Reorganise the entropy device so that high-yield entropy sources

can more easily be used INSTEAD OF the hard-working Yarrow.
The only hardware source used at this point is the one inside
the VIA C3 Nehemiah (Stepping 3 and above) CPU. More sources will
be added in due course. Contributions welcome!

1 files changed, 369 insertions, 0 deletions

diff --git a/sys/dev/random/randomdev_soft.c b/sys/dev/random/randomdev_soft.c
new file mode 100644
index 0000000..e342436
--- /dev/null
+++ b/sys/dev/random/randomdev_soft.c
@@ -0,0 +1,369 @@
+/*-
+ * 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 <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 <sys/vnode.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);
+
+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, 0, 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, 0, 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, 0, 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);
+	}
+}