New machine-independant /dev/random driver.

This is work-in-progress, and the entropy-gathering routines are not
yet present. As such, this should be viewed as a pretty reasonable
PRNG with _ABSOLUTELY_NO_ security!!

Entropy gathering will be the subject of ongoing work.

This is written as a module, and as such is unloadable, but there is
no refcounting done. I would like to use something like device_busy(9)
to achieve this (eventually).

Lots of useful ideas from:	bde, phk, Jeroen van Gelderen

Reviewed by:	dfr

1 files changed, 145 insertions, 0 deletions

diff --git a/sys/dev/random/randomdev.c b/sys/dev/random/randomdev.c
new file mode 100644
index 0000000..157fd73
--- /dev/null
+++ b/sys/dev/random/randomdev.c
@@ -0,0 +1,145 @@
+/*-
+ * Copyright (c) 2000 Mark 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.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/conf.h>
+#include <sys/fcntl.h>
+#include <sys/uio.h>
+#include <sys/kernel.h>
+#include <sys/kobj.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/bus.h>
+#include <sys/random.h>
+#include <machine/bus.h>
+#include <machine/resource.h>
+#include <sys/rman.h>
+#include <sys/signalvar.h>
+#include <sys/sysctl.h>
+#include <crypto/blowfish/blowfish.h>
+
+#include "yarrow.h"
+
+static d_read_t randomread;
+static d_write_t randomwrite;
+
+#define CDEV_MAJOR	2
+#define RANDOM_MINOR	3
+
+static struct cdevsw random_cdevsw = {
+	/* open */	(d_open_t *)nullop,
+	/* close */	(d_close_t *)nullop,
+	/* read */	randomread,
+	/* write */	randomwrite,
+	/* ioctl */	noioctl,
+	/* poll */	nopoll,
+	/* mmap */	nommap,
+	/* strategy */	nostrategy,
+	/* name */	"random",
+	/* maj */	CDEV_MAJOR,
+	/* dump */	nodump,
+	/* psize */	nopsize,
+	/* flags */	0,
+	/* bmaj */	-1
+};
+
+/* For use with make_dev(9)/destroy_dev(9). */
+static dev_t randomdev;
+
+void *buf;
+
+extern void randominit(void);
+
+extern struct state state;
+
+/* This is mostly academic at the moment; as Yarrow gets extended, it will
+   become more relevant */
+SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Random Number Generator");
+SYSCTL_NODE(_kern_random, OID_AUTO, yarrow, CTLFLAG_RW, 0, "Yarrow Parameters");
+SYSCTL_INT(_kern_random_yarrow, OID_AUTO, gengateinterval, CTLFLAG_RW, &state.gengateinterval, 10, "Generator Gate Interval");
+
+static int
+randomread(dev_t dev, struct uio *uio, int flag)
+{
+	u_int c, ret;
+	int error = 0;
+
+	c = min(uio->uio_resid, PAGE_SIZE);
+	buf = (void *)malloc(c, M_TEMP, M_WAITOK);
+	while (uio->uio_resid > 0 && error == 0) {
+		ret = read_random(buf, c);
+		error = uiomove(buf, ret, uio);
+	}
+	free(buf, M_TEMP);
+	return error;
+}
+
+static int
+randomwrite(dev_t dev, struct uio *uio, int flag)
+{
+	u_int c;
+	int error = 0;
+
+	buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
+	while (uio->uio_resid > 0) {
+		c = min(uio->uio_resid, PAGE_SIZE);
+		error = uiomove(buf, c, uio);
+		if (error)
+			break;
+		/* write_random(buf, c); */
+	}
+	free(buf, M_TEMP);
+	return error;
+}
+
+static int
+random_modevent(module_t mod, int type, void *data)
+{
+	switch(type) {
+	case MOD_LOAD:
+		if (bootverbose)
+			printf("random: <entropy source>\n");
+		randomdev = make_dev(&random_cdevsw, RANDOM_MINOR, UID_ROOT,
+			GID_WHEEL, 0666, "zero");
+		randominit();
+		return 0;
+
+	case MOD_UNLOAD:
+		destroy_dev(randomdev);
+		return 0;
+
+	case MOD_SHUTDOWN:
+		return 0;
+
+	default:
+		return EOPNOTSUPP;
+	}
+}
+
+DEV_MODULE(random, random_modevent, NULL);