path: root/src/tpm2/ContextCommands.c

/********************************************************************************/
/*										*/
/*			   Context Management	  				*/
/*			     Written by Ken Goldman				*/
/*		       IBM Thomas J. Watson Research Center			*/
/*            $Id: ContextCommands.c 1658 2021-01-22 23:14:01Z kgoldman $	*/
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#include "Tpm.h"
#include "ContextSave_fp.h"
#include "NVMarshal.h" // libtpms added
#if CC_ContextSave  // Conditional expansion of this file
#include "Context_spt_fp.h"
/* Error Returns Meaning */
/* TPM_RC_CONTEXT_GAP a contextID could not be assigned for a session context save */
/* TPM_RC_TOO_MANY_CONTEXTS no more contexts can be saved as the counter has maxed out */
TPM_RC
TPM2_ContextSave(
		 ContextSave_In      *in,            // IN: input parameter list
		 ContextSave_Out     *out            // OUT: output parameter list
		 )
{
    TPM_RC          result = TPM_RC_SUCCESS;
    UINT16          fingerprintSize;    // The size of fingerprint in context
    // blob.
    UINT64          contextID = 0;      // session context ID
    TPM2B_SYM_KEY   symKey;
    TPM2B_IV        iv;
    TPM2B_DIGEST    integrity;
    UINT16          integritySize;
    BYTE            *buffer;
    // This command may cause the orderlyState to be cleared due to
    // the update of state reset data. If the state is orderly and
    // cannot be changed, exit early.
    RETURN_IF_ORDERLY;
    
    // Internal Data Update
    
    // This implementation does not do things in quite the same way as described in
    // Part 2 of the specification. In Part 2, it indicates that the 
    // TPMS_CONTEXT_DATA contains two TPM2B values. That is not how this is 
    // implemented. Rather, the size field of the TPM2B_CONTEXT_DATA is used to 
    // determine the amount of data in the encrypted data. That part is not 
    // independently sized. This makes the actual size 2 bytes smaller than 
    // calculated using Part 2. Since this is opaque to the caller, it is not 
    // necessary to fix. The actual size is returned by TPM2_GetCapabilties().
    
    // Initialize output handle.  At the end of command action, the output
    // handle of an object will be replaced, while the output handle
    // for a session will be the same as input
    out->context.savedHandle = in->saveHandle;
    // Get the size of fingerprint in context blob.  The sequence value in
    // TPMS_CONTEXT structure is used as the fingerprint
    fingerprintSize = sizeof(out->context.sequence);
    // Compute the integrity size at the beginning of context blob
    integritySize = sizeof(integrity.t.size)
		    + CryptHashGetDigestSize(CONTEXT_INTEGRITY_HASH_ALG);
    // Perform object or session specific context save
    switch(HandleGetType(in->saveHandle))
	{
	  case TPM_HT_TRANSIENT:
	      {
		  OBJECT              *object = HandleToObject(in->saveHandle);
		  ANY_OBJECT_BUFFER   *outObject;
		  unsigned char        buffer[sizeof(OBJECT) * 2];		// libtpms changed begin
		  BYTE                *bufptr = &buffer[0];
		  INT32                size = sizeof(buffer);
		  UINT16               written = ANY_OBJECT_Marshal(object, &bufptr, &size);
		  UINT16               objectSize = written;			// libtpms changed end
		  outObject = (ANY_OBJECT_BUFFER *)(out->context.contextBlob.t.buffer
						    + integritySize + fingerprintSize);
		  // Set size of the context data.  The contents of context blob is vendor
		  // defined.  In this implementation, the size is size of integrity
		  // plus fingerprint plus the whole internal OBJECT structure
		  out->context.contextBlob.t.size = integritySize +
						    fingerprintSize + objectSize;
		  // Make sure things fit
		  pAssert(out->context.contextBlob.t.size
			  <= sizeof(out->context.contextBlob.t.buffer));
		  // Copy the whole internal OBJECT structure to context blob
		  MemoryCopy(outObject, buffer, written);			// libtpms changed
		  // Increment object context ID
		  gr.objectContextID++;
		  // If object context ID overflows, TPM should be put in failure mode
		  if(gr.objectContextID == 0)
		      FAIL(FATAL_ERROR_INTERNAL);
		  // Fill in other return values for an object.
		  out->context.sequence = gr.objectContextID;
		  // For regular object, savedHandle is 0x80000000.  For sequence object,
		  // savedHandle is 0x80000001.  For object with stClear, savedHandle
		  // is 0x80000002
		  if(ObjectIsSequence(object))
		      {
			  out->context.savedHandle = 0x80000001;
			/* ANY_OBJECT_Marshal already wrote it			// libtpms changed begin
			  SequenceDataExport((HASH_OBJECT *)object,
					     (HASH_OBJECT_BUFFER *)outObject);
			 */							// libtpms changed end
		      }
		  else
		      out->context.savedHandle = (object->attributes.stClear == SET)
						 ? 0x80000002 : 0x80000000;
		  // Get object hierarchy
		  out->context.hierarchy = ObjectGetHierarchy(object);
		  break;
	      }
	  case TPM_HT_HMAC_SESSION:
	  case TPM_HT_POLICY_SESSION:
	      {
		  SESSION         *session = SessionGet(in->saveHandle);
		  // Set size of the context data.  The contents of context blob is vendor
		  // defined.  In this implementation, the size of context blob is the
		  // size of a internal session structure plus the size of
		  // fingerprint plus the size of integrity
		  out->context.contextBlob.t.size = integritySize +
						    fingerprintSize + sizeof(*session);
		  // Make sure things fit
		  pAssert(out->context.contextBlob.t.size
			  < sizeof(out->context.contextBlob.t.buffer));
		  // Copy the whole internal SESSION structure to context blob.
		  // Save space for fingerprint at the beginning of the buffer
		  // This is done before anything else so that the actual context
		  // can be reclaimed after this call
		  pAssert(sizeof(*session) <= sizeof(out->context.contextBlob.t.buffer)
			  - integritySize - fingerprintSize);
		  MemoryCopy(out->context.contextBlob.t.buffer + integritySize
			     + fingerprintSize, session, sizeof(*session));
		  // Fill in the other return parameters for a session
		  // Get a context ID and set the session tracking values appropriately
		  // TPM_RC_CONTEXT_GAP is a possible error.
		  // SessionContextSave() will flush the in-memory context
		  // so no additional errors may occur after this call.
		  result = SessionContextSave(out->context.savedHandle, &contextID);
		  if(result != TPM_RC_SUCCESS)
		      return result;
		  // sequence number is the current session contextID
		  out->context.sequence = contextID;
		  // use TPM_RH_NULL as hierarchy for session context
		  out->context.hierarchy = TPM_RH_NULL;
		  break;
	      }
	  default:
	    // SaveContext may only take an object handle or a session handle.
	    // All the other handle type should be filtered out at unmarshal
	    FAIL(FATAL_ERROR_INTERNAL);
	    break;
	}
    // Save fingerprint at the beginning of encrypted area of context blob.
    // Reserve the integrity space
    pAssert(sizeof(out->context.sequence) <=
	    sizeof(out->context.contextBlob.t.buffer) - integritySize);
    MemoryCopy(out->context.contextBlob.t.buffer + integritySize,
	       &out->context.sequence, sizeof(out->context.sequence));
    // Compute context encryption key
    ComputeContextProtectionKey(&out->context, &symKey, &iv);
    // Encrypt context blob
    CryptSymmetricEncrypt(out->context.contextBlob.t.buffer + integritySize,
			  CONTEXT_ENCRYPT_ALG, CONTEXT_ENCRYPT_KEY_BITS,
			  symKey.t.buffer, &iv, TPM_ALG_CFB,
			  out->context.contextBlob.t.size - integritySize,
			  out->context.contextBlob.t.buffer + integritySize);
    // Compute integrity hash for the object
    // In this implementation, the same routine is used for both sessions
    // and objects.
    ComputeContextIntegrity(&out->context, &integrity);
    // add integrity at the beginning of context blob
    buffer = out->context.contextBlob.t.buffer;
    TPM2B_DIGEST_Marshal(&integrity, &buffer, NULL);
    // orderly state should be cleared because of the update of state reset and
    // state clear data
    g_clearOrderly = TRUE;
    return result;
}
#endif // CC_ContextSave
#include "Tpm.h"
#include "ContextLoad_fp.h"
#if CC_ContextLoad  // Conditional expansion of this file
#include "Context_spt_fp.h"
TPM_RC
TPM2_ContextLoad(
		 ContextLoad_In      *in,            // IN: input parameter list
		 ContextLoad_Out     *out            // OUT: output parameter list
		 )
{
    TPM_RC              result;
    TPM2B_DIGEST        integrityToCompare;
    TPM2B_DIGEST        integrity;
    BYTE                *buffer;    // defined to save some typing
    INT32               size;       // defined to save some typing
    TPM_HT              handleType;
    TPM2B_SYM_KEY       symKey;
    TPM2B_IV            iv;
    // Input Validation

    // See discussion about the context format in TPM2_ContextSave Detailed Actions

    // IF this is a session context, make sure that the sequence number is
    // consistent with the version in the slot
    // Check context blob size
    handleType = HandleGetType(in->context.savedHandle);
    // Get integrity from context blob
    buffer = in->context.contextBlob.t.buffer;
    size = (INT32)in->context.contextBlob.t.size;
    result = TPM2B_DIGEST_Unmarshal(&integrity, &buffer, &size);
    if(result != TPM_RC_SUCCESS)
	return result;
    // the size of the integrity value has to match the size of digest produced
    // by the integrity hash
    if(integrity.t.size != CryptHashGetDigestSize(CONTEXT_INTEGRITY_HASH_ALG))
	return TPM_RCS_SIZE + RC_ContextLoad_context;
    // Make sure that the context blob has enough space for the fingerprint. This
    // is elastic pants to go with the belt and suspenders we already have to make
    // sure that the context is complete and untampered.
    if((unsigned)size < sizeof(in->context.sequence))
	return TPM_RCS_SIZE + RC_ContextLoad_context;
    // After unmarshaling the integrity value, 'buffer' is pointing at the first
    // byte of the integrity protected and encrypted buffer and 'size' is the number
    // of integrity protected and encrypted bytes.
    // Compute context integrity
    ComputeContextIntegrity(&in->context, &integrityToCompare);
    // Compare integrity
    if(!MemoryEqual2B(&integrity.b, &integrityToCompare.b))
	return TPM_RCS_INTEGRITY + RC_ContextLoad_context;
    // Compute context encryption key
    ComputeContextProtectionKey(&in->context, &symKey, &iv);
    // Decrypt context data in place
    CryptSymmetricDecrypt(buffer, CONTEXT_ENCRYPT_ALG, CONTEXT_ENCRYPT_KEY_BITS,
			  symKey.t.buffer, &iv, TPM_ALG_CFB, size, buffer);
    // See if the fingerprint value matches. If not, it is symptomatic of either
    // a broken TPM or that the TPM is under attack so go into failure mode.
    if(!MemoryEqual(buffer, &in->context.sequence, sizeof(in->context.sequence)))
	FAIL(FATAL_ERROR_INTERNAL);
    // step over fingerprint
    buffer += sizeof(in->context.sequence);
    // set the remaining size of the context
    size -= sizeof(in->context.sequence);
    // Perform object or session specific input check
    switch(handleType)
	{
	  case TPM_HT_TRANSIENT:
	      {
		  OBJECT      *outObject;
		  if(size > (INT32)sizeof(OBJECT))
		      FAIL(FATAL_ERROR_INTERNAL);
		  // Discard any changes to the handle that the TRM might have made
		  in->context.savedHandle = TRANSIENT_FIRST;
		  // If hierarchy is disabled, no object context can be loaded in this
		  // hierarchy
		  if(!HierarchyIsEnabled(in->context.hierarchy))
		      return TPM_RCS_HIERARCHY + RC_ContextLoad_context;
		  // Restore object. If there is no empty space, indicate as much
		  outObject = ObjectContextLoadLibtpms(buffer, size,       // libtpms changed
						       &out->loadedHandle);
		  if(outObject == NULL)
		      return TPM_RC_OBJECT_MEMORY;
		  break;
	      }
	  case TPM_HT_POLICY_SESSION:
	  case TPM_HT_HMAC_SESSION:
	      {
		  if(size != sizeof(SESSION))
		      FAIL(FATAL_ERROR_INTERNAL);
		  // This command may cause the orderlyState to be cleared due to
		  // the update of state reset data.  If this is the case, check if NV is
		  // available first
		  RETURN_IF_ORDERLY;
		  // Check if input handle points to a valid saved session and that the
		  // sequence number makes sense
		  if(!SequenceNumberForSavedContextIsValid(&in->context))
		      return TPM_RCS_HANDLE + RC_ContextLoad_context;
		  // Restore session.  A TPM_RC_SESSION_MEMORY, TPM_RC_CONTEXT_GAP error
		  // may be returned at this point
		  result = SessionContextLoad((SESSION_BUF *)buffer,
					      &in->context.savedHandle);
		  if(result != TPM_RC_SUCCESS)
		      return result;
		  out->loadedHandle = in->context.savedHandle;
		  // orderly state should be cleared because of the update of state
		  // reset and state clear data
		  g_clearOrderly = TRUE;
		  break;
	      }
	  default:
	    // Context blob may only have an object handle or a session handle.
	    // All the other handle type should be filtered out at unmarshal
	    FAIL(FATAL_ERROR_INTERNAL);
	    break;
	}
    return TPM_RC_SUCCESS;
}
#endif // CC_ContextLoad
#include "Tpm.h"
#include "FlushContext_fp.h"
#if CC_FlushContext  // Conditional expansion of this file
TPM_RC
TPM2_FlushContext(
		  FlushContext_In     *in             // IN: input parameter list
		  )
{
    // Internal Data Update
    // Call object or session specific routine to flush
    switch(HandleGetType(in->flushHandle))
	{
	  case TPM_HT_TRANSIENT:
	    if(!IsObjectPresent(in->flushHandle))
		return TPM_RCS_HANDLE + RC_FlushContext_flushHandle;
	    // Flush object
	    FlushObject(in->flushHandle);
	    break;
	  case TPM_HT_HMAC_SESSION:
	  case TPM_HT_POLICY_SESSION:
	    if(!SessionIsLoaded(in->flushHandle)
	       && !SessionIsSaved(in->flushHandle)
	       )
		return TPM_RCS_HANDLE + RC_FlushContext_flushHandle;
	    // If the session to be flushed is the exclusive audit session, then
	    // indicate that there is no exclusive audit session any longer.
	    if(in->flushHandle == g_exclusiveAuditSession)
		g_exclusiveAuditSession = TPM_RH_UNASSIGNED;
	    // Flush session
	    SessionFlush(in->flushHandle);
	    break;
	  default:
	    // This command only takes object or session handle.  Other handles
	    // should be filtered out at handle unmarshal
	    FAIL(FATAL_ERROR_INTERNAL);
	    break;
	}
    return TPM_RC_SUCCESS;
}
#endif // CC_FlushContext
#include "Tpm.h"
#include "EvictControl_fp.h"
#if CC_EvictControl  // Conditional expansion of this file
TPM_RC
TPM2_EvictControl(
		  EvictControl_In     *in             // IN: input parameter list
		  )
{
    TPM_RC      result;
    OBJECT      *evictObject;
    // Input Validation
    // Get internal object pointer
    evictObject = HandleToObject(in->objectHandle);
    // Temporary, stClear or public only objects can not be made persistent
    if(evictObject->attributes.temporary == SET
       || evictObject->attributes.stClear == SET
       || evictObject->attributes.publicOnly == SET)
	return TPM_RCS_ATTRIBUTES + RC_EvictControl_objectHandle;
    // If objectHandle refers to a persistent object, it should be the same as
    // input persistentHandle
    if(evictObject->attributes.evict == SET
       && evictObject->evictHandle != in->persistentHandle)
	return TPM_RCS_HANDLE + RC_EvictControl_objectHandle;
    // Additional authorization validation
    if(in->auth == TPM_RH_PLATFORM)
	{
	    // To make persistent
	    if(evictObject->attributes.evict == CLEAR)
	        {
	            // PlatformAuth can not set evict object in storage or endorsement
	            // hierarchy
	            if(evictObject->attributes.ppsHierarchy == CLEAR)
	                return TPM_RCS_HIERARCHY + RC_EvictControl_objectHandle;
	            // Platform cannot use a handle outside of platform persistent range.
	            if(!NvIsPlatformPersistentHandle(in->persistentHandle))
	                return TPM_RCS_RANGE + RC_EvictControl_persistentHandle;
	        }
	    // PlatformAuth can delete any persistent object
	}
    else if(in->auth == TPM_RH_OWNER)
	{
	    // OwnerAuth can not set or clear evict object in platform hierarchy
	    if(evictObject->attributes.ppsHierarchy == SET)
		return TPM_RCS_HIERARCHY + RC_EvictControl_objectHandle;
	    // Owner cannot use a handle outside of owner persistent range.
	    if(evictObject->attributes.evict == CLEAR
	       && !NvIsOwnerPersistentHandle(in->persistentHandle))
		return TPM_RCS_RANGE + RC_EvictControl_persistentHandle;
	}
    else
	{
	    // Other authorization is not allowed in this command and should have been
	    // filtered out in unmarshal process
	    FAIL(FATAL_ERROR_INTERNAL);
	}
    // Internal Data Update
    // Change evict state
    if(evictObject->attributes.evict == CLEAR)
	{
	    // Make object persistent
	    if(NvFindHandle(in->persistentHandle) != 0)
		return TPM_RC_NV_DEFINED;
	    // A TPM_RC_NV_HANDLE or TPM_RC_NV_SPACE error may be returned at this
	    // point
	    result = NvAddEvictObject(in->persistentHandle, evictObject);
	}
    else
	{
	    // Delete the persistent object in NV
	    result = NvDeleteEvict(evictObject->evictHandle);
	}
    return result;
}
#endif // CC_EvictControl