--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/libpkix/pkix/checker/pkix_signaturechecker.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,443 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/*
+ * pkix_signaturechecker.c
+ *
+ * Functions for signature validation
+ *
+ */
+
+#include "pkix_signaturechecker.h"
+
+/*
+ * FUNCTION: pkix_SignatureCheckerstate_Destroy
+ * (see comments for PKIX_PL_DestructorCallback in pkix_pl_system.h)
+ */
+static PKIX_Error *
+pkix_SignatureCheckerState_Destroy(
+        PKIX_PL_Object *object,
+        void *plContext)
+{
+        pkix_SignatureCheckerState *state = NULL;
+
+        PKIX_ENTER(SIGNATURECHECKERSTATE,
+                    "pkix_SignatureCheckerState_Destroy");
+        PKIX_NULLCHECK_ONE(object);
+
+        /* Check that this object is a signature checker state */
+        PKIX_CHECK(pkix_CheckType
+                    (object, PKIX_SIGNATURECHECKERSTATE_TYPE, plContext),
+                    PKIX_OBJECTNOTSIGNATURECHECKERSTATE);
+
+        state = (pkix_SignatureCheckerState *) object;
+
+        state->prevCertCertSign = PKIX_FALSE;
+
+        PKIX_DECREF(state->prevPublicKey);
+        PKIX_DECREF(state->prevPublicKeyList);
+        PKIX_DECREF(state->keyUsageOID);
+
+cleanup:
+
+        PKIX_RETURN(SIGNATURECHECKERSTATE);
+}
+
+/*
+ * FUNCTION: pkix_SignatureCheckerState_RegisterSelf
+ *
+ * DESCRIPTION:
+ *  Registers PKIX_SIGNATURECHECKERSTATE_TYPE and its related functions
+ *  with systemClasses[]
+ *
+ * THREAD SAFETY:
+ *  Not Thread Safe (see Thread Safety Definitions in Programmer's Guide)
+ *
+ *  Since this function is only called by PKIX_PL_Initialize, which should
+ *  only be called once, it is acceptable that this function is not
+ *  thread-safe.
+ */
+PKIX_Error *
+pkix_SignatureCheckerState_RegisterSelf(void *plContext)
+{
+        extern pkix_ClassTable_Entry systemClasses[PKIX_NUMTYPES];
+        pkix_ClassTable_Entry entry;
+
+        PKIX_ENTER(SIGNATURECHECKERSTATE,
+                    "pkix_SignatureCheckerState_RegisterSelf");
+
+        entry.description = "SignatureCheckerState";
+        entry.objCounter = 0;
+        entry.typeObjectSize = sizeof(pkix_SignatureCheckerState);
+        entry.destructor = pkix_SignatureCheckerState_Destroy;
+        entry.equalsFunction = NULL;
+        entry.hashcodeFunction = NULL;
+        entry.toStringFunction = NULL;
+        entry.comparator = NULL;
+        entry.duplicateFunction = NULL;
+
+        systemClasses[PKIX_SIGNATURECHECKERSTATE_TYPE] = entry;
+
+        PKIX_RETURN(SIGNATURECHECKERSTATE);
+}
+
+/*
+ * FUNCTION: pkix_SignatureCheckerState_Create
+ *
+ * DESCRIPTION:
+ *  Allocate and initialize SignatureChecker state data.
+ *
+ * PARAMETERS
+ *  "trustedPubKey"
+ *      Address of trusted Anchor Public Key for verifying first Cert in the
+ *      chain. Must be non-NULL.
+ *  "certsRemaining"
+ *      Number of certificates remaining in the chain.
+ *  "pCheckerState"
+ *      Address where SignatureCheckerState will be stored. Must be non-NULL.
+ *  "plContext"
+ *      Platform-specific context pointer.
+ *
+ * THREAD SAFETY:
+ *  Not Thread Safe (see Thread Safety Definitions in Programmer's Guide)
+ *
+ * RETURNS:
+ *  Returns NULL if the function succeeds.
+ *  Returns a SignatureCheckerState Error if the function fails in a
+ *  non-fatal way.
+ *  Returns a Fatal Error if the function fails in an unrecoverable way.
+ */
+static PKIX_Error *
+pkix_SignatureCheckerState_Create(
+    PKIX_PL_PublicKey *trustedPubKey,
+    PKIX_UInt32 certsRemaining,
+    pkix_SignatureCheckerState **pCheckerState,
+    void *plContext)
+{
+        pkix_SignatureCheckerState *state = NULL;
+        PKIX_PL_OID *keyUsageOID = NULL;
+
+        PKIX_ENTER(SIGNATURECHECKERSTATE, "pkix_SignatureCheckerState_Create");
+        PKIX_NULLCHECK_TWO(trustedPubKey, pCheckerState);
+
+        PKIX_CHECK(PKIX_PL_Object_Alloc
+                    (PKIX_SIGNATURECHECKERSTATE_TYPE,
+                    sizeof (pkix_SignatureCheckerState),
+                    (PKIX_PL_Object **)&state,
+                    plContext),
+                    PKIX_COULDNOTCREATESIGNATURECHECKERSTATEOBJECT);
+
+        /* Initialize fields */
+
+        state->prevCertCertSign = PKIX_TRUE;
+        state->prevPublicKeyList = NULL;
+        state->certsRemaining = certsRemaining;
+
+        PKIX_INCREF(trustedPubKey);
+        state->prevPublicKey = trustedPubKey;
+
+        PKIX_CHECK(PKIX_PL_OID_Create
+                    (PKIX_CERTKEYUSAGE_OID,
+                    &keyUsageOID,
+                    plContext),
+                    PKIX_OIDCREATEFAILED);
+
+        state->keyUsageOID = keyUsageOID;
+        keyUsageOID = NULL;
+
+        *pCheckerState = state;
+        state = NULL;
+
+cleanup:
+
+        PKIX_DECREF(keyUsageOID);
+        PKIX_DECREF(state); 
+
+        PKIX_RETURN(SIGNATURECHECKERSTATE);
+}
+
+/* --Private-Functions-------------------------------------------- */
+
+/*
+ * FUNCTION: pkix_SignatureChecker_Check
+ * (see comments for PKIX_CertChainChecker_CheckCallback in pkix_checker.h)
+ */
+PKIX_Error *
+pkix_SignatureChecker_Check(
+        PKIX_CertChainChecker *checker,
+        PKIX_PL_Cert *cert,
+        PKIX_List *unresolvedCriticalExtensions,
+        void **pNBIOContext,
+        void *plContext)
+{
+        pkix_SignatureCheckerState *state = NULL;
+        PKIX_PL_PublicKey *prevPubKey = NULL;
+        PKIX_PL_PublicKey *currPubKey = NULL;
+        PKIX_PL_PublicKey *newPubKey = NULL;
+        PKIX_PL_PublicKey *pKey = NULL;
+        PKIX_PL_CertBasicConstraints *basicConstraints = NULL;
+        PKIX_Error *checkKeyUsageFail = NULL;
+        PKIX_Error *verifyFail = NULL;
+        PKIX_Boolean certVerified = PKIX_FALSE;
+
+        PKIX_ENTER(CERTCHAINCHECKER, "pkix_SignatureChecker_Check");
+        PKIX_NULLCHECK_THREE(checker, cert, pNBIOContext);
+
+        *pNBIOContext = NULL; /* we never block on pending I/O */
+
+        PKIX_CHECK(PKIX_CertChainChecker_GetCertChainCheckerState
+                    (checker, (PKIX_PL_Object **)&state, plContext),
+                    PKIX_CERTCHAINCHECKERGETCERTCHAINCHECKERSTATEFAILED);
+
+        (state->certsRemaining)--;
+
+        PKIX_INCREF(state->prevPublicKey);
+        prevPubKey = state->prevPublicKey;
+
+        /*
+         * Previous Cert doesn't have CertSign bit on for signature
+         * verification and it is not a self-issued Cert so there is no
+         * old key saved. This is considered error.
+         */
+        if (state->prevCertCertSign == PKIX_FALSE &&
+                state->prevPublicKeyList == NULL) {
+                    PKIX_ERROR(PKIX_KEYUSAGEKEYCERTSIGNBITNOTON);
+        }
+
+        /* Previous Cert is valid for signature verification, try it first */
+        if (state->prevCertCertSign == PKIX_TRUE) {
+                verifyFail = PKIX_PL_Cert_VerifySignature
+                        (cert, prevPubKey, plContext);
+                if (verifyFail == NULL) {
+                        certVerified = PKIX_TRUE;
+                } else {
+                        certVerified = PKIX_FALSE;
+                }
+        }
+
+#ifdef NIST_TEST_4_5_4_AND_4_5_6
+
+        /*
+         * Following codes under this compiler flag is implemented for
+         * special cases of NIST tests 4.5.4 and 4.5.6. We are not sure
+         * we should handle these two tests as what is implemented so the
+         * codes are commented out, and the tests fails (for now).
+         * For Cert chain validation, our assumption is all the Certs on
+         * the chain are using its previous Cert's public key to decode
+         * its current key. But for thses two tests, keys are used not
+         * in this precedent order, we can either
+         * 1) Use what is implemented here: take in what Cert order NIST
+         *    specified and for continuous self-issued Certs, stacking up
+         *    their keys and tries all of them in FILO order.
+         *    But this method breaks the idea of chain key presdency.
+         * 2) Use Build Chain facility: we will specify the valid Certs
+         *    order (means key precedency is kept) and count on Build Chain
+         *    to get the Certs that can fill for the needed keys. This may have
+         *    performance impact.
+         * 3) Fetch Certs from CertStore: we will specifiy the valid Certs
+         *    order and use CertSelector on SubjectName to get a list of
+         *    candidates Certs to fill in for the needed keys.
+         * Anyhow, the codes are kept around just in case we want to use
+         * solution one...
+         */
+
+        /* If failed and previous key is self-issued, try its old key(s) */
+        if (certVerified == PKIX_FALSE && state->prevPublicKeyList != NULL) {
+
+                /* Verify from keys on the list */
+                PKIX_CHECK(PKIX_List_GetLength
+                        (state->prevPublicKeyList, &numKeys, plContext),
+                        PKIX_LISTGETLENGTHFAILED);
+
+                for (i = numKeys - 1; i >= 0; i--) {
+
+                        PKIX_CHECK(PKIX_List_GetItem
+                                (state->prevPublicKeyList,
+                                i,
+                                (PKIX_PL_Object **) &pKey,
+                                plContext),
+                                PKIX_LISTGETITEMFAILED);
+
+                        PKIX_DECREF(verifyFail);
+                        verifyFail = PKIX_PL_Cert_VerifySignature
+                                (cert, pKey, plContext);
+
+                        if (verifyFail == NULL) {
+                                certVerified = PKIX_TRUE;
+                                break;
+                        } else {
+                                certVerified = PKIX_FALSE;
+                        }
+
+                        PKIX_DECREF(pKey);
+                }
+        }
+#endif
+
+        if (certVerified == PKIX_FALSE) {
+                pkixErrorResult = verifyFail;
+                verifyFail = NULL;
+                PKIX_ERROR(PKIX_VALIDATIONFAILEDCERTSIGNATURECHECKING);
+        }
+
+#ifdef NIST_TEST_4_5_4_AND_4_5_6
+        /*
+         * Check if Cert is self-issued. If so, the old key(s) is saved, in
+         * conjunction to the new key, for verifying CERT validity later.
+         */
+        PKIX_CHECK(pkix_IsCertSelfIssued(cert, &selfIssued, plContext),
+                    PKIX_ISCERTSELFISSUEFAILED);
+
+        /*
+         * Check if Cert is self-issued. If so, the public key of the Cert
+         * that issues this Cert (old key) can be used together with this
+         * current key (new key) for key verification. If there are multiple
+         * self-issued certs, keys of those Certs (old keys) can also be used
+         * for key verification. Old key(s) is saved in a list (PrevPublickKey-
+         * List) and cleared when a Cert is no longer self-issued. PrevPublic-
+         * Key keep key of the previous Cert.
+         */
+        if (selfIssued == PKIX_TRUE) {
+
+            /* Make sure previous Cert is valid for signature verification */
+            if (state->prevCertCertSign == PKIX_TRUE) {
+
+                if (state->prevPublicKeyList == NULL) {
+
+                        PKIX_CHECK(PKIX_List_Create
+                                (&state->prevPublicKeyList, plContext),
+                                PKIX_LISTCREATEFALIED);
+
+                }
+
+                PKIX_CHECK(PKIX_List_AppendItem
+                            (state->prevPublicKeyList,
+                            (PKIX_PL_Object *) state->prevPublicKey,
+                            plContext),
+                            PKIX_LISTAPPENDITEMFAILED);
+            }
+
+        } else {
+            /* Not self-issued Cert any more, clear old key(s) saved */
+            PKIX_DECREF(state->prevPublicKeyList);
+        }
+#endif
+
+        /* Save current key as prevPublicKey */
+        PKIX_CHECK(PKIX_PL_Cert_GetSubjectPublicKey
+                    (cert, &currPubKey, plContext),
+                    PKIX_CERTGETSUBJECTPUBLICKEYFAILED);
+
+        PKIX_CHECK(PKIX_PL_PublicKey_MakeInheritedDSAPublicKey
+                    (currPubKey, prevPubKey, &newPubKey, plContext),
+                    PKIX_PUBLICKEYMAKEINHERITEDDSAPUBLICKEYFAILED);
+
+        if (newPubKey == NULL){
+                PKIX_INCREF(currPubKey);
+                newPubKey = currPubKey;
+        }
+
+        PKIX_INCREF(newPubKey);
+        PKIX_DECREF(state->prevPublicKey);
+
+        state->prevPublicKey = newPubKey;
+
+        /* Save this Cert key usage CertSign bit */
+        if (state->certsRemaining != 0) {
+                checkKeyUsageFail = PKIX_PL_Cert_VerifyKeyUsage
+                        (cert, PKIX_KEY_CERT_SIGN, plContext);
+
+                state->prevCertCertSign = (checkKeyUsageFail == NULL)?
+                        PKIX_TRUE:PKIX_FALSE;
+
+                PKIX_DECREF(checkKeyUsageFail);
+        }
+
+        /* Remove Key Usage Extension OID from list */
+        if (unresolvedCriticalExtensions != NULL) {
+
+                PKIX_CHECK(pkix_List_Remove
+                            (unresolvedCriticalExtensions,
+                            (PKIX_PL_Object *) state->keyUsageOID,
+                            plContext),
+                            PKIX_LISTREMOVEFAILED);
+        }
+
+        PKIX_CHECK(PKIX_CertChainChecker_SetCertChainCheckerState
+                    (checker, (PKIX_PL_Object *)state, plContext),
+                    PKIX_CERTCHAINCHECKERSETCERTCHAINCHECKERSTATEFAILED);
+
+cleanup:
+
+        PKIX_DECREF(state);
+        PKIX_DECREF(pKey);
+        PKIX_DECREF(prevPubKey);
+        PKIX_DECREF(currPubKey);
+        PKIX_DECREF(newPubKey);
+        PKIX_DECREF(basicConstraints);
+        PKIX_DECREF(verifyFail);
+        PKIX_DECREF(checkKeyUsageFail);
+
+        PKIX_RETURN(CERTCHAINCHECKER);
+
+}
+
+/*
+ * FUNCTION: pkix_SignatureChecker_Initialize
+ * DESCRIPTION:
+ *
+ *  Creates a new CertChainChecker and stores it at "pChecker", where it will
+ *  be used by pkix_SignatureChecker_Check to check that the public key in
+ *  the checker's state is able to successfully validate the certificate's
+ *  signature. The PublicKey pointed to by "trustedPubKey" is used to
+ *  initialize the checker's state.
+ *
+ * PARAMETERS:
+ *  "trustedPubKey"
+ *      Address of PublicKey representing the trusted public key used to
+ *      initialize the state of this checker. Must be non-NULL.
+ *  "certsRemaining"
+ *      Number of certificates remaining in the chain.
+ *  "pChecker"
+ *      Address where object pointer will be stored. Must be non-NULL.
+ *  "plContext"
+ *      Platform-specific context pointer.
+ * THREAD SAFETY:
+ *  Thread Safe (see Thread Safety Definitions in Programmer's Guide)
+ * RETURNS:
+ *  Returns NULL if the function succeeds.
+ *  Returns a CertChainChecker Error if the function fails in a non-fatal way.
+ *  Returns a Fatal Error if the function fails in an unrecoverable way.
+ */
+PKIX_Error *
+pkix_SignatureChecker_Initialize(
+        PKIX_PL_PublicKey *trustedPubKey,
+        PKIX_UInt32 certsRemaining,
+        PKIX_CertChainChecker **pChecker,
+        void *plContext)
+{
+        pkix_SignatureCheckerState* state = NULL;
+        PKIX_ENTER(CERTCHAINCHECKER, "PKIX_SignatureChecker_Initialize");
+        PKIX_NULLCHECK_TWO(pChecker, trustedPubKey);
+
+        PKIX_CHECK(pkix_SignatureCheckerState_Create
+                    (trustedPubKey, certsRemaining, &state, plContext),
+                    PKIX_SIGNATURECHECKERSTATECREATEFAILED);
+
+        PKIX_CHECK(PKIX_CertChainChecker_Create
+                    (pkix_SignatureChecker_Check,
+                    PKIX_FALSE,
+                    PKIX_FALSE,
+                    NULL,
+                    (PKIX_PL_Object *) state,
+                    pChecker,
+                    plContext),
+                    PKIX_CERTCHAINCHECKERCREATEFAILED);
+
+cleanup:
+
+        PKIX_DECREF(state);
+
+        PKIX_RETURN(CERTCHAINCHECKER);
+
+}