diff options
Diffstat (limited to 'sys/dev/random/randomdev_soft.c')
| -rw-r--r-- | sys/dev/random/randomdev_soft.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/sys/dev/random/randomdev_soft.c b/sys/dev/random/randomdev_soft.c new file mode 100644 index 000000000000..cef64ab6f746 --- /dev/null +++ b/sys/dev/random/randomdev_soft.c @@ -0,0 +1,419 @@ +/*- + * Copyright (c) 2000-2009 Mark R V Murray + * Copyright (c) 2004 Robert N. M. Watson + * 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. + * + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/bus.h> +#include <sys/conf.h> +#include <sys/fcntl.h> +#include <sys/kernel.h> +#include <sys/kthread.h> +#include <sys/lock.h> +#include <sys/malloc.h> +#include <sys/mutex.h> +#include <sys/poll.h> +#include <sys/proc.h> +#include <sys/random.h> +#include <sys/selinfo.h> +#include <sys/sysctl.h> +#include <sys/uio.h> +#include <sys/unistd.h> + +#include <machine/bus.h> +#include <machine/cpu.h> + +#include <dev/random/randomdev.h> +#include <dev/random/randomdev_soft.h> + +#define RANDOM_FIFO_MAX 256 /* How many events to queue up */ + +static void random_kthread(void *); +static void +random_harvest_internal(u_int64_t, const void *, u_int, + u_int, u_int, enum esource); +static int random_yarrow_poll(int event,struct thread *td); +static int random_yarrow_block(int flag); +static void random_yarrow_flush_reseed(void); + +struct random_systat random_yarrow = { + .ident = "Software, Yarrow", + .init = random_yarrow_init, + .deinit = random_yarrow_deinit, + .block = random_yarrow_block, + .read = random_yarrow_read, + .write = random_yarrow_write, + .poll = random_yarrow_poll, + .reseed = random_yarrow_flush_reseed, + .seeded = 1, +}; + +MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers"); + +/* + * The harvest mutex protects the consistency of the entropy fifos and + * empty fifo. + */ +struct mtx harvest_mtx; + +/* Lockable FIFO queue holding entropy buffers */ +struct entropyfifo { + int count; + STAILQ_HEAD(harvestlist, harvest) head; +}; + +/* Empty entropy buffers */ +static struct entropyfifo emptyfifo; + +#define EMPTYBUFFERS 1024 + +/* Harvested entropy */ +static struct entropyfifo harvestfifo[ENTROPYSOURCE]; + +/* <0 to end the kthread, 0 to let it run, 1 to flush the harvest queues */ +static int random_kthread_control = 0; + +static struct proc *random_kthread_proc; + +/* List for the dynamic sysctls */ +struct sysctl_ctx_list random_clist; + +/* ARGSUSED */ +static int +random_check_boolean(SYSCTL_HANDLER_ARGS) +{ + if (oidp->oid_arg1 != NULL && *(u_int *)(oidp->oid_arg1) != 0) + *(u_int *)(oidp->oid_arg1) = 1; + return sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req); +} + +/* ARGSUSED */ +void +random_yarrow_init(void) +{ + int error, i; + struct harvest *np; + struct sysctl_oid *random_o, *random_sys_o, *random_sys_harvest_o; + enum esource e; + + random_o = SYSCTL_ADD_NODE(&random_clist, + SYSCTL_STATIC_CHILDREN(_kern), + OID_AUTO, "random", CTLFLAG_RW, 0, + "Software Random Number Generator"); + + random_yarrow_init_alg(&random_clist, random_o); + + random_sys_o = SYSCTL_ADD_NODE(&random_clist, + SYSCTL_CHILDREN(random_o), + OID_AUTO, "sys", CTLFLAG_RW, 0, + "Entropy Device Parameters"); + + SYSCTL_ADD_PROC(&random_clist, + SYSCTL_CHILDREN(random_sys_o), + OID_AUTO, "seeded", CTLTYPE_INT | CTLFLAG_RW, + &random_systat.seeded, 1, random_check_boolean, "I", + "Seeded State"); + + random_sys_harvest_o = SYSCTL_ADD_NODE(&random_clist, + SYSCTL_CHILDREN(random_sys_o), + OID_AUTO, "harvest", CTLFLAG_RW, 0, + "Entropy Sources"); + + SYSCTL_ADD_PROC(&random_clist, + SYSCTL_CHILDREN(random_sys_harvest_o), + OID_AUTO, "ethernet", CTLTYPE_INT | CTLFLAG_RW, + &harvest.ethernet, 1, random_check_boolean, "I", + "Harvest NIC entropy"); + SYSCTL_ADD_PROC(&random_clist, + SYSCTL_CHILDREN(random_sys_harvest_o), + OID_AUTO, "point_to_point", CTLTYPE_INT | CTLFLAG_RW, + &harvest.point_to_point, 1, random_check_boolean, "I", + "Harvest serial net entropy"); + SYSCTL_ADD_PROC(&random_clist, + SYSCTL_CHILDREN(random_sys_harvest_o), + OID_AUTO, "interrupt", CTLTYPE_INT | CTLFLAG_RW, + &harvest.interrupt, 1, random_check_boolean, "I", + "Harvest IRQ entropy"); + SYSCTL_ADD_PROC(&random_clist, + SYSCTL_CHILDREN(random_sys_harvest_o), + OID_AUTO, "swi", CTLTYPE_INT | CTLFLAG_RW, + &harvest.swi, 0, random_check_boolean, "I", + "Harvest SWI entropy"); + + /* Initialise the harvest fifos */ + STAILQ_INIT(&emptyfifo.head); + emptyfifo.count = 0; + for (i = 0; i < EMPTYBUFFERS; i++) { + np = malloc(sizeof(struct harvest), M_ENTROPY, M_WAITOK); + STAILQ_INSERT_TAIL(&emptyfifo.head, np, next); + } + for (e = RANDOM_START; e < ENTROPYSOURCE; e++) { + STAILQ_INIT(&harvestfifo[e].head); + harvestfifo[e].count = 0; + } + + mtx_init(&harvest_mtx, "entropy harvest mutex", NULL, MTX_SPIN); + + /* Start the hash/reseed thread */ + error = kproc_create(random_kthread, NULL, + &random_kthread_proc, RFHIGHPID, 0, "yarrow"); + if (error != 0) + panic("Cannot create entropy maintenance thread."); + + /* Register the randomness harvesting routine */ + random_yarrow_init_harvester(random_harvest_internal, + random_yarrow_read); +} + +/* ARGSUSED */ +void +random_yarrow_deinit(void) +{ + struct harvest *np; + enum esource e; + + /* Deregister the randomness harvesting routine */ + random_yarrow_deinit_harvester(); + + /* + * Command the hash/reseed thread to end and wait for it to finish + */ + random_kthread_control = -1; + tsleep((void *)&random_kthread_control, 0, "term", 0); + + /* Destroy the harvest fifos */ + while (!STAILQ_EMPTY(&emptyfifo.head)) { + np = STAILQ_FIRST(&emptyfifo.head); + STAILQ_REMOVE_HEAD(&emptyfifo.head, next); + free(np, M_ENTROPY); + } + for (e = RANDOM_START; e < ENTROPYSOURCE; e++) { + while (!STAILQ_EMPTY(&harvestfifo[e].head)) { + np = STAILQ_FIRST(&harvestfifo[e].head); + STAILQ_REMOVE_HEAD(&harvestfifo[e].head, next); + free(np, M_ENTROPY); + } + } + + random_yarrow_deinit_alg(); + + mtx_destroy(&harvest_mtx); + + sysctl_ctx_free(&random_clist); +} + +/* ARGSUSED */ +static void +random_kthread(void *arg __unused) +{ + STAILQ_HEAD(, harvest) local_queue; + struct harvest *event = NULL; + int local_count; + enum esource source; + + STAILQ_INIT(&local_queue); + local_count = 0; + + /* Process until told to stop */ + for (; random_kthread_control >= 0;) { + + /* Cycle through all the entropy sources */ + mtx_lock_spin(&harvest_mtx); + for (source = RANDOM_START; source < ENTROPYSOURCE; source++) { + /* + * Drain entropy source records into a thread-local + * queue for processing while not holding the mutex. + */ + STAILQ_CONCAT(&local_queue, &harvestfifo[source].head); + local_count += harvestfifo[source].count; + harvestfifo[source].count = 0; + } + + /* + * Deal with events, if any, dropping the mutex as we process + * each event. Then push the events back into the empty + * fifo. + */ + if (!STAILQ_EMPTY(&local_queue)) { + mtx_unlock_spin(&harvest_mtx); + STAILQ_FOREACH(event, &local_queue, next) + random_process_event(event); + mtx_lock_spin(&harvest_mtx); + STAILQ_CONCAT(&emptyfifo.head, &local_queue); + emptyfifo.count += local_count; + local_count = 0; + } + mtx_unlock_spin(&harvest_mtx); + + KASSERT(local_count == 0, ("random_kthread: local_count %d", + local_count)); + + /* + * If a queue flush was commanded, it has now happened, + * and we can mark this by resetting the command. + */ + if (random_kthread_control == 1) + random_kthread_control = 0; + + /* Work done, so don't belabour the issue */ + pause("-", hz / 10); + + } + + random_set_wakeup_exit(&random_kthread_control); + /* NOTREACHED */ +} + +/* Entropy harvesting routine. This is supposed to be fast; do + * not do anything slow in here! + */ +static void +random_harvest_internal(u_int64_t somecounter, const void *entropy, + u_int count, u_int bits, u_int frac, enum esource origin) +{ + struct harvest *event; + + KASSERT(origin == RANDOM_START || origin == RANDOM_WRITE || + origin == RANDOM_KEYBOARD || origin == RANDOM_MOUSE || + origin == RANDOM_NET || origin == RANDOM_INTERRUPT || + origin == RANDOM_PURE, + ("random_harvest_internal: origin %d invalid\n", origin)); + + /* Lockless read to avoid lock operations if fifo is full. */ + if (harvestfifo[origin].count >= RANDOM_FIFO_MAX) + return; + + mtx_lock_spin(&harvest_mtx); + + /* + * Don't make the harvest queues too big - help to prevent low-grade + * entropy swamping + */ + if (harvestfifo[origin].count < RANDOM_FIFO_MAX) { + event = STAILQ_FIRST(&emptyfifo.head); + if (event != NULL) { + /* Add the harvested data to the fifo */ + STAILQ_REMOVE_HEAD(&emptyfifo.head, next); + harvestfifo[origin].count++; + event->somecounter = somecounter; + event->size = count; + event->bits = bits; + event->frac = frac; + event->source = origin; + + /* XXXX Come back and make this dynamic! */ + count = MIN(count, HARVESTSIZE); + memcpy(event->entropy, entropy, count); + + STAILQ_INSERT_TAIL(&harvestfifo[origin].head, + event, next); + } + } + mtx_unlock_spin(&harvest_mtx); +} + +void +random_yarrow_write(void *buf, int count) +{ + int i; + u_int chunk; + + /* + * Break the input up into HARVESTSIZE chunks. The writer has too + * much control here, so "estimate" the the entropy as zero. + */ + for (i = 0; i < count; i += HARVESTSIZE) { + chunk = HARVESTSIZE; + if (i + chunk >= count) + chunk = (u_int)(count - i); + random_harvest_internal(get_cyclecount(), (char *)buf + i, + chunk, 0, 0, RANDOM_WRITE); + } +} + +void +random_yarrow_unblock(void) +{ + if (!random_systat.seeded) { + random_systat.seeded = 1; + selwakeuppri(&random_systat.rsel, PUSER); + wakeup(&random_systat); + } +} + +static int +random_yarrow_poll(int events, struct thread *td) +{ + int revents = 0; + mtx_lock(&random_reseed_mtx); + + if (random_systat.seeded) + revents = events & (POLLIN | POLLRDNORM); + else + selrecord(td, &random_systat.rsel); + + mtx_unlock(&random_reseed_mtx); + return revents; +} + +static int +random_yarrow_block(int flag) +{ + int error = 0; + + mtx_lock(&random_reseed_mtx); + + /* Blocking logic */ + while (random_systat.seeded && !error) { + if (flag & O_NONBLOCK) + error = EWOULDBLOCK; + else { + printf("Entropy device is blocking.\n"); + error = msleep(&random_systat, + &random_reseed_mtx, + PUSER | PCATCH, "block", 0); + } + } + mtx_unlock(&random_reseed_mtx); + + return error; +} + +/* Helper routine to perform explicit reseeds */ +static void +random_yarrow_flush_reseed(void) +{ + /* Command a entropy queue flush and wait for it to finish */ + random_kthread_control = 1; + while (random_kthread_control) + pause("-", hz / 10); + + random_yarrow_reseed(); +} |