From a6820ba482520797f3c1550fdfc95a3953b5252a Mon Sep 17 00:00:00 2001
From: dm <>
Date: Sat, 28 Dec 1996 06:33:01 +0000
Subject: arc4random() number generator, for use with things like RPC xid's.
---
src/lib/libc/crypt/Makefile.inc | 4 +-
src/lib/libc/crypt/arc4random.c | 175 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 177 insertions(+), 2 deletions(-)
create mode 100644 src/lib/libc/crypt/arc4random.c
(limited to 'src/lib')
diff --git a/src/lib/libc/crypt/Makefile.inc b/src/lib/libc/crypt/Makefile.inc
index 7b576e9e19..753396d4e4 100644
--- a/src/lib/libc/crypt/Makefile.inc
+++ b/src/lib/libc/crypt/Makefile.inc
@@ -1,8 +1,8 @@
-# $OpenBSD: Makefile.inc,v 1.4 1996/06/03 22:20:33 niklas Exp $
+# $OpenBSD: Makefile.inc,v 1.5 1996/12/28 06:33:00 dm Exp $
.PATH: ${.CURDIR}/arch/${MACHINE_ARCH}/crypt ${.CURDIR}/crypt
-SRCS+= crypt.c morecrypt.c md5crypt.c
+SRCS+= crypt.c morecrypt.c md5crypt.c arc4random.c
MAN+= crypt.3
MLINKS+=crypt.3 encrypt.3 crypt.3 setkey.3 crypt.3 des_cipher.3
diff --git a/src/lib/libc/crypt/arc4random.c b/src/lib/libc/crypt/arc4random.c
new file mode 100644
index 0000000000..078f4eeea6
--- /dev/null
+++ b/src/lib/libc/crypt/arc4random.c
@@ -0,0 +1,175 @@
+/* $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 <sys/types.h>
+#include <sys/time.h>
+
+#ifdef __GNUC__
+#define inline __inline
+#else /* !__GNUC__ */
+#define inline
+#endif /* !__GNUC__ */
+
+struct arc4_stream {
+ u_int8_t i;
+ u_int8_t j;
+ u_int8_t s[256];
+};
+
+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;
+ u_int8_t rnd[128 - sizeof(struct timeval)];
+ } rdat;
+
+ gettimeofday(&rdat.tv, NULL);
+ fd = open("/dev/arandom", O_RDONLY);
+ if (fd >= 0) {
+ 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
--
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