diff options
Diffstat (limited to 'sys/dev/random/yarrow.c')
| -rw-r--r-- | sys/dev/random/yarrow.c | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/sys/dev/random/yarrow.c b/sys/dev/random/yarrow.c new file mode 100644 index 0000000..304de5d --- /dev/null +++ b/sys/dev/random/yarrow.c @@ -0,0 +1,338 @@ +/*- + * Copyright (c) 2000 Mark R V Murray + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer + * in this position and unchanged. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * $FreeBSD$ + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/kernel.h> +#include <sys/lock.h> +#include <sys/mutex.h> +#include <sys/random.h> +#include <sys/sysctl.h> + +#include <crypto/rijndael/rijndael.h> +#include <crypto/sha2/sha2.h> + +#include <dev/random/hash.h> +#include <dev/random/randomdev.h> +#include <dev/random/yarrow.h> + +/* #define DEBUG */ + +RANDOM_CHECK_UINT(gengateinterval, 4, 64); +RANDOM_CHECK_UINT(bins, 2, 16); +RANDOM_CHECK_UINT(fastthresh, BLOCKSIZE/4, BLOCKSIZE); +RANDOM_CHECK_UINT(slowthresh, BLOCKSIZE/4, BLOCKSIZE); +RANDOM_CHECK_UINT(slowoverthresh, 1, 5); + +/* Structure holding the entropy state */ +static struct random_state random_state; + +SYSCTL_NODE(_kern_random, OID_AUTO, yarrow, CTLFLAG_RW, 0, "Yarrow Parameters"); +SYSCTL_PROC(_kern_random_yarrow, OID_AUTO, gengateinterval, + CTLTYPE_INT|CTLFLAG_RW, &random_state.gengateinterval, 10, + random_check_uint_gengateinterval, "I", "Generator Gate Interval"); +SYSCTL_PROC(_kern_random_yarrow, OID_AUTO, bins, + CTLTYPE_INT|CTLFLAG_RW, &random_state.bins, 10, + random_check_uint_bins, "I", "Execution time tuner"); +SYSCTL_PROC(_kern_random_yarrow, OID_AUTO, fastthresh, + CTLTYPE_INT|CTLFLAG_RW, &random_state.pool[0].thresh, (3*BLOCKSIZE)/4, + random_check_uint_fastthresh, "I", "Fast reseed threshold"); +SYSCTL_PROC(_kern_random_yarrow, OID_AUTO, slowthresh, + CTLTYPE_INT|CTLFLAG_RW, &random_state.pool[1].thresh, BLOCKSIZE, + random_check_uint_slowthresh, "I", "Slow reseed threshold"); +SYSCTL_PROC(_kern_random_yarrow, OID_AUTO, slowoverthresh, + CTLTYPE_INT|CTLFLAG_RW, &random_state.slowoverthresh, 2, + random_check_uint_slowoverthresh, "I", "Slow over-threshold reseed"); + +static void generator_gate(void); +static void reseed(u_int); + +/* The reseed thread mutex */ +static struct mtx random_reseed_mtx; + +/* Process a single stochastic event off the harvest queue */ +void +random_process_event(struct harvest *event) +{ + u_int pl, overthreshhold[2]; + struct source *source; + enum esource src; + + /* Unpack the event into the appropriate source accumulator */ + pl = random_state.which; + source = &random_state.pool[pl].source[event->source]; + yarrow_hash_iterate(&random_state.pool[pl].hash, event->entropy, + sizeof(event->entropy)); + yarrow_hash_iterate(&random_state.pool[pl].hash, &event->somecounter, + sizeof(event->somecounter)); + source->frac += event->frac; + source->bits += event->bits + source->frac/1024; + source->frac %= 1024; + + /* Count the over-threshold sources in each pool */ + for (pl = 0; pl < 2; pl++) { + overthreshhold[pl] = 0; + for (src = RANDOM_START; src < ENTROPYSOURCE; src++) { + if (random_state.pool[pl].source[src].bits + > random_state.pool[pl].thresh) + overthreshhold[pl]++; + } + } + + /* if any fast source over threshhold, reseed */ + if (overthreshhold[FAST]) + reseed(FAST); + + /* if enough slow sources are over threshhold, reseed */ + if (overthreshhold[SLOW] >= random_state.slowoverthresh) + reseed(SLOW); + + /* Invert the fast/slow pool selector bit */ + random_state.which = !random_state.which; +} + +void +random_init(void) +{ + int i; + + /* Yarrow parameters. Do not adjust these unless you have + * have a very good clue about what they do! + */ + random_state.gengateinterval = 10; + random_state.bins = 10; + random_state.pool[0].thresh = (3*BLOCKSIZE)/4; + random_state.pool[1].thresh = BLOCKSIZE; + random_state.slowoverthresh = 2; + random_state.which = FAST; + + /* Initialise the fast and slow entropy pools */ + for (i = 0; i < 2; i++) + yarrow_hash_init(&random_state.pool[i].hash); + + /* Clear the counter */ + for (i = 0; i < 4; i++) + random_state.counter[i] = 0; + + /* Set up a lock for the reseed process */ + mtx_init(&random_reseed_mtx, "random reseed", NULL, MTX_DEF); +} + +void +random_deinit(void) +{ + mtx_destroy(&random_reseed_mtx); +} + +static void +reseed(u_int fastslow) +{ + /* Interrupt-context stack is a limited resource; make large + * structures static. + */ + static u_char v[TIMEBIN][KEYSIZE]; /* v[i] */ + static struct yarrowhash context; + u_char hash[KEYSIZE]; /* h' */ + u_char temp[KEYSIZE]; + u_int i; + enum esource j; + +#ifdef DEBUG + printf("Reseed type %d\n", fastslow); +#endif + + /* The reseed task must not be jumped on */ + mtx_lock(&random_reseed_mtx); + + /* 1. Hash the accumulated entropy into v[0] */ + + yarrow_hash_init(&context); + /* Feed the slow pool hash in if slow */ + if (fastslow == SLOW) + yarrow_hash_iterate(&context, + &random_state.pool[SLOW].hash, + sizeof(struct yarrowhash)); + yarrow_hash_iterate(&context, + &random_state.pool[FAST].hash, sizeof(struct yarrowhash)); + yarrow_hash_finish(&context, v[0]); + + /* 2. Compute hash values for all v. _Supposed_ to be computationally + * intensive. + */ + + if (random_state.bins > TIMEBIN) + random_state.bins = TIMEBIN; + for (i = 1; i < random_state.bins; i++) { + yarrow_hash_init(&context); + /* v[i] #= h(v[i - 1]) */ + yarrow_hash_iterate(&context, v[i - 1], KEYSIZE); + /* v[i] #= h(v[0]) */ + yarrow_hash_iterate(&context, v[0], KEYSIZE); + /* v[i] #= h(i) */ + yarrow_hash_iterate(&context, &i, sizeof(u_int)); + /* Return the hashval */ + yarrow_hash_finish(&context, v[i]); + } + + /* 3. Compute a new key; h' is the identity function here; + * it is not being ignored! + */ + + yarrow_hash_init(&context); + yarrow_hash_iterate(&context, &random_state.key, KEYSIZE); + for (i = 1; i < random_state.bins; i++) + yarrow_hash_iterate(&context, &v[i], KEYSIZE); + yarrow_hash_finish(&context, temp); + yarrow_encrypt_init(&random_state.key, temp); + + /* 4. Recompute the counter */ + + for (i = 0; i < 4; i++) + random_state.counter[i] = 0; + yarrow_encrypt(&random_state.key, random_state.counter, temp); + memcpy(random_state.counter, temp, sizeof(random_state.counter)); + + /* 5. Reset entropy estimate accumulators to zero */ + + for (i = 0; i <= fastslow; i++) { + for (j = RANDOM_START; j < ENTROPYSOURCE; j++) { + random_state.pool[i].source[j].bits = 0; + random_state.pool[i].source[j].frac = 0; + } + } + + /* 6. Wipe memory of intermediate values */ + + memset((void *)v, 0, sizeof(v)); + memset((void *)temp, 0, sizeof(temp)); + memset((void *)hash, 0, sizeof(hash)); + + /* 7. Dump to seed file */ + /* XXX Not done here yet */ + + /* Release the reseed mutex */ + mtx_unlock(&random_reseed_mtx); + +#ifdef DEBUG + printf("Reseed finish\n"); +#endif + + /* Unblock the device if it was blocked due to being unseeded */ + random_unblock(); +} + +/* Internal function to return processed entropy from the PRNG */ +int +read_random_real(void *buf, int count) +{ + static int cur = 0; + static int gate = 1; + static u_char genval[KEYSIZE]; + int i; + int retval; + + /* The reseed task must not be jumped on */ + mtx_lock(&random_reseed_mtx); + + if (gate) { + generator_gate(); + random_state.outputblocks = 0; + gate = 0; + } + if (count > 0 && (size_t)count >= sizeof(random_state.counter)) { + retval = 0; + for (i = 0; i < count; i += (int)sizeof(random_state.counter)) { + random_state.counter[0]++; + yarrow_encrypt(&random_state.key, random_state.counter, + genval); + memcpy((char *)buf + i, genval, + sizeof(random_state.counter)); + if (++random_state.outputblocks >= + random_state.gengateinterval) { + generator_gate(); + random_state.outputblocks = 0; + } + retval += (int)sizeof(random_state.counter); + } + } + else { + if (!cur) { + random_state.counter[0]++; + yarrow_encrypt(&random_state.key, random_state.counter, + genval); + memcpy(buf, genval, (size_t)count); + cur = (int)sizeof(random_state.counter) - count; + if (++random_state.outputblocks >= + random_state.gengateinterval) { + generator_gate(); + random_state.outputblocks = 0; + } + retval = count; + } + else { + retval = cur < count ? cur : count; + memcpy(buf, + &genval[(int)sizeof(random_state.counter) - cur], + (size_t)retval); + cur -= retval; + } + } + mtx_unlock(&random_reseed_mtx); + return retval; +} + +static void +generator_gate(void) +{ + u_int i; + u_char temp[KEYSIZE]; + +#ifdef DEBUG + printf("Generator gate\n"); +#endif + + for (i = 0; i < KEYSIZE; i += sizeof(random_state.counter)) { + random_state.counter[0]++; + yarrow_encrypt(&random_state.key, random_state.counter, + &(temp[i])); + } + + yarrow_encrypt_init(&random_state.key, temp); + memset((void *)temp, 0, KEYSIZE); + +#ifdef DEBUG + printf("Generator gate finish\n"); +#endif +} + +/* Helper routine to perform explicit reseeds */ +void +random_reseed(void) +{ + reseed(SLOW); +} |
