yarrow.c revision 254147
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 254147 2013-08-09 15:31:50Z obrien $"); 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> 44254147Sobrien#include <dev/random/random_adaptors.h> 45128059Smarkm#include <dev/random/randomdev_soft.h> 4667112Smarkm#include <dev/random/yarrow.h> 4762053Smarkm 4874072SmarkmRANDOM_CHECK_UINT(gengateinterval, 4, 64); 4974072SmarkmRANDOM_CHECK_UINT(bins, 2, 16); 5074072SmarkmRANDOM_CHECK_UINT(fastthresh, BLOCKSIZE/4, BLOCKSIZE); 5174072SmarkmRANDOM_CHECK_UINT(slowthresh, BLOCKSIZE/4, BLOCKSIZE); 5274072SmarkmRANDOM_CHECK_UINT(slowoverthresh, 1, 5); 5374072Smarkm 5489170Smsmith/* Structure holding the entropy state */ 5589170Smsmithstatic struct random_state random_state; 5689170Smsmith 5762765Smarkmstatic void generator_gate(void); 5874072Smarkmstatic void reseed(u_int); 5962053Smarkm 6065686Smarkm/* The reseed thread mutex */ 61153575Spsstruct mtx random_reseed_mtx; 6262765Smarkm 6374072Smarkm/* Process a single stochastic event off the harvest queue */ 6474072Smarkmvoid 6574072Smarkmrandom_process_event(struct harvest *event) 6662765Smarkm{ 6791600Smarkm u_int pl, overthreshhold[2]; 6865686Smarkm struct source *source; 6991600Smarkm enum esource src; 7065686Smarkm 7174072Smarkm /* Unpack the event into the appropriate source accumulator */ 7274072Smarkm pl = random_state.which; 7374072Smarkm source = &random_state.pool[pl].source[event->source]; 7474072Smarkm yarrow_hash_iterate(&random_state.pool[pl].hash, event->entropy, 7574072Smarkm sizeof(event->entropy)); 7674072Smarkm yarrow_hash_iterate(&random_state.pool[pl].hash, &event->somecounter, 7774072Smarkm sizeof(event->somecounter)); 7874072Smarkm source->frac += event->frac; 7974072Smarkm source->bits += event->bits + source->frac/1024; 8074072Smarkm source->frac %= 1024; 8165686Smarkm 8274072Smarkm /* Count the over-threshold sources in each pool */ 8374072Smarkm for (pl = 0; pl < 2; pl++) { 8474072Smarkm overthreshhold[pl] = 0; 8591600Smarkm for (src = RANDOM_START; src < ENTROPYSOURCE; src++) { 8674072Smarkm if (random_state.pool[pl].source[src].bits 8774072Smarkm > random_state.pool[pl].thresh) 8874072Smarkm overthreshhold[pl]++; 8965686Smarkm } 9074072Smarkm } 9165686Smarkm 9274072Smarkm /* if any fast source over threshhold, reseed */ 9374072Smarkm if (overthreshhold[FAST]) 9474072Smarkm reseed(FAST); 9565686Smarkm 9674072Smarkm /* if enough slow sources are over threshhold, reseed */ 9774072Smarkm if (overthreshhold[SLOW] >= random_state.slowoverthresh) 9874072Smarkm reseed(SLOW); 9965686Smarkm 10074072Smarkm /* Invert the fast/slow pool selector bit */ 10174072Smarkm random_state.which = !random_state.which; 10262765Smarkm} 10362765Smarkm 10474072Smarkmvoid 105254147Sobrienrandom_yarrow_init_alg(struct sysctl_ctx_list *clist) 10662053Smarkm{ 10774072Smarkm int i; 108170025Srwatson struct sysctl_oid *random_yarrow_o; 10965686Smarkm 11072364Smarkm /* Yarrow parameters. Do not adjust these unless you have 11172364Smarkm * have a very good clue about what they do! 11272364Smarkm */ 113170025Srwatson random_yarrow_o = SYSCTL_ADD_NODE(clist, 114254147Sobrien SYSCTL_STATIC_CHILDREN(_kern_random), 115128059Smarkm OID_AUTO, "yarrow", CTLFLAG_RW, 0, 116128059Smarkm "Yarrow Parameters"); 117128059Smarkm 118170025Srwatson SYSCTL_ADD_PROC(clist, 119128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 120128059Smarkm "gengateinterval", CTLTYPE_INT|CTLFLAG_RW, 121128059Smarkm &random_state.gengateinterval, 10, 122128059Smarkm random_check_uint_gengateinterval, "I", 123128059Smarkm "Generation gate interval"); 124128059Smarkm 125170025Srwatson SYSCTL_ADD_PROC(clist, 126128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 127128059Smarkm "bins", CTLTYPE_INT|CTLFLAG_RW, 128128059Smarkm &random_state.bins, 10, 129128059Smarkm random_check_uint_bins, "I", 130128059Smarkm "Execution time tuner"); 131128059Smarkm 132170025Srwatson SYSCTL_ADD_PROC(clist, 133128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 134128059Smarkm "fastthresh", CTLTYPE_INT|CTLFLAG_RW, 135128059Smarkm &random_state.pool[0].thresh, (3*BLOCKSIZE)/4, 136128059Smarkm random_check_uint_fastthresh, "I", 137128059Smarkm "Fast reseed threshold"); 138128059Smarkm 139170025Srwatson SYSCTL_ADD_PROC(clist, 140128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 141128059Smarkm "slowthresh", CTLTYPE_INT|CTLFLAG_RW, 142128059Smarkm &random_state.pool[1].thresh, BLOCKSIZE, 143128059Smarkm random_check_uint_slowthresh, "I", 144128059Smarkm "Slow reseed threshold"); 145128059Smarkm 146170025Srwatson SYSCTL_ADD_PROC(clist, 147128059Smarkm SYSCTL_CHILDREN(random_yarrow_o), OID_AUTO, 148128059Smarkm "slowoverthresh", CTLTYPE_INT|CTLFLAG_RW, 149128059Smarkm &random_state.slowoverthresh, 2, 150128059Smarkm random_check_uint_slowoverthresh, "I", 151128059Smarkm "Slow over-threshold reseed"); 152128059Smarkm 15362765Smarkm random_state.gengateinterval = 10; 15462765Smarkm random_state.bins = 10; 15574072Smarkm random_state.pool[0].thresh = (3*BLOCKSIZE)/4; 15674072Smarkm random_state.pool[1].thresh = BLOCKSIZE; 15762765Smarkm random_state.slowoverthresh = 2; 15862765Smarkm random_state.which = FAST; 15965686Smarkm 16074072Smarkm /* Initialise the fast and slow entropy pools */ 16174072Smarkm for (i = 0; i < 2; i++) 16274072Smarkm yarrow_hash_init(&random_state.pool[i].hash); 16365686Smarkm 16474072Smarkm /* Clear the counter */ 16574072Smarkm for (i = 0; i < 4; i++) 16674072Smarkm random_state.counter[i] = 0; 16769526Smarkm 16874072Smarkm /* Set up a lock for the reseed process */ 16993818Sjhb mtx_init(&random_reseed_mtx, "random reseed", NULL, MTX_DEF); 17062053Smarkm} 17162053Smarkm 17262053Smarkmvoid 173128059Smarkmrandom_yarrow_deinit_alg(void) 17462053Smarkm{ 17565686Smarkm mtx_destroy(&random_reseed_mtx); 17662765Smarkm} 17762765Smarkm 17862765Smarkmstatic void 17974072Smarkmreseed(u_int fastslow) 18062765Smarkm{ 18165686Smarkm /* Interrupt-context stack is a limited resource; make large 18265686Smarkm * structures static. 18363771Smarkm */ 18465686Smarkm static u_char v[TIMEBIN][KEYSIZE]; /* v[i] */ 18565686Smarkm static struct yarrowhash context; 18665686Smarkm u_char hash[KEYSIZE]; /* h' */ 18765686Smarkm u_char temp[KEYSIZE]; 18891600Smarkm u_int i; 18991600Smarkm enum esource j; 19062053Smarkm 19165686Smarkm /* The reseed task must not be jumped on */ 19272200Sbmilekic mtx_lock(&random_reseed_mtx); 19365686Smarkm 19462053Smarkm /* 1. Hash the accumulated entropy into v[0] */ 19562053Smarkm 19674072Smarkm yarrow_hash_init(&context); 19765686Smarkm /* Feed the slow pool hash in if slow */ 19865686Smarkm if (fastslow == SLOW) 19965686Smarkm yarrow_hash_iterate(&context, 20074072Smarkm &random_state.pool[SLOW].hash, 20174072Smarkm sizeof(struct yarrowhash)); 20265686Smarkm yarrow_hash_iterate(&context, 20365686Smarkm &random_state.pool[FAST].hash, sizeof(struct yarrowhash)); 20474072Smarkm yarrow_hash_finish(&context, v[0]); 20562765Smarkm 20663771Smarkm /* 2. Compute hash values for all v. _Supposed_ to be computationally 20763771Smarkm * intensive. 20863771Smarkm */ 20962053Smarkm 21062765Smarkm if (random_state.bins > TIMEBIN) 21162765Smarkm random_state.bins = TIMEBIN; 21262765Smarkm for (i = 1; i < random_state.bins; i++) { 21374072Smarkm yarrow_hash_init(&context); 21474072Smarkm /* v[i] #= h(v[i - 1]) */ 21565686Smarkm yarrow_hash_iterate(&context, v[i - 1], KEYSIZE); 21662765Smarkm /* v[i] #= h(v[0]) */ 21765686Smarkm yarrow_hash_iterate(&context, v[0], KEYSIZE); 21862765Smarkm /* v[i] #= h(i) */ 21974072Smarkm yarrow_hash_iterate(&context, &i, sizeof(u_int)); 22065686Smarkm /* Return the hashval */ 22165686Smarkm yarrow_hash_finish(&context, v[i]); 22262053Smarkm } 22362053Smarkm 22465686Smarkm /* 3. Compute a new key; h' is the identity function here; 22565686Smarkm * it is not being ignored! 22665686Smarkm */ 22762053Smarkm 22874072Smarkm yarrow_hash_init(&context); 22965686Smarkm yarrow_hash_iterate(&context, &random_state.key, KEYSIZE); 23065686Smarkm for (i = 1; i < random_state.bins; i++) 23165686Smarkm yarrow_hash_iterate(&context, &v[i], KEYSIZE); 23265686Smarkm yarrow_hash_finish(&context, temp); 23374072Smarkm yarrow_encrypt_init(&random_state.key, temp); 23462053Smarkm 23562053Smarkm /* 4. Recompute the counter */ 23662053Smarkm 23774072Smarkm for (i = 0; i < 4; i++) 23874072Smarkm random_state.counter[i] = 0; 23974072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, temp); 24074072Smarkm memcpy(random_state.counter, temp, sizeof(random_state.counter)); 24162053Smarkm 24262765Smarkm /* 5. Reset entropy estimate accumulators to zero */ 24362053Smarkm 24462765Smarkm for (i = 0; i <= fastslow; i++) { 24591600Smarkm for (j = RANDOM_START; j < ENTROPYSOURCE; j++) { 24674072Smarkm random_state.pool[i].source[j].bits = 0; 24774072Smarkm random_state.pool[i].source[j].frac = 0; 24862765Smarkm } 24962765Smarkm } 25062053Smarkm 25162053Smarkm /* 6. Wipe memory of intermediate values */ 25262053Smarkm 25365686Smarkm memset((void *)v, 0, sizeof(v)); 25465686Smarkm memset((void *)temp, 0, sizeof(temp)); 25565686Smarkm memset((void *)hash, 0, sizeof(hash)); 25662053Smarkm 25765686Smarkm /* 7. Dump to seed file */ 25865686Smarkm /* XXX Not done here yet */ 25962053Smarkm 260153575Sps /* Unblock the device if it was blocked due to being unseeded */ 261153575Sps random_yarrow_unblock(); 262153575Sps 26365686Smarkm /* Release the reseed mutex */ 26472200Sbmilekic mtx_unlock(&random_reseed_mtx); 26562053Smarkm} 26662053Smarkm 267100082Smarkm/* Internal function to return processed entropy from the PRNG */ 26891600Smarkmint 269128059Smarkmrandom_yarrow_read(void *buf, int count) 27062053Smarkm{ 27162053Smarkm static int cur = 0; 27262053Smarkm static int gate = 1; 27374908Smarkm static u_char genval[KEYSIZE]; 274107789Smarkm size_t tomove; 27591600Smarkm int i; 27691600Smarkm int retval; 27762053Smarkm 27862875Smarkm /* The reseed task must not be jumped on */ 27972200Sbmilekic mtx_lock(&random_reseed_mtx); 28062875Smarkm 28162053Smarkm if (gate) { 28262053Smarkm generator_gate(); 28362765Smarkm random_state.outputblocks = 0; 28462053Smarkm gate = 0; 28562053Smarkm } 28691600Smarkm if (count > 0 && (size_t)count >= sizeof(random_state.counter)) { 28762053Smarkm retval = 0; 28891600Smarkm for (i = 0; i < count; i += (int)sizeof(random_state.counter)) { 28974072Smarkm random_state.counter[0]++; 29074072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 29174908Smarkm genval); 292107789Smarkm tomove = min(count - i, sizeof(random_state.counter)); 293107789Smarkm memcpy((char *)buf + i, genval, tomove); 29474072Smarkm if (++random_state.outputblocks >= 29574072Smarkm random_state.gengateinterval) { 29662053Smarkm generator_gate(); 29762765Smarkm random_state.outputblocks = 0; 29862053Smarkm } 299107789Smarkm retval += (int)tomove; 300174073Ssimon cur = 0; 30162053Smarkm } 30262053Smarkm } 30362053Smarkm else { 30462053Smarkm if (!cur) { 30574072Smarkm random_state.counter[0]++; 30674072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 30774908Smarkm genval); 30891600Smarkm memcpy(buf, genval, (size_t)count); 30991600Smarkm cur = (int)sizeof(random_state.counter) - count; 31074072Smarkm if (++random_state.outputblocks >= 31174072Smarkm random_state.gengateinterval) { 31262053Smarkm generator_gate(); 31362765Smarkm random_state.outputblocks = 0; 31462053Smarkm } 31562053Smarkm retval = count; 31662053Smarkm } 31762053Smarkm else { 318128059Smarkm retval = MIN(cur, count); 31991600Smarkm memcpy(buf, 32091600Smarkm &genval[(int)sizeof(random_state.counter) - cur], 32191600Smarkm (size_t)retval); 32262053Smarkm cur -= retval; 32362053Smarkm } 32462053Smarkm } 32572200Sbmilekic mtx_unlock(&random_reseed_mtx); 32662053Smarkm return retval; 32762053Smarkm} 32862053Smarkm 32962765Smarkmstatic void 33062053Smarkmgenerator_gate(void) 33162053Smarkm{ 33274072Smarkm u_int i; 33365686Smarkm u_char temp[KEYSIZE]; 33462053Smarkm 33562765Smarkm for (i = 0; i < KEYSIZE; i += sizeof(random_state.counter)) { 33674072Smarkm random_state.counter[0]++; 33774072Smarkm yarrow_encrypt(&random_state.key, random_state.counter, 33874072Smarkm &(temp[i])); 33962053Smarkm } 34062053Smarkm 34174072Smarkm yarrow_encrypt_init(&random_state.key, temp); 34265686Smarkm memset((void *)temp, 0, KEYSIZE); 34362875Smarkm 34462053Smarkm} 34562765Smarkm 34669172Smarkm/* Helper routine to perform explicit reseeds */ 34769172Smarkmvoid 348128059Smarkmrandom_yarrow_reseed(void) 34969172Smarkm{ 350100082Smarkm reseed(SLOW); 35169172Smarkm} 352