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
  48   while (Length > 0) {
  49     // Use RngLib to get random number
  50     Ret = GetRandomNumber64 (&TempRand);
  51
  52     if (!Ret) {
  53       return Ret;
  54     }
  55     if (Length >= sizeof (TempRand)) {
  56       *((UINT64*) RandBuffer) = TempRand;
  57       RandBuffer += sizeof (UINT64);
  58       Length -= sizeof (TempRand);
  59     }
  60     else {
  61       CopyMem (RandBuffer, &TempRand, Length);
  62       Length = 0;
  63     }
  64   }
  65
  66   return Ret;
  67 }
  68
  69 /*
  70  * Add random bytes to the pool to acquire requested amount of entropy
  71  *
  72  * This function is platform specific and tries to acquire the requested
  73  * amount of entropy by polling platform specific entropy sources.
  74  *
  75  * This is OpenSSL required interface.
  76  */
  77 size_t
  78 rand_pool_acquire_entropy (
  79   RAND_POOL *pool
  80   )
  81 {
  82   BOOLEAN        Ret;
  83   size_t         Bytes_needed;
  84   unsigned char *Buffer;
  85
  86   Bytes_needed = rand_pool_bytes_needed (pool, 1 /*entropy_factor*/);
  87   if (Bytes_needed > 0) {
  88     Buffer = rand_pool_add_begin (pool, Bytes_needed);
  89
  90     if (Buffer != NULL) {
  91       Ret = RandGetBytes (Bytes_needed, Buffer);
  92       if (FALSE == Ret) {
  93         rand_pool_add_end (pool, 0, 0);
  94       }
  95       else {
  96         rand_pool_add_end (pool, Bytes_needed, 8 * Bytes_needed);
  97       }
  98     }
  99   }
 100
 101   return rand_pool_entropy_available (pool);
 102 }
 103
 104 /*
 105  * Implementation for UEFI
 106  *
 107  * This is OpenSSL required interface.
 108  */
 109 int
 110 rand_pool_add_nonce_data (
 111   RAND_POOL *pool
 112   )
 113 {
 114   UINT8 data[16];
 115   RandGetBytes (sizeof(data), data);
 116
 117   return rand_pool_add (pool, (unsigned char*)&data, sizeof(data), 0);
 118 }
 119
 120 /*
 121  * Implementation for UEFI
 122  *
 123  * This is OpenSSL required interface.
 124  */
 125 int
 126 rand_pool_add_additional_data (
 127   RAND_POOL *pool
 128   )
 129 {
 130   UINT8 data[16];
 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 }