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Diffstat (limited to '3rdParty/Unbound/src/src/util/random.c')
-rw-r--r-- | 3rdParty/Unbound/src/src/util/random.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/3rdParty/Unbound/src/src/util/random.c b/3rdParty/Unbound/src/src/util/random.c new file mode 100644 index 0000000..1458104 --- /dev/null +++ b/3rdParty/Unbound/src/src/util/random.c @@ -0,0 +1,198 @@ +/* + * util/random.c - thread safe random generator, which is reasonably secure. + * + * Copyright (c) 2007, NLnet Labs. All rights reserved. + * + * This software is open source. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of the NLNET LABS nor the names of its contributors may + * be used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/** + * \file + * Thread safe random functions. Similar to arc4random() with an explicit + * initialisation routine. + * + * The code in this file is based on arc4random from + * openssh-4.0p1/openbsd-compat/bsd-arc4random.c + * That code is also BSD licensed. Here is their statement: + * + * 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. + */ +#include "config.h" +#include "util/random.h" +#include "util/log.h" +#include <openssl/rand.h> +#include <openssl/rc4.h> +#include <openssl/err.h> + +/** + * Struct with per-thread random state. + * Keeps SSL types away from the header file. + */ +struct ub_randstate { + /** key used for arc4random generation */ + RC4_KEY rc4; + /** keeps track of key usage */ + int rc4_ready; +}; + +/** Size of key to use */ +#define SEED_SIZE 20 + +/** + * Max random value. Similar to RAND_MAX, but more portable + * (mingw uses only 15 bits random). + */ +#define MAX_VALUE 0x7fffffff + +/** Number of bytes to reseed after */ +#define REKEY_BYTES (1 << 24) + +/* (re)setup system seed */ +void +ub_systemseed(unsigned int seed) +{ + /* RAND_ is threadsafe, by the way */ + if(!RAND_status()) { + /* try to seed it */ + unsigned char buf[256]; + unsigned int v = seed; + size_t i; + for(i=0; i<256/sizeof(seed); i++) { + memmove(buf+i*sizeof(seed), &v, sizeof(seed)); + v = v*seed + (unsigned int)i; + } + RAND_seed(buf, 256); + if(!RAND_status()) { + log_err("Random generator has no entropy " + "(error %ld)", ERR_get_error()); + } else { + verbose(VERB_OPS, "openssl has no entropy, " + "seeding with time and pid"); + } + } +} + +/** reseed random generator */ +static void +ub_arc4random_stir(struct ub_randstate* s, struct ub_randstate* from) +{ + unsigned char rand_buf[SEED_SIZE]; + int i; + + memset(&s->rc4, 0, sizeof(s->rc4)); + memset(rand_buf, 0xc, sizeof(rand_buf)); + if (from) { + for(i=0; i<SEED_SIZE; i++) + rand_buf[i] = (unsigned char)ub_random(from); + } else { + if(!RAND_status()) + ub_systemseed((unsigned)getpid()^(unsigned)time(NULL)); + if (RAND_bytes(rand_buf, (int)sizeof(rand_buf)) <= 0) { + /* very unlikely that this happens, since we seeded + * above, if it does; complain and keep going */ + log_err("Couldn't obtain random bytes (error %ld)", + ERR_get_error()); + s->rc4_ready = 256; + return; + } + } + RC4_set_key(&s->rc4, SEED_SIZE, rand_buf); + + /* + * 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 += sizeof(rand_buf)) + RC4(&s->rc4, sizeof(rand_buf), rand_buf, rand_buf); + + memset(rand_buf, 0, sizeof(rand_buf)); + + s->rc4_ready = REKEY_BYTES; +} + +struct ub_randstate* +ub_initstate(unsigned int seed, struct ub_randstate* from) +{ + struct ub_randstate* s = (struct ub_randstate*)calloc(1, sizeof(*s)); + if(!s) { + log_err("malloc failure in random init"); + return NULL; + } + ub_systemseed(seed); + ub_arc4random_stir(s, from); + return s; +} + +long int +ub_random(struct ub_randstate* s) +{ + unsigned int r = 0; + if (s->rc4_ready <= 0) { + ub_arc4random_stir(s, NULL); + } + + RC4(&s->rc4, sizeof(r), + (unsigned char *)&r, (unsigned char *)&r); + s->rc4_ready -= sizeof(r); + return (long int)((r) % (((unsigned)MAX_VALUE + 1))); +} + +long int +ub_random_max(struct ub_randstate* state, long int x) +{ + /* make sure we fetch in a range that is divisible by x. ignore + * values from d .. MAX_VALUE, instead draw a new number */ + long int d = MAX_VALUE - (MAX_VALUE % x); /* d is divisible by x */ + long int v = ub_random(state); + while(d <= v) + v = ub_random(state); + return (v % x); +} + +void +ub_randfree(struct ub_randstate* s) +{ + if(s) + free(s); + /* user app must do RAND_cleanup(); */ +} |