diff options
Diffstat (limited to 'sys/dev/random/randomdev.c')
| -rw-r--r-- | sys/dev/random/randomdev.c | 467 |
1 files changed, 467 insertions, 0 deletions
diff --git a/sys/dev/random/randomdev.c b/sys/dev/random/randomdev.c new file mode 100644 index 0000000..8086841 --- /dev/null +++ b/sys/dev/random/randomdev.c @@ -0,0 +1,467 @@ +/*- + * 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 <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/filio.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 <sys/vnode.h> + +#include <machine/bus.h> +#include <machine/cpu.h> + +#include <dev/random/randomdev.h> + +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"); + +/* 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]; + +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 */ + 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 (i = 0; i < ENTROPYSOURCE; i++) { + STAILQ_INIT(&harvestfifo[i].head); + harvestfifo[i].count = 0; + mtx_init(&harvestfifo[i].lock, "entropy harvest", NULL, + MTX_SPIN); + } + + if (bootverbose) + printf("random: <entropy source>\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 */ + 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 (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_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, 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 = count > HARVESTSIZE ? HARVESTSIZE : count; + memcpy(event->entropy, entropy, count); + + STAILQ_INSERT_TAIL(&harvestfifo[origin].head, event, next); + } + + } + + mtx_unlock_spin(&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); + } +} |
