githubmirror/libtpms

src/tpm2/ContextCommands.c
589 строк22 KB
Stefan Berger
tpm2: Rename buffer to objbuf to avoid shadowing buffer variable
24 сен 2024, 02:39
24 сен 2024, 02:39a811c35
/********************************************************************************/
/*										*/
/*			   Context Management	  				*/
/*			     Written by Ken Goldman				*/
/*		       IBM Thomas J. Watson Research Center			*/
/*										*/
/*  Licenses and Notices							*/
/*										*/
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/*    information herein.							*/
/*										*/
/*  (c) Copyright IBM Corp. and others, 2016 - 2023				*/
/*										*/
/********************************************************************************/

#include "Tpm.h"

#if CC_ContextSave  // Conditional expansion of this file

#  include "ContextSave_fp.h"
#  include "Marshal.h"
#  include "Context_spt_fp.h"
#  include "NVMarshal.h" // libtpms added

/*(See part 3 specification)
  Save context
*/
//  Return Type: TPM_RC
//      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      objbuf[sizeof(OBJECT) * 2];		// libtpms changed begin
		  BYTE*              bufptr = &objbuf[0];
		  INT32              size = sizeof(objbuf);
		  UINT16             objectSize;				// 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
#  if 0											// libtpms: added
		  out->context.contextBlob.t.size =
		      integritySize + fingerprintSize + objectSize;
#  endif										// libtpms: added
#  if ALG_RSA
		  // For an RSA key, make sure that the key has had the private exponent
		  // computed before saving.
		  if(object->publicArea.type == TPM_ALG_RSA
		     && !(object->attributes.publicOnly))
		      CryptRsaLoadPrivateExponent(&object->publicArea, &object->sensitive, object); // libtpms: added object param
#  endif
		  objectSize = ANY_OBJECT_Marshal(object, &bufptr, &size, &g_RuntimeProfile);	// libtpms: added begin

		  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, objbuf, objectSize);			// 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 = object->hierarchy;

		  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
    result = ComputeContextProtectionKey(&out->context, &symKey, &iv);
    if(result != TPM_RC_SUCCESS)
	return result;

    // 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.
    result = ComputeContextIntegrity(&out->context, &integrity);
    if(result != TPM_RC_SUCCESS)
	return result;

    // 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"

#if CC_ContextLoad  // Conditional expansion of this file

#  include "ContextLoad_fp.h"
#  include "Marshal.h"
#  include "Context_spt_fp.h"

/*(See part 3 specification)
// Load context
*/

//  Return Type: TPM_RC
//      TPM_RC_CONTEXT_GAP          there is only one available slot and this is not
//                                  the oldest saved session context
//      TPM_RC_HANDLE               'context.savedHandle' does not reference a saved
//                                  session
//      TPM_RC_HIERARCHY            'context.hierarchy' is disabled
//      TPM_RC_INTEGRITY            'context' integrity check fail
//      TPM_RC_OBJECT_MEMORY        no free slot for an object
//      TPM_RC_SESSION_MEMORY       no free session slots
//      TPM_RC_SIZE                 incorrect context blob size
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
    result = ComputeContextIntegrity(&in->context, &integrityToCompare);
    if(result != TPM_RC_SUCCESS)
	return result;

    // Compare integrity
    if(!MemoryEqual2B(&integrity.b, &integrityToCompare.b))
	return TPM_RCS_INTEGRITY + RC_ContextLoad_context;
    // Compute context encryption key
    result = ComputeContextProtectionKey(&in->context, &symKey, &iv);
    if(result != TPM_RC_SUCCESS)
	return result;

    // 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

/*(See part 3 specification)
// Make a transient object persistent or evict a persistent object
*/
//  Return Type: TPM_RC
//      TPM_RC_ATTRIBUTES   an object with 'temporary', 'stClear' or 'publicOnly'
//                          attribute SET cannot be made persistent
//      TPM_RC_HIERARCHY    'auth' cannot authorize the operation in the hierarchy
//                          of 'evictObject';
//                          an object in a firmware-bound or SVN-bound hierarchy
//                          cannot be made persistent.
//      TPM_RC_HANDLE       'evictHandle' of the persistent object to be evicted is
//                          not the same as the 'persistentHandle' argument
//      TPM_RC_NV_HANDLE    'persistentHandle' is unavailable
//      TPM_RC_NV_SPACE     no space in NV to make 'evictHandle' persistent
//      TPM_RC_RANGE        'persistentHandle' is not in the range corresponding to
//                          the hierarchy of 'evictObject'
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);

    // Objects in a firmware-limited or SVN-limited hierarchy cannot be made
    // persistent.
    if(HierarchyIsFirmwareLimited(evictObject->hierarchy)
       || HierarchyIsSvnLimited(evictObject->hierarchy))
	return TPM_RCS_HIERARCHY + RC_EvictControl_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