600Smarkm for (i = 0; i < count; i += (int)sizeof(random_state.counter)) { 27574072Smarkm random_state.counter[0]++; 27674072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 27774908Smarkm genval); 27874908Smarkm memcpy((char *)buf + i, genval, 27963855Smarkm sizeof(random_state.counter)); 28074072Smarkm if (++random_state.outputblocks >= 28174072Smarkm random_state.gengateinterval) { 28262053Smarkm generator_gate(); 28362765Smarkm random_state.outputblocks = 0; 28462053Smarkm } 28591600Smarkm retval += (int)sizeof(random_state.counter); 28662053Smarkm } 28762053Smarkm } 28862053Smarkm else { 28962053Smarkm if (!cur) { 29074072Smarkm random_state.counter[0]++; 29174072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 29274908Smarkm genval); 29391600Smarkm memcpy(buf, genval, (size_t)count); 29491600Smarkm cur = (int)sizeof(random_state.counter) - count; 29574072Smarkm if (++random_state.outputblocks >= 29674072Smarkm random_state.gengateinterval) { 29762053Smarkm generator_gate(); 29862765Smarkm random_state.outputblocks = 0; 29962053Smarkm } 30062053Smarkm retval = count; 30162053Smarkm } 30262053Smarkm else { 30362053Smarkm retval = cur < count ? cur : count; 30491600Smarkm memcpy(buf, 30591600Smarkm &genval[(int)sizeof(random_state.counter) - cur], 30691600Smarkm (size_t)retval); 30762053Smarkm cur -= retval; 30862053Smarkm } 30962053Smarkm } 31072200Sbmilekic mtx_unlock(&random_reseed_mtx); 31162053Smarkm return retval; 31262053Smarkm} 31362053Smarkm 31462765Smarkmstatic void 31562053Smarkmgenerator_gate(void) 31662053Smarkm{ 31774072Smarkm u_int i; 31865686Smarkm u_char temp[KEYSIZE]; 31962053Smarkm 32062765Smarkm#ifdef DEBUG 32172200Sbmilekic mtx_lock(&Giant); 32262875Smarkm printf("Generator gate\n"); 32372200Sbmilekic mtx_unlock(&Giant); 32462765Smarkm#endif 32562875Smarkm 32662765Smarkm for (i = 0; i < KEYSIZE; i += sizeof(random_state.counter)) { 32774072Smarkm random_state.counter[0]++; 32874072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 32974072Smarkm &(temp[i])); 33062053Smarkm } 33162053Smarkm 33274072Smarkm yarrow_encrypt_init(&random_state.key, temp); 33365686Smarkm memset((void *)temp, 0, KEYSIZE); 33462875Smarkm 33565686Smarkm#ifdef DEBUG 33672200Sbmilekic mtx_lock(&Giant); 33765686Smarkm printf("Generator gate finish\n"); 33872200Sbmilekic mtx_unlock(&Giant); 33965686Smarkm#endif 34062053Smarkm} 34162765Smarkm 34269172Smarkm/* Helper routine to perform explicit reseeds */ 34369172Smarkmvoid 34469172Smarkmrandom_reseed(void) 34569172Smarkm{ 34669172Smarkm reseed(FAST); 34769172Smarkm} 348