CryptRandTsc.c

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#include "InternalCryptLib.h"
#include <openssl/rand.h>
#include <openssl/evp.h>
#include <Library/PrintLib.h>
 
BOOLEAN
EFIAPI
RandomSeed (
  IN  CONST  UINT8  *Seed  OPTIONAL,
  IN  UINTN         SeedSize
  )
{
  CHAR8  DefaultSeed[128];
 
  if (SeedSize > INT_MAX) {
    return FALSE;
  }
 
  //
  // Seed the pseudorandom number generator with user-supplied value.
  // NOTE: A cryptographic PRNG must be seeded with unpredictable data.
  //
  if (Seed != NULL) {
    RAND_seed (Seed, (UINT32)SeedSize);
  } else {
    //
    // Retrieve current time.
    //
    AsciiSPrint (
      DefaultSeed,
      sizeof (DefaultSeed),
      "UEFI Crypto Library default seed (%ld)",
      AsmReadTsc ()
      );
 
    RAND_seed (DefaultSeed, sizeof (DefaultSeed));
  }
 
  if (RAND_status () == 1) {
    return TRUE;
  }
 
  return FALSE;
}
 
BOOLEAN
EFIAPI
RandomBytes (
  OUT  UINT8  *Output,
  IN   UINTN  Size
  )
{
  //
  // Check input parameters.
  //
  if ((Output == NULL) || (Size > INT_MAX)) {
    return FALSE;
  }
 
  //
  // Generate random data.
  //
  if (RAND_bytes (Output, (UINT32)Size) != 1) {
    return FALSE;
  }
 
  return TRUE;
}