// Copyright (c) 2012 The Chromium 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 "net/cert/cert_verify_proc_mac.h"
#include <CommonCrypto/CommonDigest.h>
#include <CoreServices/CoreServices.h>
#include <Security/Security.h>
#include <string>
#include <vector>
#include "base/logging.h"
#include "base/mac/mac_logging.h"
#include "base/mac/scoped_cftyperef.h"
#include "base/sha1.h"
#include "base/strings/string_piece.h"
#include "base/synchronization/lock.h"
#include "crypto/mac_security_services_lock.h"
#include "crypto/sha2.h"
#include "net/base/net_errors.h"
#include "net/cert/asn1_util.h"
#include "net/cert/cert_status_flags.h"
#include "net/cert/cert_verifier.h"
#include "net/cert/cert_verify_result.h"
#include "net/cert/crl_set.h"
#include "net/cert/test_root_certs.h"
#include "net/cert/x509_certificate.h"
#include "net/cert/x509_certificate_known_roots_mac.h"
#include "net/cert/x509_util_mac.h"
// From 10.7.2 libsecurity_keychain-55035/lib/SecTrustPriv.h, for use with
// SecTrustCopyExtendedResult.
#ifndef kSecEVOrganizationName
#define kSecEVOrganizationName CFSTR("Organization")
#endif
using base::ScopedCFTypeRef;
namespace net {
namespace {
typedef OSStatus (*SecTrustCopyExtendedResultFuncPtr)(SecTrustRef,
CFDictionaryRef*);
int NetErrorFromOSStatus(OSStatus status) {
switch (status) {
case noErr:
return OK;
case errSecNotAvailable:
case errSecNoCertificateModule:
case errSecNoPolicyModule:
return ERR_NOT_IMPLEMENTED;
case errSecAuthFailed:
return ERR_ACCESS_DENIED;
default: {
OSSTATUS_LOG(ERROR, status) << "Unknown error mapped to ERR_FAILED";
return ERR_FAILED;
}
}
}
CertStatus CertStatusFromOSStatus(OSStatus status) {
switch (status) {
case noErr:
return 0;
case CSSMERR_TP_INVALID_ANCHOR_CERT:
case CSSMERR_TP_NOT_TRUSTED:
case CSSMERR_TP_INVALID_CERT_AUTHORITY:
return CERT_STATUS_AUTHORITY_INVALID;
case CSSMERR_TP_CERT_EXPIRED:
case CSSMERR_TP_CERT_NOT_VALID_YET:
// "Expired" and "not yet valid" collapse into a single status.
return CERT_STATUS_DATE_INVALID;
case CSSMERR_TP_CERT_REVOKED:
case CSSMERR_TP_CERT_SUSPENDED:
return CERT_STATUS_REVOKED;
case CSSMERR_APPLETP_HOSTNAME_MISMATCH:
return CERT_STATUS_COMMON_NAME_INVALID;
case CSSMERR_APPLETP_CRL_NOT_FOUND:
case CSSMERR_APPLETP_OCSP_UNAVAILABLE:
case CSSMERR_APPLETP_INCOMPLETE_REVOCATION_CHECK:
return CERT_STATUS_NO_REVOCATION_MECHANISM;
case CSSMERR_APPLETP_CRL_EXPIRED:
case CSSMERR_APPLETP_CRL_NOT_VALID_YET:
case CSSMERR_APPLETP_CRL_SERVER_DOWN:
case CSSMERR_APPLETP_CRL_NOT_TRUSTED:
case CSSMERR_APPLETP_CRL_INVALID_ANCHOR_CERT:
case CSSMERR_APPLETP_CRL_POLICY_FAIL:
case CSSMERR_APPLETP_OCSP_BAD_RESPONSE:
case CSSMERR_APPLETP_OCSP_BAD_REQUEST:
case CSSMERR_APPLETP_OCSP_STATUS_UNRECOGNIZED:
case CSSMERR_APPLETP_NETWORK_FAILURE:
case CSSMERR_APPLETP_OCSP_NOT_TRUSTED:
case CSSMERR_APPLETP_OCSP_INVALID_ANCHOR_CERT:
case CSSMERR_APPLETP_OCSP_SIG_ERROR:
case CSSMERR_APPLETP_OCSP_NO_SIGNER:
case CSSMERR_APPLETP_OCSP_RESP_MALFORMED_REQ:
case CSSMERR_APPLETP_OCSP_RESP_INTERNAL_ERR:
case CSSMERR_APPLETP_OCSP_RESP_TRY_LATER:
case CSSMERR_APPLETP_OCSP_RESP_SIG_REQUIRED:
case CSSMERR_APPLETP_OCSP_RESP_UNAUTHORIZED:
case CSSMERR_APPLETP_OCSP_NONCE_MISMATCH:
// We asked for a revocation check, but didn't get it.
return CERT_STATUS_UNABLE_TO_CHECK_REVOCATION;
case CSSMERR_APPLETP_SSL_BAD_EXT_KEY_USE:
// TODO(wtc): Should we add CERT_STATUS_WRONG_USAGE?
return CERT_STATUS_INVALID;
case CSSMERR_APPLETP_CRL_BAD_URI:
case CSSMERR_APPLETP_IDP_FAIL:
return CERT_STATUS_INVALID;
case CSSMERR_CSP_UNSUPPORTED_KEY_SIZE:
// Mapping UNSUPPORTED_KEY_SIZE to CERT_STATUS_WEAK_KEY is not strictly
// accurate, as the error may have been returned due to a key size
// that exceeded the maximum supported. However, within
// CertVerifyProcMac::VerifyInternal(), this code should only be
// encountered as a certificate status code, and only when the key size
// is smaller than the minimum required (1024 bits).
return CERT_STATUS_WEAK_KEY;
default: {
// Failure was due to something Chromium doesn't define a
// specific status for (such as basic constraints violation, or
// unknown critical extension)
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. |flags| is
// a bitwise-OR of VerifyFlags that can further alter how trust is validated,
// such as how revocation is checked. If successful, returns noErr, and
// stores the resultant array of SecPolicyRefs in |policies|.
OSStatus CreateTrustPolicies(const std::string& hostname,
int flags,
ScopedCFTypeRef<CFArrayRef>* policies) {
ScopedCFTypeRef<CFMutableArrayRef> local_policies(
CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks));
if (!local_policies)
return memFullErr;
SecPolicyRef ssl_policy;
OSStatus status = x509_util::CreateSSLServerPolicy(hostname, &ssl_policy);
if (status)
return status;
CFArrayAppendValue(local_policies, ssl_policy);
CFRelease(ssl_policy);
// Explicitly add revocation policies, in order to override system
// revocation checking policies and instead respect the application-level
// revocation preference.
status = x509_util::CreateRevocationPolicies(
(flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED),
(flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY),
local_policies);
if (status)
return status;
policies->reset(local_policies.release());
return noErr;
}
// Saves some information about the certificate chain |cert_chain| in
// |*verify_result|. The caller MUST initialize |*verify_result| before
// calling this function.
void GetCertChainInfo(CFArrayRef cert_chain,
CSSM_TP_APPLE_EVIDENCE_INFO* chain_info,
CertVerifyResult* verify_result) {
SecCertificateRef verified_cert = NULL;
std::vector<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 = chain_cert;
} else {
verified_chain.push_back(chain_cert);
}
if ((chain_info[i].StatusBits & CSSM_CERT_STATUS_IS_IN_ANCHORS) ||
(chain_info[i].StatusBits & CSSM_CERT_STATUS_IS_ROOT)) {
// The current certificate is either in the user's trusted store or is
// a root (self-signed) certificate. Ignore the signature algorithm for
// these certificates, as it is meaningless for security. We allow
// self-signed certificates (i == 0 & IS_ROOT), since we accept that
// any security assertions by such a cert are inherently meaningless.
continue;
}
x509_util::CSSMCachedCertificate cached_cert;
OSStatus status = cached_cert.Init(chain_cert);
if (status)
continue;
x509_util::CSSMFieldValue signature_field;
status = cached_cert.GetField(&CSSMOID_X509V1SignatureAlgorithm,
&signature_field);
if (status || !signature_field.field())
continue;
// Match the behaviour of OS X system tools and defensively check that
// sizes are appropriate. This would indicate a critical failure of the
// OS X certificate library, but based on history, it is best to play it
// safe.
const CSSM_X509_ALGORITHM_IDENTIFIER* sig_algorithm =
signature_field.GetAs<CSSM_X509_ALGORITHM_IDENTIFIER>();
if (!sig_algorithm)
continue;
const CSSM_OID* alg_oid = &sig_algorithm->algorithm;
if (CSSMOIDEqual(alg_oid, &CSSMOID_MD2WithRSA)) {
verify_result->has_md2 = true;
} else if (CSSMOIDEqual(alg_oid, &CSSMOID_MD4WithRSA)) {
verify_result->has_md4 = true;
} else if (CSSMOIDEqual(alg_oid, &CSSMOID_MD5WithRSA)) {
verify_result->has_md5 = true;
}
}
if (!verified_cert)
return;
verify_result->verified_cert =
X509Certificate::CreateFromHandle(verified_cert, verified_chain);
}
void AppendPublicKeyHashes(CFArrayRef chain,
HashValueVector* hashes) {
const CFIndex n = CFArrayGetCount(chain);
for (CFIndex i = 0; i < n; i++) {
SecCertificateRef cert = reinterpret_cast<SecCertificateRef>(
const_cast<void*>(CFArrayGetValueAtIndex(chain, i)));
CSSM_DATA cert_data;
OSStatus err = SecCertificateGetData(cert, &cert_data);
DCHECK_EQ(err, noErr);
base::StringPiece der_bytes(reinterpret_cast<const char*>(cert_data.Data),
cert_data.Length);
base::StringPiece spki_bytes;
if (!asn1::ExtractSPKIFromDERCert(der_bytes, &spki_bytes))
continue;
HashValue sha1(HASH_VALUE_SHA1);
CC_SHA1(spki_bytes.data(), spki_bytes.size(), sha1.data());
hashes->push_back(sha1);
HashValue sha256(HASH_VALUE_SHA256);
CC_SHA256(spki_bytes.data(), spki_bytes.size(), sha256.data());
hashes->push_back(sha256);
}
}
bool CheckRevocationWithCRLSet(CFArrayRef chain, CRLSet* crl_set) {
if (CFArrayGetCount(chain) == 0)
return true;
// We iterate from the root certificate down to the leaf, keeping track of
// the issuer's SPKI at each step.
std::string issuer_spki_hash;
for (CFIndex i = CFArrayGetCount(chain) - 1; i >= 0; i--) {
SecCertificateRef cert = reinterpret_cast<SecCertificateRef>(
const_cast<void*>(CFArrayGetValueAtIndex(chain, i)));
CSSM_DATA cert_data;
OSStatus err = SecCertificateGetData(cert, &cert_data);
if (err != noErr) {
NOTREACHED();
continue;
}
base::StringPiece der_bytes(reinterpret_cast<const char*>(cert_data.Data),
cert_data.Length);
base::StringPiece spki;
if (!asn1::ExtractSPKIFromDERCert(der_bytes, &spki)) {
NOTREACHED();
continue;
}
const std::string spki_hash = crypto::SHA256HashString(spki);
x509_util::CSSMCachedCertificate cached_cert;
if (cached_cert.Init(cert) != CSSM_OK) {
NOTREACHED();
continue;
}
x509_util::CSSMFieldValue serial_number;
err = cached_cert.GetField(&CSSMOID_X509V1SerialNumber, &serial_number);
if (err || !serial_number.field()) {
NOTREACHED();
continue;
}
base::StringPiece serial(
reinterpret_cast<const char*>(serial_number.field()->Data),
serial_number.field()->Length);
CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
result = crl_set->CheckSerial(serial, issuer_spki_hash);
issuer_spki_hash = spki_hash;
switch (result) {
case CRLSet::REVOKED:
return false;
case CRLSet::UNKNOWN:
case CRLSet::GOOD:
continue;
default:
NOTREACHED();
return false;
}
}
return true;
}
// IsIssuedByKnownRoot returns true if the given chain is rooted at a root CA
// that we recognise as a standard root.
// static
bool IsIssuedByKnownRoot(CFArrayRef chain) {
int n = CFArrayGetCount(chain);
if (n < 1)
return false;
SecCertificateRef root_ref = reinterpret_cast<SecCertificateRef>(
const_cast<void*>(CFArrayGetValueAtIndex(chain, n - 1)));
SHA1HashValue hash = X509Certificate::CalculateFingerprint(root_ref);
return IsSHA1HashInSortedArray(
hash, &kKnownRootCertSHA1Hashes[0][0], sizeof(kKnownRootCertSHA1Hashes));
}
// 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|, |trust_result|,
// |verified_chain|, and |chain_info| with the verification results. 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.
//
// This function should only be called while the Mac Security Services lock is
// held.
int BuildAndEvaluateSecTrustRef(CFArrayRef cert_array,
CFArrayRef trust_policies,
int flags,
ScopedCFTypeRef<SecTrustRef>* trust_ref,
SecTrustResultType* trust_result,
ScopedCFTypeRef<CFArrayRef>* verified_chain,
CSSM_TP_APPLE_EVIDENCE_INFO** chain_info) {
SecTrustRef tmp_trust = NULL;
OSStatus status = SecTrustCreateWithCertificates(cert_array, trust_policies,
&tmp_trust);
if (status)
return NetErrorFromOSStatus(status);
ScopedCFTypeRef<SecTrustRef> scoped_tmp_trust(tmp_trust);
if (TestRootCerts::HasInstance()) {
status = TestRootCerts::GetInstance()->FixupSecTrustRef(tmp_trust);
if (status)
return NetErrorFromOSStatus(status);
}
CSSM_APPLE_TP_ACTION_DATA tp_action_data;
memset(&tp_action_data, 0, sizeof(tp_action_data));
tp_action_data.Version = CSSM_APPLE_TP_ACTION_VERSION;
// Allow CSSM to download any missing intermediate certificates if an
// authorityInfoAccess extension or issuerAltName extension is present.
tp_action_data.ActionFlags = CSSM_TP_ACTION_FETCH_CERT_FROM_NET |
CSSM_TP_ACTION_TRUST_SETTINGS;
// Note: For EV certificates, the Apple TP will handle setting these flags
// as part of EV evaluation.
if (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED) {
// Require a positive result from an OCSP responder or a CRL (or both)
// for every certificate in the chain. The Apple TP automatically
// excludes the self-signed root from this requirement. If a certificate
// is missing both a crlDistributionPoints extension and an
// authorityInfoAccess extension with an OCSP responder URL, then we
// will get a kSecTrustResultRecoverableTrustFailure back from
// SecTrustEvaluate(), with a
// CSSMERR_APPLETP_INCOMPLETE_REVOCATION_CHECK error code. In that case,
// we'll set our own result to include
// CERT_STATUS_NO_REVOCATION_MECHANISM. If one or both extensions are
// present, and a check fails (server unavailable, OCSP retry later,
// signature mismatch), then we'll set our own result to include
// CERT_STATUS_UNABLE_TO_CHECK_REVOCATION.
tp_action_data.ActionFlags |= CSSM_TP_ACTION_REQUIRE_REV_PER_CERT;
// Note, even if revocation checking is disabled, SecTrustEvaluate() will
// modify the OCSP options so as to attempt OCSP checking if it believes a
// certificate may chain to an EV root. However, because network fetches
// are disabled in CreateTrustPolicies() when revocation checking is
// disabled, these will only go against the local cache.
}
CFDataRef action_data_ref =
CFDataCreateWithBytesNoCopy(kCFAllocatorDefault,
reinterpret_cast<UInt8*>(&tp_action_data),
sizeof(tp_action_data), kCFAllocatorNull);
if (!action_data_ref)
return ERR_OUT_OF_MEMORY;
ScopedCFTypeRef<CFDataRef> scoped_action_data_ref(action_data_ref);
status = SecTrustSetParameters(tmp_trust, CSSM_TP_ACTION_DEFAULT,
action_data_ref);
if (status)
return NetErrorFromOSStatus(status);
// Verify the certificate. A non-zero result from SecTrustGetResult()
// indicates that some fatal error occurred and the chain couldn't be
// processed, not that the chain contains no errors. We need to examine the
// output of SecTrustGetResult() to determine that.
SecTrustResultType tmp_trust_result;
status = SecTrustEvaluate(tmp_trust, &tmp_trust_result);
if (status)
return NetErrorFromOSStatus(status);
CFArrayRef tmp_verified_chain = NULL;
CSSM_TP_APPLE_EVIDENCE_INFO* tmp_chain_info;
status = SecTrustGetResult(tmp_trust, &tmp_trust_result, &tmp_verified_chain,
&tmp_chain_info);
if (status)
return NetErrorFromOSStatus(status);
trust_ref->swap(scoped_tmp_trust);
*trust_result = tmp_trust_result;
verified_chain->reset(tmp_verified_chain);
*chain_info = tmp_chain_info;
return OK;
}
// OS X ships with both "GTE CyberTrust Global Root" and "Baltimore CyberTrust
// Root" as part of its trusted root store. However, a cross-certified version
// of the "Baltimore CyberTrust Root" exists that chains to "GTE CyberTrust
// Global Root". When OS X/Security.framework attempts to evaluate such a
// certificate chain, it disregards the "Baltimore CyberTrust Root" that exists
// within Keychain and instead attempts to terminate the chain in the "GTE
// CyberTrust Global Root". However, the GTE root is scheduled to be removed in
// a future OS X update (for sunsetting purposes), and once removed, such
// chains will fail validation, even though a trust anchor still exists.
//
// Rather than over-generalizing a solution that may mask a number of TLS
// misconfigurations, attempt to specifically match the affected
// cross-certified certificate and remove it from certificate chain processing.
bool IsBadBaltimoreGTECertificate(SecCertificateRef cert) {
// Matches the GTE-signed Baltimore CyberTrust Root
// https://cacert.omniroot.com/Baltimore-to-GTE-04-12.pem
static const SHA1HashValue kBadBaltimoreHashNew =
{ { 0x4D, 0x34, 0xEA, 0x92, 0x76, 0x4B, 0x3A, 0x31, 0x49, 0x11,
0x99, 0x52, 0xF4, 0x19, 0x30, 0xCA, 0x11, 0x34, 0x83, 0x61 } };
// Matches the legacy GTE-signed Baltimore CyberTrust Root
// https://cacert.omniroot.com/gte-2-2025.pem
static const SHA1HashValue kBadBaltimoreHashOld =
{ { 0x54, 0xD8, 0xCB, 0x49, 0x1F, 0xA1, 0x6D, 0xF8, 0x87, 0xDC,
0x94, 0xA9, 0x34, 0xCC, 0x83, 0x6B, 0xDA, 0xA8, 0xA3, 0x69 } };
SHA1HashValue fingerprint = X509Certificate::CalculateFingerprint(cert);
return fingerprint.Equals(kBadBaltimoreHashNew) ||
fingerprint.Equals(kBadBaltimoreHashOld);
}
// Attempts to re-verify |cert_array| after adjusting the inputs to work around
// known issues in OS X. To be used if BuildAndEvaluateSecTrustRef fails to
// return a positive result for verification.
//
// This function should only be called while the Mac Security Services lock is
// held.
void RetrySecTrustEvaluateWithAdjustedChain(
CFArrayRef cert_array,
CFArrayRef trust_policies,
int flags,
ScopedCFTypeRef<SecTrustRef>* trust_ref,
SecTrustResultType* trust_result,
ScopedCFTypeRef<CFArrayRef>* verified_chain,
CSSM_TP_APPLE_EVIDENCE_INFO** chain_info) {
CFIndex count = CFArrayGetCount(*verified_chain);
CFIndex slice_point = 0;
for (CFIndex i = 1; i < count; ++i) {
SecCertificateRef cert = reinterpret_cast<SecCertificateRef>(
const_cast<void*>(CFArrayGetValueAtIndex(*verified_chain, i)));
if (cert == NULL)
return; // Strange times; can't fix things up.
if (IsBadBaltimoreGTECertificate(cert)) {
slice_point = i;
break;
}
}
if (slice_point == 0)
return; // Nothing to do.
ScopedCFTypeRef<CFMutableArrayRef> adjusted_cert_array(
CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks));
// Note: This excludes the certificate at |slice_point|.
CFArrayAppendArray(adjusted_cert_array, cert_array,
CFRangeMake(0, slice_point));
// Ignore the result; failure will preserve the old verification results.
BuildAndEvaluateSecTrustRef(
adjusted_cert_array, trust_policies, flags, trust_ref, trust_result,
verified_chain, chain_info);
}
} // namespace
CertVerifyProcMac::CertVerifyProcMac() {}
CertVerifyProcMac::~CertVerifyProcMac() {}
bool CertVerifyProcMac::SupportsAdditionalTrustAnchors() const {
return false;
}
int CertVerifyProcMac::VerifyInternal(
X509Certificate* cert,
const std::string& hostname,
int flags,
CRLSet* crl_set,
const CertificateList& additional_trust_anchors,
CertVerifyResult* verify_result) {
ScopedCFTypeRef<CFArrayRef> trust_policies;
OSStatus status = CreateTrustPolicies(hostname, flags, &trust_policies);
if (status)
return NetErrorFromOSStatus(status);
// Create and configure a SecTrustRef, which takes our certificate(s)
// and our SSL SecPolicyRef. SecTrustCreateWithCertificates() takes an
// array of certificates, the first of which is the certificate we're
// verifying, and the subsequent (optional) certificates are used for
// chain building.
ScopedCFTypeRef<CFArrayRef> cert_array(cert->CreateOSCertChainForCert());
// Serialize all calls that may use the Keychain, to work around various
// issues in OS X 10.6+ with multi-threaded access to Security.framework.
base::AutoLock lock(crypto::GetMacSecurityServicesLock());
ScopedCFTypeRef<SecTrustRef> trust_ref;
SecTrustResultType trust_result = kSecTrustResultDeny;
ScopedCFTypeRef<CFArrayRef> completed_chain;
CSSM_TP_APPLE_EVIDENCE_INFO* chain_info = NULL;
int rv = BuildAndEvaluateSecTrustRef(
cert_array, trust_policies, flags, &trust_ref, &trust_result,
&completed_chain, &chain_info);
if (rv != OK)
return rv;
if (trust_result != kSecTrustResultUnspecified &&
trust_result != kSecTrustResultProceed) {
RetrySecTrustEvaluateWithAdjustedChain(
cert_array, trust_policies, flags, &trust_ref, &trust_result,
&completed_chain, &chain_info);
}
if (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED)
verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
if (crl_set && !CheckRevocationWithCRLSet(completed_chain, crl_set))
verify_result->cert_status |= CERT_STATUS_REVOKED;
GetCertChainInfo(completed_chain, chain_info, verify_result);
// As of Security Update 2012-002/OS X 10.7.4, when an RSA key < 1024 bits
// is encountered, CSSM returns CSSMERR_TP_VERIFY_ACTION_FAILED and adds
// CSSMERR_CSP_UNSUPPORTED_KEY_SIZE as a certificate status. Avoid mapping
// the CSSMERR_TP_VERIFY_ACTION_FAILED to CERT_STATUS_INVALID if the only
// error was due to an unsupported key size.
bool policy_failed = false;
bool weak_key_or_signature_algorithm = false;
// Evaluate the results
OSStatus cssm_result;
switch (trust_result) {
case kSecTrustResultUnspecified:
case kSecTrustResultProceed:
// Certificate chain is valid and trusted ("unspecified" indicates that
// the user has not explicitly set a trust setting)
break;
// According to SecTrust.h, kSecTrustResultConfirm isn't returned on 10.5+,
// and it is marked deprecated in the 10.9 SDK.
case kSecTrustResultDeny:
// Certificate chain is explicitly untrusted.
verify_result->cert_status |= CERT_STATUS_AUTHORITY_INVALID;
break;
case kSecTrustResultRecoverableTrustFailure:
// Certificate chain has a failure that can be overridden by the user.
status = SecTrustGetCssmResultCode(trust_ref, &cssm_result);
if (status)
return NetErrorFromOSStatus(status);
if (cssm_result == CSSMERR_TP_VERIFY_ACTION_FAILED) {
policy_failed = true;
} else {
verify_result->cert_status |= CertStatusFromOSStatus(cssm_result);
}
// Walk the chain of error codes in the CSSM_TP_APPLE_EVIDENCE_INFO
// structure which can catch multiple errors from each certificate.
for (CFIndex index = 0, chain_count = CFArrayGetCount(completed_chain);
index < chain_count; ++index) {
if (chain_info[index].StatusBits & CSSM_CERT_STATUS_EXPIRED ||
chain_info[index].StatusBits & CSSM_CERT_STATUS_NOT_VALID_YET)
verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
if (!IsCertStatusError(verify_result->cert_status) &&
chain_info[index].NumStatusCodes == 0) {
LOG(WARNING) << "chain_info[" << index << "].NumStatusCodes is 0"
", chain_info[" << index << "].StatusBits is "
<< chain_info[index].StatusBits;
}
for (uint32 status_code_index = 0;
status_code_index < chain_info[index].NumStatusCodes;
++status_code_index) {
// As of OS X 10.9, attempting to verify a certificate chain that
// contains a weak signature algorithm (MD2, MD5) in an intermediate
// or leaf cert will be treated as a (recoverable) policy validation
// failure, with the status code CSSMERR_TP_INVALID_CERTIFICATE
// added to the Status Codes. Don't treat this code as an invalid
// certificate; instead, map it to a weak key. Any truly invalid
// certificates will have the major error (cssm_result) set to
// CSSMERR_TP_INVALID_CERTIFICATE, rather than
// CSSMERR_TP_VERIFY_ACTION_FAILED.
CertStatus mapped_status = 0;
if (policy_failed &&
chain_info[index].StatusCodes[status_code_index] ==
CSSMERR_TP_INVALID_CERTIFICATE) {
mapped_status = CERT_STATUS_WEAK_SIGNATURE_ALGORITHM;
weak_key_or_signature_algorithm = true;
} else {
mapped_status = CertStatusFromOSStatus(
chain_info[index].StatusCodes[status_code_index]);
if (mapped_status == CERT_STATUS_WEAK_KEY)
weak_key_or_signature_algorithm = true;
}
verify_result->cert_status |= mapped_status;
}
}
if (policy_failed && !weak_key_or_signature_algorithm) {
// If CSSMERR_TP_VERIFY_ACTION_FAILED wasn't returned due to a weak
// key, map it back to an appropriate error code.
verify_result->cert_status |= CertStatusFromOSStatus(cssm_result);
}
if (!IsCertStatusError(verify_result->cert_status)) {
LOG(ERROR) << "cssm_result=" << cssm_result;
verify_result->cert_status |= CERT_STATUS_INVALID;
NOTREACHED();
}
break;
default:
status = SecTrustGetCssmResultCode(trust_ref, &cssm_result);
if (status)
return NetErrorFromOSStatus(status);
verify_result->cert_status |= CertStatusFromOSStatus(cssm_result);
if (!IsCertStatusError(verify_result->cert_status)) {
LOG(WARNING) << "trust_result=" << trust_result;
verify_result->cert_status |= CERT_STATUS_INVALID;
}
break;
}
// Perform hostname verification independent of SecTrustEvaluate. In order to
// do so, mask off any reported name errors first.
verify_result->cert_status &= ~CERT_STATUS_COMMON_NAME_INVALID;
if (!cert->VerifyNameMatch(hostname,
&verify_result->common_name_fallback_used)) {
verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
}
// TODO(wtc): Suppress CERT_STATUS_NO_REVOCATION_MECHANISM for now to be
// compatible with Windows, which in turn implements this behavior to be
// compatible with WinHTTP, which doesn't report this error (bug 3004).
verify_result->cert_status &= ~CERT_STATUS_NO_REVOCATION_MECHANISM;
AppendPublicKeyHashes(completed_chain, &verify_result->public_key_hashes);
verify_result->is_issued_by_known_root = IsIssuedByKnownRoot(completed_chain);
if (IsCertStatusError(verify_result->cert_status))
return MapCertStatusToNetError(verify_result->cert_status);
if (flags & CertVerifier::VERIFY_EV_CERT) {
// Determine the certificate's EV status using SecTrustCopyExtendedResult(),
// which is an internal/private API function added in OS X 10.5.7.
// Note: "ExtendedResult" means extended validation results.
CFBundleRef bundle =
CFBundleGetBundleWithIdentifier(CFSTR("com.apple.security"));
if (bundle) {
SecTrustCopyExtendedResultFuncPtr copy_extended_result =
reinterpret_cast<SecTrustCopyExtendedResultFuncPtr>(
CFBundleGetFunctionPointerForName(bundle,
CFSTR("SecTrustCopyExtendedResult")));
if (copy_extended_result) {
CFDictionaryRef ev_dict_temp = NULL;
status = copy_extended_result(trust_ref, &ev_dict_temp);
ScopedCFTypeRef<CFDictionaryRef> ev_dict(ev_dict_temp);
ev_dict_temp = NULL;
if (status == noErr && ev_dict) {
// In 10.7.3, SecTrustCopyExtendedResult returns noErr and populates
// ev_dict even for non-EV certificates, but only EV certificates
// will cause ev_dict to contain kSecEVOrganizationName. In previous
// releases, SecTrustCopyExtendedResult would only return noErr and
// populate ev_dict for EV certificates, but would always include
// kSecEVOrganizationName in that case, so checking for this key is
// appropriate for all known versions of SecTrustCopyExtendedResult.
// The actual organization name is unneeded here and can be accessed
// through other means. All that matters here is the OS' conception
// of whether or not the certificate is EV.
if (CFDictionaryContainsKey(ev_dict,
kSecEVOrganizationName)) {
verify_result->cert_status |= CERT_STATUS_IS_EV;
if (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY)
verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
}
}
}
}
}
return OK;
}
} // namespace net