Add arc4random() functions from OpenBSD. They are almost same as our

srandomdev(), but can be used inside libraries. random() can't be used
inside libraries because it breaks its possible predictable sequence.
arc4random() is true random as designed, so its usage is library-safe.
Obtained from: OpenBSD

3 files changed, 261 insertions, 5 deletions

diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc
index e5f7a28..b223d9a 100644
--- a/lib/libc/gen/Makefile.inc
+++ b/lib/libc/gen/Makefile.inc
@@ -1,11 +1,11 @@
 #	@(#)Makefile.inc	8.6 (Berkeley) 5/4/95
-#	$Id: Makefile.inc,v 1.33 1997/05/03 03:49:54 jb Exp $
+#	$Id: Makefile.inc,v 1.34 1997/05/30 20:53:13 phk Exp $
 
 # machine-independent gen sources
 .PATH: ${.CURDIR}/../libc/${MACHINE}/gen ${.CURDIR}/../libc/gen
 
-SRCS+=	alarm.c assert.c clock.c closedir.c config.c confstr.c crypt.c \
-	ctermid.c daemon.c devname.c disklabel.c err.c errlst.c \
+SRCS+=  alarm.c arc4random.c assert.c clock.c closedir.c config.c confstr.c \
+	crypt.c ctermid.c daemon.c devname.c disklabel.c err.c errlst.c \
 	exec.c fnmatch.c frexp.c fstab.c fts.c getbootfile.c getbsize.c \
 	getcap.c getcwd.c getdomainname.c getgrent.c getgrouplist.c \
 	gethostname.c getloadavg.c getlogin.c getmntinfo.c getnetgrent.c \
@@ -39,8 +39,8 @@ errlst.o errlst.po:
 
 # Only build man pages with libc.
 .if ${LIB} == "c"
-MAN3+=	gen/alarm.3 gen/clock.3 gen/confstr.3 gen/config_open.3 \
-	gen/crypt.3 gen/ctermid.3 \
+MAN3+=  gen/alarm.3 gen/arc4random.3 gen/clock.3 gen/confstr.3 \
+	gen/config_open.3 gen/crypt.3 gen/ctermid.3 \
 	gen/daemon.3 gen/devname.3 gen/directory.3 gen/err.3 gen/exec.3 \
 	gen/fnmatch.3 gen/frexp.3 gen/fts.3 gen/getbsize.3 gen/getbootfile.3 \
 	gen/getcap.3 gen/getcwd.3 gen/getdiskbyname.3 gen/getdomainname.3 \
@@ -61,6 +61,7 @@ MAN3+=	gen/alarm.3 gen/clock.3 gen/confstr.3 gen/config_open.3 \
 	gen/times.3 gen/timezone.3 gen/ttyname.3 gen/tzset.3 gen/ualarm.3 \
 	gen/uname.3 gen/unvis.3 gen/usleep.3 gen/utime.3 gen/valloc.3 gen/vis.3
 
+MLINKS+=arc4random.3 arc4random_stir.3 arc4random.3 arc4random_addrandom.3
 MLINKS+=config_open.3 config_next.3 config_open.3 config_close.3 \
 	config_open.3 config_skip.3
 MLINKS+=crypt.3 encrypt.3 crypt.3 setkey.3 crypt.3  des_setkey.3 \
diff --git a/lib/libc/gen/arc4random.3 b/lib/libc/gen/arc4random.3
new file mode 100644
index 0000000..42bb413
--- /dev/null
+++ b/lib/libc/gen/arc4random.3
@@ -0,0 +1,83 @@
+.\" $OpenBSD: arc4random.3,v 1.2 1997/04/27 22:40:25 angelos Exp $
+.\" Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
+.\" 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.
+.\" 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.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"      This product includes software developed by Niels Provos.
+.\" 4. The name of the author may not be used to endorse or promote products
+.\"    derived from this software without specific prior written permission.
+.\"
+.\" 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.
+.\"
+.\" Manual page, using -mandoc macros
+.\"
+.Dd April 15, 1997
+.Dt ARC4RANDOM 3
+.Os
+.Sh NAME
+.Nm arc4random,
+.Nm arc4random_stir,
+.Nm arc4random_addrandom
+.Nd arc4 random number generator.
+.Sh SYNOPSIS
+.Fd #include <stdlib.h>
+.Ft u_int32_t
+.Fn arc4random "void"
+.Ft void
+.Fn arc4random_stir "void"
+.Ft void
+.Fn arc4random_addrandom "u_char *dat" "int datlen"
+.Sh DESCRIPTION
+The
+.Fn arc4random 
+function uses the key stream generator employed by the
+arc4 cipher, which uses 8*8 8 bit S-Boxes. The S-Boxes
+can be in about 
+.if t 2\u\s71700\s10\d
+.if n (2**1700)
+states.
+.Pp
+The
+.Fn arc4random_stir
+function reads data from 
+.Pa /dev/urandom
+and uses it to permutate the S-Boxes via
+.Fn arc4random_addrandom .
+.Pp
+There is no need to call 
+.Fn arc4random_stir
+before using
+.Fn arc4random ,
+since
+.Fn arc4random
+automatically initalizes itself.
+.Sh SEE ALSO
+.Xr rand 3 ,
+.Xr random 3 ,
+.Xr srandomdev 3
+.Sh HISTORY
+.Pa RC4 
+has been designed by RSA Data Security, Inc. It was posted anonymously
+to the USENET and was confirmed to be equivalent by several sources who
+had access to the original cipher. Since 
+.Pa RC4
+used to be a trade secret, the cipher is now refered to as 
+.Pa ARC4 .
diff --git a/lib/libc/gen/arc4random.c b/lib/libc/gen/arc4random.c
new file mode 100644
index 0000000..b9f8a48
--- /dev/null
+++ b/lib/libc/gen/arc4random.c
@@ -0,0 +1,172 @@
+/* $Id: arc4random.c,v 1.1 1996/12/28 06:33:01 dm Exp $ */
+
+/*
+ * Arc4 random number generator for OpenBSD.
+ * Copyright 1996 David Mazieres <dm@lcs.mit.edu>.
+ *
+ * Modification and redistribution in source and binary forms is
+ * permitted provided that due credit is given to the author and the
+ * OpenBSD project (for instance by leaving this copyright notice
+ * intact).
+ */
+
+/*
+ * This code is derived from section 17.1 of Applied Cryptography,
+ * second edition, which describes a stream cipher allegedly
+ * compatible with RSA Labs "RC4" cipher (the actual description of
+ * which is a trade secret).  The same algorithm is used as a stream
+ * cipher called "arcfour" in Tatu Ylonen's ssh package.
+ *
+ * Here the stream cipher has been modified always to include the time
+ * when initializing the state.  That makes it impossible to
+ * regenerate the same random sequence twice, so this can't be used
+ * for encryption, but will generate good random numbers.
+ *
+ * RC4 is a registered trademark of RSA Laboratories.
+ */
+
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+struct arc4_stream {
+	u_int8_t i;
+	u_int8_t j;
+	u_int8_t s[256];
+};
+
+static int rs_initialized;
+static struct arc4_stream rs;
+
+static inline void
+arc4_init(as)
+	struct arc4_stream *as;
+{
+	int     n;
+
+	for (n = 0; n < 256; n++)
+		as->s[n] = n;
+	as->i = 0;
+	as->j = 0;
+}
+
+static inline void
+arc4_addrandom(as, dat, datlen)
+	struct arc4_stream *as;
+	u_char *dat;
+	int     datlen;
+{
+	int     n;
+	u_int8_t si;
+
+	as->i--;
+	for (n = 0; n < 256; n++) {
+		as->i = (as->i + 1);
+		si = as->s[as->i];
+		as->j = (as->j + si + dat[n % datlen]);
+		as->s[as->i] = as->s[as->j];
+		as->s[as->j] = si;
+	}
+}
+
+static void
+arc4_stir(as)
+	struct arc4_stream *as;
+{
+	int     fd;
+	struct {
+		struct timeval tv;
+		pid_t pid;
+		u_int8_t rnd[128 - sizeof(struct timeval) - sizeof(pid_t)];
+	}       rdat;
+
+	gettimeofday(&rdat.tv, NULL);
+	rdat.pid = getpid();
+	fd = open("/dev/urandom", O_RDONLY, 0);
+	if (fd >= 0) {
+		(void) read(fd, rdat.rnd, sizeof(rdat.rnd));
+		close(fd);
+	}
+	/* fd < 0?  Ah, what the heck. We'll just take whatever was on the
+	 * stack... */
+
+	arc4_addrandom(as, (void *) &rdat, sizeof(rdat));
+}
+
+static inline u_int8_t
+arc4_getbyte(as)
+	struct arc4_stream *as;
+{
+	u_int8_t si, sj;
+
+	as->i = (as->i + 1);
+	si = as->s[as->i];
+	as->j = (as->j + si);
+	sj = as->s[as->j];
+	as->s[as->i] = sj;
+	as->s[as->j] = si;
+	return (as->s[(si + sj) & 0xff]);
+}
+
+static inline u_int32_t
+arc4_getword(as)
+	struct arc4_stream *as;
+{
+	u_int32_t val;
+	val = arc4_getbyte(as) << 24;
+	val |= arc4_getbyte(as) << 16;
+	val |= arc4_getbyte(as) << 8;
+	val |= arc4_getbyte(as);
+	return val;
+}
+
+void
+arc4random_stir()
+{
+	if (!rs_initialized) {
+		arc4_init(&rs);
+		rs_initialized = 1;
+	}
+	arc4_stir(&rs);
+}
+
+void
+arc4random_addrandom(dat, datlen)
+	u_char *dat;
+	int     datlen;
+{
+	if (!rs_initialized)
+		arc4random_stir();
+	arc4_addrandom(&rs, dat, datlen);
+}
+
+u_int32_t
+arc4random()
+{
+	if (!rs_initialized)
+		arc4random_stir();
+	return arc4_getword(&rs);
+}
+
+#if 0
+/*-------- Test code for i386 --------*/
+#include <stdio.h>
+#include <machine/pctr.h>
+int
+main(int argc, char **argv)
+{
+	const int iter = 1000000;
+	int     i;
+	pctrval v;
+
+	v = rdtsc();
+	for (i = 0; i < iter; i++)
+		arc4random();
+	v = rdtsc() - v;
+	v /= iter;
+
+	printf("%qd cycles\n", v);
+}
+#endif