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Merge "Sync to current upstream arc4random."

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This commit is contained in:
Elliott Hughes
2014-06-24 21:24:55 +00:00
committed by Gerrit Code Review
parent 598f4b3ac1 0468feb286
commit 52f9b051c8
6 changed files with 450 additions and 218 deletions
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403
libc/bionic/arc4random.c
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@@ -1,8 +1,9 @@
/* $OpenBSD: arc4random.c,v 1.19 2008/06/04 00:50:23 djm Exp $ */
/* $OpenBSD: arc4random.c,v 1.33 2014/06/13 18:58:58 deraadt Exp $ */
/*
* Copyright (c) 1996, David Mazieres <dm@uun.org>
* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
* Copyright (c) 2013, Markus Friedl <markus@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
@@ -18,214 +19,236 @@
*/
/*
* 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.
*
* 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.
* ChaCha based random number generator for OpenBSD.
*/
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/mman.h>
#if defined(__ANDROID__)
#include <sys/stat.h>
#include <linux/random.h>
#include "private/libc_logging.h"
#include "private/thread_private.h"
/* BIONIC-BEGIN */
/* this lock should protect the global variables in this file */
static pthread_mutex_t _arc4_lock = PTHREAD_MUTEX_INITIALIZER;
#define _ARC4_LOCK() pthread_mutex_lock(&_arc4_lock)
#define _ARC4_UNLOCK() pthread_mutex_unlock(&_arc4_lock)
/* BIONIC-END */
#define explicit_bzero(p, s) memset(p, 0, s)
#undef MAP_ANON
#define MAP_ANON (MAP_PRIVATE | MAP_ANONYMOUS)
/*
* XXX Should be replaced with a proper entropy measure.
*/
static int
gotdata(u_char *buf, size_t len)
{
char any_set = 0;
size_t i;
for (i = 0; i < len; ++i)
any_set |= buf[i];
if (any_set == 0)
return -1;
return 0;
}
static int
getentropy/*_urandom*/(u_char *buf, size_t len)
{
int save_errno = errno;
int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOFOLLOW, 0));
if (fd == -1) {
__libc_fatal("getentropy_urandom failed to open \"/dev/urandom\": %s",
strerror(errno));
}
/* Lightly verify that the device node looks sane */
struct stat st;
if (fstat(fd, &st) == -1 || !S_ISCHR(st.st_mode)) {
__libc_fatal("getentropy_urandom failed to fstat \"/dev/urandom\": %s",
strerror(errno));
}
int cnt;
if (ioctl(fd, RNDGETENTCNT, &cnt) == -1) {
__libc_fatal("getentropy_urandom failed to ioctl \"/dev/urandom\": %s",
strerror(errno));
}
for (size_t i = 0; i < len; ) {
size_t wanted = len - i;
ssize_t ret = TEMP_FAILURE_RETRY(read(fd, buf + i, wanted));
if (ret == -1) {
__libc_fatal("getentropy_urandom failed to read \"/dev/urandom\": %s",
strerror(errno));
}
i += ret;
}
close(fd);
if (gotdata(buf, len) == -1) {
__libc_fatal("getentropy_urandom failed to get enough entropy: %s",
strerror(errno));
}
errno = save_errno;
return 0;
}
#endif /* __ANDROID__ */
#define KEYSTREAM_ONLY
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#include "../upstream-openbsd/lib/libc/crypt/chacha_private.h"
#pragma GCC diagnostic pop
#ifdef __GNUC__
#define inline __inline
#else /* !__GNUC__ */
#else /* !__GNUC__ */
#define inline
#endif /* !__GNUC__ */
struct arc4_stream {
u_int8_t i;
u_int8_t j;
u_int8_t s[256];
};
#endif /* !__GNUC__ */
#define KEYSZ 32
#define IVSZ 8
#define BLOCKSZ 64
#define RSBUFSZ (16*BLOCKSZ)
static int rs_initialized;
static struct arc4_stream rs;
static pid_t arc4_stir_pid;
static int arc4_count;
static pid_t rs_stir_pid;
static chacha_ctx *rs; /* chacha context for random keystream */
static u_char *rs_buf; /* keystream blocks */
static size_t rs_have; /* valid bytes at end of rs_buf */
static size_t rs_count; /* bytes till reseed */
static inline u_int8_t arc4_getbyte(void);
static inline void _rs_rekey(u_char *dat, size_t datlen);
static inline void
arc4_init(void)
_rs_init(u_char *buf, size_t n)
{
int n;
if (n < KEYSZ + IVSZ)
return;
for (n = 0; n < 256; n++)
rs.s[n] = n;
rs.i = 0;
rs.j = 0;
}
if (rs == NULL && (rs = mmap(NULL, sizeof(*rs), PROT_READ|PROT_WRITE,
MAP_ANON, -1, 0)) == MAP_FAILED)
abort();
if (rs_buf == NULL && (rs_buf = mmap(NULL, RSBUFSZ, PROT_READ|PROT_WRITE,
MAP_ANON, -1, 0)) == MAP_FAILED)
abort();
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;
chacha_keysetup(rs, buf, KEYSZ * 8, 0);
chacha_ivsetup(rs, buf + KEYSZ);
}
static void
arc4_stir(void)
_rs_stir(void)
{
#if 1 /* BIONIC-BEGIN */
int i, fd;
union {
struct timeval tv;
u_int rnd[128 / sizeof(u_int)];
} rdat;
int n;
u_char rnd[KEYSZ + IVSZ];
if (!rs_initialized) {
arc4_init();
rs_initialized = 1;
}
/* XXX */
(void) getentropy(rnd, sizeof rnd);
fd = open("/dev/urandom", O_RDONLY);
if (fd != -1) {
read(fd, rdat.rnd, sizeof(rdat.rnd));
close(fd);
}
else
{
/* fd < 0 ? Ah, what the heck. We'll just take
* whatever was on the stack. just add a little more
* time-based randomness though
*/
gettimeofday(&rdat.tv, NULL);
}
if (!rs_initialized) {
rs_initialized = 1;
_rs_init(rnd, sizeof(rnd));
} else
_rs_rekey(rnd, sizeof(rnd));
explicit_bzero(rnd, sizeof(rnd));
arc4_stir_pid = getpid();
arc4_addrandom((void *) &rdat, sizeof(rdat));
#else /* BIONIC-END */
int i, mib[2];
size_t len;
u_char rnd[128];
/* invalidate rs_buf */
rs_have = 0;
memset(rs_buf, 0, RSBUFSZ);
if (!rs_initialized) {
arc4_init();
rs_initialized = 1;
}
rs_count = 1600000;
}
mib[0] = CTL_KERN;
mib[1] = KERN_ARND;
static inline void
_rs_stir_if_needed(size_t len)
{
pid_t pid = getpid();
len = sizeof(rnd);
sysctl(mib, 2, rnd, &len, NULL, 0);
if (rs_count <= len || !rs_initialized || rs_stir_pid != pid) {
rs_stir_pid = pid;
_rs_stir();
} else
rs_count -= len;
}
arc4_stir_pid = getpid();
arc4_addrandom(rnd, sizeof(rnd));
static inline void
_rs_rekey(u_char *dat, size_t datlen)
{
#ifndef KEYSTREAM_ONLY
memset(rs_buf, 0,RSBUFSZ);
#endif
/*
* Discard early keystream, as per recommendations in:
* http://www.wisdom.weizmann.ac.il/~itsik/RC4/Papers/Rc4_ksa.ps
*/
for (i = 0; i < 256; i++)
(void)arc4_getbyte();
arc4_count = 1600000;
/* fill rs_buf with the keystream */
chacha_encrypt_bytes(rs, rs_buf, rs_buf, RSBUFSZ);
/* mix in optional user provided data */
if (dat) {
size_t i, m;
m = MIN(datlen, KEYSZ + IVSZ);
for (i = 0; i < m; i++)
rs_buf[i] ^= dat[i];
}
/* immediately reinit for backtracking resistance */
_rs_init(rs_buf, KEYSZ + IVSZ);
memset(rs_buf, 0, KEYSZ + IVSZ);
rs_have = RSBUFSZ - KEYSZ - IVSZ;
}
static inline u_int8_t
arc4_getbyte(void)
static inline void
_rs_random_buf(void *_buf, size_t n)
{
u_int8_t si, sj;
u_char *buf = (u_char *)_buf;
size_t m;
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]);
_rs_stir_if_needed(n);
while (n > 0) {
if (rs_have > 0) {
m = MIN(n, rs_have);
memcpy(buf, rs_buf + RSBUFSZ - rs_have, m);
memset(rs_buf + RSBUFSZ - rs_have, 0, m);
buf += m;
n -= m;
rs_have -= m;
}
if (rs_have == 0)
_rs_rekey(NULL, 0);
}
}
static inline u_int32_t
arc4_getword(void)
static inline void
_rs_random_u32(u_int32_t *val)
{
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();
_rs_stir_if_needed(sizeof(*val));
if (rs_have < sizeof(*val))
_rs_rekey(NULL, 0);
memcpy(val, rs_buf + RSBUFSZ - rs_have, sizeof(*val));
memset(rs_buf + RSBUFSZ - rs_have, 0, sizeof(*val));
rs_have -= sizeof(*val);
}
u_int32_t
arc4random(void)
{
u_int32_t val;
_ARC4_LOCK();
arc4_count -= 4;
if (arc4_count <= 0 || !rs_initialized || arc4_stir_pid != getpid())
arc4_stir();
val = arc4_getword();
_ARC4_UNLOCK();
return val;
u_int32_t val;
_ARC4_LOCK();
_rs_random_u32(&val);
_ARC4_UNLOCK();
return val;
}
void
arc4random_buf(void *_buf, size_t n)
arc4random_buf(void *buf, size_t n)
{
u_char *buf = (u_char *)_buf;
_ARC4_LOCK();
if (!rs_initialized || arc4_stir_pid != getpid())
arc4_stir();
while (n--) {
if (--arc4_count <= 0)
arc4_stir();
buf[n] = arc4_getbyte();
}
_ARC4_UNLOCK();
_ARC4_LOCK();
_rs_random_buf(buf, n);
_ARC4_UNLOCK();
}
/*
@@ -241,55 +264,25 @@ arc4random_buf(void *_buf, size_t n)
u_int32_t
arc4random_uniform(u_int32_t upper_bound)
{
u_int32_t r, min;
u_int32_t r, min;
if (upper_bound < 2)
return 0;
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
/* 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;
}
/*
* 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;
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

20
libc/bionic/thread_atexit.cpp → libc/bionic/thread_private.cpp
View File

@@ -26,17 +26,13 @@
* SUCH DAMAGE.
*/
/* some simple glue used to make the BSD atexit code happy */
#include <pthread.h>
#include "private/thread_private.h"
// Some simple glue used to make BSD code thread-safe.
static pthread_mutex_t g_atexit_lock = PTHREAD_MUTEX_INITIALIZER;
__BEGIN_DECLS
__LIBC_HIDDEN__ void _thread_atexit_lock();
__LIBC_HIDDEN__ void _thread_atexit_unlock();
__END_DECLS
void _thread_atexit_lock() {
pthread_mutex_lock(&g_atexit_lock);
}
@@ -44,3 +40,13 @@ void _thread_atexit_lock() {
void _thread_atexit_unlock() {
pthread_mutex_unlock(&g_atexit_lock);
}
static pthread_mutex_t g_arc4_lock = PTHREAD_MUTEX_INITIALIZER;
void _thread_arc4_lock() {
pthread_mutex_lock(&g_arc4_lock);
}
void _thread_arc4_unlock() {
pthread_mutex_unlock(&g_arc4_lock);
}