src/crypto/x509/root_windows.go - go - Git at Google

 // Copyright 2012 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package x509

 import (
 	"errors"
 	"syscall"
 	"unsafe"
 )

 // Creates a new *syscall.CertContext representing the leaf certificate in an in-memory
 // certificate store containing itself and all of the intermediate certificates specified
 // in the opts.Intermediates CertPool.
 //
 // A pointer to the in-memory store is available in the returned CertContext's Store field.
 // The store is automatically freed when the CertContext is freed using
 // syscall.CertFreeCertificateContext.
 func createStoreContext(leaf *Certificate, opts *VerifyOptions) (*syscall.CertContext, error) {
 	var storeCtx *syscall.CertContext

 	leafCtx, err := syscall.CertCreateCertificateContext(syscall.X509_ASN_ENCODING|syscall.PKCS_7_ASN_ENCODING, &leaf.Raw[0], uint32(len(leaf.Raw)))
 	if err != nil {
 		return nil, err
 	}
 	defer syscall.CertFreeCertificateContext(leafCtx)

 	handle, err := syscall.CertOpenStore(syscall.CERT_STORE_PROV_MEMORY, 0, 0, syscall.CERT_STORE_DEFER_CLOSE_UNTIL_LAST_FREE_FLAG, 0)
 	if err != nil {
 		return nil, err
 	}
 	defer syscall.CertCloseStore(handle, 0)

 	err = syscall.CertAddCertificateContextToStore(handle, leafCtx, syscall.CERT_STORE_ADD_ALWAYS, &storeCtx)
 	if err != nil {
 		return nil, err
 	}

 	if opts.Intermediates != nil {
 		for i := 0; i < opts.Intermediates.len(); i++ {
 			intermediate, err := opts.Intermediates.cert(i)
 			if err != nil {
 				return nil, err
 			}
 			ctx, err := syscall.CertCreateCertificateContext(syscall.X509_ASN_ENCODING|syscall.PKCS_7_ASN_ENCODING, &intermediate.Raw[0], uint32(len(intermediate.Raw)))
 			if err != nil {
 				return nil, err
 			}

 			err = syscall.CertAddCertificateContextToStore(handle, ctx, syscall.CERT_STORE_ADD_ALWAYS, nil)
 			syscall.CertFreeCertificateContext(ctx)
 			if err != nil {
 				return nil, err
 			}
 		}
 	}

 	return storeCtx, nil
 }

 // extractSimpleChain extracts the final certificate chain from a CertSimpleChain.
 func extractSimpleChain(simpleChain **syscall.CertSimpleChain, count int) (chain []*Certificate, err error) {
 	if simpleChain == nil || count == 0 {
 		return nil, errors.New("x509: invalid simple chain")
 	}

 	simpleChains := (*[1 << 20]*syscall.CertSimpleChain)(unsafe.Pointer(simpleChain))[:count:count]
 	lastChain := simpleChains[count-1]
 	elements := (*[1 << 20]*syscall.CertChainElement)(unsafe.Pointer(lastChain.Elements))[:lastChain.NumElements:lastChain.NumElements]
 	for i := 0; i < int(lastChain.NumElements); i++ {
 		// Copy the buf, since ParseCertificate does not create its own copy.
 		cert := elements[i].CertContext
 		encodedCert := (*[1 << 20]byte)(unsafe.Pointer(cert.EncodedCert))[:cert.Length:cert.Length]
 		buf := make([]byte, cert.Length)
 		copy(buf, encodedCert)
 		parsedCert, err := ParseCertificate(buf)
 		if err != nil {
 			return nil, err
 		}
 		chain = append(chain, parsedCert)
 	}

 	return chain, nil
 }

 // checkChainTrustStatus checks the trust status of the certificate chain, translating
 // any errors it finds into Go errors in the process.
 func checkChainTrustStatus(c *Certificate, chainCtx *syscall.CertChainContext) error {
 	if chainCtx.TrustStatus.ErrorStatus != syscall.CERT_TRUST_NO_ERROR {
 		status := chainCtx.TrustStatus.ErrorStatus
 		switch status {
 		case syscall.CERT_TRUST_IS_NOT_TIME_VALID:
 			return CertificateInvalidError{c, Expired, ""}
 		case syscall.CERT_TRUST_IS_NOT_VALID_FOR_USAGE:
 			return CertificateInvalidError{c, IncompatibleUsage, ""}
 		// TODO(filippo): surface more error statuses.
 		default:
 			return UnknownAuthorityError{c, nil, nil}
 		}
 	}
 	return nil
 }

 // checkChainSSLServerPolicy checks that the certificate chain in chainCtx is valid for
 // use as a certificate chain for a SSL/TLS server.
 func checkChainSSLServerPolicy(c *Certificate, chainCtx *syscall.CertChainContext, opts *VerifyOptions) error {
 	servernamep, err := syscall.UTF16PtrFromString(opts.DNSName)
 	if err != nil {
 		return err
 	}
 	sslPara := &syscall.SSLExtraCertChainPolicyPara{
 		AuthType:   syscall.AUTHTYPE_SERVER,
 		ServerName: servernamep,
 	}
 	sslPara.Size = uint32(unsafe.Sizeof(*sslPara))

 	para := &syscall.CertChainPolicyPara{
 		ExtraPolicyPara: (syscall.Pointer)(unsafe.Pointer(sslPara)),
 	}
 	para.Size = uint32(unsafe.Sizeof(*para))

 	status := syscall.CertChainPolicyStatus{}
 	err = syscall.CertVerifyCertificateChainPolicy(syscall.CERT_CHAIN_POLICY_SSL, chainCtx, para, &status)
 	if err != nil {
 		return err
 	}

 	// TODO(mkrautz): use the lChainIndex and lElementIndex fields
 	// of the CertChainPolicyStatus to provide proper context, instead
 	// using c.
 	if status.Error != 0 {
 		switch status.Error {
 		case syscall.CERT_E_EXPIRED:
 			return CertificateInvalidError{c, Expired, ""}
 		case syscall.CERT_E_CN_NO_MATCH:
 			return HostnameError{c, opts.DNSName}
 		case syscall.CERT_E_UNTRUSTEDROOT:
 			return UnknownAuthorityError{c, nil, nil}
 		default:
 			return UnknownAuthorityError{c, nil, nil}
 		}
 	}

 	return nil
 }

 // windowsExtKeyUsageOIDs are the C NUL-terminated string representations of the
 // OIDs for use with the Windows API.
 var windowsExtKeyUsageOIDs = make(map[ExtKeyUsage][]byte, len(extKeyUsageOIDs))

 func init() {
 	for _, eku := range extKeyUsageOIDs {
 		windowsExtKeyUsageOIDs[eku.extKeyUsage] = []byte(eku.oid.String() + "\x00")
 	}
 }

 func verifyChain(c *Certificate, chainCtx *syscall.CertChainContext, opts *VerifyOptions) (chain []*Certificate, err error) {
 	err = checkChainTrustStatus(c, chainCtx)
 	if err != nil {
 		return nil, err
 	}

 	if opts != nil && len(opts.DNSName) > 0 {
 		err = checkChainSSLServerPolicy(c, chainCtx, opts)
 		if err != nil {
 			return nil, err
 		}
 	}

 	chain, err = extractSimpleChain(chainCtx.Chains, int(chainCtx.ChainCount))
 	if err != nil {
 		return nil, err
 	}
 	if len(chain) == 0 {
 		return nil, errors.New("x509: internal error: system verifier returned an empty chain")
 	}

 	// Mitigate CVE-2020-0601, where the Windows system verifier might be
 	// tricked into using custom curve parameters for a trusted root, by
 	// double-checking all ECDSA signatures. If the system was tricked into
 	// using spoofed parameters, the signature will be invalid for the correct
 	// ones we parsed. (We don't support custom curves ourselves.)
 	for i, parent := range chain[1:] {
 		if parent.PublicKeyAlgorithm != ECDSA {
 			continue
 		}
 		if err := parent.CheckSignature(chain[i].SignatureAlgorithm,
 			chain[i].RawTBSCertificate, chain[i].Signature); err != nil {
 			return nil, err
 		}
 	}
 	return chain, nil
 }

 // systemVerify is like Verify, except that it uses CryptoAPI calls
 // to build certificate chains and verify them.
 func (c *Certificate) systemVerify(opts *VerifyOptions) (chains [][]*Certificate, err error) {
 	storeCtx, err := createStoreContext(c, opts)
 	if err != nil {
 		return nil, err
 	}
 	defer syscall.CertFreeCertificateContext(storeCtx)

 	para := new(syscall.CertChainPara)
 	para.Size = uint32(unsafe.Sizeof(*para))

 	keyUsages := opts.KeyUsages
 	if len(keyUsages) == 0 {
 		keyUsages = []ExtKeyUsage{ExtKeyUsageServerAuth}
 	}
 	oids := make([]*byte, 0, len(keyUsages))
 	for _, eku := range keyUsages {
 		if eku == ExtKeyUsageAny {
 			oids = nil
 			break
 		}
 		if oid, ok := windowsExtKeyUsageOIDs[eku]; ok {
 			oids = append(oids, &oid[0])
 		}
 		// Like the standard verifier, accept SGC EKUs as equivalent to ServerAuth.
 		if eku == ExtKeyUsageServerAuth {
 			oids = append(oids, &syscall.OID_SERVER_GATED_CRYPTO[0])
 			oids = append(oids, &syscall.OID_SGC_NETSCAPE[0])
 		}
 	}
 	if oids != nil {
 		para.RequestedUsage.Type = syscall.USAGE_MATCH_TYPE_OR
 		para.RequestedUsage.Usage.Length = uint32(len(oids))
 		para.RequestedUsage.Usage.UsageIdentifiers = &oids[0]
 	} else {
 		para.RequestedUsage.Type = syscall.USAGE_MATCH_TYPE_AND
 		para.RequestedUsage.Usage.Length = 0
 		para.RequestedUsage.Usage.UsageIdentifiers = nil
 	}

 	var verifyTime *syscall.Filetime
 	if opts != nil && !opts.CurrentTime.IsZero() {
 		ft := syscall.NsecToFiletime(opts.CurrentTime.UnixNano())
 		verifyTime = &ft
 	}

 	// The default is to return only the highest quality chain,
 	// setting this flag will add additional lower quality contexts.
 	// These are returned in the LowerQualityChains field.
 	const CERT_CHAIN_RETURN_LOWER_QUALITY_CONTEXTS = 0x00000080

 	// CertGetCertificateChain will traverse Windows's root stores in an attempt to build a verified certificate chain
 	var topCtx *syscall.CertChainContext
 	err = syscall.CertGetCertificateChain(syscall.Handle(0), storeCtx, verifyTime, storeCtx.Store, para, CERT_CHAIN_RETURN_LOWER_QUALITY_CONTEXTS, 0, &topCtx)
 	if err != nil {
 		return nil, err
 	}
 	defer syscall.CertFreeCertificateChain(topCtx)

 	chain, topErr := verifyChain(c, topCtx, opts)
 	if topErr == nil {
 		chains = append(chains, chain)
 	}

 	if lqCtxCount := topCtx.LowerQualityChainCount; lqCtxCount > 0 {
 		lqCtxs := (*[1 << 20]*syscall.CertChainContext)(unsafe.Pointer(topCtx.LowerQualityChains))[:lqCtxCount:lqCtxCount]

 		for _, ctx := range lqCtxs {
 			chain, err := verifyChain(c, ctx, opts)
 			if err == nil {
 				chains = append(chains, chain)
 			}
 		}
 	}

 	if len(chains) == 0 {
 		// Return the error from the highest quality context.
 		return nil, topErr
 	}

 	return chains, nil
 }

 func loadSystemRoots() (*CertPool, error) {
 	// TODO: restore this functionality on Windows. We tried to do
 	// it in Go 1.8 but had to revert it. See Issue 18609.
 	// Returning (nil, nil) was the old behavior, prior to CL 30578.
 	// The if statement here avoids vet complaining about
 	// unreachable code below.
 	if true {
 		return nil, nil
 	}

 	const CRYPT_E_NOT_FOUND = 0x80092004

 	store, err := syscall.CertOpenSystemStore(0, syscall.StringToUTF16Ptr("ROOT"))
 	if err != nil {
 		return nil, err
 	}
 	defer syscall.CertCloseStore(store, 0)

 	roots := NewCertPool()
 	var cert *syscall.CertContext
 	for {
 		cert, err = syscall.CertEnumCertificatesInStore(store, cert)
 		if err != nil {
 			if errno, ok := err.(syscall.Errno); ok {
 				if errno == CRYPT_E_NOT_FOUND {
 					break
 				}
 			}
 			return nil, err
 		}
 		if cert == nil {
 			break
 		}
 		// Copy the buf, since ParseCertificate does not create its own copy.
 		buf := (*[1 << 20]byte)(unsafe.Pointer(cert.EncodedCert))[:cert.Length:cert.Length]
 		buf2 := make([]byte, cert.Length)
 		copy(buf2, buf)
 		if c, err := ParseCertificate(buf2); err == nil {
 			roots.AddCert(c)
 		}
 	}
 	return roots, nil
 }
	// Copyright 2012 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package x509

	import (
	"errors"
	"syscall"
	"unsafe"
	)

	// Creates a new *syscall.CertContext representing the leaf certificate in an in-memory
	// certificate store containing itself and all of the intermediate certificates specified
	// in the opts.Intermediates CertPool.
	//
	// A pointer to the in-memory store is available in the returned CertContext's Store field.
	// The store is automatically freed when the CertContext is freed using
	// syscall.CertFreeCertificateContext.
	func createStoreContext(leaf Certificate, opts VerifyOptions) (*syscall.CertContext, error) {
	var storeCtx *syscall.CertContext

	leafCtx, err := syscall.CertCreateCertificateContext(syscall.X509_ASN_ENCODING\|syscall.PKCS_7_ASN_ENCODING, &leaf.Raw[0], uint32(len(leaf.Raw)))
	if err != nil {
	return nil, err
	}
	defer syscall.CertFreeCertificateContext(leafCtx)

	handle, err := syscall.CertOpenStore(syscall.CERT_STORE_PROV_MEMORY, 0, 0, syscall.CERT_STORE_DEFER_CLOSE_UNTIL_LAST_FREE_FLAG, 0)
	if err != nil {
	return nil, err
	}
	defer syscall.CertCloseStore(handle, 0)

	err = syscall.CertAddCertificateContextToStore(handle, leafCtx, syscall.CERT_STORE_ADD_ALWAYS, &storeCtx)
	if err != nil {
	return nil, err
	}

	if opts.Intermediates != nil {
	for i := 0; i < opts.Intermediates.len(); i++ {
	intermediate, err := opts.Intermediates.cert(i)
	if err != nil {
	return nil, err
	}
	ctx, err := syscall.CertCreateCertificateContext(syscall.X509_ASN_ENCODING\|syscall.PKCS_7_ASN_ENCODING, &intermediate.Raw[0], uint32(len(intermediate.Raw)))
	if err != nil {
	return nil, err
	}

	err = syscall.CertAddCertificateContextToStore(handle, ctx, syscall.CERT_STORE_ADD_ALWAYS, nil)
	syscall.CertFreeCertificateContext(ctx)
	if err != nil {
	return nil, err
	}
	}
	}

	return storeCtx, nil
	}

	// extractSimpleChain extracts the final certificate chain from a CertSimpleChain.
	func extractSimpleChain(simpleChain *syscall.CertSimpleChain, count int) (chain []Certificate, err error) {
	if simpleChain == nil \|\| count == 0 {
	return nil, errors.New("x509: invalid simple chain")
	}

	simpleChains := ([1 << 20]syscall.CertSimpleChain)(unsafe.Pointer(simpleChain))[:count:count]
	lastChain := simpleChains[count-1]
	elements := ([1 << 20]syscall.CertChainElement)(unsafe.Pointer(lastChain.Elements))[:lastChain.NumElements:lastChain.NumElements]
	for i := 0; i < int(lastChain.NumElements); i++ {
	// Copy the buf, since ParseCertificate does not create its own copy.
	cert := elements[i].CertContext
	encodedCert := (*[1 << 20]byte)(unsafe.Pointer(cert.EncodedCert))[:cert.Length:cert.Length]
	buf := make([]byte, cert.Length)
	copy(buf, encodedCert)
	parsedCert, err := ParseCertificate(buf)
	if err != nil {
	return nil, err
	}
	chain = append(chain, parsedCert)
	}

	return chain, nil
	}

	// checkChainTrustStatus checks the trust status of the certificate chain, translating
	// any errors it finds into Go errors in the process.
	func checkChainTrustStatus(c Certificate, chainCtx syscall.CertChainContext) error {
	if chainCtx.TrustStatus.ErrorStatus != syscall.CERT_TRUST_NO_ERROR {
	status := chainCtx.TrustStatus.ErrorStatus
	switch status {
	case syscall.CERT_TRUST_IS_NOT_TIME_VALID:
	return CertificateInvalidError{c, Expired, ""}
	case syscall.CERT_TRUST_IS_NOT_VALID_FOR_USAGE:
	return CertificateInvalidError{c, IncompatibleUsage, ""}
	// TODO(filippo): surface more error statuses.
	default:
	return UnknownAuthorityError{c, nil, nil}
	}
	}
	return nil
	}

	// checkChainSSLServerPolicy checks that the certificate chain in chainCtx is valid for
	// use as a certificate chain for a SSL/TLS server.
	func checkChainSSLServerPolicy(c Certificate, chainCtx syscall.CertChainContext, opts *VerifyOptions) error {
	servernamep, err := syscall.UTF16PtrFromString(opts.DNSName)
	if err != nil {
	return err
	}
	sslPara := &syscall.SSLExtraCertChainPolicyPara{
	AuthType: syscall.AUTHTYPE_SERVER,
	ServerName: servernamep,
	}
	sslPara.Size = uint32(unsafe.Sizeof(*sslPara))

	para := &syscall.CertChainPolicyPara{
	ExtraPolicyPara: (syscall.Pointer)(unsafe.Pointer(sslPara)),
	}
	para.Size = uint32(unsafe.Sizeof(*para))

	status := syscall.CertChainPolicyStatus{}
	err = syscall.CertVerifyCertificateChainPolicy(syscall.CERT_CHAIN_POLICY_SSL, chainCtx, para, &status)
	if err != nil {
	return err
	}

	// TODO(mkrautz): use the lChainIndex and lElementIndex fields
	// of the CertChainPolicyStatus to provide proper context, instead
	// using c.
	if status.Error != 0 {
	switch status.Error {
	case syscall.CERT_E_EXPIRED:
	return CertificateInvalidError{c, Expired, ""}
	case syscall.CERT_E_CN_NO_MATCH:
	return HostnameError{c, opts.DNSName}
	case syscall.CERT_E_UNTRUSTEDROOT:
	return UnknownAuthorityError{c, nil, nil}
	default:
	return UnknownAuthorityError{c, nil, nil}
	}
	}

	return nil
	}

	// windowsExtKeyUsageOIDs are the C NUL-terminated string representations of the
	// OIDs for use with the Windows API.
	var windowsExtKeyUsageOIDs = make(map[ExtKeyUsage][]byte, len(extKeyUsageOIDs))

	func init() {
	for _, eku := range extKeyUsageOIDs {
	windowsExtKeyUsageOIDs[eku.extKeyUsage] = []byte(eku.oid.String() + "\x00")
	}
	}

	func verifyChain(c Certificate, chainCtx syscall.CertChainContext, opts VerifyOptions) (chain []Certificate, err error) {
	err = checkChainTrustStatus(c, chainCtx)
	if err != nil {
	return nil, err
	}

	if opts != nil && len(opts.DNSName) > 0 {
	err = checkChainSSLServerPolicy(c, chainCtx, opts)
	if err != nil {
	return nil, err
	}
	}

	chain, err = extractSimpleChain(chainCtx.Chains, int(chainCtx.ChainCount))
	if err != nil {
	return nil, err
	}
	if len(chain) == 0 {
	return nil, errors.New("x509: internal error: system verifier returned an empty chain")
	}

	// Mitigate CVE-2020-0601, where the Windows system verifier might be
	// tricked into using custom curve parameters for a trusted root, by
	// double-checking all ECDSA signatures. If the system was tricked into
	// using spoofed parameters, the signature will be invalid for the correct
	// ones we parsed. (We don't support custom curves ourselves.)
	for i, parent := range chain[1:] {
	if parent.PublicKeyAlgorithm != ECDSA {
	continue
	}
	if err := parent.CheckSignature(chain[i].SignatureAlgorithm,
	chain[i].RawTBSCertificate, chain[i].Signature); err != nil {
	return nil, err
	}
	}
	return chain, nil
	}

	// systemVerify is like Verify, except that it uses CryptoAPI calls
	// to build certificate chains and verify them.
	func (c Certificate) systemVerify(opts VerifyOptions) (chains [][]*Certificate, err error) {
	storeCtx, err := createStoreContext(c, opts)
	if err != nil {
	return nil, err
	}
	defer syscall.CertFreeCertificateContext(storeCtx)

	para := new(syscall.CertChainPara)
	para.Size = uint32(unsafe.Sizeof(*para))

	keyUsages := opts.KeyUsages
	if len(keyUsages) == 0 {
	keyUsages = []ExtKeyUsage{ExtKeyUsageServerAuth}
	}
	oids := make([]*byte, 0, len(keyUsages))
	for _, eku := range keyUsages {
	if eku == ExtKeyUsageAny {
	oids = nil
	break
	}
	if oid, ok := windowsExtKeyUsageOIDs[eku]; ok {
	oids = append(oids, &oid[0])
	}
	// Like the standard verifier, accept SGC EKUs as equivalent to ServerAuth.
	if eku == ExtKeyUsageServerAuth {
	oids = append(oids, &syscall.OID_SERVER_GATED_CRYPTO[0])
	oids = append(oids, &syscall.OID_SGC_NETSCAPE[0])
	}
	}
	if oids != nil {
	para.RequestedUsage.Type = syscall.USAGE_MATCH_TYPE_OR
	para.RequestedUsage.Usage.Length = uint32(len(oids))
	para.RequestedUsage.Usage.UsageIdentifiers = &oids[0]
	} else {
	para.RequestedUsage.Type = syscall.USAGE_MATCH_TYPE_AND
	para.RequestedUsage.Usage.Length = 0
	para.RequestedUsage.Usage.UsageIdentifiers = nil
	}

	var verifyTime *syscall.Filetime
	if opts != nil && !opts.CurrentTime.IsZero() {
	ft := syscall.NsecToFiletime(opts.CurrentTime.UnixNano())
	verifyTime = &ft
	}

	// The default is to return only the highest quality chain,
	// setting this flag will add additional lower quality contexts.
	// These are returned in the LowerQualityChains field.
	const CERT_CHAIN_RETURN_LOWER_QUALITY_CONTEXTS = 0x00000080

	// CertGetCertificateChain will traverse Windows's root stores in an attempt to build a verified certificate chain
	var topCtx *syscall.CertChainContext
	err = syscall.CertGetCertificateChain(syscall.Handle(0), storeCtx, verifyTime, storeCtx.Store, para, CERT_CHAIN_RETURN_LOWER_QUALITY_CONTEXTS, 0, &topCtx)
	if err != nil {
	return nil, err
	}
	defer syscall.CertFreeCertificateChain(topCtx)

	chain, topErr := verifyChain(c, topCtx, opts)
	if topErr == nil {
	chains = append(chains, chain)
	}

	if lqCtxCount := topCtx.LowerQualityChainCount; lqCtxCount > 0 {
	lqCtxs := ([1 << 20]syscall.CertChainContext)(unsafe.Pointer(topCtx.LowerQualityChains))[:lqCtxCount:lqCtxCount]

	for _, ctx := range lqCtxs {
	chain, err := verifyChain(c, ctx, opts)
	if err == nil {
	chains = append(chains, chain)
	}
	}
	}

	if len(chains) == 0 {
	// Return the error from the highest quality context.
	return nil, topErr
	}

	return chains, nil
	}

	func loadSystemRoots() (*CertPool, error) {
	// TODO: restore this functionality on Windows. We tried to do
	// it in Go 1.8 but had to revert it. See Issue 18609.
	// Returning (nil, nil) was the old behavior, prior to CL 30578.
	// The if statement here avoids vet complaining about
	// unreachable code below.
	if true {
	return nil, nil
	}

	const CRYPT_E_NOT_FOUND = 0x80092004

	store, err := syscall.CertOpenSystemStore(0, syscall.StringToUTF16Ptr("ROOT"))
	if err != nil {
	return nil, err
	}
	defer syscall.CertCloseStore(store, 0)

	roots := NewCertPool()
	var cert *syscall.CertContext
	for {
	cert, err = syscall.CertEnumCertificatesInStore(store, cert)
	if err != nil {
	if errno, ok := err.(syscall.Errno); ok {
	if errno == CRYPT_E_NOT_FOUND {
	break
	}
	}
	return nil, err
	}
	if cert == nil {
	break
	}
	// Copy the buf, since ParseCertificate does not create its own copy.
	buf := (*[1 << 20]byte)(unsafe.Pointer(cert.EncodedCert))[:cert.Length:cert.Length]
	buf2 := make([]byte, cert.Length)
	copy(buf2, buf)
	if c, err := ParseCertificate(buf2); err == nil {
	roots.AddCert(c)
	}
	}
	return roots, nil
	}