michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: /*
michael@0:  * pkix_signaturechecker.c
michael@0:  *
michael@0:  * Functions for signature validation
michael@0:  *
michael@0:  */
michael@0: 
michael@0: #include "pkix_signaturechecker.h"
michael@0: 
michael@0: /*
michael@0:  * FUNCTION: pkix_SignatureCheckerstate_Destroy
michael@0:  * (see comments for PKIX_PL_DestructorCallback in pkix_pl_system.h)
michael@0:  */
michael@0: static PKIX_Error *
michael@0: pkix_SignatureCheckerState_Destroy(
michael@0:         PKIX_PL_Object *object,
michael@0:         void *plContext)
michael@0: {
michael@0:         pkix_SignatureCheckerState *state = NULL;
michael@0: 
michael@0:         PKIX_ENTER(SIGNATURECHECKERSTATE,
michael@0:                     "pkix_SignatureCheckerState_Destroy");
michael@0:         PKIX_NULLCHECK_ONE(object);
michael@0: 
michael@0:         /* Check that this object is a signature checker state */
michael@0:         PKIX_CHECK(pkix_CheckType
michael@0:                     (object, PKIX_SIGNATURECHECKERSTATE_TYPE, plContext),
michael@0:                     PKIX_OBJECTNOTSIGNATURECHECKERSTATE);
michael@0: 
michael@0:         state = (pkix_SignatureCheckerState *) object;
michael@0: 
michael@0:         state->prevCertCertSign = PKIX_FALSE;
michael@0: 
michael@0:         PKIX_DECREF(state->prevPublicKey);
michael@0:         PKIX_DECREF(state->prevPublicKeyList);
michael@0:         PKIX_DECREF(state->keyUsageOID);
michael@0: 
michael@0: cleanup:
michael@0: 
michael@0:         PKIX_RETURN(SIGNATURECHECKERSTATE);
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * FUNCTION: pkix_SignatureCheckerState_RegisterSelf
michael@0:  *
michael@0:  * DESCRIPTION:
michael@0:  *  Registers PKIX_SIGNATURECHECKERSTATE_TYPE and its related functions
michael@0:  *  with systemClasses[]
michael@0:  *
michael@0:  * THREAD SAFETY:
michael@0:  *  Not Thread Safe (see Thread Safety Definitions in Programmer's Guide)
michael@0:  *
michael@0:  *  Since this function is only called by PKIX_PL_Initialize, which should
michael@0:  *  only be called once, it is acceptable that this function is not
michael@0:  *  thread-safe.
michael@0:  */
michael@0: PKIX_Error *
michael@0: pkix_SignatureCheckerState_RegisterSelf(void *plContext)
michael@0: {
michael@0:         extern pkix_ClassTable_Entry systemClasses[PKIX_NUMTYPES];
michael@0:         pkix_ClassTable_Entry entry;
michael@0: 
michael@0:         PKIX_ENTER(SIGNATURECHECKERSTATE,
michael@0:                     "pkix_SignatureCheckerState_RegisterSelf");
michael@0: 
michael@0:         entry.description = "SignatureCheckerState";
michael@0:         entry.objCounter = 0;
michael@0:         entry.typeObjectSize = sizeof(pkix_SignatureCheckerState);
michael@0:         entry.destructor = pkix_SignatureCheckerState_Destroy;
michael@0:         entry.equalsFunction = NULL;
michael@0:         entry.hashcodeFunction = NULL;
michael@0:         entry.toStringFunction = NULL;
michael@0:         entry.comparator = NULL;
michael@0:         entry.duplicateFunction = NULL;
michael@0: 
michael@0:         systemClasses[PKIX_SIGNATURECHECKERSTATE_TYPE] = entry;
michael@0: 
michael@0:         PKIX_RETURN(SIGNATURECHECKERSTATE);
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * FUNCTION: pkix_SignatureCheckerState_Create
michael@0:  *
michael@0:  * DESCRIPTION:
michael@0:  *  Allocate and initialize SignatureChecker state data.
michael@0:  *
michael@0:  * PARAMETERS
michael@0:  *  "trustedPubKey"
michael@0:  *      Address of trusted Anchor Public Key for verifying first Cert in the
michael@0:  *      chain. Must be non-NULL.
michael@0:  *  "certsRemaining"
michael@0:  *      Number of certificates remaining in the chain.
michael@0:  *  "pCheckerState"
michael@0:  *      Address where SignatureCheckerState will be stored. Must be non-NULL.
michael@0:  *  "plContext"
michael@0:  *      Platform-specific context pointer.
michael@0:  *
michael@0:  * THREAD SAFETY:
michael@0:  *  Not Thread Safe (see Thread Safety Definitions in Programmer's Guide)
michael@0:  *
michael@0:  * RETURNS:
michael@0:  *  Returns NULL if the function succeeds.
michael@0:  *  Returns a SignatureCheckerState Error if the function fails in a
michael@0:  *  non-fatal way.
michael@0:  *  Returns a Fatal Error if the function fails in an unrecoverable way.
michael@0:  */
michael@0: static PKIX_Error *
michael@0: pkix_SignatureCheckerState_Create(
michael@0:     PKIX_PL_PublicKey *trustedPubKey,
michael@0:     PKIX_UInt32 certsRemaining,
michael@0:     pkix_SignatureCheckerState **pCheckerState,
michael@0:     void *plContext)
michael@0: {
michael@0:         pkix_SignatureCheckerState *state = NULL;
michael@0:         PKIX_PL_OID *keyUsageOID = NULL;
michael@0: 
michael@0:         PKIX_ENTER(SIGNATURECHECKERSTATE, "pkix_SignatureCheckerState_Create");
michael@0:         PKIX_NULLCHECK_TWO(trustedPubKey, pCheckerState);
michael@0: 
michael@0:         PKIX_CHECK(PKIX_PL_Object_Alloc
michael@0:                     (PKIX_SIGNATURECHECKERSTATE_TYPE,
michael@0:                     sizeof (pkix_SignatureCheckerState),
michael@0:                     (PKIX_PL_Object **)&state,
michael@0:                     plContext),
michael@0:                     PKIX_COULDNOTCREATESIGNATURECHECKERSTATEOBJECT);
michael@0: 
michael@0:         /* Initialize fields */
michael@0: 
michael@0:         state->prevCertCertSign = PKIX_TRUE;
michael@0:         state->prevPublicKeyList = NULL;
michael@0:         state->certsRemaining = certsRemaining;
michael@0: 
michael@0:         PKIX_INCREF(trustedPubKey);
michael@0:         state->prevPublicKey = trustedPubKey;
michael@0: 
michael@0:         PKIX_CHECK(PKIX_PL_OID_Create
michael@0:                     (PKIX_CERTKEYUSAGE_OID,
michael@0:                     &keyUsageOID,
michael@0:                     plContext),
michael@0:                     PKIX_OIDCREATEFAILED);
michael@0: 
michael@0:         state->keyUsageOID = keyUsageOID;
michael@0:         keyUsageOID = NULL;
michael@0: 
michael@0:         *pCheckerState = state;
michael@0:         state = NULL;
michael@0: 
michael@0: cleanup:
michael@0: 
michael@0:         PKIX_DECREF(keyUsageOID);
michael@0:         PKIX_DECREF(state); 
michael@0: 
michael@0:         PKIX_RETURN(SIGNATURECHECKERSTATE);
michael@0: }
michael@0: 
michael@0: /* --Private-Functions-------------------------------------------- */
michael@0: 
michael@0: /*
michael@0:  * FUNCTION: pkix_SignatureChecker_Check
michael@0:  * (see comments for PKIX_CertChainChecker_CheckCallback in pkix_checker.h)
michael@0:  */
michael@0: PKIX_Error *
michael@0: pkix_SignatureChecker_Check(
michael@0:         PKIX_CertChainChecker *checker,
michael@0:         PKIX_PL_Cert *cert,
michael@0:         PKIX_List *unresolvedCriticalExtensions,
michael@0:         void **pNBIOContext,
michael@0:         void *plContext)
michael@0: {
michael@0:         pkix_SignatureCheckerState *state = NULL;
michael@0:         PKIX_PL_PublicKey *prevPubKey = NULL;
michael@0:         PKIX_PL_PublicKey *currPubKey = NULL;
michael@0:         PKIX_PL_PublicKey *newPubKey = NULL;
michael@0:         PKIX_PL_PublicKey *pKey = NULL;
michael@0:         PKIX_PL_CertBasicConstraints *basicConstraints = NULL;
michael@0:         PKIX_Error *checkKeyUsageFail = NULL;
michael@0:         PKIX_Error *verifyFail = NULL;
michael@0:         PKIX_Boolean certVerified = PKIX_FALSE;
michael@0: 
michael@0:         PKIX_ENTER(CERTCHAINCHECKER, "pkix_SignatureChecker_Check");
michael@0:         PKIX_NULLCHECK_THREE(checker, cert, pNBIOContext);
michael@0: 
michael@0:         *pNBIOContext = NULL; /* we never block on pending I/O */
michael@0: 
michael@0:         PKIX_CHECK(PKIX_CertChainChecker_GetCertChainCheckerState
michael@0:                     (checker, (PKIX_PL_Object **)&state, plContext),
michael@0:                     PKIX_CERTCHAINCHECKERGETCERTCHAINCHECKERSTATEFAILED);
michael@0: 
michael@0:         (state->certsRemaining)--;
michael@0: 
michael@0:         PKIX_INCREF(state->prevPublicKey);
michael@0:         prevPubKey = state->prevPublicKey;
michael@0: 
michael@0:         /*
michael@0:          * Previous Cert doesn't have CertSign bit on for signature
michael@0:          * verification and it is not a self-issued Cert so there is no
michael@0:          * old key saved. This is considered error.
michael@0:          */
michael@0:         if (state->prevCertCertSign == PKIX_FALSE &&
michael@0:                 state->prevPublicKeyList == NULL) {
michael@0:                     PKIX_ERROR(PKIX_KEYUSAGEKEYCERTSIGNBITNOTON);
michael@0:         }
michael@0: 
michael@0:         /* Previous Cert is valid for signature verification, try it first */
michael@0:         if (state->prevCertCertSign == PKIX_TRUE) {
michael@0:                 verifyFail = PKIX_PL_Cert_VerifySignature
michael@0:                         (cert, prevPubKey, plContext);
michael@0:                 if (verifyFail == NULL) {
michael@0:                         certVerified = PKIX_TRUE;
michael@0:                 } else {
michael@0:                         certVerified = PKIX_FALSE;
michael@0:                 }
michael@0:         }
michael@0: 
michael@0: #ifdef NIST_TEST_4_5_4_AND_4_5_6
michael@0: 
michael@0:         /*
michael@0:          * Following codes under this compiler flag is implemented for
michael@0:          * special cases of NIST tests 4.5.4 and 4.5.6. We are not sure
michael@0:          * we should handle these two tests as what is implemented so the
michael@0:          * codes are commented out, and the tests fails (for now).
michael@0:          * For Cert chain validation, our assumption is all the Certs on
michael@0:          * the chain are using its previous Cert's public key to decode
michael@0:          * its current key. But for thses two tests, keys are used not
michael@0:          * in this precedent order, we can either
michael@0:          * 1) Use what is implemented here: take in what Cert order NIST
michael@0:          *    specified and for continuous self-issued Certs, stacking up
michael@0:          *    their keys and tries all of them in FILO order.
michael@0:          *    But this method breaks the idea of chain key presdency.
michael@0:          * 2) Use Build Chain facility: we will specify the valid Certs
michael@0:          *    order (means key precedency is kept) and count on Build Chain
michael@0:          *    to get the Certs that can fill for the needed keys. This may have
michael@0:          *    performance impact.
michael@0:          * 3) Fetch Certs from CertStore: we will specifiy the valid Certs
michael@0:          *    order and use CertSelector on SubjectName to get a list of
michael@0:          *    candidates Certs to fill in for the needed keys.
michael@0:          * Anyhow, the codes are kept around just in case we want to use
michael@0:          * solution one...
michael@0:          */
michael@0: 
michael@0:         /* If failed and previous key is self-issued, try its old key(s) */
michael@0:         if (certVerified == PKIX_FALSE && state->prevPublicKeyList != NULL) {
michael@0: 
michael@0:                 /* Verify from keys on the list */
michael@0:                 PKIX_CHECK(PKIX_List_GetLength
michael@0:                         (state->prevPublicKeyList, &numKeys, plContext),
michael@0:                         PKIX_LISTGETLENGTHFAILED);
michael@0: 
michael@0:                 for (i = numKeys - 1; i >= 0; i--) {
michael@0: 
michael@0:                         PKIX_CHECK(PKIX_List_GetItem
michael@0:                                 (state->prevPublicKeyList,
michael@0:                                 i,
michael@0:                                 (PKIX_PL_Object **) &pKey,
michael@0:                                 plContext),
michael@0:                                 PKIX_LISTGETITEMFAILED);
michael@0: 
michael@0:                         PKIX_DECREF(verifyFail);
michael@0:                         verifyFail = PKIX_PL_Cert_VerifySignature
michael@0:                                 (cert, pKey, plContext);
michael@0: 
michael@0:                         if (verifyFail == NULL) {
michael@0:                                 certVerified = PKIX_TRUE;
michael@0:                                 break;
michael@0:                         } else {
michael@0:                                 certVerified = PKIX_FALSE;
michael@0:                         }
michael@0: 
michael@0:                         PKIX_DECREF(pKey);
michael@0:                 }
michael@0:         }
michael@0: #endif
michael@0: 
michael@0:         if (certVerified == PKIX_FALSE) {
michael@0:                 pkixErrorResult = verifyFail;
michael@0:                 verifyFail = NULL;
michael@0:                 PKIX_ERROR(PKIX_VALIDATIONFAILEDCERTSIGNATURECHECKING);
michael@0:         }
michael@0: 
michael@0: #ifdef NIST_TEST_4_5_4_AND_4_5_6
michael@0:         /*
michael@0:          * Check if Cert is self-issued. If so, the old key(s) is saved, in
michael@0:          * conjunction to the new key, for verifying CERT validity later.
michael@0:          */
michael@0:         PKIX_CHECK(pkix_IsCertSelfIssued(cert, &selfIssued, plContext),
michael@0:                     PKIX_ISCERTSELFISSUEFAILED);
michael@0: 
michael@0:         /*
michael@0:          * Check if Cert is self-issued. If so, the public key of the Cert
michael@0:          * that issues this Cert (old key) can be used together with this
michael@0:          * current key (new key) for key verification. If there are multiple
michael@0:          * self-issued certs, keys of those Certs (old keys) can also be used
michael@0:          * for key verification. Old key(s) is saved in a list (PrevPublickKey-
michael@0:          * List) and cleared when a Cert is no longer self-issued. PrevPublic-
michael@0:          * Key keep key of the previous Cert.
michael@0:          */
michael@0:         if (selfIssued == PKIX_TRUE) {
michael@0: 
michael@0:             /* Make sure previous Cert is valid for signature verification */
michael@0:             if (state->prevCertCertSign == PKIX_TRUE) {
michael@0: 
michael@0:                 if (state->prevPublicKeyList == NULL) {
michael@0: 
michael@0:                         PKIX_CHECK(PKIX_List_Create
michael@0:                                 (&state->prevPublicKeyList, plContext),
michael@0:                                 PKIX_LISTCREATEFALIED);
michael@0: 
michael@0:                 }
michael@0: 
michael@0:                 PKIX_CHECK(PKIX_List_AppendItem
michael@0:                             (state->prevPublicKeyList,
michael@0:                             (PKIX_PL_Object *) state->prevPublicKey,
michael@0:                             plContext),
michael@0:                             PKIX_LISTAPPENDITEMFAILED);
michael@0:             }
michael@0: 
michael@0:         } else {
michael@0:             /* Not self-issued Cert any more, clear old key(s) saved */
michael@0:             PKIX_DECREF(state->prevPublicKeyList);
michael@0:         }
michael@0: #endif
michael@0: 
michael@0:         /* Save current key as prevPublicKey */
michael@0:         PKIX_CHECK(PKIX_PL_Cert_GetSubjectPublicKey
michael@0:                     (cert, &currPubKey, plContext),
michael@0:                     PKIX_CERTGETSUBJECTPUBLICKEYFAILED);
michael@0: 
michael@0:         PKIX_CHECK(PKIX_PL_PublicKey_MakeInheritedDSAPublicKey
michael@0:                     (currPubKey, prevPubKey, &newPubKey, plContext),
michael@0:                     PKIX_PUBLICKEYMAKEINHERITEDDSAPUBLICKEYFAILED);
michael@0: 
michael@0:         if (newPubKey == NULL){
michael@0:                 PKIX_INCREF(currPubKey);
michael@0:                 newPubKey = currPubKey;
michael@0:         }
michael@0: 
michael@0:         PKIX_INCREF(newPubKey);
michael@0:         PKIX_DECREF(state->prevPublicKey);
michael@0: 
michael@0:         state->prevPublicKey = newPubKey;
michael@0: 
michael@0:         /* Save this Cert key usage CertSign bit */
michael@0:         if (state->certsRemaining != 0) {
michael@0:                 checkKeyUsageFail = PKIX_PL_Cert_VerifyKeyUsage
michael@0:                         (cert, PKIX_KEY_CERT_SIGN, plContext);
michael@0: 
michael@0:                 state->prevCertCertSign = (checkKeyUsageFail == NULL)?
michael@0:                         PKIX_TRUE:PKIX_FALSE;
michael@0: 
michael@0:                 PKIX_DECREF(checkKeyUsageFail);
michael@0:         }
michael@0: 
michael@0:         /* Remove Key Usage Extension OID from list */
michael@0:         if (unresolvedCriticalExtensions != NULL) {
michael@0: 
michael@0:                 PKIX_CHECK(pkix_List_Remove
michael@0:                             (unresolvedCriticalExtensions,
michael@0:                             (PKIX_PL_Object *) state->keyUsageOID,
michael@0:                             plContext),
michael@0:                             PKIX_LISTREMOVEFAILED);
michael@0:         }
michael@0: 
michael@0:         PKIX_CHECK(PKIX_CertChainChecker_SetCertChainCheckerState
michael@0:                     (checker, (PKIX_PL_Object *)state, plContext),
michael@0:                     PKIX_CERTCHAINCHECKERSETCERTCHAINCHECKERSTATEFAILED);
michael@0: 
michael@0: cleanup:
michael@0: 
michael@0:         PKIX_DECREF(state);
michael@0:         PKIX_DECREF(pKey);
michael@0:         PKIX_DECREF(prevPubKey);
michael@0:         PKIX_DECREF(currPubKey);
michael@0:         PKIX_DECREF(newPubKey);
michael@0:         PKIX_DECREF(basicConstraints);
michael@0:         PKIX_DECREF(verifyFail);
michael@0:         PKIX_DECREF(checkKeyUsageFail);
michael@0: 
michael@0:         PKIX_RETURN(CERTCHAINCHECKER);
michael@0: 
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * FUNCTION: pkix_SignatureChecker_Initialize
michael@0:  * DESCRIPTION:
michael@0:  *
michael@0:  *  Creates a new CertChainChecker and stores it at "pChecker", where it will
michael@0:  *  be used by pkix_SignatureChecker_Check to check that the public key in
michael@0:  *  the checker's state is able to successfully validate the certificate's
michael@0:  *  signature. The PublicKey pointed to by "trustedPubKey" is used to
michael@0:  *  initialize the checker's state.
michael@0:  *
michael@0:  * PARAMETERS:
michael@0:  *  "trustedPubKey"
michael@0:  *      Address of PublicKey representing the trusted public key used to
michael@0:  *      initialize the state of this checker. Must be non-NULL.
michael@0:  *  "certsRemaining"
michael@0:  *      Number of certificates remaining in the chain.
michael@0:  *  "pChecker"
michael@0:  *      Address where object pointer will be stored. Must be non-NULL.
michael@0:  *  "plContext"
michael@0:  *      Platform-specific context pointer.
michael@0:  * THREAD SAFETY:
michael@0:  *  Thread Safe (see Thread Safety Definitions in Programmer's Guide)
michael@0:  * RETURNS:
michael@0:  *  Returns NULL if the function succeeds.
michael@0:  *  Returns a CertChainChecker Error if the function fails in a non-fatal way.
michael@0:  *  Returns a Fatal Error if the function fails in an unrecoverable way.
michael@0:  */
michael@0: PKIX_Error *
michael@0: pkix_SignatureChecker_Initialize(
michael@0:         PKIX_PL_PublicKey *trustedPubKey,
michael@0:         PKIX_UInt32 certsRemaining,
michael@0:         PKIX_CertChainChecker **pChecker,
michael@0:         void *plContext)
michael@0: {
michael@0:         pkix_SignatureCheckerState* state = NULL;
michael@0:         PKIX_ENTER(CERTCHAINCHECKER, "PKIX_SignatureChecker_Initialize");
michael@0:         PKIX_NULLCHECK_TWO(pChecker, trustedPubKey);
michael@0: 
michael@0:         PKIX_CHECK(pkix_SignatureCheckerState_Create
michael@0:                     (trustedPubKey, certsRemaining, &state, plContext),
michael@0:                     PKIX_SIGNATURECHECKERSTATECREATEFAILED);
michael@0: 
michael@0:         PKIX_CHECK(PKIX_CertChainChecker_Create
michael@0:                     (pkix_SignatureChecker_Check,
michael@0:                     PKIX_FALSE,
michael@0:                     PKIX_FALSE,
michael@0:                     NULL,
michael@0:                     (PKIX_PL_Object *) state,
michael@0:                     pChecker,
michael@0:                     plContext),
michael@0:                     PKIX_CERTCHAINCHECKERCREATEFAILED);
michael@0: 
michael@0: cleanup:
michael@0: 
michael@0:         PKIX_DECREF(state);
michael@0: 
michael@0:         PKIX_RETURN(CERTCHAINCHECKER);
michael@0: 
michael@0: }