yarrow.c revision 174073
162053Smarkm/*- 2128059Smarkm * Copyright (c) 2000-2004 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 */ 2762053Smarkm 28119418Sobrien#include <sys/cdefs.h> 29119418Sobrien__FBSDID("$FreeBSD: head/sys/dev/random/yarrow.c 174073 2007-11-29 16:06:12Z simon $"); 30119418Sobrien 3162053Smarkm#include <sys/param.h> 3265686Smarkm#include <sys/kernel.h> 3374914Sjhb#include <sys/lock.h> 34122871Smarkm#include <sys/malloc.h> 3567365Sjhb#include <sys/mutex.h> 3662053Smarkm#include <sys/random.h> 3774072Smarkm#include <sys/sysctl.h> 38122871Smarkm#include <sys/systm.h> 3969168Smarkm 40143418Sume#include <crypto/rijndael/rijndael-api-fst.h> 41100082Smarkm#include <crypto/sha2/sha2.h> 4269168Smarkm 4367112Smarkm#include <dev/random/hash.h> 44128059Smarkm#include <dev/random/randomdev_soft.h> 4567112Smarkm#include <dev/random/yarrow.h> 4662053Smarkm 4774072SmarkmRANDOM_CHECK_UINT(gengateinterval, 4, 64); 4874072SmarkmRANDOM_CHECK_UINT(bins, 2, 16); 4974072SmarkmRANDOM_CHECK_UINT(fastthresh, BLOCKSIZE/4, BLOCKSIZE); 5074072SmarkmRANDOM_CHECK_UINT(slowthresh, BLOCKSIZE/4, BLOCKSIZE); 5174072SmarkmRANDOM_CHECK_UINT(slowoverthresh, 1, 5); 5274072Smarkm 5389170Smsmith/* Structure holding the entropy state */ 5489170Smsmithstatic struct random_state random_state; 5589170Smsmith 5662765Smarkmstatic void generator_gate(void); 5774072Smarkmstatic void reseed(u_int); 5862053Smarkm 5965686Smarkm/* The reseed thread mutex */ 60153575Spsstruct mtx random_reseed_mtx; 6162765Smarkm 6274072Smarkm/* Process a single stochastic event off the harvest queue */ 6374072Smarkmvoid 6474072Smarkmrandom_process_event(struct harvest *event) 6562765Smarkm{ 6691600Smarkm u_int pl, overthreshhold[2]; 6765686Smarkm struct source *source; 6891600Smarkm enum esource src; 6965686Smarkm 7074072Smarkm /* Unpack the event into the appropriate source accumulator */ 7174072Smarkm pl = random_state.which; 7274072Smarkm source = &random_state.pool[pl].source[event->source]; 7374072Smarkm yarrow_hash_iterate(&random_state.pool[pl].hash, event->entropy, 7474072Smarkm sizeof(event->entropy)); 7574072Smarkm yarrow_hash_iterate(&random_state.pool[pl].hash, &event->somecounter, 7674072Smarkm sizeof(event->somecounter)); 7774072Smarkm source->frac += event->frac; 7874072Smarkm source->bits += event->bits + source->frac/1024; 7974072Smarkm source->frac %= 1024; 8065686Smarkm 8174072Smarkm /* Count the over-threshold sources in each pool */ 8274072Smarkm for (pl = 0; pl < 2; pl++) { 8374072Smarkm overthreshhold[pl] = 0; 8491600Smarkm for (src = RANDOM_START; src < ENTROPYSOURCE; src++) { 8574072Smarkm if (random_state.pool[pl].source[src].bits 8674072Smarkm > random_state.pool[pl].thresh) 8774072Smarkm overthreshhold[pl]++; 8865686Smarkm } 8974072Smarkm } 9065686Smarkm 9174072Smarkm /* if any fast source over threshhold, reseed */ 9274072Smarkm if (overthreshhold[FAST]) 9374072Smarkm reseed(FAST); 9465686Smarkm 9574072Smarkm /* if enough slow sources are over threshhold, reseed */ 9674072Smarkm if (overthreshhold[SLOW] >= random_state.slowoverthresh) 9774072Smarkm reseed(SLOW); 9865686Smarkm 9974072Smarkm /* Invert the fast/slow pool selector bit */ 10074072Smarkm random_state.which = !random_state.which; 10162765Smarkm} 10262765Smarkm 10374072Smarkmvoid 104128059Smarkmrandom_yarrow_init_alg(struct sysctl_ctx_list *clist, struct sysctl_oid *in_o) 10562053Smarkm{ 10674072Smarkm int i; 107170025Srwatson struct sysctl_oid *random_yarrow_o; 10865686Smarkm 10972364Smarkm /* Yarrow parameters. Do not adjust these unless you have 11072364Smarkm * have a very good clue about what they do! 11172364Smarkm */ 112170025Srwatson random_yarrow_o = SYSCTL_ADD_NODE(clist, 113128059Smarkm SYSCTL_CHILDREN(in_o), 114128059Smarkm OID_AUTO, "yarrow", CTLFLAG_RW, 0, 115128059Smarkm "Yarrow Parameters"); 116128059Smarkm 117170025Srwatson SYSCTL_ADD_PROC(clist, 118128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 119128059Smarkm "gengateinterval", CTLTYPE_INT|CTLFLAG_RW, 120128059Smarkm &random_state.gengateinterval, 10, 121128059Smarkm random_check_uint_gengateinterval, "I", 122128059Smarkm "Generation gate interval"); 123128059Smarkm 124170025Srwatson SYSCTL_ADD_PROC(clist, 125128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 126128059Smarkm "bins", CTLTYPE_INT|CTLFLAG_RW, 127128059Smarkm &random_state.bins, 10, 128128059Smarkm random_check_uint_bins, "I", 129128059Smarkm "Execution time tuner"); 130128059Smarkm 131170025Srwatson SYSCTL_ADD_PROC(clist, 132128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 133128059Smarkm "fastthresh", CTLTYPE_INT|CTLFLAG_RW, 134128059Smarkm &random_state.pool[0].thresh, (3*BLOCKSIZE)/4, 135128059Smarkm random_check_uint_fastthresh, "I", 136128059Smarkm "Fast reseed threshold"); 137128059Smarkm 138170025Srwatson SYSCTL_ADD_PROC(clist, 139128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 140128059Smarkm "slowthresh", CTLTYPE_INT|CTLFLAG_RW, 141128059Smarkm &random_state.pool[1].thresh, BLOCKSIZE, 142128059Smarkm random_check_uint_slowthresh, "I", 143128059Smarkm "Slow reseed threshold"); 144128059Smarkm 145170025Srwatson SYSCTL_ADD_PROC(clist, 146128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 147128059Smarkm "slowoverthresh", CTLTYPE_INT|CTLFLAG_RW, 148128059Smarkm &random_state.slowoverthresh, 2, 149128059Smarkm random_check_uint_slowoverthresh, "I", 150128059Smarkm "Slow over-threshold reseed"); 151128059Smarkm 15262765Smarkm random_state.gengateinterval = 10; 15362765Smarkm random_state.bins = 10; 15474072Smarkm random_state.pool[0].thresh = (3*BLOCKSIZE)/4; 15574072Smarkm random_state.pool[1].thresh = BLOCKSIZE; 15662765Smarkm random_state.slowoverthresh = 2; 15762765Smarkm random_state.which = FAST; 15865686Smarkm 15974072Smarkm /* Initialise the fast and slow entropy pools */ 16074072Smarkm for (i = 0; i < 2; i++) 16174072Smarkm yarrow_hash_init(&random_state.pool[i].hash); 16265686Smarkm 16374072Smarkm /* Clear the counter */ 16474072Smarkm for (i = 0; i < 4; i++) 16574072Smarkm random_state.counter[i] = 0; 16669526Smarkm 16774072Smarkm /* Set up a lock for the reseed process */ 16893818Sjhb mtx_init(&random_reseed_mtx, "random reseed", NULL, MTX_DEF); 16962053Smarkm} 17062053Smarkm 17162053Smarkmvoid 172128059Smarkmrandom_yarrow_deinit_alg(void) 17362053Smarkm{ 17465686Smarkm mtx_destroy(&random_reseed_mtx); 17562765Smarkm} 17662765Smarkm 17762765Smarkmstatic void 17874072Smarkmreseed(u_int fastslow) 17962765Smarkm{ 18065686Smarkm /* Interrupt-context stack is a limited resource; make large 18165686Smarkm * structures static. 18263771Smarkm */ 18365686Smarkm static u_char v[TIMEBIN][KEYSIZE]; /* v[i] */ 18465686Smarkm static struct yarrowhash context; 18565686Smarkm u_char hash[KEYSIZE]; /* h' */ 18665686Smarkm u_char temp[KEYSIZE]; 18791600Smarkm u_int i; 18891600Smarkm enum esource j; 18962053Smarkm 19065686Smarkm /* The reseed task must not be jumped on */ 19172200Sbmilekic mtx_lock(&random_reseed_mtx); 19265686Smarkm 19362053Smarkm /* 1. Hash the accumulated entropy into v[0] */ 19462053Smarkm 19574072Smarkm yarrow_hash_init(&context); 19665686Smarkm /* Feed the slow pool hash in if slow */ 19765686Smarkm if (fastslow == SLOW) 19865686Smarkm yarrow_hash_iterate(&context, 19974072Smarkm &random_state.pool[SLOW].hash, 20074072Smarkm sizeof(struct yarrowhash)); 20165686Smarkm yarrow_hash_iterate(&context, 20265686Smarkm &random_state.pool[FAST].hash, sizeof(struct yarrowhash)); 20374072Smarkm yarrow_hash_finish(&context, v[0]); 20462765Smarkm 20563771Smarkm /* 2. Compute hash values for all v. _Supposed_ to be computationally 20663771Smarkm * intensive. 20763771Smarkm */ 20862053Smarkm 20962765Smarkm if (random_state.bins > TIMEBIN) 21062765Smarkm random_state.bins = TIMEBIN; 21162765Smarkm for (i = 1; i < random_state.bins; i++) { 21274072Smarkm yarrow_hash_init(&context); 21374072Smarkm /* v[i] #= h(v[i - 1]) */ 21465686Smarkm yarrow_hash_iterate(&context, v[i - 1], KEYSIZE); 21562765Smarkm /* v[i] #= h(v[0]) */ 21665686Smarkm yarrow_hash_iterate(&context, v[0], KEYSIZE); 21762765Smarkm /* v[i] #= h(i) */ 21874072Smarkm yarrow_hash_iterate(&context, &i, sizeof(u_int)); 21965686Smarkm /* Return the hashval */ 22065686Smarkm yarrow_hash_finish(&context, v[i]); 22162053Smarkm } 22262053Smarkm 22365686Smarkm /* 3. Compute a new key; h' is the identity function here; 22465686Smarkm * it is not being ignored! 22565686Smarkm */ 22662053Smarkm 22774072Smarkm yarrow_hash_init(&context); 22865686Smarkm yarrow_hash_iterate(&context, &random_state.key, KEYSIZE); 22965686Smarkm for (i = 1; i < random_state.bins; i++) 23065686Smarkm yarrow_hash_iterate(&context, &v[i], KEYSIZE); 23165686Smarkm yarrow_hash_finish(&context, temp); 23274072Smarkm yarrow_encrypt_init(&random_state.key, temp); 23362053Smarkm 23462053Smarkm /* 4. Recompute the counter */ 23562053Smarkm 23674072Smarkm for (i = 0; i < 4; i++) 23774072Smarkm random_state.counter[i] = 0; 23874072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, temp); 23974072Smarkm memcpy(random_state.counter, temp, sizeof(random_state.counter)); 24062053Smarkm 24162765Smarkm /* 5. Reset entropy estimate accumulators to zero */ 24262053Smarkm 24362765Smarkm for (i = 0; i <= fastslow; i++) { 24491600Smarkm for (j = RANDOM_START; j < ENTROPYSOURCE; j++) { 24574072Smarkm random_state.pool[i].source[j].bits = 0; 24674072Smarkm random_state.pool[i].source[j].frac = 0; 24762765Smarkm } 24862765Smarkm } 24962053Smarkm 25062053Smarkm /* 6. Wipe memory of intermediate values */ 25162053Smarkm 25265686Smarkm memset((void *)v, 0, sizeof(v)); 25365686Smarkm memset((void *)temp, 0, sizeof(temp)); 25465686Smarkm memset((void *)hash, 0, sizeof(hash)); 25562053Smarkm 25665686Smarkm /* 7. Dump to seed file */ 25765686Smarkm /* XXX Not done here yet */ 25862053Smarkm 259153575Sps /* Unblock the device if it was blocked due to being unseeded */ 260153575Sps random_yarrow_unblock(); 261153575Sps 26265686Smarkm /* Release the reseed mutex */ 26372200Sbmilekic mtx_unlock(&random_reseed_mtx); 26462053Smarkm} 26562053Smarkm 266100082Smarkm/* Internal function to return processed entropy from the PRNG */ 26791600Smarkmint 268128059Smarkmrandom_yarrow_read(void *buf, int count) 26962053Smarkm{ 27062053Smarkm static int cur = 0; 27162053Smarkm static int gate = 1; 27274908Smarkm static u_char genval[KEYSIZE]; 273107789Smarkm size_t tomove; 27491600Smarkm int i; 27591600Smarkm int retval; 27662053Smarkm 27762875Smarkm /* The reseed task must not be jumped on */ 27872200Sbmilekic mtx_lock(&random_reseed_mtx); 27962875Smarkm 28062053Smarkm if (gate) { 28162053Smarkm generator_gate(); 28262765Smarkm random_state.outputblocks = 0; 28362053Smarkm gate = 0; 28462053Smarkm } 28591600Smarkm if (count > 0 && (size_t)count >= sizeof(random_state.counter)) { 28662053Smarkm retval = 0; 28791600Smarkm for (i = 0; i < count; i += (int)sizeof(random_state.counter)) { 28874072Smarkm random_state.counter[0]++; 28974072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 29074908Smarkm genval); 291107789Smarkm tomove = min(count - i, sizeof(random_state.counter)); 292107789Smarkm memcpy((char *)buf + i, genval, tomove); 29374072Smarkm if (++random_state.outputblocks >= 29474072Smarkm random_state.gengateinterval) { 29562053Smarkm generator_gate(); 29662765Smarkm random_state.outputblocks = 0; 29762053Smarkm } 298107789Smarkm retval += (int)tomove; 299174073Ssimon cur = 0; 30062053Smarkm } 30162053Smarkm } 30262053Smarkm else { 30362053Smarkm if (!cur) { 30474072Smarkm random_state.counter[0]++; 30574072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 30674908Smarkm genval); 30791600Smarkm memcpy(buf, genval, (size_t)count); 30891600Smarkm cur = (int)sizeof(random_state.counter) - count; 30974072Smarkm if (++random_state.outputblocks >= 31074072Smarkm random_state.gengateinterval) { 31162053Smarkm generator_gate(); 31262765Smarkm random_state.outputblocks = 0; 31362053Smarkm } 31462053Smarkm retval = count; 31562053Smarkm } 31662053Smarkm else { 317128059Smarkm retval = MIN(cur, count); 31891600Smarkm memcpy(buf, 31991600Smarkm &genval[(int)sizeof(random_state.counter) - cur], 32091600Smarkm (size_t)retval); 32162053Smarkm cur -= retval; 32262053Smarkm } 32362053Smarkm } 32472200Sbmilekic mtx_unlock(&random_reseed_mtx); 32562053Smarkm return retval; 32662053Smarkm} 32762053Smarkm 32862765Smarkmstatic void 32962053Smarkmgenerator_gate(void) 33062053Smarkm{ 33174072Smarkm u_int i; 33265686Smarkm u_char temp[KEYSIZE]; 33362053Smarkm 33462765Smarkm for (i = 0; i < KEYSIZE; i += sizeof(random_state.counter)) { 33574072Smarkm random_state.counter[0]++; 33674072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 33774072Smarkm &(temp[i])); 33862053Smarkm } 33962053Smarkm 34074072Smarkm yarrow_encrypt_init(&random_state.key, temp); 34165686Smarkm memset((void *)temp, 0, KEYSIZE); 34262875Smarkm 34362053Smarkm} 34462765Smarkm 34569172Smarkm/* Helper routine to perform explicit reseeds */ 34669172Smarkmvoid 347128059Smarkmrandom_yarrow_reseed(void) 34869172Smarkm{ 349100082Smarkm reseed(SLOW); 35069172Smarkm} 351