* Makefile.in (DLL_OFILES): Add arc4random.o.
* common.din: Export arc4random, arc4random_addrandom, arc4random_buf, arc4random_stir and arc4random_uniform. * mktemp.cc (arc4random): Remove static replacement function. * posix.sgml (std-bsd): Add arc4random functions. * include/cygwin/stdlib.h: Declare arc4random functions. * include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Bump. * libc/arc4random.cc: New file implementing arc4random functions taken from FreeBSD.
This commit is contained in:
Corinna Vinschen
363
winsup/cygwin/libc/arc4random.cc
Normal file
363
winsup/cygwin/libc/arc4random.cc
Normal file
@@ -0,0 +1,363 @@
|
||||
/* $OpenBSD: arc4random.c,v 1.22 2010/12/22 08:23:42 otto Exp $ */
|
||||
|
||||
/*
|
||||
* Copyright (c) 1996, David Mazieres <dm@uun.org>
|
||||
* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
|
||||
*
|
||||
* Permission to use, copy, modify, and distribute this software for any
|
||||
* purpose with or without fee is hereby granted, provided that the above
|
||||
* copyright notice and this permission notice appear in all copies.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
||||
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
||||
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
||||
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
||||
* 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.
|
||||
*/
|
||||
|
||||
#include <sys/cdefs.h>
|
||||
__FBSDID("$FreeBSD: src/lib/libc/gen/arc4random.c,v 1.30 2012/11/17 01:49:23 svnexp Exp $");
|
||||
|
||||
#ifdef __CYGWIN__
|
||||
#include "winsup.h"
|
||||
#include "sync.h"
|
||||
#else
|
||||
#include "namespace.h"
|
||||
#endif
|
||||
#include <fcntl.h>
|
||||
#include <limits.h>
|
||||
#include <stdlib.h>
|
||||
#include <unistd.h>
|
||||
#include <sys/types.h>
|
||||
#include <sys/param.h>
|
||||
#ifndef __CYGWIN__
|
||||
#include <sys/sysctl.h>
|
||||
#endif
|
||||
#include <sys/time.h>
|
||||
#include <pthread.h>
|
||||
|
||||
#ifndef __CYGWIN__
|
||||
#include "libc_private.h"
|
||||
#include "un-namespace.h"
|
||||
#endif
|
||||
|
||||
#ifdef __CYGWIN__
|
||||
#define _open open
|
||||
#define _read read
|
||||
#define _close close
|
||||
#endif
|
||||
|
||||
#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];
|
||||
};
|
||||
|
||||
#ifdef __CYGWIN__
|
||||
static NO_COPY muto arc4random_mtx;
|
||||
#else
|
||||
static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
|
||||
#endif
|
||||
|
||||
#define RANDOMDEV "/dev/random"
|
||||
#define KEYSIZE 128
|
||||
#ifdef __CYGWIN__
|
||||
#define _ARC4_LOCK() \
|
||||
do { \
|
||||
if (__isthreaded) \
|
||||
arc4random_mtx.init ("arc4random_mtx")->acquire (); \
|
||||
} while (0)
|
||||
#define _ARC4_UNLOCK() \
|
||||
do { \
|
||||
if (__isthreaded) \
|
||||
arc4random_mtx.release (); \
|
||||
} while (0)
|
||||
#else
|
||||
#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)
|
||||
#endif
|
||||
|
||||
static int rs_initialized;
|
||||
static struct arc4_stream rs;
|
||||
static pid_t arc4_stir_pid;
|
||||
static int arc4_count;
|
||||
|
||||
#ifndef __CYGWIN__
|
||||
extern int __sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
|
||||
void *newp, size_t newlen);
|
||||
#endif
|
||||
|
||||
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;
|
||||
}
|
||||
|
||||
#ifndef __CYGWIN__
|
||||
static 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);
|
||||
}
|
||||
#endif
|
||||
|
||||
static void
|
||||
arc4_stir(void)
|
||||
{
|
||||
int done, fd, i;
|
||||
struct {
|
||||
struct timeval tv;
|
||||
pid_t pid;
|
||||
u_char rnd[KEYSIZE];
|
||||
} rdat;
|
||||
|
||||
if (!rs_initialized) {
|
||||
arc4_init();
|
||||
rs_initialized = 1;
|
||||
}
|
||||
done = 0;
|
||||
#ifndef __CYGWIN__
|
||||
if (arc4_sysctl((u_char *)&rdat, KEYSIZE) == KEYSIZE)
|
||||
done = 1;
|
||||
#endif
|
||||
if (!done) {
|
||||
fd = _open(RANDOMDEV, O_RDONLY | O_CLOEXEC, 0);
|
||||
if (fd >= 0) {
|
||||
if (_read(fd, &rdat, KEYSIZE) == KEYSIZE)
|
||||
done = 1;
|
||||
(void)_close(fd);
|
||||
}
|
||||
}
|
||||
if (!done) {
|
||||
(void)gettimeofday(&rdat.tv, NULL);
|
||||
rdat.pid = getpid();
|
||||
/* We'll just take whatever was on the stack too... */
|
||||
}
|
||||
|
||||
arc4_addrandom((u_char *)&rdat, KEYSIZE);
|
||||
|
||||
/*
|
||||
* Discard early keystream, as per recommendations in:
|
||||
* "(Not So) Random Shuffles of RC4" by Ilya Mironov.
|
||||
*/
|
||||
for (i = 0; i < 1024; 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".
|
||||
*
|
||||
* 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;
|
||||
|
||||
#if (ULONG_MAX > 0xffffffffUL)
|
||||
min = 0x100000000UL % upper_bound;
|
||||
#else
|
||||
/* Calculate (2**32 % upper_bound) avoiding 64-bit math */
|
||||
if (upper_bound > 0x80000000)
|
||||
min = 1 + ~upper_bound; /* 2**32 - upper_bound */
|
||||
else {
|
||||
/* (2**32 - (x * 2)) % x == 2**32 % x when x <= 2**31 */
|
||||
min = ((0xffffffff - (upper_bound * 2)) + 1) % upper_bound;
|
||||
}
|
||||
#endif
|
||||
|
||||
/*
|
||||
* 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>
|
||||
#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
|
||||
Reference in New Issue
Block a user