/*

 * Copyright 2019 The Chromium OS Authors. All rights reserved.

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#include "InternalRoutines.h"

#include "PolicyFidoSigned_fp.h"

/*

 * PolicyFidoContextUpdate

 *

 * @param commandCode      IN: TPM Ext command code

 * @param name             IN: name of entity

 * @param in               IN: input buffer of the command

 * @param policyTimeout    IN: policy timeout

 * @param session          IN/OUT: policy session to be updated

 * @return none

 */

static void PolicyFidoContextUpdate(TPM_CC commandCode,

                                    TPM2B_NAME *entityName,

                                    PolicyFidoSigned_In *in,

                                    SESSION *session)

{

  HASH_STATE hashState;

  UINT16 policyDigestSize;

  int i;

  /* Start hash */

  policyDigestSize = CryptStartHash(session->authHashAlg, &hashState);

  /*

   * policyDigest size should always be the digest size of session hash

   * algorithm.

   */

  pAssert(session->u2.policyDigest.t.size == policyDigestSize);

  /* add old digest */

  CryptUpdateDigest2B(&hashState, &session->u2.policyDigest.b);

  /* add commandCode */

  CryptUpdateDigestInt(&hashState, sizeof(TPM_CC), &commandCode);

  /* add name if applicable */

  if (entityName != NULL)

    CryptUpdateDigest2B(&hashState, &entityName->b);

  /* Complete the digest and get the results */

  CryptCompleteHash2B(&hashState, &session->u2.policyDigest.b);

  /* Start second hash computation */

  CryptStartHash(session->authHashAlg, &hashState);

  /* add policy digest */

  CryptUpdateDigest2B(&hashState, &session->u2.policyDigest.b);

  /* add authDataDescr */

  CryptUpdateDigest(&hashState,

                    in->authDataDescrCount * sizeof(DATA_OFFSET),

                    (BYTE *)in->authDataDescr);

  /* add authData[authDataDescr] */

  for (i = 0; i < in->authDataDescrCount; i++) {

    CryptUpdateDigest(&hashState,

                      in->authDataDescr[i].size,

                      &(in->authData.t.buffer[in->authDataDescr[i].offset]));

  }

  /* Complete second digest */

  CryptCompleteHash2B(&hashState, &session->u2.policyDigest.b);

  return;

}

TPM_RC TPM2_PolicyFidoSigned(PolicyFidoSigned_In *in,

                             PolicyFidoSigned_Out *out)

{

  TPM_RC result = TPM_RC_SUCCESS;

  SESSION *session;

  TPM2B_NAME entityName;

  session = SessionGet(in->policySession);

  /* Only do input validation if this is not a trial policy session */

  if (session->attributes.isTrialPolicy == CLEAR) {

    TPM2B_DIGEST authHash;

    HASH_STATE hashState;

    /*

     * Re-compute the digest being signed:

     *

     * aHash := hash (authenticatorData[] || nonceTPM)

     *

     * Start hash

     */

    authHash.t.size = CryptStartHash(CryptGetSignHashAlg(&in->auth),

                                     &hashState);

    /* add authData */

    CryptUpdateDigest(&hashState,

                      in->authData.t.size,

                      (BYTE *)in->authData.t.buffer);

    /* Add the sesson nonce */

    CryptUpdateDigest2B(&hashState, &session->nonceTPM.b);

    /* Complete digest */

    CryptCompleteHash2B(&hashState, &authHash.b);

    /*

     * Validate Signature. A TPM_RC_SCHEME, TPM_RC_HANDLE or

     * TPM_RC_SIGNATURE error may be returned at this point.

     */

    result = CryptVerifySignature(in->authObject, &authHash, &in->auth);

    if (result != TPM_RC_SUCCESS)

      return RcSafeAddToResult(result, RC_PolicySigned_auth);

  }

  /* Internal Data Update */

  /* Need the Name of the signing entity */

  entityName.t.size = EntityGetName(in->authObject, &entityName.t.name);

  /*

   * Update policy with input policyRef and name of auth key

   * These values are updated even if the session is a trial session

   */

  PolicyFidoContextUpdate(TPM_CCE_PolicyFidoSigned,

                          &entityName,

                          in,

                          session);

  /*

   * Command Output

   *

   *   No output to generate.

   */

  return TPM_RC_SUCCESS;

}