Diff: include/polarssl/entropy.h

Revision:

0:137634ff4186

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/polarssl/entropy.h	Thu Jun 11 03:27:03 2015 +0000
@@ -0,0 +1,244 @@
+/**
+ * \file entropy.h
+ *
+ * \brief Entropy accumulator implementation
+ *
+ *  Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef POLARSSL_ENTROPY_H
+#define POLARSSL_ENTROPY_H
+
+#if !defined(POLARSSL_CONFIG_FILE)
+#include "config.h"
+#else
+#include POLARSSL_CONFIG_FILE
+#endif
+
+#include <stddef.h>
+
+#if defined(POLARSSL_SHA512_C) && !defined(POLARSSL_ENTROPY_FORCE_SHA256)
+#include "sha512.h"
+#define POLARSSL_ENTROPY_SHA512_ACCUMULATOR
+#else
+#if defined(POLARSSL_SHA256_C)
+#define POLARSSL_ENTROPY_SHA256_ACCUMULATOR
+#include "sha256.h"
+#endif
+#endif
+
+#if defined(POLARSSL_THREADING_C)
+#include "threading.h"
+#endif
+
+#if defined(POLARSSL_HAVEGE_C)
+#include "havege.h"
+#endif
+
+#define POLARSSL_ERR_ENTROPY_SOURCE_FAILED                 -0x003C  /**< Critical entropy source failure. */
+#define POLARSSL_ERR_ENTROPY_MAX_SOURCES                   -0x003E  /**< No more sources can be added. */
+#define POLARSSL_ERR_ENTROPY_NO_SOURCES_DEFINED            -0x0040  /**< No sources have been added to poll. */
+#define POLARSSL_ERR_ENTROPY_FILE_IO_ERROR                 -0x0058  /**< Read/write error in file. */
+
+/**
+ * \name SECTION: Module settings
+ *
+ * The configuration options you can set for this module are in this section.
+ * Either change them in config.h or define them on the compiler command line.
+ * \{
+ */
+
+#if !defined(ENTROPY_MAX_SOURCES)
+#define ENTROPY_MAX_SOURCES     20      /**< Maximum number of sources supported */
+#endif
+
+#if !defined(ENTROPY_MAX_GATHER)
+#define ENTROPY_MAX_GATHER      128     /**< Maximum amount requested from entropy sources */
+#endif
+
+/* \} name SECTION: Module settings */
+
+#if defined(POLARSSL_ENTROPY_SHA512_ACCUMULATOR)
+#define ENTROPY_BLOCK_SIZE      64      /**< Block size of entropy accumulator (SHA-512) */
+#else
+#define ENTROPY_BLOCK_SIZE      32      /**< Block size of entropy accumulator (SHA-256) */
+#endif
+
+#define ENTROPY_MAX_SEED_SIZE   1024    /**< Maximum size of seed we read from seed file */
+#define ENTROPY_SOURCE_MANUAL   ENTROPY_MAX_SOURCES
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief           Entropy poll callback pointer
+ *
+ * \param data      Callback-specific data pointer
+ * \param output    Data to fill
+ * \param len       Maximum size to provide
+ * \param olen      The actual amount of bytes put into the buffer (Can be 0)
+ *
+ * \return          0 if no critical failures occurred,
+ *                  POLARSSL_ERR_ENTROPY_SOURCE_FAILED otherwise
+ */
+typedef int (*f_source_ptr)(void *data, unsigned char *output, size_t len,
+                            size_t *olen);
+
+/**
+ * \brief           Entropy source state
+ */
+typedef struct
+{
+    f_source_ptr    f_source;   /**< The entropy source callback */
+    void *          p_source;   /**< The callback data pointer */
+    size_t          size;       /**< Amount received */
+    size_t          threshold;  /**< Minimum level required before release */
+}
+source_state;
+
+/**
+ * \brief           Entropy context structure
+ */
+typedef struct
+{
+#if defined(POLARSSL_ENTROPY_SHA512_ACCUMULATOR)
+    sha512_context  accumulator;
+#else
+    sha256_context  accumulator;
+#endif
+    int             source_count;
+    source_state    source[ENTROPY_MAX_SOURCES];
+#if defined(POLARSSL_HAVEGE_C)
+    havege_state    havege_data;
+#endif
+#if defined(POLARSSL_THREADING_C)
+    threading_mutex_t mutex;    /*!< mutex                  */
+#endif
+}
+entropy_context;
+
+/**
+ * \brief           Initialize the context
+ *
+ * \param ctx       Entropy context to initialize
+ */
+void entropy_init( entropy_context *ctx );
+
+/**
+ * \brief           Free the data in the context
+ *
+ * \param ctx       Entropy context to free
+ */
+void entropy_free( entropy_context *ctx );
+
+/**
+ * \brief           Adds an entropy source to poll
+ *                  (Thread-safe if POLARSSL_THREADING_C is enabled)
+ *
+ * \param ctx       Entropy context
+ * \param f_source  Entropy function
+ * \param p_source  Function data
+ * \param threshold Minimum required from source before entropy is released
+ *                  ( with entropy_func() )
+ *
+ * \return          0 if successful or POLARSSL_ERR_ENTROPY_MAX_SOURCES
+ */
+int entropy_add_source( entropy_context *ctx,
+                        f_source_ptr f_source, void *p_source,
+                        size_t threshold );
+
+/**
+ * \brief           Trigger an extra gather poll for the accumulator
+ *                  (Thread-safe if POLARSSL_THREADING_C is enabled)
+ *
+ * \param ctx       Entropy context
+ *
+ * \return          0 if successful, or POLARSSL_ERR_ENTROPY_SOURCE_FAILED
+ */
+int entropy_gather( entropy_context *ctx );
+
+/**
+ * \brief           Retrieve entropy from the accumulator
+ *                  (Maximum length: ENTROPY_BLOCK_SIZE)
+ *                  (Thread-safe if POLARSSL_THREADING_C is enabled)
+ *
+ * \param data      Entropy context
+ * \param output    Buffer to fill
+ * \param len       Number of bytes desired, must be at most ENTROPY_BLOCK_SIZE
+ *
+ * \return          0 if successful, or POLARSSL_ERR_ENTROPY_SOURCE_FAILED
+ */
+int entropy_func( void *data, unsigned char *output, size_t len );
+
+/**
+ * \brief           Add data to the accumulator manually
+ *                  (Thread-safe if POLARSSL_THREADING_C is enabled)
+ *
+ * \param ctx       Entropy context
+ * \param data      Data to add
+ * \param len       Length of data
+ *
+ * \return          0 if successful
+ */
+int entropy_update_manual( entropy_context *ctx,
+                           const unsigned char *data, size_t len );
+
+#if defined(POLARSSL_FS_IO)
+/**
+ * \brief               Write a seed file
+ *
+ * \param ctx           Entropy context
+ * \param path          Name of the file
+ *
+ * \return              0 if successful,
+ *                      POLARSSL_ERR_ENTROPY_FILE_IO_ERROR on file error, or
+ *                      POLARSSL_ERR_ENTROPY_SOURCE_FAILED
+ */
+int entropy_write_seed_file( entropy_context *ctx, const char *path );
+
+/**
+ * \brief               Read and update a seed file. Seed is added to this
+ *                      instance. No more than ENTROPY_MAX_SEED_SIZE bytes are
+ *                      read from the seed file. The rest is ignored.
+ *
+ * \param ctx           Entropy context
+ * \param path          Name of the file
+ *
+ * \return              0 if successful,
+ *                      POLARSSL_ERR_ENTROPY_FILE_IO_ERROR on file error,
+ *                      POLARSSL_ERR_ENTROPY_SOURCE_FAILED
+ */
+int entropy_update_seed_file( entropy_context *ctx, const char *path );
+#endif /* POLARSSL_FS_IO */
+
+#if defined(POLARSSL_SELF_TEST)
+/**
+ * \brief          Checkup routine
+ *
+ * \return         0 if successful, or 1 if a test failed
+ */
+int entropy_self_test( int verbose );
+#endif /* POLARSSL_SELF_TEST */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* entropy.h */
+