Use current time value as default random seed in BaseCryptLib.

[mirror_edk2.git] / CryptoPkg / Library / BaseCryptLib / Rand / CryptRandTsc.c

diff --git a/CryptoPkg/Library/BaseCryptLib/Rand/CryptRandTsc.c b/CryptoPkg/Library/BaseCryptLib/Rand/CryptRandTsc.c
new file mode 100644 (file)
index 0000000..bb8783d
--- /dev/null
+++ b/CryptoPkg/Library/BaseCryptLib/Rand/CryptRandTsc.c
@@ -0,0 +1,101 @@
+/** @file\r
+  Pseudorandom Number Generator Wrapper Implementation over OpenSSL.\r
+\r
+Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>\r
+This program and the accompanying materials\r
+are licensed and made available under the terms and conditions of the BSD License\r
+which accompanies this distribution.  The full text of the license may be found at\r
+http://opensource.org/licenses/bsd-license.php\r
+\r
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+\r
+**/\r
+\r
+#include "InternalCryptLib.h"\r
+#include <openssl/rand.h>\r
+#include <Library/PrintLib.h>\r
+\r
+/**\r
+  Sets up the seed value for the pseudorandom number generator.\r
+\r
+  This function sets up the seed value for the pseudorandom number generator.\r
+  If Seed is not NULL, then the seed passed in is used.\r
+  If Seed is NULL, then default seed is used.\r
+\r
+  @param[in]  Seed      Pointer to seed value.\r
+                        If NULL, default seed is used.\r
+  @param[in]  SeedSize  Size of seed value.\r
+                        If Seed is NULL, this parameter is ignored.\r
+\r
+  @retval TRUE   Pseudorandom number generator has enough entropy for random generation.\r
+  @retval FALSE  Pseudorandom number generator does not have enough entropy for random generation.\r
+\r
+**/\r
+BOOLEAN\r
+EFIAPI\r
+RandomSeed (\r
+  IN  CONST  UINT8  *Seed  OPTIONAL,\r
+  IN  UINTN         SeedSize\r
+  )\r
+{\r
+  CHAR8  DefaultSeed[128];\r
+\r
+  //\r
+  // Seed the pseudorandom number generator with user-supplied value.\r
+  // NOTE: A cryptographic PRNG must be seeded with unpredictable data.\r
+  //\r
+  if (Seed != NULL) {\r
+    RAND_seed (Seed, (UINT32) SeedSize);\r
+  } else {\r
+    //\r
+    // Retrieve current time.\r
+    //\r
+    AsciiSPrint (\r
+      DefaultSeed,\r
+      sizeof (DefaultSeed),\r
+      "UEFI Crypto Library default seed (%ld)",\r
+      AsmReadTsc ()\r
+      ); \r
+\r
+    RAND_seed (DefaultSeed, sizeof (DefaultSeed));\r
+  }\r
+\r
+  return TRUE;\r
+}\r
+\r
+/**\r
+  Generates a pseudorandom byte stream of the specified size.\r
+\r
+  If Output is NULL, then return FALSE.\r
+\r
+  @param[out]  Output  Pointer to buffer to receive random value.\r
+  @param[in]   Size    Size of randome bytes to generate.\r
+\r
+  @retval TRUE   Pseudorandom byte stream generated successfully.\r
+  @retval FALSE  Pseudorandom number generator fails to generate due to lack of entropy.\r
+\r
+**/\r
+BOOLEAN\r
+EFIAPI\r
+RandomBytes (\r
+  OUT  UINT8  *Output,\r
+  IN   UINTN  Size\r
+  )\r
+{\r
+  //\r
+  // Check input parameters.\r
+  //\r
+  if (Output == NULL) {\r
+    return FALSE;\r
+  }\r
+\r
+  //\r
+  // Generate random data.\r
+  //\r
+  if (RAND_bytes (Output, (UINT32) Size) != 1) {\r
+    return FALSE;\r
+  }\r
+\r
+  return TRUE;\r
+}\r