release/src/router/dropbear/ltc_prng.c

   1 /* Copied from libtomcrypt/src/prngs/sprng.c and modified to
   2  * use Dropbear's genrandom(). */
   3
   4 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
   5  *
   6  * LibTomCrypt is a library that provides various cryptographic
   7  * algorithms in a highly modular and flexible manner.
   8  *
   9  * The library is free for all purposes without any express
  10  * guarantee it works.
  11  *
  12  * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
  13  */
  14 #include "options.h"
  15 #include "includes.h"
  16 #include "dbrandom.h"
  17 #include "ltc_prng.h"
  18
  19 /**
  20    @file sprng.c
  21    Secure PRNG, Tom St Denis
  22 */
  23
  24 /* A secure PRNG using the RNG functions.  Basically this is a
  25  * wrapper that allows you to use a secure RNG as a PRNG
  26  * in the various other functions.
  27  */
  28
  29 #ifdef DROPBEAR_LTC_PRNG
  30
  31 /**
  32   Start the PRNG
  33   @param prng     [out] The PRNG state to initialize
  34   @return CRYPT_OK if successful
  35 */
  36 int dropbear_prng_start(prng_state* UNUSED(prng))
  37 {
  38    return CRYPT_OK;
  39 }
  40
  41 /**
  42   Add entropy to the PRNG state
  43   @param in       The data to add
  44   @param inlen    Length of the data to add
  45   @param prng     PRNG state to update
  46   @return CRYPT_OK if successful
  47 */
  48 int dropbear_prng_add_entropy(const unsigned char* UNUSED(in), unsigned long UNUSED(inlen), prng_state* UNUSED(prng))
  49 {
  50    return CRYPT_OK;
  51 }
  52
  53 /**
  54   Make the PRNG ready to read from
  55   @param prng   The PRNG to make active
  56   @return CRYPT_OK if successful
  57 */
  58 int dropbear_prng_ready(prng_state* UNUSED(prng))
  59 {
  60    return CRYPT_OK;
  61 }
  62
  63 /**
  64   Read from the PRNG
  65   @param out      Destination
  66   @param outlen   Length of output
  67   @param prng     The active PRNG to read from
  68   @return Number of octets read
  69 */
  70 unsigned long dropbear_prng_read(unsigned char* out, unsigned long outlen, prng_state* UNUSED(prng))
  71 {
  72    LTC_ARGCHK(out != NULL);
  73    genrandom(out, outlen);
  74    return outlen;
  75 }
  76
  77 /**
  78   Terminate the PRNG
  79   @param prng   The PRNG to terminate
  80   @return CRYPT_OK if successful
  81 */
  82 int dropbear_prng_done(prng_state* UNUSED(prng))
  83 {
  84    return CRYPT_OK;
  85 }
  86
  87 /**
  88   Export the PRNG state
  89   @param out       [out] Destination
  90   @param outlen    [in/out] Max size and resulting size of the state
  91   @param prng      The PRNG to export
  92   @return CRYPT_OK if successful
  93 */
  94 int dropbear_prng_export(unsigned char* UNUSED(out), unsigned long* outlen, prng_state* UNUSED(prng))
  95 {
  96    LTC_ARGCHK(outlen != NULL);
  97
  98    *outlen = 0;
  99    return CRYPT_OK;
 100 }
 101
 102 /**
 103   Import a PRNG state
 104   @param in       The PRNG state
 105   @param inlen    Size of the state
 106   @param prng     The PRNG to import
 107   @return CRYPT_OK if successful
 108 */
 109 int dropbear_prng_import(const unsigned char* UNUSED(in), unsigned long UNUSED(inlen), prng_state* UNUSED(prng))
 110 {
 111    return CRYPT_OK;
 112 }
 113
 114 /**
 115   PRNG self-test
 116   @return CRYPT_OK if successful, CRYPT_NOP if self-testing has been disabled
 117 */
 118 int dropbear_prng_test(void)
 119 {
 120    return CRYPT_OK;
 121 }
 122
 123 const struct ltc_prng_descriptor dropbear_prng_desc =
 124 {
 125     "dropbear_prng", 0,
 126     dropbear_prng_start,
 127     dropbear_prng_add_entropy,
 128     dropbear_prng_ready,
 129     dropbear_prng_read,
 130     dropbear_prng_done,
 131     dropbear_prng_export,
 132     dropbear_prng_import,
 133     dropbear_prng_test
 134 };
 135
 136
 137 #endif /* DROPBEAR_LTC_PRNG */