CryptoPkg/Library/OpensslLib/rand_pool.c

   1 /** @file
   2   OpenSSL_1_1_1b doesn't implement rand_pool_* functions for UEFI.
   3   The file implement these functions.
   4
   5   Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7
   8 **/
   9
  10 #include "crypto/rand.h"
  11 #include <openssl/aes.h>
  12
  13 #include <Uefi.h>
  14 #include <Library/RngLib.h>
  15
  16 /**
  17   Calls RandomNumber64 to fill
  18   a buffer of arbitrary size with random bytes.
  19   This is a shim layer to RngLib.
  20
  21   @param[in]   Length        Size of the buffer, in bytes,  to fill with.
  22   @param[out]  RandBuffer    Pointer to the buffer to store the random result.
  23
  24   @retval TRUE        Random bytes generation succeeded.
  25   @retval FALSE       Failed to request random bytes.
  26
  27 **/
  28 STATIC
  29 BOOLEAN
  30 EFIAPI
  31 RandGetBytes (
  32   IN UINTN   Length,
  33   OUT UINT8  *RandBuffer
  34   )
  35 {
  36   BOOLEAN  Ret;
  37   UINT64   TempRand;
  38
  39   Ret = FALSE;
  40
  41   if (RandBuffer == NULL) {
  42     DEBUG ((DEBUG_ERROR, "[OPENSSL_RAND_POOL] NULL RandBuffer. No random numbers are generated and your system is not secure\n"));
  43     ASSERT (RandBuffer != NULL); // Since we can't generate random numbers, we should assert. Otherwise we will just blow up later.
  44     return Ret;
  45   }
  46
  47   while (Length > 0) {
  48     // Use RngLib to get random number
  49     Ret = GetRandomNumber64 (&TempRand);
  50
  51     if (!Ret) {
  52       return Ret;
  53     }
  54
  55     if (Length >= sizeof (TempRand)) {
  56       *((UINT64 *)RandBuffer) = TempRand;
  57       RandBuffer             += sizeof (UINT64);
  58       Length                 -= sizeof (TempRand);
  59     } else {
  60       CopyMem (RandBuffer, &TempRand, Length);
  61       Length = 0;
  62     }
  63   }
  64
  65   return Ret;
  66 }
  67
  68 /*
  69  * Add random bytes to the pool to acquire requested amount of entropy
  70  *
  71  * This function is platform specific and tries to acquire the requested
  72  * amount of entropy by polling platform specific entropy sources.
  73  *
  74  * This is OpenSSL required interface.
  75  */
  76 size_t
  77 rand_pool_acquire_entropy (
  78   RAND_POOL  *pool
  79   )
  80 {
  81   BOOLEAN        Ret;
  82   size_t         Bytes_needed;
  83   unsigned char  *Buffer;
  84
  85   Bytes_needed = rand_pool_bytes_needed (pool, 1 /*entropy_factor*/);
  86   if (Bytes_needed > 0) {
  87     Buffer = rand_pool_add_begin (pool, Bytes_needed);
  88
  89     if (Buffer != NULL) {
  90       Ret = RandGetBytes (Bytes_needed, Buffer);
  91       if (FALSE == Ret) {
  92         rand_pool_add_end (pool, 0, 0);
  93       } else {
  94         rand_pool_add_end (pool, Bytes_needed, 8 * Bytes_needed);
  95       }
  96     }
  97   }
  98
  99   return rand_pool_entropy_available (pool);
 100 }
 101
 102 /*
 103  * Implementation for UEFI
 104  *
 105  * This is OpenSSL required interface.
 106  */
 107 int
 108 rand_pool_add_nonce_data (
 109   RAND_POOL  *pool
 110   )
 111 {
 112   UINT8  data[16];
 113
 114   RandGetBytes (sizeof (data), data);
 115
 116   return rand_pool_add (pool, (unsigned char *)&data, sizeof (data), 0);
 117 }
 118
 119 /*
 120  * Implementation for UEFI
 121  *
 122  * This is OpenSSL required interface.
 123  */
 124 int
 125 rand_pool_add_additional_data (
 126   RAND_POOL  *pool
 127   )
 128 {
 129   UINT8  data[16];
 130
 131   RandGetBytes (sizeof (data), data);
 132
 133   return rand_pool_add (pool, (unsigned char *)&data, sizeof (data), 0);
 134 }
 135
 136 /*
 137  * Dummy Implementation for UEFI
 138  *
 139  * This is OpenSSL required interface.
 140  */
 141 int
 142 rand_pool_init (
 143   VOID
 144   )
 145 {
 146   return 1;
 147 }
 148
 149 /*
 150  * Dummy Implementation for UEFI
 151  *
 152  * This is OpenSSL required interface.
 153  */
 154 VOID
 155 rand_pool_cleanup (
 156   VOID
 157   )
 158 {
 159 }
 160
 161 /*
 162  * Dummy Implementation for UEFI
 163  *
 164  * This is OpenSSL required interface.
 165  */
 166 VOID
 167 rand_pool_keep_random_devices_open (
 168   int  keep
 169   )
 170 {
 171 }