| // Copyright 2016 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "net/cert/cert_verify_proc_ios.h" |
| |
| #include <CommonCrypto/CommonDigest.h> |
| |
| #include <string_view> |
| |
| #include "base/apple/foundation_util.h" |
| #include "base/apple/osstatus_logging.h" |
| #include "base/apple/scoped_cftyperef.h" |
| #include "base/logging.h" |
| #include "base/notreached.h" |
| #include "crypto/sha2.h" |
| #include "net/base/net_errors.h" |
| #include "net/cert/asn1_util.h" |
| #include "net/cert/cert_verify_result.h" |
| #include "net/cert/crl_set.h" |
| #include "net/cert/ct_serialization.h" |
| #include "net/cert/known_roots.h" |
| #include "net/cert/test_root_certs.h" |
| #include "net/cert/x509_certificate.h" |
| #include "net/cert/x509_util.h" |
| #include "net/cert/x509_util_apple.h" |
| |
| using base::apple::ScopedCFTypeRef; |
| |
| namespace net { |
| |
| namespace { |
| |
| int NetErrorFromOSStatus(OSStatus status) { |
| switch (status) { |
| case noErr: |
| return OK; |
| case errSecNotAvailable: |
| return ERR_NOT_IMPLEMENTED; |
| case errSecAuthFailed: |
| return ERR_ACCESS_DENIED; |
| default: |
| return ERR_FAILED; |
| } |
| } |
| |
| // Maps errors from OSStatus codes to CertStatus flags. |
| // |
| // The selection of errors is based off of Apple's SecPolicyChecks.list, and |
| // any unknown errors are mapped to CERT_STATUS_INVALID for safety. |
| CertStatus CertStatusFromOSStatus(OSStatus status) { |
| switch (status) { |
| case errSecHostNameMismatch: |
| return CERT_STATUS_COMMON_NAME_INVALID; |
| |
| case errSecCertificateExpired: |
| case errSecCertificateNotValidYet: |
| return CERT_STATUS_DATE_INVALID; |
| |
| case errSecCreateChainFailed: |
| case errSecNotTrusted: |
| // errSecVerifyActionFailed is used when CT is required |
| // and not present. The OS rejected this chain, and so mapping |
| // to CERT_STATUS_CT_COMPLIANCE_FAILED (which is informational, |
| // as policy enforcement is not handled in the CertVerifier) |
| // would cause this error to be ignored and mapped to |
| // CERT_STATUS_INVALID. Rather than do that, mark it simply as |
| // "untrusted". The CT_COMPLIANCE_FAILED bit is not set, since |
| // it's not necessarily a compliance failure with the embedder's |
| // CT policy. It's a bit of a hack, but hopefully temporary. |
| // errSecNotTrusted is somewhat similar. It applies for |
| // situations where a root isn't trusted or an intermediate |
| // isn't trusted, when a key is restricted, or when the calling |
| // application requested CT enforcement (which CertVerifier |
| // should never being doing). |
| case errSecVerifyActionFailed: |
| return CERT_STATUS_AUTHORITY_INVALID; |
| |
| case errSecInvalidIDLinkage: |
| case errSecNoBasicConstraintsCA: |
| case errSecInvalidSubjectName: |
| case errSecInvalidExtendedKeyUsage: |
| case errSecInvalidKeyUsageForPolicy: |
| case errSecMissingRequiredExtension: |
| case errSecNoBasicConstraints: |
| case errSecPathLengthConstraintExceeded: |
| case errSecUnknownCertExtension: |
| case errSecUnknownCriticalExtensionFlag: |
| // errSecCertificatePolicyNotAllowed and errSecCertificateNameNotAllowed |
| // are used for certificates that violate the constraints imposed upon the |
| // issuer. Nominally this could be mapped to CERT_STATUS_AUTHORITY_INVALID, |
| // except the trustd behaviour is to treat this as a fatal |
| // (non-recoverable) error. That behavior is preserved here for consistency |
| // with Safari. |
| case errSecCertificatePolicyNotAllowed: |
| case errSecCertificateNameNotAllowed: |
| return CERT_STATUS_INVALID; |
| |
| // Unfortunately, iOS's handling of weak digest algorithms and key sizes |
| // doesn't map exactly to Chrome's. errSecInvalidDigestAlgorithm and |
| // errSecUnsupportedKeySize may indicate errors that iOS considers fatal |
| // (too weak to process at all) or recoverable (too weak according to |
| // compliance policies). |
| // Further, because SecTrustEvaluateWithError only returns a single error |
| // code, a fatal error may have occurred elsewhere in the chain, so the |
| // overall result can't be used to distinguish individual certificate |
| // errors. For this complicated reason, the weak key and weak digest cases |
| // also map to CERT_STATUS_INVALID for safety. |
| case errSecInvalidDigestAlgorithm: |
| return CERT_STATUS_WEAK_SIGNATURE_ALGORITHM | CERT_STATUS_INVALID; |
| case errSecUnsupportedKeySize: |
| return CERT_STATUS_WEAK_KEY | CERT_STATUS_INVALID; |
| |
| case errSecCertificateRevoked: |
| return CERT_STATUS_REVOKED; |
| |
| case errSecIncompleteCertRevocationCheck: |
| return CERT_STATUS_UNABLE_TO_CHECK_REVOCATION; |
| |
| case errSecCertificateValidityPeriodTooLong: |
| return CERT_STATUS_VALIDITY_TOO_LONG; |
| |
| case errSecInvalidCertificateRef: |
| case errSecInvalidName: |
| case errSecInvalidPolicyIdentifiers: |
| return CERT_STATUS_INVALID; |
| |
| // This function should only be called on errors, so should always return a |
| // CertStatus code that is considered an error. If the input is unexpectedly |
| // errSecSuccess, return CERT_STATUS_INVALID for safety. |
| case errSecSuccess: |
| default: |
| OSSTATUS_LOG(WARNING, status) |
| << "Unknown error mapped to CERT_STATUS_INVALID"; |
| return CERT_STATUS_INVALID; |
| } |
| } |
| |
| // Creates a series of SecPolicyRefs to be added to a SecTrustRef used to |
| // validate a certificate for an SSL server. |hostname| contains the name of |
| // the SSL server that the certificate should be verified against. If |
| // successful, returns noErr, and stores the resultant array of SecPolicyRefs |
| // in |policies|. |
| OSStatus CreateTrustPolicies(ScopedCFTypeRef<CFArrayRef>* policies) { |
| ScopedCFTypeRef<CFMutableArrayRef> local_policies( |
| CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks)); |
| if (!local_policies) |
| return errSecAllocate; |
| |
| base::apple::ScopedCFTypeRef<SecPolicyRef> ssl_policy( |
| SecPolicyCreateBasicX509()); |
| CFArrayAppendValue(local_policies.get(), ssl_policy.get()); |
| ssl_policy.reset(SecPolicyCreateSSL(/*server=*/true, /*hostname=*/nullptr)); |
| CFArrayAppendValue(local_policies.get(), ssl_policy.get()); |
| |
| *policies = std::move(local_policies); |
| return noErr; |
| } |
| |
| // Builds and evaluates a SecTrustRef for the certificate chain contained |
| // in |cert_array|, using the verification policies in |trust_policies|. On |
| // success, returns OK, and updates |trust_ref|, |is_trusted|, and |
| // |trust_error|. On failure, no output parameters are modified. |
| // |
| // Note: An OK return does not mean that |cert_array| is trusted, merely that |
| // verification was performed successfully. |
| int BuildAndEvaluateSecTrustRef(CFArrayRef cert_array, |
| CFArrayRef trust_policies, |
| CFDataRef ocsp_response_ref, |
| CFArrayRef sct_array_ref, |
| ScopedCFTypeRef<SecTrustRef>* trust_ref, |
| ScopedCFTypeRef<CFArrayRef>* verified_chain, |
| bool* is_trusted, |
| ScopedCFTypeRef<CFErrorRef>* trust_error) { |
| ScopedCFTypeRef<SecTrustRef> tmp_trust; |
| OSStatus status = SecTrustCreateWithCertificates(cert_array, trust_policies, |
| tmp_trust.InitializeInto()); |
| if (status) |
| return NetErrorFromOSStatus(status); |
| |
| if (TestRootCerts::HasInstance()) { |
| status = TestRootCerts::GetInstance()->FixupSecTrustRef(tmp_trust.get()); |
| if (status) |
| return NetErrorFromOSStatus(status); |
| } |
| |
| if (ocsp_response_ref) { |
| status = SecTrustSetOCSPResponse(tmp_trust.get(), ocsp_response_ref); |
| if (status) |
| return NetErrorFromOSStatus(status); |
| } |
| |
| if (sct_array_ref) { |
| if (__builtin_available(iOS 12.1.1, *)) { |
| status = SecTrustSetSignedCertificateTimestamps(tmp_trust.get(), |
| sct_array_ref); |
| if (status) |
| return NetErrorFromOSStatus(status); |
| } |
| } |
| |
| ScopedCFTypeRef<CFErrorRef> tmp_error; |
| bool tmp_is_trusted = false; |
| if (__builtin_available(iOS 12.0, *)) { |
| tmp_is_trusted = |
| SecTrustEvaluateWithError(tmp_trust.get(), tmp_error.InitializeInto()); |
| } else { |
| #if !defined(__IPHONE_12_0) || __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_12_0 |
| SecTrustResultType tmp_trust_result; |
| status = SecTrustEvaluate(tmp_trust.get(), &tmp_trust_result); |
| if (status) |
| return NetErrorFromOSStatus(status); |
| switch (tmp_trust_result) { |
| case kSecTrustResultUnspecified: |
| case kSecTrustResultProceed: |
| tmp_is_trusted = true; |
| break; |
| case kSecTrustResultInvalid: |
| return ERR_FAILED; |
| default: |
| tmp_is_trusted = false; |
| } |
| #endif |
| } |
| |
| trust_ref->swap(tmp_trust); |
| trust_error->swap(tmp_error); |
| *verified_chain = x509_util::CertificateChainFromSecTrust(trust_ref->get()); |
| *is_trusted = tmp_is_trusted; |
| return OK; |
| } |
| |
| void GetCertChainInfo(CFArrayRef cert_chain, CertVerifyResult* verify_result) { |
| DCHECK_LT(0, CFArrayGetCount(cert_chain)); |
| |
| base::apple::ScopedCFTypeRef<SecCertificateRef> verified_cert; |
| std::vector<base::apple::ScopedCFTypeRef<SecCertificateRef>> verified_chain; |
| for (CFIndex i = 0, count = CFArrayGetCount(cert_chain); i < count; ++i) { |
| SecCertificateRef chain_cert = reinterpret_cast<SecCertificateRef>( |
| const_cast<void*>(CFArrayGetValueAtIndex(cert_chain, i))); |
| if (i == 0) { |
| verified_cert.reset(chain_cert, base::scoped_policy::RETAIN); |
| } else { |
| verified_chain.emplace_back(chain_cert, base::scoped_policy::RETAIN); |
| } |
| |
| base::apple::ScopedCFTypeRef<CFDataRef> der_data( |
| SecCertificateCopyData(chain_cert)); |
| if (!der_data) { |
| verify_result->cert_status |= CERT_STATUS_INVALID; |
| return; |
| } |
| |
| std::string_view spki_bytes; |
| if (!asn1::ExtractSPKIFromDERCert( |
| std::string_view( |
| reinterpret_cast<const char*>(CFDataGetBytePtr(der_data.get())), |
| CFDataGetLength(der_data.get())), |
| &spki_bytes)) { |
| verify_result->cert_status |= CERT_STATUS_INVALID; |
| return; |
| } |
| |
| HashValue sha256(HASH_VALUE_SHA256); |
| CC_SHA256(spki_bytes.data(), spki_bytes.size(), sha256.data()); |
| verify_result->public_key_hashes.push_back(sha256); |
| } |
| if (!verified_cert.get()) { |
| NOTREACHED(); |
| verify_result->cert_status |= CERT_STATUS_INVALID; |
| return; |
| } |
| |
| scoped_refptr<X509Certificate> verified_cert_with_chain = |
| x509_util::CreateX509CertificateFromSecCertificate(verified_cert, |
| verified_chain); |
| if (verified_cert_with_chain) |
| verify_result->verified_cert = std::move(verified_cert_with_chain); |
| else |
| verify_result->cert_status |= CERT_STATUS_INVALID; |
| } |
| |
| } // namespace |
| |
| CertVerifyProcIOS::CertVerifyProcIOS(scoped_refptr<CRLSet> crl_set) |
| : CertVerifyProc(std::move(crl_set)) {} |
| |
| // static |
| CertStatus CertVerifyProcIOS::GetCertFailureStatusFromError(CFErrorRef error) { |
| if (!error) |
| return CERT_STATUS_INVALID; |
| |
| base::apple::ScopedCFTypeRef<CFStringRef> error_domain( |
| CFErrorGetDomain(error)); |
| CFIndex error_code = CFErrorGetCode(error); |
| |
| if (error_domain.get() != kCFErrorDomainOSStatus) { |
| LOG(WARNING) << "Unhandled error domain: " << error; |
| return CERT_STATUS_INVALID; |
| } |
| |
| return CertStatusFromOSStatus(error_code); |
| } |
| |
| #if !defined(__IPHONE_12_0) || __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_12_0 |
| // The iOS APIs don't expose an API-stable set of reasons for certificate |
| // validation failures. However, internally, the reason is tracked, and it's |
| // converted to user-facing localized strings. |
| // |
| // In the absence of a consistent API, convert the English strings to their |
| // localized counterpart, and then compare that with the error properties. If |
| // they're equal, it's a strong sign that this was the cause for the error. |
| // While this will break if/when iOS changes the contents of these strings, |
| // it's sufficient enough for now. |
| // |
| // TODO(rsleevi): https://crbug.com/601915 - Use a less brittle solution when |
| // possible. |
| // static |
| CertStatus CertVerifyProcIOS::GetCertFailureStatusFromTrust(SecTrustRef trust) { |
| CertStatus reason = 0; |
| |
| base::apple::ScopedCFTypeRef<CFArrayRef> properties( |
| SecTrustCopyProperties(trust)); |
| if (!properties) |
| return CERT_STATUS_INVALID; |
| |
| const CFIndex properties_length = CFArrayGetCount(properties.get()); |
| if (properties_length == 0) |
| return CERT_STATUS_INVALID; |
| |
| CFBundleRef bundle = |
| CFBundleGetBundleWithIdentifier(CFSTR("com.apple.Security")); |
| CFStringRef date_string = |
| CFSTR("One or more certificates have expired or are not valid yet."); |
| ScopedCFTypeRef<CFStringRef> date_error(CFBundleCopyLocalizedString( |
| bundle, date_string, date_string, CFSTR("SecCertificate"))); |
| CFStringRef trust_string = CFSTR("Root certificate is not trusted."); |
| ScopedCFTypeRef<CFStringRef> trust_error(CFBundleCopyLocalizedString( |
| bundle, trust_string, trust_string, CFSTR("SecCertificate"))); |
| CFStringRef weak_string = |
| CFSTR("One or more certificates is using a weak key size."); |
| ScopedCFTypeRef<CFStringRef> weak_error(CFBundleCopyLocalizedString( |
| bundle, weak_string, weak_string, CFSTR("SecCertificate"))); |
| CFStringRef hostname_mismatch_string = CFSTR("Hostname mismatch."); |
| ScopedCFTypeRef<CFStringRef> hostname_mismatch_error( |
| CFBundleCopyLocalizedString(bundle, hostname_mismatch_string, |
| hostname_mismatch_string, |
| CFSTR("SecCertificate"))); |
| CFStringRef root_certificate_string = |
| CFSTR("Unable to build chain to root certificate."); |
| ScopedCFTypeRef<CFStringRef> root_certificate_error( |
| CFBundleCopyLocalizedString(bundle, root_certificate_string, |
| root_certificate_string, |
| CFSTR("SecCertificate"))); |
| CFStringRef policy_requirements_not_met_string = |
| CFSTR("Policy requirements not met."); |
| ScopedCFTypeRef<CFStringRef> policy_requirements_not_met_error( |
| CFBundleCopyLocalizedString(bundle, policy_requirements_not_met_string, |
| policy_requirements_not_met_string, |
| CFSTR("SecCertificate"))); |
| |
| for (CFIndex i = 0; i < properties_length; ++i) { |
| CFDictionaryRef dict = reinterpret_cast<CFDictionaryRef>( |
| const_cast<void*>(CFArrayGetValueAtIndex(properties.get(), i))); |
| CFStringRef error = reinterpret_cast<CFStringRef>( |
| const_cast<void*>(CFDictionaryGetValue(dict, CFSTR("value")))); |
| |
| if (CFEqual(error, date_error.get())) { |
| reason |= CERT_STATUS_DATE_INVALID; |
| } else if (CFEqual(error, trust_error.get())) { |
| reason |= CERT_STATUS_AUTHORITY_INVALID; |
| } else if (CFEqual(error, weak_error.get())) { |
| reason |= CERT_STATUS_WEAK_KEY; |
| } else if (CFEqual(error, hostname_mismatch_error.get())) { |
| reason |= CERT_STATUS_COMMON_NAME_INVALID; |
| } else if (CFEqual(error, policy_requirements_not_met_error.get())) { |
| reason |= CERT_STATUS_INVALID | CERT_STATUS_AUTHORITY_INVALID; |
| } else if (CFEqual(error, root_certificate_error.get())) { |
| reason |= CERT_STATUS_AUTHORITY_INVALID; |
| } else { |
| LOG(ERROR) << "Unrecognized error: " << error; |
| reason |= CERT_STATUS_INVALID; |
| } |
| } |
| |
| return reason; |
| } |
| #endif // !defined(__IPHONE_12_0) || __IPHONE_OS_VERSION_MIN_REQUIRED < |
| // __IPHONE_12_0 |
| |
| CertVerifyProcIOS::~CertVerifyProcIOS() = default; |
| |
| int CertVerifyProcIOS::VerifyInternal(X509Certificate* cert, |
| const std::string& hostname, |
| const std::string& ocsp_response, |
| const std::string& sct_list, |
| int flags, |
| CertVerifyResult* verify_result, |
| const NetLogWithSource& net_log, |
| std::optional<base::Time> time_now) { |
| ScopedCFTypeRef<CFArrayRef> trust_policies; |
| OSStatus status = CreateTrustPolicies(&trust_policies); |
| if (status) |
| return NetErrorFromOSStatus(status); |
| |
| ScopedCFTypeRef<CFMutableArrayRef> cert_array( |
| x509_util::CreateSecCertificateArrayForX509Certificate( |
| cert, x509_util::InvalidIntermediateBehavior::kIgnore)); |
| if (!cert_array) { |
| verify_result->cert_status |= CERT_STATUS_INVALID; |
| return ERR_CERT_INVALID; |
| } |
| |
| ScopedCFTypeRef<CFDataRef> ocsp_response_ref; |
| if (!ocsp_response.empty()) { |
| ocsp_response_ref.reset( |
| CFDataCreate(kCFAllocatorDefault, |
| reinterpret_cast<const UInt8*>(ocsp_response.data()), |
| base::checked_cast<CFIndex>(ocsp_response.size()))); |
| if (!ocsp_response_ref) |
| return ERR_OUT_OF_MEMORY; |
| } |
| |
| ScopedCFTypeRef<CFMutableArrayRef> sct_array_ref; |
| if (!sct_list.empty()) { |
| if (__builtin_available(iOS 12.1.1, *)) { |
| std::vector<std::string_view> decoded_sct_list; |
| if (ct::DecodeSCTList(sct_list, &decoded_sct_list)) { |
| sct_array_ref.reset(CFArrayCreateMutable(kCFAllocatorDefault, |
| decoded_sct_list.size(), |
| &kCFTypeArrayCallBacks)); |
| if (!sct_array_ref) |
| return ERR_OUT_OF_MEMORY; |
| for (const auto& sct : decoded_sct_list) { |
| ScopedCFTypeRef<CFDataRef> sct_ref(CFDataCreate( |
| kCFAllocatorDefault, reinterpret_cast<const UInt8*>(sct.data()), |
| base::checked_cast<CFIndex>(sct.size()))); |
| if (!sct_ref) |
| return ERR_OUT_OF_MEMORY; |
| CFArrayAppendValue(sct_array_ref.get(), sct_ref.get()); |
| } |
| } |
| } |
| } |
| |
| ScopedCFTypeRef<SecTrustRef> trust_ref; |
| bool is_trusted = false; |
| ScopedCFTypeRef<CFArrayRef> final_chain; |
| ScopedCFTypeRef<CFErrorRef> trust_error; |
| |
| int err = BuildAndEvaluateSecTrustRef( |
| cert_array.get(), trust_policies.get(), ocsp_response_ref.get(), |
| sct_array_ref.get(), &trust_ref, &final_chain, &is_trusted, &trust_error); |
| if (err) |
| return err; |
| |
| if (CFArrayGetCount(final_chain.get()) == 0) { |
| return ERR_FAILED; |
| } |
| |
| // TODO(rsleevi): Support CRLSet revocation. |
| if (!is_trusted) { |
| if (__builtin_available(iOS 12.0, *)) { |
| verify_result->cert_status |= |
| GetCertFailureStatusFromError(trust_error.get()); |
| } else { |
| #if !defined(__IPHONE_12_0) || __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_12_0 |
| SecTrustResultType trust_result = kSecTrustResultInvalid; |
| status = SecTrustGetTrustResult(trust_ref.get(), &trust_result); |
| if (status) |
| return NetErrorFromOSStatus(status); |
| switch (trust_result) { |
| case kSecTrustResultUnspecified: |
| case kSecTrustResultProceed: |
| NOTREACHED(); |
| break; |
| case kSecTrustResultDeny: |
| verify_result->cert_status |= CERT_STATUS_AUTHORITY_INVALID; |
| break; |
| default: |
| verify_result->cert_status |= |
| GetCertFailureStatusFromTrust(trust_ref.get()); |
| } |
| #else |
| // It should be impossible to reach this code, but if somehow it is |
| // reached it would allow any certificate as valid since no errors would |
| // be added to cert_status. Therefore, add a CHECK as a fail safe. |
| CHECK(false); |
| #endif |
| } |
| } |
| GetCertChainInfo(final_chain.get(), verify_result); |
| |
| // While iOS lacks the ability to distinguish system-trusted versus |
| // user-installed roots, the set of roots that are expected to comply with |
| // the Baseline Requirements can be determined by |
| // GetNetTrustAnchorHistogramForSPKI() - a non-zero value means that it is |
| // known as a publicly trusted, and therefore subject to the BRs, cert. |
| for (auto it = verify_result->public_key_hashes.rbegin(); |
| it != verify_result->public_key_hashes.rend() && |
| !verify_result->is_issued_by_known_root; |
| ++it) { |
| verify_result->is_issued_by_known_root = |
| GetNetTrustAnchorHistogramIdForSPKI(*it) != 0; |
| } |
| |
| if (IsCertStatusError(verify_result->cert_status)) |
| return MapCertStatusToNetError(verify_result->cert_status); |
| |
| if (TestRootCerts::HasInstance() && |
| !verify_result->verified_cert->intermediate_buffers().empty() && |
| TestRootCerts::GetInstance()->IsKnownRoot(x509_util::CryptoBufferAsSpan( |
| verify_result->verified_cert->intermediate_buffers().back().get()))) { |
| verify_result->is_issued_by_known_root = true; |
| } |
| |
| LogNameNormalizationMetrics(".IOS", verify_result->verified_cert.get(), |
| verify_result->is_issued_by_known_root); |
| |
| return OK; |
| } |
| |
| } // namespace net |
