| Index: libsrtp/crypto/rng/rand_source.c
|
| ===================================================================
|
| --- libsrtp/crypto/rng/rand_source.c (revision 0)
|
| +++ libsrtp/crypto/rng/rand_source.c (revision 0)
|
| @@ -0,0 +1,158 @@
|
| +/*
|
| + * rand_source.c
|
| + *
|
| + * implements a random source based on /dev/random
|
| + *
|
| + * David A. McGrew
|
| + * Cisco Systems, Inc.
|
| + */
|
| +/*
|
| + *
|
| + * Copyright(c) 2001-2006 Cisco Systems, Inc.
|
| + * All rights reserved.
|
| + *
|
| + * 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 Cisco Systems, Inc. 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
|
| + * COPYRIGHT HOLDERS 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.
|
| + *
|
| + */
|
| +
|
| +#include "config.h"
|
| +
|
| +#ifdef DEV_URANDOM
|
| +# include <fcntl.h> /* for open() */
|
| +# include <unistd.h> /* for close() */
|
| +#elif defined(HAVE_RAND_S)
|
| +# define _CRT_RAND_S
|
| +# include <stdlib.h>
|
| +#else
|
| +# include <stdio.h>
|
| +#endif
|
| +
|
| +#include "rand_source.h"
|
| +
|
| +
|
| +/*
|
| + * global dev_rand_fdes is file descriptor for /dev/random
|
| + *
|
| + * This variable is also used to indicate that the random source has
|
| + * been initialized. When this variable is set to the value of the
|
| + * #define RAND_SOURCE_NOT_READY, it indicates that the random source
|
| + * is not ready to be used. The value of the #define
|
| + * RAND_SOURCE_READY is for use whenever that variable is used as an
|
| + * indicator of the state of the random source, but not as a file
|
| + * descriptor.
|
| + */
|
| +
|
| +#define RAND_SOURCE_NOT_READY (-1)
|
| +#define RAND_SOURCE_READY (17)
|
| +
|
| +static int dev_random_fdes = RAND_SOURCE_NOT_READY;
|
| +
|
| +
|
| +err_status_t
|
| +rand_source_init(void) {
|
| + if (dev_random_fdes >= 0) {
|
| + /* already open */
|
| + return err_status_ok;
|
| + }
|
| +#ifdef DEV_URANDOM
|
| + /* open random source for reading */
|
| + dev_random_fdes = open(DEV_URANDOM, O_RDONLY);
|
| + if (dev_random_fdes < 0)
|
| + return err_status_init_fail;
|
| +#elif defined(HAVE_RAND_S)
|
| + dev_random_fdes = RAND_SOURCE_READY;
|
| +#else
|
| + /* no random source available; let the user know */
|
| + fprintf(stderr, "WARNING: no real random source present!\n");
|
| + dev_random_fdes = RAND_SOURCE_READY;
|
| +#endif
|
| + return err_status_ok;
|
| +}
|
| +
|
| +err_status_t
|
| +rand_source_get_octet_string(void *dest, uint32_t len) {
|
| +
|
| + /*
|
| + * read len octets from /dev/random to dest, and
|
| + * check return value to make sure enough octets were
|
| + * written
|
| + */
|
| +#ifdef DEV_URANDOM
|
| + uint8_t *dst = (uint8_t *)dest;
|
| + while (len)
|
| + {
|
| + ssize_t num_read = read(dev_random_fdes, dst, len);
|
| + if (num_read <= 0 || num_read > len)
|
| + return err_status_fail;
|
| + len -= num_read;
|
| + dst += num_read;
|
| + }
|
| +#elif defined(HAVE_RAND_S)
|
| + uint8_t *dst = (uint8_t *)dest;
|
| + while (len)
|
| + {
|
| + unsigned int val;
|
| + errno_t err = rand_s(&val);
|
| +
|
| + if (err != 0)
|
| + return err_status_fail;
|
| +
|
| + *dst++ = val & 0xff;
|
| + len--;
|
| + }
|
| +#else
|
| + /* Generic C-library (rand()) version */
|
| + /* This is a random source of last resort */
|
| + uint8_t *dst = (uint8_t *)dest;
|
| + while (len)
|
| + {
|
| + int val = rand();
|
| + /* rand() returns 0-32767 (ugh) */
|
| + /* Is this a good enough way to get random bytes?
|
| + It is if it passes FIPS-140... */
|
| + *dst++ = val & 0xff;
|
| + len--;
|
| + }
|
| +#endif
|
| + return err_status_ok;
|
| +}
|
| +
|
| +err_status_t
|
| +rand_source_deinit(void) {
|
| + if (dev_random_fdes < 0)
|
| + return err_status_dealloc_fail; /* well, we haven't really failed, *
|
| + * but there is something wrong */
|
| +#ifdef DEV_URANDOM
|
| + close(dev_random_fdes);
|
| +#endif
|
| + dev_random_fdes = RAND_SOURCE_NOT_READY;
|
| +
|
| + return err_status_ok;
|
| +}
|
|
|
| Property changes on: libsrtp/crypto/rng/rand_source.c
|
| ___________________________________________________________________
|
| Added: svn:eol-style
|
| + LF
|
|
|
|
|