1d9072f026
lib/krb5/crypto.c was a large, monolithic block of code which made it very difficult to selectively enable and disable particular alogrithms. Reorganise crypto.c into individual files for each encryption and salt time, and place the structures which tie everything together into their own file (crypto-algs.c) Add a non-installed library (librfc3961) and test program (test_rfc3961) which builds a minimal rfc3961 crypto library, and checks that it is usable.
110 lines
3.4 KiB
C
110 lines
3.4 KiB
C
/*
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* Copyright (c) 1997 - 2008 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "krb5_locl.h"
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#define ENTROPY_NEEDED 128
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static HEIMDAL_MUTEX crypto_mutex = HEIMDAL_MUTEX_INITIALIZER;
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static int
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seed_something(void)
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{
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char buf[1024], seedfile[256];
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/* If there is a seed file, load it. But such a file cannot be trusted,
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so use 0 for the entropy estimate */
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if (RAND_file_name(seedfile, sizeof(seedfile))) {
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int fd;
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fd = open(seedfile, O_RDONLY | O_BINARY | O_CLOEXEC);
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if (fd >= 0) {
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ssize_t ret;
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rk_cloexec(fd);
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ret = read(fd, buf, sizeof(buf));
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if (ret > 0)
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RAND_add(buf, ret, 0.0);
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close(fd);
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} else
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seedfile[0] = '\0';
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} else
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seedfile[0] = '\0';
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/* Calling RAND_status() will try to use /dev/urandom if it exists so
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we do not have to deal with it. */
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if (RAND_status() != 1) {
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#ifndef _WIN32
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krb5_context context;
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const char *p;
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/* Try using egd */
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if (!krb5_init_context(&context)) {
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p = krb5_config_get_string(context, NULL, "libdefaults",
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"egd_socket", NULL);
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if (p != NULL)
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RAND_egd_bytes(p, ENTROPY_NEEDED);
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krb5_free_context(context);
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}
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#else
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/* TODO: Once a Windows CryptoAPI RAND method is defined, we
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can use that and failover to another method. */
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#endif
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}
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if (RAND_status() == 1) {
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/* Update the seed file */
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if (seedfile[0])
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RAND_write_file(seedfile);
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return 0;
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} else
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return -1;
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}
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KRB5_LIB_FUNCTION void KRB5_LIB_CALL
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krb5_generate_random_block(void *buf, size_t len)
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{
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static int rng_initialized = 0;
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HEIMDAL_MUTEX_lock(&crypto_mutex);
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if (!rng_initialized) {
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if (seed_something())
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krb5_abortx(NULL, "Fatal: could not seed the "
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"random number generator");
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rng_initialized = 1;
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}
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HEIMDAL_MUTEX_unlock(&crypto_mutex);
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if (RAND_bytes(buf, len) <= 0)
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krb5_abortx(NULL, "Failed to generate random block");
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}
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