/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* 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/. */ #include "CertVerifier.h" #include #include "ExtendedValidation.h" #include "NSSCertDBTrustDomain.h" #include "NSSErrorsService.h" #include "cert.h" #include "pk11pub.h" #include "pkix/pkix.h" #include "pkix/pkixnss.h" #include "prerror.h" #include "secerr.h" #include "sslerr.h" using namespace mozilla::pkix; using namespace mozilla::psm; PRLogModuleInfo* gCertVerifierLog = nullptr; namespace mozilla { namespace psm { const CertVerifier::Flags CertVerifier::FLAG_LOCAL_ONLY = 1; const CertVerifier::Flags CertVerifier::FLAG_MUST_BE_EV = 2; const CertVerifier::Flags CertVerifier::FLAG_TLS_IGNORE_STATUS_REQUEST = 4; CertVerifier::CertVerifier(OcspDownloadConfig odc, OcspStrictConfig osc, OcspGetConfig ogc, uint32_t certShortLifetimeInDays, PinningMode pinningMode, SHA1Mode sha1Mode) : mOCSPDownloadConfig(odc) , mOCSPStrict(osc == ocspStrict) , mOCSPGETEnabled(ogc == ocspGetEnabled) , mCertShortLifetimeInDays(certShortLifetimeInDays) , mPinningMode(pinningMode) , mSHA1Mode(sha1Mode) { } CertVerifier::~CertVerifier() { } void InitCertVerifierLog() { if (!gCertVerifierLog) { gCertVerifierLog = PR_NewLogModule("certverifier"); } } SECStatus IsCertBuiltInRoot(CERTCertificate* cert, bool& result) { result = false; ScopedPK11SlotList slots; slots = PK11_GetAllSlotsForCert(cert, nullptr); if (!slots) { if (PORT_GetError() == SEC_ERROR_NO_TOKEN) { // no list return SECSuccess; } return SECFailure; } for (PK11SlotListElement* le = slots->head; le; le = le->next) { char* token = PK11_GetTokenName(le->slot); MOZ_LOG(gCertVerifierLog, LogLevel::Debug, ("BuiltInRoot? subject=%s token=%s",cert->subjectName, token)); if (strcmp("Builtin Object Token", token) == 0) { result = true; return SECSuccess; } } return SECSuccess; } static Result BuildCertChainForOneKeyUsage(NSSCertDBTrustDomain& trustDomain, Input certDER, Time time, KeyUsage ku1, KeyUsage ku2, KeyUsage ku3, KeyPurposeId eku, const CertPolicyId& requiredPolicy, const Input* stapledOCSPResponse, /*optional out*/ CertVerifier::OCSPStaplingStatus* ocspStaplingStatus) { trustDomain.ResetOCSPStaplingStatus(); Result rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, ku1, eku, requiredPolicy, stapledOCSPResponse); if (rv == Result::ERROR_INADEQUATE_KEY_USAGE) { trustDomain.ResetOCSPStaplingStatus(); rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, ku2, eku, requiredPolicy, stapledOCSPResponse); if (rv == Result::ERROR_INADEQUATE_KEY_USAGE) { trustDomain.ResetOCSPStaplingStatus(); rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, ku3, eku, requiredPolicy, stapledOCSPResponse); if (rv != Success) { rv = Result::ERROR_INADEQUATE_KEY_USAGE; } } } if (ocspStaplingStatus) { *ocspStaplingStatus = trustDomain.GetOCSPStaplingStatus(); } return rv; } static const unsigned int MIN_RSA_BITS = 2048; static const unsigned int MIN_RSA_BITS_WEAK = 1024; SECStatus CertVerifier::VerifyCert(CERTCertificate* cert, SECCertificateUsage usage, Time time, void* pinArg, const char* hostname, const Flags flags, /*optional*/ const SECItem* stapledOCSPResponseSECItem, /*optional out*/ ScopedCERTCertList* builtChain, /*optional out*/ SECOidTag* evOidPolicy, /*optional out*/ OCSPStaplingStatus* ocspStaplingStatus, /*optional out*/ KeySizeStatus* keySizeStatus, /*optional out*/ SignatureDigestStatus* sigDigestStatus, /*optional out*/ PinningTelemetryInfo* pinningTelemetryInfo) { MOZ_LOG(gCertVerifierLog, LogLevel::Debug, ("Top of VerifyCert\n")); PR_ASSERT(cert); PR_ASSERT(usage == certificateUsageSSLServer || !(flags & FLAG_MUST_BE_EV)); PR_ASSERT(usage == certificateUsageSSLServer || !keySizeStatus); PR_ASSERT(usage == certificateUsageSSLServer || !sigDigestStatus); if (builtChain) { *builtChain = nullptr; } if (evOidPolicy) { *evOidPolicy = SEC_OID_UNKNOWN; } if (ocspStaplingStatus) { if (usage != certificateUsageSSLServer) { PR_SetError(SEC_ERROR_INVALID_ARGS, 0); return SECFailure; } *ocspStaplingStatus = OCSP_STAPLING_NEVER_CHECKED; } if (keySizeStatus) { if (usage != certificateUsageSSLServer) { PR_SetError(SEC_ERROR_INVALID_ARGS, 0); return SECFailure; } *keySizeStatus = KeySizeStatus::NeverChecked; } if (sigDigestStatus) { if (usage != certificateUsageSSLServer) { PR_SetError(SEC_ERROR_INVALID_ARGS, 0); return SECFailure; } *sigDigestStatus = SignatureDigestStatus::NeverChecked; } if (!cert || (usage != certificateUsageSSLServer && (flags & FLAG_MUST_BE_EV))) { PR_SetError(SEC_ERROR_INVALID_ARGS, 0); return SECFailure; } Result rv; Input certDER; rv = certDER.Init(cert->derCert.data, cert->derCert.len); if (rv != Success) { PR_SetError(MapResultToPRErrorCode(rv), 0); return SECFailure; } // We configure the OCSP fetching modes separately for EV and non-EV // verifications. NSSCertDBTrustDomain::OCSPFetching defaultOCSPFetching = (mOCSPDownloadConfig == ocspOff) || (mOCSPDownloadConfig == ocspEVOnly) || (flags & FLAG_LOCAL_ONLY) ? NSSCertDBTrustDomain::NeverFetchOCSP : !mOCSPStrict ? NSSCertDBTrustDomain::FetchOCSPForDVSoftFail : NSSCertDBTrustDomain::FetchOCSPForDVHardFail; OcspGetConfig ocspGETConfig = mOCSPGETEnabled ? ocspGetEnabled : ocspGetDisabled; Input stapledOCSPResponseInput; const Input* stapledOCSPResponse = nullptr; if (stapledOCSPResponseSECItem) { rv = stapledOCSPResponseInput.Init(stapledOCSPResponseSECItem->data, stapledOCSPResponseSECItem->len); if (rv != Success) { // The stapled OCSP response was too big. PR_SetError(SEC_ERROR_OCSP_MALFORMED_RESPONSE, 0); return SECFailure; } stapledOCSPResponse = &stapledOCSPResponseInput; } switch (usage) { case certificateUsageSSLClient: { // XXX: We don't really have a trust bit for SSL client authentication so // just use trustEmail as it is the closest alternative. NSSCertDBTrustDomain trustDomain(trustEmail, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, pinningDisabled, MIN_RSA_BITS_WEAK, ValidityCheckingMode::CheckingOff, AcceptAllAlgorithms, SHA1Mode::Allowed, nullptr, nullptr, builtChain); rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, KeyUsage::digitalSignature, KeyPurposeId::id_kp_clientAuth, CertPolicyId::anyPolicy, stapledOCSPResponse); break; } case certificateUsageSSLServer: { // TODO: When verifying a certificate in an SSL handshake, we should // restrict the acceptable key usage based on the key exchange method // chosen by the server. SignatureDigestOption digestAlgorithmOptions[] = { DisableSHA1Everywhere, DisableSHA1ForCA, DisableSHA1ForEE, AcceptAllAlgorithms }; SignatureDigestStatus digestAlgorithmStatuses[] = { SignatureDigestStatus::GoodAlgorithmsOnly, SignatureDigestStatus::WeakEECert, SignatureDigestStatus::WeakCACert, SignatureDigestStatus::WeakCAAndEE }; size_t digestAlgorithmOptionsCount = MOZ_ARRAY_LENGTH(digestAlgorithmStatuses); static_assert(MOZ_ARRAY_LENGTH(digestAlgorithmOptions) == MOZ_ARRAY_LENGTH(digestAlgorithmStatuses), "digestAlgorithm array lengths differ"); rv = Result::ERROR_UNKNOWN_ERROR; #ifndef MOZ_NO_EV_CERTS // Try to validate for EV first. NSSCertDBTrustDomain::OCSPFetching evOCSPFetching = (mOCSPDownloadConfig == ocspOff) || (flags & FLAG_LOCAL_ONLY) ? NSSCertDBTrustDomain::LocalOnlyOCSPForEV : NSSCertDBTrustDomain::FetchOCSPForEV; CertPolicyId evPolicy; SECOidTag evPolicyOidTag; SECStatus srv = GetFirstEVPolicy(cert, evPolicy, evPolicyOidTag); for (size_t i=0; i < digestAlgorithmOptionsCount && rv != Success && srv == SECSuccess; i++) { // Because of the try-strict and fallback approach, we have to clear any // previously noted telemetry information if (pinningTelemetryInfo) { pinningTelemetryInfo->Reset(); } NSSCertDBTrustDomain trustDomain(trustSSL, evOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, mPinningMode, MIN_RSA_BITS, ValidityCheckingMode::CheckForEV, digestAlgorithmOptions[i], mSHA1Mode, pinningTelemetryInfo, hostname, builtChain); rv = BuildCertChainForOneKeyUsage(trustDomain, certDER, time, KeyUsage::digitalSignature,// (EC)DHE KeyUsage::keyEncipherment, // RSA KeyUsage::keyAgreement, // (EC)DH KeyPurposeId::id_kp_serverAuth, evPolicy, stapledOCSPResponse, ocspStaplingStatus); if (rv == Success) { MOZ_LOG(gCertVerifierLog, LogLevel::Debug, ("cert is EV with status %i\n", digestAlgorithmStatuses[i])); if (evOidPolicy) { *evOidPolicy = evPolicyOidTag; } if (sigDigestStatus) { *sigDigestStatus = digestAlgorithmStatuses[i]; } } } if (rv == Success) { break; } #endif if (flags & FLAG_MUST_BE_EV) { rv = Result::ERROR_POLICY_VALIDATION_FAILED; break; } // Now try non-EV. unsigned int keySizeOptions[] = { MIN_RSA_BITS, MIN_RSA_BITS_WEAK }; KeySizeStatus keySizeStatuses[] = { KeySizeStatus::LargeMinimumSucceeded, KeySizeStatus::CompatibilityRisk }; static_assert(MOZ_ARRAY_LENGTH(keySizeOptions) == MOZ_ARRAY_LENGTH(keySizeStatuses), "keySize array lengths differ"); size_t keySizeOptionsCount = MOZ_ARRAY_LENGTH(keySizeStatuses); for (size_t i=0; iReset(); } // If we're not going to do SHA-1 in any case, don't try if (mSHA1Mode == SHA1Mode::Forbidden && digestAlgorithmOptions[i] != DisableSHA1Everywhere) { continue; } NSSCertDBTrustDomain trustDomain(trustSSL, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, mPinningMode, keySizeOptions[i], ValidityCheckingMode::CheckingOff, digestAlgorithmOptions[j], mSHA1Mode, pinningTelemetryInfo, hostname, builtChain); rv = BuildCertChainForOneKeyUsage(trustDomain, certDER, time, KeyUsage::digitalSignature,//(EC)DHE KeyUsage::keyEncipherment,//RSA KeyUsage::keyAgreement,//(EC)DH KeyPurposeId::id_kp_serverAuth, CertPolicyId::anyPolicy, stapledOCSPResponse, ocspStaplingStatus); if (rv == Success) { if (keySizeStatus) { *keySizeStatus = keySizeStatuses[i]; } if (sigDigestStatus) { *sigDigestStatus = digestAlgorithmStatuses[j]; } } } } if (rv == Success) { // If SHA-1 is forbidden by preference, don't accumulate SHA-1 // telemetry, to avoid skewing the results. if (sigDigestStatus && mSHA1Mode == SHA1Mode::Forbidden) { *sigDigestStatus = SignatureDigestStatus::NeverChecked; } break; } if (keySizeStatus) { *keySizeStatus = KeySizeStatus::AlreadyBad; } if (sigDigestStatus && mSHA1Mode != SHA1Mode::Forbidden) { *sigDigestStatus = SignatureDigestStatus::AlreadyBad; } break; } case certificateUsageSSLCA: { NSSCertDBTrustDomain trustDomain(trustSSL, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, pinningDisabled, MIN_RSA_BITS_WEAK, ValidityCheckingMode::CheckingOff, AcceptAllAlgorithms, mSHA1Mode, nullptr, nullptr, builtChain); rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeCA, KeyUsage::keyCertSign, KeyPurposeId::id_kp_serverAuth, CertPolicyId::anyPolicy, stapledOCSPResponse); break; } case certificateUsageEmailSigner: { NSSCertDBTrustDomain trustDomain(trustEmail, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, pinningDisabled, MIN_RSA_BITS_WEAK, ValidityCheckingMode::CheckingOff, AcceptAllAlgorithms, SHA1Mode::Allowed, nullptr, nullptr, builtChain); rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, KeyUsage::digitalSignature, KeyPurposeId::id_kp_emailProtection, CertPolicyId::anyPolicy, stapledOCSPResponse); if (rv == Result::ERROR_INADEQUATE_KEY_USAGE) { rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, KeyUsage::nonRepudiation, KeyPurposeId::id_kp_emailProtection, CertPolicyId::anyPolicy, stapledOCSPResponse); } break; } case certificateUsageEmailRecipient: { // TODO: The higher level S/MIME processing should pass in which key // usage it is trying to verify for, and base its algorithm choices // based on the result of the verification(s). NSSCertDBTrustDomain trustDomain(trustEmail, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, pinningDisabled, MIN_RSA_BITS_WEAK, ValidityCheckingMode::CheckingOff, AcceptAllAlgorithms, SHA1Mode::Allowed, nullptr, nullptr, builtChain); rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, KeyUsage::keyEncipherment, // RSA KeyPurposeId::id_kp_emailProtection, CertPolicyId::anyPolicy, stapledOCSPResponse); if (rv == Result::ERROR_INADEQUATE_KEY_USAGE) { rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, KeyUsage::keyAgreement, // ECDH/DH KeyPurposeId::id_kp_emailProtection, CertPolicyId::anyPolicy, stapledOCSPResponse); } break; } case certificateUsageObjectSigner: { NSSCertDBTrustDomain trustDomain(trustObjectSigning, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, pinningDisabled, MIN_RSA_BITS_WEAK, ValidityCheckingMode::CheckingOff, AcceptAllAlgorithms, SHA1Mode::Allowed, nullptr, nullptr, builtChain); rv = BuildCertChain(trustDomain, certDER, time, EndEntityOrCA::MustBeEndEntity, KeyUsage::digitalSignature, KeyPurposeId::id_kp_codeSigning, CertPolicyId::anyPolicy, stapledOCSPResponse); break; } case certificateUsageVerifyCA: case certificateUsageStatusResponder: { // XXX This is a pretty useless way to verify a certificate. It is used // by the certificate viewer UI. Because we don't know what trust bit is // interesting, we just try them all. mozilla::pkix::EndEntityOrCA endEntityOrCA; mozilla::pkix::KeyUsage keyUsage; KeyPurposeId eku; if (usage == certificateUsageVerifyCA) { endEntityOrCA = EndEntityOrCA::MustBeCA; keyUsage = KeyUsage::keyCertSign; eku = KeyPurposeId::anyExtendedKeyUsage; } else { endEntityOrCA = EndEntityOrCA::MustBeEndEntity; keyUsage = KeyUsage::digitalSignature; eku = KeyPurposeId::id_kp_OCSPSigning; } NSSCertDBTrustDomain sslTrust(trustSSL, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, pinningDisabled, MIN_RSA_BITS_WEAK, ValidityCheckingMode::CheckingOff, AcceptAllAlgorithms, SHA1Mode::Allowed, nullptr, nullptr, builtChain); rv = BuildCertChain(sslTrust, certDER, time, endEntityOrCA, keyUsage, eku, CertPolicyId::anyPolicy, stapledOCSPResponse); if (rv == Result::ERROR_UNKNOWN_ISSUER) { NSSCertDBTrustDomain emailTrust(trustEmail, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, pinningDisabled, MIN_RSA_BITS_WEAK, ValidityCheckingMode::CheckingOff, AcceptAllAlgorithms, SHA1Mode::Allowed, nullptr, nullptr, builtChain); rv = BuildCertChain(emailTrust, certDER, time, endEntityOrCA, keyUsage, eku, CertPolicyId::anyPolicy, stapledOCSPResponse); if (rv == Result::ERROR_UNKNOWN_ISSUER) { NSSCertDBTrustDomain objectSigningTrust(trustObjectSigning, defaultOCSPFetching, mOCSPCache, pinArg, ocspGETConfig, mCertShortLifetimeInDays, pinningDisabled, MIN_RSA_BITS_WEAK, ValidityCheckingMode::CheckingOff, AcceptAllAlgorithms, SHA1Mode::Allowed, nullptr, nullptr, builtChain); rv = BuildCertChain(objectSigningTrust, certDER, time, endEntityOrCA, keyUsage, eku, CertPolicyId::anyPolicy, stapledOCSPResponse); } } break; } default: rv = Result::FATAL_ERROR_INVALID_ARGS; } if (rv != Success) { PR_SetError(MapResultToPRErrorCode(rv), 0); return SECFailure; } return SECSuccess; } SECStatus CertVerifier::VerifySSLServerCert(CERTCertificate* peerCert, /*optional*/ const SECItem* stapledOCSPResponse, Time time, /*optional*/ void* pinarg, const char* hostname, bool saveIntermediatesInPermanentDatabase, Flags flags, /*optional out*/ ScopedCERTCertList* builtChain, /*optional out*/ SECOidTag* evOidPolicy, /*optional out*/ OCSPStaplingStatus* ocspStaplingStatus, /*optional out*/ KeySizeStatus* keySizeStatus, /*optional out*/ SignatureDigestStatus* sigDigestStatus, /*optional out*/ PinningTelemetryInfo* pinningTelemetryInfo) { PR_ASSERT(peerCert); // XXX: PR_ASSERT(pinarg) PR_ASSERT(hostname); PR_ASSERT(hostname[0]); if (builtChain) { *builtChain = nullptr; } if (evOidPolicy) { *evOidPolicy = SEC_OID_UNKNOWN; } if (!hostname || !hostname[0]) { PR_SetError(SSL_ERROR_BAD_CERT_DOMAIN, 0); return SECFailure; } ScopedCERTCertList builtChainTemp; // CreateCertErrorRunnable assumes that CheckCertHostname is only called // if VerifyCert succeeded. SECStatus rv = VerifyCert(peerCert, certificateUsageSSLServer, time, pinarg, hostname, flags, stapledOCSPResponse, &builtChainTemp, evOidPolicy, ocspStaplingStatus, keySizeStatus, sigDigestStatus, pinningTelemetryInfo); if (rv != SECSuccess) { return rv; } Input peerCertInput; Result result = peerCertInput.Init(peerCert->derCert.data, peerCert->derCert.len); if (result != Success) { PR_SetError(MapResultToPRErrorCode(result), 0); return SECFailure; } Input stapledOCSPResponseInput; Input* responseInputPtr = nullptr; if (stapledOCSPResponse) { result = stapledOCSPResponseInput.Init(stapledOCSPResponse->data, stapledOCSPResponse->len); if (result != Success) { // The stapled OCSP response was too big. PR_SetError(SEC_ERROR_OCSP_MALFORMED_RESPONSE, 0); return SECFailure; } responseInputPtr = &stapledOCSPResponseInput; } if (!(flags & FLAG_TLS_IGNORE_STATUS_REQUEST)) { result = CheckTLSFeaturesAreSatisfied(peerCertInput, responseInputPtr); if (result != Success) { PR_SetError(MapResultToPRErrorCode(result), 0); return SECFailure; } } Input hostnameInput; result = hostnameInput.Init(uint8_t_ptr_cast(hostname), strlen(hostname)); if (result != Success) { PR_SetError(SEC_ERROR_INVALID_ARGS, 0); return SECFailure; } result = CheckCertHostname(peerCertInput, hostnameInput); if (result != Success) { // Treat malformed name information as a domain mismatch. if (result == Result::ERROR_BAD_DER) { PR_SetError(SSL_ERROR_BAD_CERT_DOMAIN, 0); } else { PR_SetError(MapResultToPRErrorCode(result), 0); } return SECFailure; } if (saveIntermediatesInPermanentDatabase) { SaveIntermediateCerts(builtChainTemp); } if (builtChain) { *builtChain = builtChainTemp.forget(); } return SECSuccess; } } } // namespace mozilla::psm