Re: [PATCH v6 5/5] CryptoPkg: OpensslLib: Use RngLib to generate entropy in rand_pool

["Ard Biesheuvel" <ard.biesheuvel@arm.com>]

On 8/13/20 12:43 AM, matthewfcarlson@gmail.com wrote:
> From: Matthew Carlson <macarl@microsoft.com>
> 
> Ref: https://github.com/tianocore/edk2/pull/845
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1871
> 
> Changes OpenSSL to no longer depend on TimerLib and instead use RngLib.
> This allows platforms to decide for themsevles what sort of entropy source
> they provide to OpenSSL and TlsLib.
> 
> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Xiaoyu Lu <xiaoyux.lu@intel.com>
> Signed-off-by: Matthew Carlson <matthewfcarlson@gmail.com>

With the coding style/whitespace violations fixed:

Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>

> ---
>   CryptoPkg/Library/OpensslLib/rand_pool.c           | 203 ++------------------
>   CryptoPkg/Library/OpensslLib/rand_pool_noise.c     |  29 ---
>   CryptoPkg/Library/OpensslLib/rand_pool_noise_tsc.c |  43 -----
>   CryptoPkg/CryptoPkg.dsc                            |   1 +
>   CryptoPkg/Library/OpensslLib/OpensslLib.inf        |  15 +-
>   CryptoPkg/Library/OpensslLib/OpensslLibCrypto.inf  |  15 +-
>   CryptoPkg/Library/OpensslLib/rand_pool_noise.h     |  29 ---
>   7 files changed, 22 insertions(+), 313 deletions(-)
> 
> diff --git a/CryptoPkg/Library/OpensslLib/rand_pool.c b/CryptoPkg/Library/OpensslLib/rand_pool.c
> index 9e0179b03490..3da92699fef6 100644
> --- a/CryptoPkg/Library/OpensslLib/rand_pool.c
> +++ b/CryptoPkg/Library/OpensslLib/rand_pool.c
> @@ -11,53 +11,18 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
>   #include <openssl/aes.h>
>   
>   #include <Uefi.h>
> -#include <Library/TimerLib.h>
> -
> -#include "rand_pool_noise.h"
> -
> -/**
> -  Get some randomness from low-order bits of GetPerformanceCounter results.
> -  And combine them to the 64-bit value
> -
> -  @param[out] Rand    Buffer pointer to store the 64-bit random value.
> -
> -  @retval TRUE        Random number generated successfully.
> -  @retval FALSE       Failed to generate.
> -**/
> -STATIC
> -BOOLEAN
> -EFIAPI
> -GetRandNoise64FromPerformanceCounter(
> -  OUT UINT64      *Rand
> -  )
> -{
> -  UINT32 Index;
> -  UINT32 *RandPtr;
> -
> -  if (NULL == Rand) {
> -    return FALSE;
> -  }
> -
> -  RandPtr = (UINT32 *) Rand;
> -
> -  for (Index = 0; Index < 2; Index ++) {
> -    *RandPtr = (UINT32) (GetPerformanceCounter () & 0xFF);
> -    MicroSecondDelay (10);
> -    RandPtr++;
> -  }
> -
> -  return TRUE;
> -}
> +#include <Library/RngLib.h>
>   
>   /**
>     Calls RandomNumber64 to fill
>     a buffer of arbitrary size with random bytes.
> +  This is a shim layer to RngLib.
>   
>     @param[in]   Length        Size of the buffer, in bytes,  to fill with.
>     @param[out]  RandBuffer    Pointer to the buffer to store the random result.
>   
> -  @retval EFI_SUCCESS        Random bytes generation succeeded.
> -  @retval EFI_NOT_READY      Failed to request random bytes.
> +  @retval TRUE        Random bytes generation succeeded.
> +  @retval FALSE       Failed to request random bytes.
>   
>   **/
>   STATIC
> @@ -73,17 +38,17 @@ RandGetBytes (
>   
>     Ret = FALSE;
>   
> +  if (RandBuffer == NULL) {
> +    DEBUG((DEBUG_ERROR, "[OPENSSL_RAND_POOL] NULL RandBuffer. No random numbers are generated and your system is not secure\n"));
> +    ASSERT(FALSE); // Since we can't generate random numbers, we should assert. Otherwise we will just blow up later.
> +    return Ret;
> +  }
> +
> +
>     while (Length > 0) {
> -    //
> -    // Get random noise from platform.
> -    // If it failed, fallback to PerformanceCounter
> -    // If you really care about security, you must override
> -    // GetRandomNoise64FromPlatform.
> -    //
> -    Ret = GetRandomNoise64 (&TempRand);
> -    if (Ret == FALSE) {
> -      Ret = GetRandNoise64FromPerformanceCounter (&TempRand);
> -    }
> +    // Use RngLib to get random number
> +    Ret = GetRandomNumber64(&TempRand);
> +
>       if (!Ret) {
>         return Ret;
>       }
> @@ -100,125 +65,6 @@ RandGetBytes (
>     return Ret;
>   }
>   
> -/**
> -  Creates a 128bit random value that is fully forward and backward prediction resistant,
> -  suitable for seeding a NIST SP800-90 Compliant.
> -  This function takes multiple random numbers from PerformanceCounter to ensure reseeding
> -  and performs AES-CBC-MAC over the data to compute the seed value.
> -
> -  @param[out]  SeedBuffer    Pointer to a 128bit buffer to store the random seed.
> -
> -  @retval TRUE        Random seed generation succeeded.
> -  @retval FALSE      Failed to request random bytes.
> -
> -**/
> -STATIC
> -BOOLEAN
> -EFIAPI
> -RandGetSeed128 (
> -  OUT UINT8        *SeedBuffer
> -  )
> -{
> -  BOOLEAN     Ret;
> -  UINT8       RandByte[16];
> -  UINT8       Key[16];
> -  UINT8       Ffv[16];
> -  UINT8       Xored[16];
> -  UINT32      Index;
> -  UINT32      Index2;
> -  AES_KEY     AESKey;
> -
> -  //
> -  // Chose an arbitrary key and zero the feed_forward_value (FFV)
> -  //
> -  for (Index = 0; Index < 16; Index++) {
> -    Key[Index] = (UINT8) Index;
> -    Ffv[Index] = 0;
> -  }
> -
> -  AES_set_encrypt_key (Key, 16 * 8, &AESKey);
> -
> -  //
> -  // Perform CBC_MAC over 32 * 128 bit values, with 10us gaps between 128 bit value
> -  // The 10us gaps will ensure multiple reseeds within the system time with a large
> -  // design margin.
> -  //
> -  for (Index = 0; Index < 32; Index++) {
> -    MicroSecondDelay (10);
> -    Ret = RandGetBytes (16, RandByte);
> -    if (!Ret) {
> -      return Ret;
> -    }
> -
> -    //
> -    // Perform XOR operations on two 128-bit value.
> -    //
> -    for (Index2 = 0; Index2 < 16; Index2++) {
> -      Xored[Index2] = RandByte[Index2] ^ Ffv[Index2];
> -    }
> -
> -    AES_encrypt (Xored, Ffv, &AESKey);
> -  }
> -
> -  for (Index = 0; Index < 16; Index++) {
> -    SeedBuffer[Index] = Ffv[Index];
> -  }
> -
> -  return Ret;
> -}
> -
> -/**
> -  Generate high-quality entropy source.
> -
> -  @param[in]   Length        Size of the buffer, in bytes, to fill with.
> -  @param[out]  Entropy       Pointer to the buffer to store the entropy data.
> -
> -  @retval EFI_SUCCESS        Entropy generation succeeded.
> -  @retval EFI_NOT_READY      Failed to request random data.
> -
> -**/
> -STATIC
> -BOOLEAN
> -EFIAPI
> -RandGenerateEntropy (
> -  IN UINTN         Length,
> -  OUT UINT8        *Entropy
> -  )
> -{
> -  BOOLEAN     Ret;
> -  UINTN       BlockCount;
> -  UINT8       Seed[16];
> -  UINT8       *Ptr;
> -
> -  BlockCount = Length / 16;
> -  Ptr        = (UINT8 *) Entropy;
> -
> -  //
> -  // Generate high-quality seed for DRBG Entropy
> -  //
> -  while (BlockCount > 0) {
> -    Ret = RandGetSeed128 (Seed);
> -    if (!Ret) {
> -      return Ret;
> -    }
> -    CopyMem (Ptr, Seed, 16);
> -
> -    BlockCount--;
> -    Ptr = Ptr + 16;
> -  }
> -
> -  //
> -  // Populate the remained data as request.
> -  //
> -  Ret = RandGetSeed128 (Seed);
> -  if (!Ret) {
> -    return Ret;
> -  }
> -  CopyMem (Ptr, Seed, (Length % 16));
> -
> -  return Ret;
> -}
> -
>   /*
>    * Add random bytes to the pool to acquire requested amount of entropy
>    *
> @@ -238,7 +84,7 @@ size_t rand_pool_acquire_entropy(RAND_POOL *pool)
>       buffer = rand_pool_add_begin(pool, bytes_needed);
>   
>       if (buffer != NULL) {
> -      Ret = RandGenerateEntropy(bytes_needed, buffer);
> +      Ret = RandGetBytes(bytes_needed, buffer);
>         if (FALSE == Ret) {
>           rand_pool_add_end(pool, 0, 0);
>         } else {
> @@ -257,13 +103,8 @@ size_t rand_pool_acquire_entropy(RAND_POOL *pool)
>    */
>   int rand_pool_add_nonce_data(RAND_POOL *pool)
>   {
> -  struct {
> -    UINT64  Rand;
> -    UINT64  TimerValue;
> -  } data = { 0 };
> -
> -  RandGetBytes(8, (UINT8 *)&(data.Rand));
> -  data.TimerValue = GetPerformanceCounter();
> +  UINT8 data[16];
> +  RandGetBytes(sizeof(data), data);
>   
>     return rand_pool_add(pool, (unsigned char*)&data, sizeof(data), 0);
>   }
> @@ -275,13 +116,8 @@ int rand_pool_add_nonce_data(RAND_POOL *pool)
>    */
>   int rand_pool_add_additional_data(RAND_POOL *pool)
>   {
> -  struct {
> -    UINT64  Rand;
> -    UINT64  TimerValue;
> -  } data = { 0 };
> -
> -  RandGetBytes(8, (UINT8 *)&(data.Rand));
> -  data.TimerValue = GetPerformanceCounter();
> +  UINT8 data[16];
> +  RandGetBytes(sizeof(data), data);
>   
>     return rand_pool_add(pool, (unsigned char*)&data, sizeof(data), 0);
>   }
> @@ -313,4 +149,3 @@ void rand_pool_cleanup(void)
>   void rand_pool_keep_random_devices_open(int keep)
>   {
>   }
> -
> diff --git a/CryptoPkg/Library/OpensslLib/rand_pool_noise.c b/CryptoPkg/Library/OpensslLib/rand_pool_noise.c
> deleted file mode 100644
> index 212834e27acc..000000000000
> --- a/CryptoPkg/Library/OpensslLib/rand_pool_noise.c
> +++ /dev/null
> @@ -1,29 +0,0 @@
> -/** @file
> -  Provide rand noise source.
> -
> -Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
> -SPDX-License-Identifier: BSD-2-Clause-Patent
> -
> -**/
> -
> -#include <Library/BaseLib.h>
> -
> -/**
> -  Get 64-bit noise source
> -
> -  @param[out] Rand         Buffer pointer to store 64-bit noise source
> -
> -  @retval FALSE            Failed to generate
> -**/
> -BOOLEAN
> -EFIAPI
> -GetRandomNoise64 (
> -  OUT UINT64         *Rand
> -  )
> -{
> -  //
> -  // Return FALSE will fallback to use PerformanceCounter to
> -  // generate noise.
> -  //
> -  return FALSE;
> -}
> diff --git a/CryptoPkg/Library/OpensslLib/rand_pool_noise_tsc.c b/CryptoPkg/Library/OpensslLib/rand_pool_noise_tsc.c
> deleted file mode 100644
> index 4158106231fd..000000000000
> --- a/CryptoPkg/Library/OpensslLib/rand_pool_noise_tsc.c
> +++ /dev/null
> @@ -1,43 +0,0 @@
> -/** @file
> -  Provide rand noise source.
> -
> -Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
> -SPDX-License-Identifier: BSD-2-Clause-Patent
> -
> -**/
> -
> -#include <Library/BaseLib.h>
> -#include <Library/DebugLib.h>
> -#include <Library/TimerLib.h>
> -
> -/**
> -  Get 64-bit noise source
> -
> -  @param[out] Rand         Buffer pointer to store 64-bit noise source
> -
> -  @retval TRUE             Get randomness successfully.
> -  @retval FALSE            Failed to generate
> -**/
> -BOOLEAN
> -EFIAPI
> -GetRandomNoise64 (
> -  OUT UINT64         *Rand
> -  )
> -{
> -  UINT32 Index;
> -  UINT32 *RandPtr;
> -
> -  if (NULL == Rand) {
> -    return FALSE;
> -  }
> -
> -  RandPtr = (UINT32 *)Rand;
> -
> -  for (Index = 0; Index < 2; Index ++) {
> -    *RandPtr = (UINT32) ((AsmReadTsc ()) & 0xFF);
> -    RandPtr++;
> -    MicroSecondDelay (10);
> -  }
> -
> -  return TRUE;
> -}
> diff --git a/CryptoPkg/CryptoPkg.dsc b/CryptoPkg/CryptoPkg.dsc
> index 1af78468a19c..0490eeb7e22f 100644
> --- a/CryptoPkg/CryptoPkg.dsc
> +++ b/CryptoPkg/CryptoPkg.dsc
> @@ -60,6 +60,7 @@
>     BaseCryptLib|CryptoPkg/Library/BaseCryptLibNull/BaseCryptLibNull.inf
>     TlsLib|CryptoPkg/Library/TlsLibNull/TlsLibNull.inf
>     HashApiLib|CryptoPkg/Library/BaseHashApiLib/BaseHashApiLib.inf
> +  RngLib|MdePkg/Library/BaseRngLibNull/BaseRngLibNull.inf
>   
>   [LibraryClasses.ARM, LibraryClasses.AARCH64]
>     #
> diff --git a/CryptoPkg/Library/OpensslLib/OpensslLib.inf b/CryptoPkg/Library/OpensslLib/OpensslLib.inf
> index dbbe5386a10c..4baad565564c 100644
> --- a/CryptoPkg/Library/OpensslLib/OpensslLib.inf
> +++ b/CryptoPkg/Library/OpensslLib/OpensslLib.inf
> @@ -571,22 +571,9 @@
>     $(OPENSSL_PATH)/ssl/statem/statem_local.h
>   # Autogenerated files list ends here
>     buildinf.h
> -  rand_pool_noise.h
>     ossl_store.c
>     rand_pool.c
>   
> -[Sources.Ia32]
> -  rand_pool_noise_tsc.c
> -
> -[Sources.X64]
> -  rand_pool_noise_tsc.c
> -
> -[Sources.ARM]
> -  rand_pool_noise.c
> -
> -[Sources.AARCH64]
> -  rand_pool_noise.c
> -
>   [Packages]
>     MdePkg/MdePkg.dec
>     CryptoPkg/CryptoPkg.dec
> @@ -594,7 +581,7 @@
>   [LibraryClasses]
>     BaseLib
>     DebugLib
> -  TimerLib
> +  RngLib
>     PrintLib
>   
>   [LibraryClasses.ARM]
> diff --git a/CryptoPkg/Library/OpensslLib/OpensslLibCrypto.inf b/CryptoPkg/Library/OpensslLib/OpensslLibCrypto.inf
> index 616ccd9f62d1..3557711bd85a 100644
> --- a/CryptoPkg/Library/OpensslLib/OpensslLibCrypto.inf
> +++ b/CryptoPkg/Library/OpensslLib/OpensslLibCrypto.inf
> @@ -520,22 +520,9 @@
>     $(OPENSSL_PATH)/crypto/x509v3/v3_admis.h
>   # Autogenerated files list ends here
>     buildinf.h
> -  rand_pool_noise.h
>     ossl_store.c
>     rand_pool.c
>   
> -[Sources.Ia32]
> -  rand_pool_noise_tsc.c
> -
> -[Sources.X64]
> -  rand_pool_noise_tsc.c
> -
> -[Sources.ARM]
> -  rand_pool_noise.c
> -
> -[Sources.AARCH64]
> -  rand_pool_noise.c
> -
>   [Packages]
>     MdePkg/MdePkg.dec
>     CryptoPkg/CryptoPkg.dec
> @@ -543,7 +530,7 @@
>   [LibraryClasses]
>     BaseLib
>     DebugLib
> -  TimerLib
> +  RngLib
>     PrintLib
>   
>   [LibraryClasses.ARM]
> diff --git a/CryptoPkg/Library/OpensslLib/rand_pool_noise.h b/CryptoPkg/Library/OpensslLib/rand_pool_noise.h
> deleted file mode 100644
> index 75acc686a9f1..000000000000
> --- a/CryptoPkg/Library/OpensslLib/rand_pool_noise.h
> +++ /dev/null
> @@ -1,29 +0,0 @@
> -/** @file
> -  Provide rand noise source.
> -
> -Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
> -SPDX-License-Identifier: BSD-2-Clause-Patent
> -
> -**/
> -
> -#ifndef __RAND_POOL_NOISE_H__
> -#define __RAND_POOL_NOISE_H__
> -
> -#include <Uefi/UefiBaseType.h>
> -
> -/**
> -   Get 64-bit noise source.
> -
> -   @param[out] Rand         Buffer pointer to store 64-bit noise source
> -
> -   @retval TRUE             Get randomness successfully.
> -   @retval FALSE            Failed to generate
> -**/
> -BOOLEAN
> -EFIAPI
> -GetRandomNoise64 (
> -  OUT UINT64         *Rand
> -  );
> -
> -
> -#endif // __RAND_POOL_NOISE_H__
>