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Diffstat (limited to 'external/libevent_files/arc4random.c')
| -rw-r--r-- | external/libevent_files/arc4random.c | 555 |
1 files changed, 0 insertions, 555 deletions
diff --git a/external/libevent_files/arc4random.c b/external/libevent_files/arc4random.c deleted file mode 100644 index ee13a34f..00000000 --- a/external/libevent_files/arc4random.c +++ /dev/null @@ -1,555 +0,0 @@ -/* Portable arc4random.c based on arc4random.c from OpenBSD. - * Portable version by Chris Davis, adapted for Libevent by Nick Mathewson - * Copyright (c) 2010 Chris Davis, Niels Provos, and Nick Mathewson - * Copyright (c) 2010-2012 Niels Provos and Nick Mathewson - * - * Note that in Libevent, this file isn't compiled directly. Instead, - * it's included from evutil_rand.c - */ - -/* - * 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. - * - * 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. - */ - -#ifndef ARC4RANDOM_EXPORT -#define ARC4RANDOM_EXPORT -#endif - -#ifndef ARC4RANDOM_UINT32 -#define ARC4RANDOM_UINT32 uint32_t -#endif - -#ifndef ARC4RANDOM_NO_INCLUDES -#ifdef WIN32 -#include <wincrypt.h> -#include <process.h> -#else -#include <fcntl.h> -#include <unistd.h> -#include <sys/param.h> -#include <sys/time.h> -#ifdef _EVENT_HAVE_SYS_SYSCTL_H -#include <sys/sysctl.h> -#endif -#endif -#include <limits.h> -#include <stdlib.h> -#include <string.h> -#endif - -/* Add platform entropy 32 bytes (256 bits) at a time. */ -#define ADD_ENTROPY 32 - -/* Re-seed from the platform RNG after generating this many bytes. */ -#define BYTES_BEFORE_RESEED 1600000 - -struct arc4_stream { - unsigned char i; - unsigned char j; - unsigned char s[256]; -}; - -#ifdef WIN32 -#define getpid _getpid -#define pid_t int -#endif - -static int rs_initialized; -static struct arc4_stream rs; -static pid_t arc4_stir_pid; -static int arc4_count; -static int arc4_seeded_ok; - -static inline unsigned char arc4_getbyte(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(const unsigned char *dat, int datlen) -{ - int n; - unsigned char 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 WIN32 -static ssize_t -read_all(int fd, unsigned char *buf, size_t count) -{ - size_t numread = 0; - ssize_t result; - - while (numread < count) { - result = read(fd, buf+numread, count-numread); - if (result<0) - return -1; - else if (result == 0) - break; - numread += result; - } - - return (ssize_t)numread; -} -#endif - -#ifdef WIN32 -#define TRY_SEED_WIN32 -static int -arc4_seed_win32(void) -{ - /* This is adapted from Tor's crypto_seed_rng() */ - static int provider_set = 0; - static HCRYPTPROV provider; - unsigned char buf[ADD_ENTROPY]; - - if (!provider_set) { - if (!CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL, - CRYPT_VERIFYCONTEXT)) { - if (GetLastError() != (DWORD)NTE_BAD_KEYSET) - return -1; - } - provider_set = 1; - } - if (!CryptGenRandom(provider, sizeof(buf), buf)) - return -1; - arc4_addrandom(buf, sizeof(buf)); - evutil_memclear_(buf, sizeof(buf)); - arc4_seeded_ok = 1; - return 0; -} -#endif - -#if defined(_EVENT_HAVE_SYS_SYSCTL_H) && defined(_EVENT_HAVE_SYSCTL) -#if _EVENT_HAVE_DECL_CTL_KERN && _EVENT_HAVE_DECL_KERN_RANDOM && _EVENT_HAVE_DECL_RANDOM_UUID -#define TRY_SEED_SYSCTL_LINUX -static int -arc4_seed_sysctl_linux(void) -{ - /* Based on code by William Ahern, this function tries to use the - * RANDOM_UUID sysctl to get entropy from the kernel. This can work - * even if /dev/urandom is inaccessible for some reason (e.g., we're - * running in a chroot). */ - int mib[] = { CTL_KERN, KERN_RANDOM, RANDOM_UUID }; - unsigned char buf[ADD_ENTROPY]; - size_t len, n; - unsigned i; - int any_set; - - memset(buf, 0, sizeof(buf)); - - for (len = 0; len < sizeof(buf); len += n) { - n = sizeof(buf) - len; - - if (0 != sysctl(mib, 3, &buf[len], &n, NULL, 0)) - return -1; - } - /* make sure that the buffer actually got set. */ - for (i=0,any_set=0; i<sizeof(buf); ++i) { - any_set |= buf[i]; - } - if (!any_set) - return -1; - - arc4_addrandom(buf, sizeof(buf)); - evutil_memclear_(buf, sizeof(buf)); - arc4_seeded_ok = 1; - return 0; -} -#endif - -#if _EVENT_HAVE_DECL_CTL_KERN && _EVENT_HAVE_DECL_KERN_ARND -#define TRY_SEED_SYSCTL_BSD -static int -arc4_seed_sysctl_bsd(void) -{ - /* Based on code from William Ahern and from OpenBSD, this function - * tries to use the KERN_ARND syscall to get entropy from the kernel. - * This can work even if /dev/urandom is inaccessible for some reason - * (e.g., we're running in a chroot). */ - int mib[] = { CTL_KERN, KERN_ARND }; - unsigned char buf[ADD_ENTROPY]; - size_t len, n; - int i, any_set; - - memset(buf, 0, sizeof(buf)); - - len = sizeof(buf); - if (sysctl(mib, 2, buf, &len, NULL, 0) == -1) { - for (len = 0; len < sizeof(buf); len += sizeof(unsigned)) { - n = sizeof(unsigned); - if (n + len > sizeof(buf)) - n = len - sizeof(buf); - if (sysctl(mib, 2, &buf[len], &n, NULL, 0) == -1) - return -1; - } - } - /* make sure that the buffer actually got set. */ - for (i=any_set=0; i<sizeof(buf); ++i) { - any_set |= buf[i]; - } - if (!any_set) - return -1; - - arc4_addrandom(buf, sizeof(buf)); - evutil_memclear_(buf, sizeof(buf)); - arc4_seeded_ok = 1; - return 0; -} -#endif -#endif /* defined(_EVENT_HAVE_SYS_SYSCTL_H) */ - -#ifdef __linux__ -#define TRY_SEED_PROC_SYS_KERNEL_RANDOM_UUID -static int -arc4_seed_proc_sys_kernel_random_uuid(void) -{ - /* Occasionally, somebody will make /proc/sys accessible in a chroot, - * but not /dev/urandom. Let's try /proc/sys/kernel/random/uuid. - * Its format is stupid, so we need to decode it from hex. - */ - int fd; - char buf[128]; - unsigned char entropy[64]; - int bytes, n, i, nybbles; - for (bytes = 0; bytes<ADD_ENTROPY; ) { - fd = evutil_open_closeonexec("/proc/sys/kernel/random/uuid", O_RDONLY, 0); - if (fd < 0) - return -1; - n = read(fd, buf, sizeof(buf)); - close(fd); - if (n<=0) - return -1; - memset(entropy, 0, sizeof(entropy)); - for (i=nybbles=0; i<n; ++i) { - if (EVUTIL_ISXDIGIT(buf[i])) { - int nyb = evutil_hex_char_to_int(buf[i]); - if (nybbles & 1) { - entropy[nybbles/2] |= nyb; - } else { - entropy[nybbles/2] |= nyb<<4; - } - ++nybbles; - } - } - if (nybbles < 2) - return -1; - arc4_addrandom(entropy, nybbles/2); - bytes += nybbles/2; - } - evutil_memclear_(entropy, sizeof(entropy)); - evutil_memclear_(buf, sizeof(buf)); - arc4_seeded_ok = 1; - return 0; -} -#endif - -#ifndef WIN32 -#define TRY_SEED_URANDOM -static char *arc4random_urandom_filename = NULL; - -static int arc4_seed_urandom_helper_(const char *fname) -{ - unsigned char buf[ADD_ENTROPY]; - int fd; - size_t n; - - fd = evutil_open_closeonexec(fname, O_RDONLY, 0); - if (fd<0) - return -1; - n = read_all(fd, buf, sizeof(buf)); - close(fd); - if (n != sizeof(buf)) - return -1; - arc4_addrandom(buf, sizeof(buf)); - evutil_memclear_(buf, sizeof(buf)); - arc4_seeded_ok = 1; - return 0; -} - -static int -arc4_seed_urandom(void) -{ - /* This is adapted from Tor's crypto_seed_rng() */ - static const char *filenames[] = { - "/dev/srandom", "/dev/urandom", "/dev/random", NULL - }; - int i; - if (arc4random_urandom_filename) - return arc4_seed_urandom_helper_(arc4random_urandom_filename); - - for (i = 0; filenames[i]; ++i) { - if (arc4_seed_urandom_helper_(filenames[i]) == 0) { - return 0; - } - } - - return -1; -} -#endif - -static int -arc4_seed(void) -{ - int ok = 0; - /* We try every method that might work, and don't give up even if one - * does seem to work. There's no real harm in over-seeding, and if - * one of these sources turns out to be broken, that would be bad. */ -#ifdef TRY_SEED_WIN32 - if (0 == arc4_seed_win32()) - ok = 1; -#endif -#ifdef TRY_SEED_URANDOM - if (0 == arc4_seed_urandom()) - ok = 1; -#endif -#ifdef TRY_SEED_PROC_SYS_KERNEL_RANDOM_UUID - if (arc4random_urandom_filename == NULL && - 0 == arc4_seed_proc_sys_kernel_random_uuid()) - ok = 1; -#endif -#ifdef TRY_SEED_SYSCTL_LINUX - /* Apparently Linux is deprecating sysctl, and spewing warning - * messages when you try to use it. */ - if (!ok && 0 == arc4_seed_sysctl_linux()) - ok = 1; -#endif -#ifdef TRY_SEED_SYSCTL_BSD - if (0 == arc4_seed_sysctl_bsd()) - ok = 1; -#endif - return ok ? 0 : -1; -} - -static int -arc4_stir(void) -{ - int i; - - if (!rs_initialized) { - arc4_init(); - rs_initialized = 1; - } - - arc4_seed(); - if (!arc4_seeded_ok) - return -1; - - /* - * Discard early keystream, as per recommendations in - * "Weaknesses in the Key Scheduling Algorithm of RC4" by - * Scott Fluhrer, Itsik Mantin, and Adi Shamir. - * http://www.wisdom.weizmann.ac.il/~itsik/RC4/Papers/Rc4_ksa.ps - * - * Ilya Mironov's "(Not So) Random Shuffles of RC4" suggests that - * we drop at least 2*256 bytes, with 12*256 as a conservative - * value. - * - * RFC4345 says to drop 6*256. - * - * At least some versions of this code drop 4*256, in a mistaken - * belief that "words" in the Fluhrer/Mantin/Shamir paper refers - * to processor words. - * - * We add another sect to the cargo cult, and choose 12*256. - */ - for (i = 0; i < 12*256; i++) - (void)arc4_getbyte(); - - arc4_count = BYTES_BEFORE_RESEED; - - return 0; -} - - -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 unsigned char -arc4_getbyte(void) -{ - unsigned char 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 unsigned int -arc4_getword(void) -{ - unsigned int val; - - val = arc4_getbyte() << 24; - val |= arc4_getbyte() << 16; - val |= arc4_getbyte() << 8; - val |= arc4_getbyte(); - - return val; -} - -#ifndef ARC4RANDOM_NOSTIR -ARC4RANDOM_EXPORT int -arc4random_stir(void) -{ - int val; - //_ARC4_LOCK(); - val = arc4_stir(); - //_ARC4_UNLOCK(); - return val; -} -#endif - -#ifndef ARC4RANDOM_NOADDRANDOM -ARC4RANDOM_EXPORT void -arc4random_addrandom(const unsigned char *dat, int datlen) -{ - int j; - //_ARC4_LOCK(); - if (!rs_initialized) - arc4_stir(); - for (j = 0; j < datlen; j += 256) { - /* arc4_addrandom() ignores all but the first 256 bytes of - * its input. We want to make sure to look at ALL the - * data in 'dat', just in case the user is doing something - * crazy like passing us all the files in /var/log. */ - arc4_addrandom(dat + j, datlen - j); - } - //_ARC4_UNLOCK(); -} -#endif - -#ifndef ARC4RANDOM_NORANDOM -ARC4RANDOM_EXPORT ARC4RANDOM_UINT32 -arc4random(void) -{ - ARC4RANDOM_UINT32 val; - //_ARC4_LOCK(); - arc4_count -= 4; - arc4_stir_if_needed(); - val = arc4_getword(); - //_ARC4_UNLOCK(); - return val; -} -#endif - -ARC4RANDOM_EXPORT void -arc4random_buf(void *_buf, size_t n) -{ - unsigned char *buf = _buf; - //_ARC4_LOCK(); - arc4_stir_if_needed(); - while (n--) { - if (--arc4_count <= 0) - arc4_stir(); - buf[n] = arc4_getbyte(); - } - //_ARC4_UNLOCK(); -} - -#ifndef ARC4RANDOM_NOUNIFORM -/* - * 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. - */ -ARC4RANDOM_EXPORT unsigned int -arc4random_uniform(unsigned int upper_bound) -{ - ARC4RANDOM_UINT32 r, min; - - if (upper_bound < 2) - return 0; - -#if (UINT_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; -} -#endif |