This file is indexed.

/usr/include/polarssl/entropy.h is in libpolarssl-dev 1.3.4-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
/**
 * \file entropy.h
 *
 * \brief Entropy accumulator implementation
 *
 *  Copyright (C) 2006-2013, Brainspark B.V.
 *
 *  This file is part of PolarSSL (http://www.polarssl.org)
 *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
 *
 *  All rights reserved.
 *
 *  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

#include <string.h>

#include "config.h"

#if defined(POLARSSL_SHA512_C)
#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. */

#if !defined(POLARSSL_CONFIG_OPTIONS)
#define ENTROPY_MAX_SOURCES     20      /**< Maximum number of sources supported */
#define ENTROPY_MAX_GATHER      128     /**< Maximum amount requested from entropy sources */
#endif /* !POLARSSL_CONFIG_OPTIONS  */

#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_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
 *
 * \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
 *
 * \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 (Max ENTROPY_BLOCK_SIZE)
 *                  (Thread-safe if POLARSSL_THREADING_C is enabled)
 *
 * \param data      Entropy context
 * \param output    Buffer to fill
 * \param len       Length of buffer
 *
 * \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
 * 
 * \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 );

#ifdef __cplusplus
}
#endif

#endif /* entropy.h */