SecurityPkg: Reallocate TPM Active PCRs based on platform support

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3515

In V4: Fixed patch format and uncrustify cleanup

In V3: Cleaned up comments, debug prints and updated patch to use the
new debug ENUM definitions.

- Replaced EFI_D_INFO with DEBUG_INFO.
- Replaced EFI_D_VERBOSE with DEBUG_VERBOSE.

In V2: Add case to RegisterHashInterfaceLib logic

RegisterHashInterfaceLib needs to correctly handle registering the HashLib
instance supported algorithm bitmap when PcdTpm2HashMask is set to zero.

The current implementation of SyncPcrAllocationsAndPcrMask() triggers
PCR bank reallocation only based on the intersection between
TpmActivePcrBanks and PcdTpm2HashMask.

When the software HashLibBaseCryptoRouter solution is used, no PCR bank
reallocation is occurring based on the supported hashing algorithms
registered by the HashLib instances.

Need to have an additional check for the intersection between the
TpmActivePcrBanks and the PcdTcg2HashAlgorithmBitmap populated by the
HashLib instances present on the platform's BIOS.

Signed-off-by: Rodrigo Gonzalez del Cueto <rodrigo.gonzalez.del.cueto@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>

2 files changed, 31 insertions, 11 deletions

diff --git a/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c b/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c
index 622989aff3..26bb5282a5 100644
--- a/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c
+++ b/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.c
@@ -252,7 +252,7 @@ EndofPeiSignalNotifyCallBack (
 

 /**

   Make sure that the current PCR allocations, the TPM supported PCRs,

-  and the PcdTpm2HashMask are all in agreement.

+  PcdTcg2HashAlgorithmBitmap and the PcdTpm2HashMask are all in agreement.

 **/

 VOID

 SyncPcrAllocationsAndPcrMask (

@@ -261,6 +261,7 @@ SyncPcrAllocationsAndPcrMask (
 {

   EFI_STATUS                       Status;

   EFI_TCG2_EVENT_ALGORITHM_BITMAP  TpmHashAlgorithmBitmap;

+  EFI_TCG2_EVENT_ALGORITHM_BITMAP  BiosHashAlgorithmBitmap;

   UINT32                           TpmActivePcrBanks;

   UINT32                           NewTpmActivePcrBanks;

   UINT32                           Tpm2PcrMask;

@@ -274,33 +275,50 @@ SyncPcrAllocationsAndPcrMask (
   Status = Tpm2GetCapabilitySupportedAndActivePcrs (&TpmHashAlgorithmBitmap, &TpmActivePcrBanks);

   ASSERT_EFI_ERROR (Status);

 

+  DEBUG ((DEBUG_INFO, "Tpm2GetCapabilitySupportedAndActivePcrs - TpmHashAlgorithmBitmap: 0x%08x\n", TpmHashAlgorithmBitmap));

+  DEBUG ((DEBUG_INFO, "Tpm2GetCapabilitySupportedAndActivePcrs - TpmActivePcrBanks 0x%08x\n", TpmActivePcrBanks));

+

   Tpm2PcrMask = PcdGet32 (PcdTpm2HashMask);

   if (Tpm2PcrMask == 0) {

     //

-    // if PcdTPm2HashMask is zero, use ActivePcr setting

+    // If PcdTpm2HashMask is zero, use ActivePcr setting.

+    // Only when PcdTpm2HashMask is initialized to 0, will it be updated to current Active Pcrs.

     //

     PcdSet32S (PcdTpm2HashMask, TpmActivePcrBanks);

     Tpm2PcrMask = TpmActivePcrBanks;

   }

 

-  //

-  // Find the intersection of Pcd support and TPM support.

-  // If banks are missing from the TPM support that are in the PCD, update the PCD.

-  // If banks are missing from the PCD that are active in the TPM, reallocate the banks and reboot.

-  //

+  DEBUG ((DEBUG_INFO, "Tpm2PcrMask 0x%08x\n", Tpm2PcrMask));

 

   //

-  // If there are active PCR banks that are not supported by the Platform mask,

-  // update the TPM allocations and reboot the machine.

+  // The Active PCRs in the TPM need to be a strict subset of the hashing algorithms supported by BIOS.

   //

-  if ((TpmActivePcrBanks & Tpm2PcrMask) != TpmActivePcrBanks) {

-    NewTpmActivePcrBanks = TpmActivePcrBanks & Tpm2PcrMask;

+  // * Find the intersection of Pcd support and TPM active PCRs. If banks are missing from the TPM support

+  // that are in the PCD, update the PCD.

+  // * Find intersection of TPM Active PCRs and BIOS supported algorithms. If there are active PCR banks

+  // that are not supported by the platform, update the TPM allocations and reboot.

+  // Note: When the HashLibBaseCryptoRouter solution is used, the hash algorithm support from BIOS is reported

+  //       by Tcg2HashAlgorithmBitmap, which is populated by HashLib instances at runtime.

+  BiosHashAlgorithmBitmap = PcdGet32 (PcdTcg2HashAlgorithmBitmap);

+  DEBUG ((DEBUG_INFO, "Tcg2HashAlgorithmBitmap: 0x%08x\n", BiosHashAlgorithmBitmap));

+

+  if (((TpmActivePcrBanks & Tpm2PcrMask) != TpmActivePcrBanks) ||

+      ((TpmActivePcrBanks & BiosHashAlgorithmBitmap) != TpmActivePcrBanks))

+  {

+    DEBUG ((DEBUG_INFO, "TpmActivePcrBanks & Tpm2PcrMask = 0x%08x\n", (TpmActivePcrBanks & Tpm2PcrMask)));

+    DEBUG ((DEBUG_INFO, "TpmActivePcrBanks & BiosHashAlgorithmBitmap = 0x%08x\n", (TpmActivePcrBanks & BiosHashAlgorithmBitmap)));

+    NewTpmActivePcrBanks  = TpmActivePcrBanks;

+    NewTpmActivePcrBanks &= Tpm2PcrMask;

+    NewTpmActivePcrBanks &= BiosHashAlgorithmBitmap;

+    DEBUG ((DEBUG_INFO, "NewTpmActivePcrBanks 0x%08x\n", NewTpmActivePcrBanks));

 

     DEBUG ((DEBUG_INFO, "%a - Reallocating PCR banks from 0x%X to 0x%X.\n", __FUNCTION__, TpmActivePcrBanks, NewTpmActivePcrBanks));

+

     if (NewTpmActivePcrBanks == 0) {

       DEBUG ((DEBUG_ERROR, "%a - No viable PCRs active! Please set a less restrictive value for PcdTpm2HashMask!\n", __FUNCTION__));

       ASSERT (FALSE);

     } else {

+      DEBUG ((DEBUG_ERROR, "Tpm2PcrAllocateBanks (TpmHashAlgorithmBitmap: 0x%08x, NewTpmActivePcrBanks: 0x%08x)\n", TpmHashAlgorithmBitmap, NewTpmActivePcrBanks));

       Status = Tpm2PcrAllocateBanks (NULL, (UINT32)TpmHashAlgorithmBitmap, NewTpmActivePcrBanks);

       if (EFI_ERROR (Status)) {

         //

@@ -331,6 +349,7 @@ SyncPcrAllocationsAndPcrMask (
     }

 

     Status = PcdSet32S (PcdTpm2HashMask, NewTpm2PcrMask);

+    DEBUG ((DEBUG_ERROR, "Set PcdTpm2Hash Mask to 0x%08x\n", NewTpm2PcrMask));

     ASSERT_EFI_ERROR (Status);

   }

 }

diff --git a/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.inf b/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.inf
index 06c26a2904..17ad116126 100644
--- a/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.inf
+++ b/SecurityPkg/Tcg/Tcg2Pei/Tcg2Pei.inf
@@ -86,6 +86,7 @@
   ## SOMETIMES_CONSUMES

   ## SOMETIMES_PRODUCES

   gEfiSecurityPkgTokenSpaceGuid.PcdTpm2HashMask

+  gEfiSecurityPkgTokenSpaceGuid.PcdTcg2HashAlgorithmBitmap                  ## CONSUMES

 

 [Depex]

   gEfiPeiMasterBootModePpiGuid AND