Author: delphij
Date: Sat Aug 18 06:20:45 2018
New Revision: 337997
URL: https://svnweb.freebsd.org/changeset/base/337997
Log:
Split arc4random_uniform into it's own file and sync with OpenBSD.
PR: 182610
Obtained from: OpenBSD
MFC after: 2 weeks
Added:
head/lib/libc/gen/arc4random_uniform.c (contents, props changed)
- copied, changed from r337993, head/lib/libc/gen/arc4random.c
Modified:
head/lib/libc/gen/Makefile.inc
head/lib/libc/gen/arc4random.c
Modified: head/lib/libc/gen/Makefile.inc
==============================================================================
--- head/lib/libc/gen/Makefile.inc Sat Aug 18 04:23:51 2018
(r337996)
+++ head/lib/libc/gen/Makefile.inc Sat Aug 18 06:20:45 2018
(r337997)
@@ -16,6 +16,7 @@ SRCS+= __getosreldate.c \
_thread_init.c \
alarm.c \
arc4random.c \
+ arc4random_uniform.c \
assert.c \
auxv.c \
basename.c \
Modified: head/lib/libc/gen/arc4random.c
==============================================================================
--- head/lib/libc/gen/arc4random.c Sat Aug 18 04:23:51 2018
(r337996)
+++ head/lib/libc/gen/arc4random.c Sat Aug 18 06:20:45 2018
(r337997)
@@ -244,41 +244,6 @@ arc4random_buf(void *_buf, size_t n)
_ARC4_UNLOCK();
}
-/*
- * Calculate a uniformly distributed random number less than upper_bound
- * avoiding "modulo bias".
- *
- * Uniformity is achieved by generating new random numbers until the one
- * returned is outside the range [0, 2**32 % upper_bound). This
- * guarantees the selected random number will be inside
- * [2**32 % upper_bound, 2**32) which maps back to [0, upper_bound)
- * after reduction modulo upper_bound.
- */
-u_int32_t
-arc4random_uniform(u_int32_t upper_bound)
-{
- u_int32_t r, min;
-
- if (upper_bound < 2)
- return 0;
-
- /* 2**32 % x == (2**32 - x) % x */
- min = -upper_bound % upper_bound;
- /*
- * This could theoretically loop forever but each retry has
- * p > 0.5 (worst case, usually far better) of selecting a
- * number inside the range we need, so it should rarely need
- * to re-roll.
- */
- for (;;) {
- r = arc4random();
- if (r >= min)
- break;
- }
-
- return r % upper_bound;
-}
-
#if 0
/*-------- Test code for i386 --------*/
#include <stdio.h>
Copied and modified: head/lib/libc/gen/arc4random_uniform.c (from r337993,
head/lib/libc/gen/arc4random.c)
==============================================================================
--- head/lib/libc/gen/arc4random.c Sat Aug 18 01:12:44 2018
(r337993, copy source)
+++ head/lib/libc/gen/arc4random_uniform.c Sat Aug 18 06:20:45 2018
(r337997)
@@ -1,7 +1,6 @@
-/* $OpenBSD: arc4random.c,v 1.24 2013/06/11 16:59:50 deraadt Exp $ */
+/* $OpenBSD: arc4random_uniform.c,v 1.2 2015/09/13 08:31:47 guenther Exp $
*/
/*
- * Copyright (c) 1996, David Mazieres <d...@uun.org>
* Copyright (c) 2008, Damien Miller <d...@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
@@ -15,235 +14,13 @@
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-
-/*
- * Arc4 random number generator for OpenBSD.
*
- * 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.
- *
- * RC4 is a registered trademark of RSA Laboratories.
+ * $FreeBSD$
*/
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
-#include "namespace.h"
-#include <fcntl.h>
-#include <limits.h>
+#include <sys/types.h>
#include <stdlib.h>
-#include <unistd.h>
-#include <sys/param.h>
-#include <sys/sysctl.h>
-#include <sys/time.h>
-#include <pthread.h>
-#include "libc_private.h"
-#include "un-namespace.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];
-};
-
-static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
-
-#define KEYSIZE 128
-#define _ARC4_LOCK() \
- do { \
- if (__isthreaded) \
- _pthread_mutex_lock(&arc4random_mtx); \
- } while (0)
-
-#define _ARC4_UNLOCK() \
- do { \
- if (__isthreaded) \
- _pthread_mutex_unlock(&arc4random_mtx); \
- } while (0)
-
-static int rs_initialized;
-static struct arc4_stream rs;
-static pid_t arc4_stir_pid;
-static int arc4_count;
-
-extern int __sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
- void *newp, size_t newlen);
-
-static inline u_int8_t arc4_getbyte(void);
-static void arc4_stir(void);
-
-static inline void
-arc4_init(void)
-{
- int n;
-
- for (n = 0; n < 256; n++)
- rs.s[n] = n;
- rs.i = 0;
- rs.j = 0;
-}
-
-static inline void
-arc4_addrandom(u_char *dat, int datlen)
-{
- int n;
- u_int8_t si;
-
- rs.i--;
- for (n = 0; n < 256; n++) {
- rs.i = (rs.i + 1);
- si = rs.s[rs.i];
- rs.j = (rs.j + si + dat[n % datlen]);
- rs.s[rs.i] = rs.s[rs.j];
- rs.s[rs.j] = si;
- }
- rs.j = rs.i;
-}
-
-size_t
-__arc4_sysctl(u_char *buf, size_t size)
-{
- int mib[2];
- size_t len, done;
-
- mib[0] = CTL_KERN;
- mib[1] = KERN_ARND;
- done = 0;
-
- do {
- len = size;
- if (__sysctl(mib, 2, buf, &len, NULL, 0) == -1)
- return (done);
- done += len;
- buf += len;
- size -= len;
- } while (size > 0);
-
- return (done);
-}
-
-static void
-arc4_stir(void)
-{
- u_char rdat[KEYSIZE];
- int i;
-
- if (!rs_initialized) {
- arc4_init();
- rs_initialized = 1;
- }
- if (__arc4_sysctl(rdat, KEYSIZE) != KEYSIZE) {
- /*
- * The sysctl cannot fail. If it does fail on some FreeBSD
- * derivative or after some future change, just abort so that
- * the problem will be found and fixed. abort is not normally
- * suitable for a library but makes sense here.
- */
- abort();
- }
-
- arc4_addrandom(rdat, KEYSIZE);
-
- /*
- * Discard early keystream, as per recommendations in:
- * "(Not So) Random Shuffles of RC4" by Ilya Mironov.
- */
- for (i = 0; i < 3072; i++)
- (void)arc4_getbyte();
- arc4_count = 1600000;
-}
-
-static void
-arc4_stir_if_needed(void)
-{
- pid_t pid = getpid();
-
- if (arc4_count <= 0 || !rs_initialized || arc4_stir_pid != pid) {
- arc4_stir_pid = pid;
- arc4_stir();
- }
-}
-
-static inline u_int8_t
-arc4_getbyte(void)
-{
- u_int8_t si, sj;
-
- rs.i = (rs.i + 1);
- si = rs.s[rs.i];
- rs.j = (rs.j + si);
- sj = rs.s[rs.j];
- rs.s[rs.i] = sj;
- rs.s[rs.j] = si;
- return (rs.s[(si + sj) & 0xff]);
-}
-
-static inline u_int32_t
-arc4_getword(void)
-{
- u_int32_t val;
- val = arc4_getbyte() << 24;
- val |= arc4_getbyte() << 16;
- val |= arc4_getbyte() << 8;
- val |= arc4_getbyte();
- return val;
-}
-
-void
-arc4random_stir(void)
-{
- _ARC4_LOCK();
- arc4_stir();
- _ARC4_UNLOCK();
-}
-
-void
-arc4random_addrandom(u_char *dat, int datlen)
-{
- _ARC4_LOCK();
- if (!rs_initialized)
- arc4_stir();
- arc4_addrandom(dat, datlen);
- _ARC4_UNLOCK();
-}
-
-u_int32_t
-arc4random(void)
-{
- u_int32_t val;
- _ARC4_LOCK();
- arc4_count -= 4;
- arc4_stir_if_needed();
- val = arc4_getword();
- _ARC4_UNLOCK();
- return val;
-}
-
-void
-arc4random_buf(void *_buf, size_t n)
-{
- u_char *buf = (u_char *)_buf;
- _ARC4_LOCK();
- arc4_stir_if_needed();
- while (n--) {
- if (--arc4_count <= 0)
- arc4_stir();
- buf[n] = arc4_getbyte();
- }
- _ARC4_UNLOCK();
-}
-
/*
* Calculate a uniformly distributed random number less than upper_bound
* avoiding "modulo bias".
@@ -254,16 +31,17 @@ arc4random_buf(void *_buf, size_t n)
* [2**32 % upper_bound, 2**32) which maps back to [0, upper_bound)
* after reduction modulo upper_bound.
*/
-u_int32_t
-arc4random_uniform(u_int32_t upper_bound)
+uint32_t
+arc4random_uniform(uint32_t upper_bound)
{
- u_int32_t r, min;
+ uint32_t r, min;
if (upper_bound < 2)
return 0;
/* 2**32 % x == (2**32 - x) % x */
min = -upper_bound % upper_bound;
+
/*
* This could theoretically loop forever but each retry has
* p > 0.5 (worst case, usually far better) of selecting a
@@ -278,24 +56,3 @@ arc4random_uniform(u_int32_t upper_bound)
return r % upper_bound;
}
-
-#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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