/*- * Copyright (c) 2000-2004 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. * */ #include __FBSDID("$FreeBSD: head/sys/dev/random/randomdev_soft.c 128320 2004-04-16 17:07:11Z markm $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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); struct random_systat random_yarrow = { .ident = "Software, Yarrow", .init = random_yarrow_init, .deinit = random_yarrow_deinit, .read = random_yarrow_read, .write = random_yarrow_write, .reseed = random_yarrow_reseed, .seeded = 0, }; MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers"); /* Lockable FIFO queue holding entropy buffers */ struct entropyfifo { struct mtx lock; 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 */ 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 *o, *random_o, *random_sys_o, *random_sys_harvest_o; enum esource e; o = SYSCTL_ADD_NODE(&random_clist, SYSCTL_STATIC_CHILDREN(_kern), OID_AUTO, "random", CTLFLAG_RW, 0, "Software Random Number Generator"); random_o = o; random_yarrow_init_alg(&random_clist, random_o); o = SYSCTL_ADD_NODE(&random_clist, SYSCTL_CHILDREN(random_o), OID_AUTO, "sys", CTLFLAG_RW, 0, "Entropy Device Parameters"); random_sys_o = o; o = SYSCTL_ADD_PROC(&random_clist, SYSCTL_CHILDREN(random_sys_o), OID_AUTO, "seeded", CTLTYPE_INT | CTLFLAG_RW, &random_systat.seeded, 0, random_check_boolean, "I", "Seeded State"); o = SYSCTL_ADD_NODE(&random_clist, SYSCTL_CHILDREN(random_sys_o), OID_AUTO, "harvest", CTLFLAG_RW, 0, "Entropy Sources"); random_sys_harvest_o = o; o = 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"); o = 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"); o = 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"); o = 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; mtx_init(&emptyfifo.lock, "entropy harvest buffers", NULL, MTX_SPIN); 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(&harvestfifo[e].lock, "entropy harvest", NULL, MTX_SPIN); } /* Start the hash/reseed thread */ error = kthread_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, PUSER, "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); } mtx_destroy(&emptyfifo.lock); 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); } mtx_destroy(&harvestfifo[e].lock); } random_yarrow_deinit_alg(); sysctl_ctx_free(&random_clist); } /* ARGSUSED */ static void random_kthread(void *arg __unused) { struct harvest *event = NULL; int found, active; enum esource source; /* Process until told to stop */ for (; random_kthread_control == 0;) { active = 0; /* Cycle through all the entropy sources */ for (source = RANDOM_START; source < ENTROPYSOURCE; source++) { found = 0; /* Lock up queue draining */ mtx_lock_spin(&harvestfifo[source].lock); if (!STAILQ_EMPTY(&harvestfifo[source].head)) { /* Get a harvested entropy event */ harvestfifo[source].count--; event = STAILQ_FIRST(&harvestfifo[source].head); STAILQ_REMOVE_HEAD(&harvestfifo[source].head, next); active = found = 1; } /* Unlock the queue */ mtx_unlock_spin(&harvestfifo[source].lock); /* Deal with the event and dispose of it */ if (found) { random_process_event(event); /* Lock the empty event buffer fifo */ mtx_lock_spin(&emptyfifo.lock); STAILQ_INSERT_TAIL(&emptyfifo.head, event, next); mtx_unlock_spin(&emptyfifo.lock); } } /* Found nothing, so don't belabour the issue */ if (!active) tsleep(&harvestfifo, PUSER, "-", 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; /* Lock the particular fifo */ mtx_lock_spin(&harvestfifo[origin].lock); /* * Don't make the harvest queues too big - help to prevent low-grade * entropy swamping */ if (harvestfifo[origin].count < RANDOM_FIFO_MAX) { /* Lock the empty event buffer fifo */ mtx_lock_spin(&emptyfifo.lock); if (!STAILQ_EMPTY(&emptyfifo.head)) { event = STAILQ_FIRST(&emptyfifo.head); STAILQ_REMOVE_HEAD(&emptyfifo.head, next); } else event = NULL; mtx_unlock_spin(&emptyfifo.lock); /* If we didn't obtain a buffer, tough */ if (event) { /* Add the harvested data to the fifo */ 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(&harvestfifo[origin].lock); } 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); } }