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 |