/*- * Copyright (c) 2000, 2001, 2002, 2003 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.c 122871 2003-11-17 23:02:21Z markm $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static d_close_t random_close; static d_read_t random_read; static d_write_t random_write; static d_ioctl_t random_ioctl; static d_poll_t random_poll; #define RANDOM_MINOR 0 #define RANDOM_FIFO_MAX 256 /* How many events to queue up */ static struct cdevsw random_cdevsw = { .d_close = random_close, .d_read = random_read, .d_write = random_write, .d_ioctl = random_ioctl, .d_poll = random_poll, .d_name = "random", }; static void random_kthread(void *); static void random_harvest_internal(u_int64_t, void *, u_int, u_int, u_int, enum esource); static void random_write_internal(void *, int); MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers"); /* FIFO queues holding harvested entropy */ static struct harvestfifo { struct mtx lock; int count; STAILQ_HEAD(harvestlist, harvest) head; } harvestfifo[ENTROPYSOURCE]; static struct random_systat { u_int seeded; /* 0 causes blocking 1 allows normal output */ struct selinfo rsel; /* For poll(2) */ } random_systat; /* <0 to end the kthread, 0 to let it run */ static int random_kthread_control = 0; static struct proc *random_kthread_proc; /* For use with make_dev(9)/destroy_dev(9). */ static dev_t random_dev; static dev_t urandom_dev; /* 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); } SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Random Number Generator"); SYSCTL_NODE(_kern_random, OID_AUTO, sys, CTLFLAG_RW, 0, "Entropy Device Parameters"); SYSCTL_PROC(_kern_random_sys, OID_AUTO, seeded, CTLTYPE_INT|CTLFLAG_RW, &random_systat.seeded, 1, random_check_boolean, "I", "Seeded State"); SYSCTL_NODE(_kern_random_sys, OID_AUTO, harvest, CTLFLAG_RW, 0, "Entropy Sources"); SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, ethernet, CTLTYPE_INT|CTLFLAG_RW, &harvest.ethernet, 0, random_check_boolean, "I", "Harvest NIC entropy"); SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, point_to_point, CTLTYPE_INT|CTLFLAG_RW, &harvest.point_to_point, 0, random_check_boolean, "I", "Harvest serial net entropy"); SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, interrupt, CTLTYPE_INT|CTLFLAG_RW, &harvest.interrupt, 0, random_check_boolean, "I", "Harvest IRQ entropy"); SYSCTL_PROC(_kern_random_sys_harvest, OID_AUTO, swi, CTLTYPE_INT|CTLFLAG_RW, &harvest.swi, 0, random_check_boolean, "I", "Harvest SWI entropy"); /* ARGSUSED */ static int random_close(dev_t dev __unused, int flags, int fmt __unused, struct thread *td) { if (flags & FWRITE) { if (suser(td) == 0 && securelevel_gt(td->td_ucred, 0) == 0) random_reseed(); } return 0; } /* ARGSUSED */ static int random_read(dev_t dev __unused, struct uio *uio, int flag) { int c, ret; int error = 0; void *random_buf; while (!random_systat.seeded) { if (flag & IO_NDELAY) error = EWOULDBLOCK; else error = tsleep(&random_systat, PUSER|PCATCH, "block", 0); if (error != 0) return error; } c = uio->uio_resid < PAGE_SIZE ? uio->uio_resid : PAGE_SIZE; random_buf = (void *)malloc((u_long)c, M_TEMP, M_WAITOK); while (uio->uio_resid > 0 && error == 0) { ret = read_random_real(random_buf, c); error = uiomove(random_buf, ret, uio); } free(random_buf, M_TEMP); return error; } /* ARGSUSED */ static int random_write(dev_t dev __unused, struct uio *uio, int flag __unused) { int c; int error; void *random_buf; error = 0; random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK); while (uio->uio_resid > 0) { c = (int)(uio->uio_resid < PAGE_SIZE ? uio->uio_resid : PAGE_SIZE); error = uiomove(random_buf, c, uio); if (error) break; random_write_internal(random_buf, c); } free(random_buf, M_TEMP); return error; } /* ARGSUSED */ static int random_ioctl(dev_t dev __unused, u_long cmd, caddr_t addr __unused, int flags __unused, struct thread *td __unused) { switch (cmd) { /* Really handled in upper layer */ case FIOASYNC: case FIONBIO: return 0; default: return ENOTTY; } } /* ARGSUSED */ static int random_poll(dev_t dev __unused, int events, struct thread *td) { int revents; revents = 0; if (events & (POLLIN | POLLRDNORM)) { if (random_systat.seeded) revents = events & (POLLIN | POLLRDNORM); else selrecord(td, &random_systat.rsel); } return revents; } /* ARGSUSED */ static int random_modevent(module_t mod __unused, int type, void *data __unused) { int error, i; struct harvest *np; switch(type) { case MOD_LOAD: random_init(); /* This can be turned off by the very paranoid * a reseed will turn it back on. */ random_systat.seeded = 1; /* Initialise the harvest fifos */ for (i = 0; i < ENTROPYSOURCE; i++) { STAILQ_INIT(&harvestfifo[i].head); harvestfifo[i].count = 0; mtx_init(&harvestfifo[i].lock, "entropy harvest", NULL, MTX_DEF); } if (bootverbose) printf("random: \n"); random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, UID_ROOT, GID_WHEEL, 0666, "random"); urandom_dev = make_dev_alias(random_dev, "urandom"); /* Start the hash/reseed thread */ error = kthread_create(random_kthread, NULL, &random_kthread_proc, RFHIGHPID, 0, "random"); if (error != 0) return error; /* Register the randomness harvesting routine */ random_init_harvester(random_harvest_internal, read_random_real); return 0; case MOD_UNLOAD: /* Deregister the randomness harvesting routine */ random_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 */ for (i = 0; i < ENTROPYSOURCE; i++) { while (!STAILQ_EMPTY(&harvestfifo[i].head)) { np = STAILQ_FIRST(&harvestfifo[i].head); STAILQ_REMOVE_HEAD(&harvestfifo[i].head, next); free(np, M_ENTROPY); } mtx_destroy(&harvestfifo[i].lock); } random_deinit(); destroy_dev(random_dev); destroy_dev(urandom_dev); return 0; case MOD_SHUTDOWN: return 0; default: return EOPNOTSUPP; } } DEV_MODULE(random, random_modevent, NULL); /* 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 = 0; source < ENTROPYSOURCE; source++) { found = 0; /* Lock up queue draining */ mtx_lock(&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(&harvestfifo[source].lock); /* Deal with the event and dispose of it */ if (found) { random_process_event(event); free(event, M_ENTROPY); } } /* 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, void *entropy, u_int count, u_int bits, u_int frac, enum esource origin) { struct harvest *event; /* Lock the particular fifo */ mtx_lock(&harvestfifo[origin].lock); /* Don't make the harvest queues too big - memory is precious */ if (harvestfifo[origin].count < RANDOM_FIFO_MAX) { event = malloc(sizeof(struct harvest), M_ENTROPY, M_NOWAIT); /* If we can't malloc() 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 = count > HARVESTSIZE ? HARVESTSIZE : count; memcpy(event->entropy, entropy, count); STAILQ_INSERT_TAIL(&harvestfifo[origin].head, event, next); } } mtx_unlock(&harvestfifo[origin].lock); } static void random_write_internal(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_unblock(void) { if (!random_systat.seeded) { random_systat.seeded = 1; selwakeuppri(&random_systat.rsel, PUSER); wakeup(&random_systat); } }