diff options
Diffstat (limited to 'sys/dev/random/other_algorithm.c')
| -rw-r--r-- | sys/dev/random/other_algorithm.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/sys/dev/random/other_algorithm.c b/sys/dev/random/other_algorithm.c new file mode 100644 index 0000000..740e879 --- /dev/null +++ b/sys/dev/random/other_algorithm.c @@ -0,0 +1,209 @@ +/*- + * Copyright (c) 2015 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. + * + */ + +/*- + * This is a skeleton for folks who wish to build a loadable module + * containing an alternative entropy-processing algorithm for random(4). + * + * The functions below should be completed with the appropriate code, + * and the nearby yarrow.c and fortuna.c may be consulted for examples + * of working code. + * + * The author is willing to provide reasonable help to those wishing to + * write such a module for themselves. Please use the markm@ FreeBSD + * email address, and ensure that you are developing this on a suitably + * supported branch (This is currently 11-CURRENT, and will be no + * older than 11-STABLE in the future). + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/lock.h> +#include <sys/malloc.h> +#include <sys/mutex.h> +#include <sys/random.h> +#include <sys/sysctl.h> +#include <sys/systm.h> + +#include <machine/cpu.h> + +#include <crypto/rijndael/rijndael-api-fst.h> +#include <crypto/sha2/sha2.h> + +#include <dev/random/hash.h> +#include <dev/random/randomdev.h> +#include <dev/random/random_harvestq.h> +#include <dev/random/uint128.h> +#include <dev/random/other_algorithm.h> + +static void random_other_pre_read(void); +static void random_other_read(uint8_t *, u_int); +static bool random_other_seeded(void); +static void random_other_process_event(struct harvest_event *); +static void random_other_init_alg(void *); +static void random_other_deinit_alg(void *); + +/* + * RANDOM_OTHER_NPOOLS is used when reading hardware random + * number sources to ensure that each pool gets one read sample + * per loop iteration. Yarrow has 2 such pools (FAST and SLOW), + * and fortuna has 32 (0-31). The RNG used prior to Yarrow and + * ported from Linux had just 1 pool. + */ +#define RANDOM_OTHER_NPOOLS 1 + +struct random_algorithm random_alg_context = { + .ra_ident = "other", + .ra_init_alg = random_other_init_alg, + .ra_deinit_alg = random_other_deinit_alg, + .ra_pre_read = random_other_pre_read, + .ra_read = random_other_read, + .ra_seeded = random_other_seeded, + .ra_event_processor = random_other_process_event, + .ra_poolcount = RANDOM_OTHER_NPOOLS, +}; + +/* Use a mutex to protect your reseed variables? */ +static mtx_t other_mtx; + +/* + * void random_other_init_alg(void *unused __unused) + * + * Do algorithm-specific initialisation here. + */ +void +random_other_init_alg(void *unused __unused) +{ + + RANDOM_RESEED_INIT_LOCK(); + /* + * Do set-up work here! + */ +} + +/* + * void random_other_deinit_alg(void *unused __unused) + * + * Do algorithm-specific deinitialisation here. + */ +static void +random_other_deinit_alg(void *unused __unused) +{ + + /* + * Do tear-down work here! + */ + RANDOM_RESEED_DEINIT_LOCK(); +} + +/* + * void random_other_pre_read(void) + * + * Do any pre-read preparation you need to. This will be called + * before >=1 calls to random_other_read() corresponding to one + * read(2). + * + * This routine will be called periodically while the generator is + * still blocked and a read is being attempted, giving you an + * opportunity to unblock. + */ +static void +random_other_pre_read(void) +{ + + RANDOM_RESEED_LOCK(); + /* + * Do pre-read housekeeping work here! + * You may use this as a chance to unblock the generator. + */ + RANDOM_RESEED_UNLOCK(); +} + +/* + * void random_other_read(uint8_t *buf, u_int count) + * + * Generate <count> bytes of output into <*buf>. + * You may use the fact that <count> will be a multiple of + * RANDOM_BLOCKSIZE for optimization purposes. + * + * This function will always be called with your generator + * unblocked and ready. If you are not ready to generate + * output here, then feel free to KASSERT() or panic(). + */ +static void +random_other_read(uint8_t *buf, u_int count) +{ + + RANDOM_RESEED_LOCK(); + /* + * Do random-number generation work here! + */ + RANDOM_RESEED_UNLOCK(); +} + +/* + * bool random_other_seeded(void) + * + * Return true if your generator is ready to generate + * output, and false otherwise. + */ +static bool +random_other_seeded(void) +{ + bool seeded = false; + + /* + * Find out if your generator is seeded here! + */ + return (seeded); +} + +/* + * void random_other_process_event(struct harvest_event *event) + * + * Process one stochastic event <*event> into your entropy + * processor. + * + * The structure of the event may change, so it is easier to + * just grab the whole thing into your accumulation system. + * You may pick-and-choose bits, but please don't complain + * when/if these change. + */ +static void +random_other_process_event(struct harvest_event *event) +{ + + RANDOM_RESEED_LOCK(); + /* + * Do entropy accumulation work here! + * You may use this as a chance to unblock the generator. + */ + RANDOM_RESEED_UNLOCK(); +} |
