vendor: add cfssl dependency

vendor/github.com/google/certificate-transparency/go/x509/cert_pool.go

@@ -0,0 +1,116 @@
+// Copyright 2011 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 (
+	"encoding/pem"
+)
+
+// CertPool is a set of certificates.
+type CertPool struct {
+	bySubjectKeyId map[string][]int
+	byName         map[string][]int
+	certs          []*Certificate
+}
+
+// NewCertPool returns a new, empty CertPool.
+func NewCertPool() *CertPool {
+	return &CertPool{
+		make(map[string][]int),
+		make(map[string][]int),
+		nil,
+	}
+}
+
+// findVerifiedParents attempts to find certificates in s which have signed the
+// given certificate. If any candidates were rejected then errCert will be set
+// to one of them, arbitrarily, and err will contain the reason that it was
+// rejected.
+func (s *CertPool) findVerifiedParents(cert *Certificate) (parents []int, errCert *Certificate, err error) {
+	if s == nil {
+		return
+	}
+	var candidates []int
+
+	if len(cert.AuthorityKeyId) > 0 {
+		candidates = s.bySubjectKeyId[string(cert.AuthorityKeyId)]
+	}
+	if len(candidates) == 0 {
+		candidates = s.byName[string(cert.RawIssuer)]
+	}
+
+	for _, c := range candidates {
+		if err = cert.CheckSignatureFrom(s.certs[c]); err == nil {
+			parents = append(parents, c)
+		} else {
+			errCert = s.certs[c]
+		}
+	}
+
+	return
+}
+
+// AddCert adds a certificate to a pool.
+func (s *CertPool) AddCert(cert *Certificate) {
+	if cert == nil {
+		panic("adding nil Certificate to CertPool")
+	}
+
+	// Check that the certificate isn't being added twice.
+	for _, c := range s.certs {
+		if c.Equal(cert) {
+			return
+		}
+	}
+
+	n := len(s.certs)
+	s.certs = append(s.certs, cert)
+
+	if len(cert.SubjectKeyId) > 0 {
+		keyId := string(cert.SubjectKeyId)
+		s.bySubjectKeyId[keyId] = append(s.bySubjectKeyId[keyId], n)
+	}
+	name := string(cert.RawSubject)
+	s.byName[name] = append(s.byName[name], n)
+}
+
+// AppendCertsFromPEM attempts to parse a series of PEM encoded certificates.
+// It appends any certificates found to s and returns true if any certificates
+// were successfully parsed.
+//
+// On many Linux systems, /etc/ssl/cert.pem will contain the system wide set
+// of root CAs in a format suitable for this function.
+func (s *CertPool) AppendCertsFromPEM(pemCerts []byte) (ok bool) {
+	for len(pemCerts) > 0 {
+		var block *pem.Block
+		block, pemCerts = pem.Decode(pemCerts)
+		if block == nil {
+			break
+		}
+		if block.Type != "CERTIFICATE" || len(block.Headers) != 0 {
+			continue
+		}
+
+		cert, err := ParseCertificate(block.Bytes)
+		if err != nil {
+			continue
+		}
+
+		s.AddCert(cert)
+		ok = true
+	}
+
+	return
+}
+
+// Subjects returns a list of the DER-encoded subjects of
+// all of the certificates in the pool.
+func (s *CertPool) Subjects() (res [][]byte) {
+	res = make([][]byte, len(s.certs))
+	for i, c := range s.certs {
+		res[i] = c.RawSubject
+	}
+	return
+}

vendor/github.com/google/certificate-transparency/go/x509/pem_decrypt.go

@@ -0,0 +1,233 @@
+// 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
+
+// RFC 1423 describes the encryption of PEM blocks. The algorithm used to
+// generate a key from the password was derived by looking at the OpenSSL
+// implementation.
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/des"
+	"crypto/md5"
+	"encoding/hex"
+	"encoding/pem"
+	"errors"
+	"io"
+	"strings"
+)
+
+type PEMCipher int
+
+// Possible values for the EncryptPEMBlock encryption algorithm.
+const (
+	_ PEMCipher = iota
+	PEMCipherDES
+	PEMCipher3DES
+	PEMCipherAES128
+	PEMCipherAES192
+	PEMCipherAES256
+)
+
+// rfc1423Algo holds a method for enciphering a PEM block.
+type rfc1423Algo struct {
+	cipher     PEMCipher
+	name       string
+	cipherFunc func(key []byte) (cipher.Block, error)
+	keySize    int
+	blockSize  int
+}
+
+// rfc1423Algos holds a slice of the possible ways to encrypt a PEM
+// block.  The ivSize numbers were taken from the OpenSSL source.
+var rfc1423Algos = []rfc1423Algo{{
+	cipher:     PEMCipherDES,
+	name:       "DES-CBC",
+	cipherFunc: des.NewCipher,
+	keySize:    8,
+	blockSize:  des.BlockSize,
+}, {
+	cipher:     PEMCipher3DES,
+	name:       "DES-EDE3-CBC",
+	cipherFunc: des.NewTripleDESCipher,
+	keySize:    24,
+	blockSize:  des.BlockSize,
+}, {
+	cipher:     PEMCipherAES128,
+	name:       "AES-128-CBC",
+	cipherFunc: aes.NewCipher,
+	keySize:    16,
+	blockSize:  aes.BlockSize,
+}, {
+	cipher:     PEMCipherAES192,
+	name:       "AES-192-CBC",
+	cipherFunc: aes.NewCipher,
+	keySize:    24,
+	blockSize:  aes.BlockSize,
+}, {
+	cipher:     PEMCipherAES256,
+	name:       "AES-256-CBC",
+	cipherFunc: aes.NewCipher,
+	keySize:    32,
+	blockSize:  aes.BlockSize,
+},
+}
+
+// deriveKey uses a key derivation function to stretch the password into a key
+// with the number of bits our cipher requires. This algorithm was derived from
+// the OpenSSL source.
+func (c rfc1423Algo) deriveKey(password, salt []byte) []byte {
+	hash := md5.New()
+	out := make([]byte, c.keySize)
+	var digest []byte
+
+	for i := 0; i < len(out); i += len(digest) {
+		hash.Reset()
+		hash.Write(digest)
+		hash.Write(password)
+		hash.Write(salt)
+		digest = hash.Sum(digest[:0])
+		copy(out[i:], digest)
+	}
+	return out
+}
+
+// IsEncryptedPEMBlock returns if the PEM block is password encrypted.
+func IsEncryptedPEMBlock(b *pem.Block) bool {
+	_, ok := b.Headers["DEK-Info"]
+	return ok
+}
+
+// IncorrectPasswordError is returned when an incorrect password is detected.
+var IncorrectPasswordError = errors.New("x509: decryption password incorrect")
+
+// DecryptPEMBlock takes a password encrypted PEM block and the password used to
+// encrypt it and returns a slice of decrypted DER encoded bytes. It inspects
+// the DEK-Info header to determine the algorithm used for decryption. If no
+// DEK-Info header is present, an error is returned. If an incorrect password
+// is detected an IncorrectPasswordError is returned.
+func DecryptPEMBlock(b *pem.Block, password []byte) ([]byte, error) {
+	dek, ok := b.Headers["DEK-Info"]
+	if !ok {
+		return nil, errors.New("x509: no DEK-Info header in block")
+	}
+
+	idx := strings.Index(dek, ",")
+	if idx == -1 {
+		return nil, errors.New("x509: malformed DEK-Info header")
+	}
+
+	mode, hexIV := dek[:idx], dek[idx+1:]
+	ciph := cipherByName(mode)
+	if ciph == nil {
+		return nil, errors.New("x509: unknown encryption mode")
+	}
+	iv, err := hex.DecodeString(hexIV)
+	if err != nil {
+		return nil, err
+	}
+	if len(iv) != ciph.blockSize {
+		return nil, errors.New("x509: incorrect IV size")
+	}
+
+	// Based on the OpenSSL implementation. The salt is the first 8 bytes
+	// of the initialization vector.
+	key := ciph.deriveKey(password, iv[:8])
+	block, err := ciph.cipherFunc(key)
+	if err != nil {
+		return nil, err
+	}
+
+	data := make([]byte, len(b.Bytes))
+	dec := cipher.NewCBCDecrypter(block, iv)
+	dec.CryptBlocks(data, b.Bytes)
+
+	// Blocks are padded using a scheme where the last n bytes of padding are all
+	// equal to n. It can pad from 1 to blocksize bytes inclusive. See RFC 1423.
+	// For example:
+	//	[x y z 2 2]
+	//	[x y 7 7 7 7 7 7 7]
+	// If we detect a bad padding, we assume it is an invalid password.
+	dlen := len(data)
+	if dlen == 0 || dlen%ciph.blockSize != 0 {
+		return nil, errors.New("x509: invalid padding")
+	}
+	last := int(data[dlen-1])
+	if dlen < last {
+		return nil, IncorrectPasswordError
+	}
+	if last == 0 || last > ciph.blockSize {
+		return nil, IncorrectPasswordError
+	}
+	for _, val := range data[dlen-last:] {
+		if int(val) != last {
+			return nil, IncorrectPasswordError
+		}
+	}
+	return data[:dlen-last], nil
+}
+
+// EncryptPEMBlock returns a PEM block of the specified type holding the
+// given DER-encoded data encrypted with the specified algorithm and
+// password.
+func EncryptPEMBlock(rand io.Reader, blockType string, data, password []byte, alg PEMCipher) (*pem.Block, error) {
+	ciph := cipherByKey(alg)
+	if ciph == nil {
+		return nil, errors.New("x509: unknown encryption mode")
+	}
+	iv := make([]byte, ciph.blockSize)
+	if _, err := io.ReadFull(rand, iv); err != nil {
+		return nil, errors.New("x509: cannot generate IV: " + err.Error())
+	}
+	// The salt is the first 8 bytes of the initialization vector,
+	// matching the key derivation in DecryptPEMBlock.
+	key := ciph.deriveKey(password, iv[:8])
+	block, err := ciph.cipherFunc(key)
+	if err != nil {
+		return nil, err
+	}
+	enc := cipher.NewCBCEncrypter(block, iv)
+	pad := ciph.blockSize - len(data)%ciph.blockSize
+	encrypted := make([]byte, len(data), len(data)+pad)
+	// We could save this copy by encrypting all the whole blocks in
+	// the data separately, but it doesn't seem worth the additional
+	// code.
+	copy(encrypted, data)
+	// See RFC 1423, section 1.1
+	for i := 0; i < pad; i++ {
+		encrypted = append(encrypted, byte(pad))
+	}
+	enc.CryptBlocks(encrypted, encrypted)
+
+	return &pem.Block{
+		Type: blockType,
+		Headers: map[string]string{
+			"Proc-Type": "4,ENCRYPTED",
+			"DEK-Info":  ciph.name + "," + hex.EncodeToString(iv),
+		},
+		Bytes: encrypted,
+	}, nil
+}
+
+func cipherByName(name string) *rfc1423Algo {
+	for i := range rfc1423Algos {
+		alg := &rfc1423Algos[i]
+		if alg.name == name {
+			return alg
+		}
+	}
+	return nil
+}
+
+func cipherByKey(key PEMCipher) *rfc1423Algo {
+	for i := range rfc1423Algos {
+		alg := &rfc1423Algos[i]
+		if alg.cipher == key {
+			return alg
+		}
+	}
+	return nil
+}

vendor/github.com/google/certificate-transparency/go/x509/pkcs1.go

@@ -0,0 +1,124 @@
+// Copyright 2011 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 (
+	"crypto/rsa"
+	// START CT CHANGES
+	"github.com/google/certificate-transparency/go/asn1"
+	// END CT CHANGES
+	"errors"
+	"math/big"
+)
+
+// pkcs1PrivateKey is a structure which mirrors the PKCS#1 ASN.1 for an RSA private key.
+type pkcs1PrivateKey struct {
+	Version int
+	N       *big.Int
+	E       int
+	D       *big.Int
+	P       *big.Int
+	Q       *big.Int
+	// We ignore these values, if present, because rsa will calculate them.
+	Dp   *big.Int `asn1:"optional"`
+	Dq   *big.Int `asn1:"optional"`
+	Qinv *big.Int `asn1:"optional"`
+
+	AdditionalPrimes []pkcs1AdditionalRSAPrime `asn1:"optional,omitempty"`
+}
+
+type pkcs1AdditionalRSAPrime struct {
+	Prime *big.Int
+
+	// We ignore these values because rsa will calculate them.
+	Exp   *big.Int
+	Coeff *big.Int
+}
+
+// ParsePKCS1PrivateKey returns an RSA private key from its ASN.1 PKCS#1 DER encoded form.
+func ParsePKCS1PrivateKey(der []byte) (key *rsa.PrivateKey, err error) {
+	var priv pkcs1PrivateKey
+	rest, err := asn1.Unmarshal(der, &priv)
+	if len(rest) > 0 {
+		err = asn1.SyntaxError{Msg: "trailing data"}
+		return
+	}
+	if err != nil {
+		return
+	}
+
+	if priv.Version > 1 {
+		return nil, errors.New("x509: unsupported private key version")
+	}
+
+	if priv.N.Sign() <= 0 || priv.D.Sign() <= 0 || priv.P.Sign() <= 0 || priv.Q.Sign() <= 0 {
+		return nil, errors.New("x509: private key contains zero or negative value")
+	}
+
+	key = new(rsa.PrivateKey)
+	key.PublicKey = rsa.PublicKey{
+		E: priv.E,
+		N: priv.N,
+	}
+
+	key.D = priv.D
+	key.Primes = make([]*big.Int, 2+len(priv.AdditionalPrimes))
+	key.Primes[0] = priv.P
+	key.Primes[1] = priv.Q
+	for i, a := range priv.AdditionalPrimes {
+		if a.Prime.Sign() <= 0 {
+			return nil, errors.New("x509: private key contains zero or negative prime")
+		}
+		key.Primes[i+2] = a.Prime
+		// We ignore the other two values because rsa will calculate
+		// them as needed.
+	}
+
+	err = key.Validate()
+	if err != nil {
+		return nil, err
+	}
+	key.Precompute()
+
+	return
+}
+
+// MarshalPKCS1PrivateKey converts a private key to ASN.1 DER encoded form.
+func MarshalPKCS1PrivateKey(key *rsa.PrivateKey) []byte {
+	key.Precompute()
+
+	version := 0
+	if len(key.Primes) > 2 {
+		version = 1
+	}
+
+	priv := pkcs1PrivateKey{
+		Version: version,
+		N:       key.N,
+		E:       key.PublicKey.E,
+		D:       key.D,
+		P:       key.Primes[0],
+		Q:       key.Primes[1],
+		Dp:      key.Precomputed.Dp,
+		Dq:      key.Precomputed.Dq,
+		Qinv:    key.Precomputed.Qinv,
+	}
+
+	priv.AdditionalPrimes = make([]pkcs1AdditionalRSAPrime, len(key.Precomputed.CRTValues))
+	for i, values := range key.Precomputed.CRTValues {
+		priv.AdditionalPrimes[i].Prime = key.Primes[2+i]
+		priv.AdditionalPrimes[i].Exp = values.Exp
+		priv.AdditionalPrimes[i].Coeff = values.Coeff
+	}
+
+	b, _ := asn1.Marshal(priv)
+	return b
+}
+
+// rsaPublicKey reflects the ASN.1 structure of a PKCS#1 public key.
+type rsaPublicKey struct {
+	N *big.Int
+	E int
+}

vendor/github.com/google/certificate-transparency/go/x509/pkcs8.go

@@ -0,0 +1,56 @@
+// Copyright 2011 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 (
+	// START CT CHANGES
+	"github.com/google/certificate-transparency/go/asn1"
+	"github.com/google/certificate-transparency/go/x509/pkix"
+	// END CT CHANGES
+	"errors"
+	"fmt"
+)
+
+// pkcs8 reflects an ASN.1, PKCS#8 PrivateKey. See
+// ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-8/pkcs-8v1_2.asn
+// and RFC5208.
+type pkcs8 struct {
+	Version    int
+	Algo       pkix.AlgorithmIdentifier
+	PrivateKey []byte
+	// optional attributes omitted.
+}
+
+// ParsePKCS8PrivateKey parses an unencrypted, PKCS#8 private key. See
+// http://www.rsa.com/rsalabs/node.asp?id=2130 and RFC5208.
+func ParsePKCS8PrivateKey(der []byte) (key interface{}, err error) {
+	var privKey pkcs8
+	if _, err := asn1.Unmarshal(der, &privKey); err != nil {
+		return nil, err
+	}
+	switch {
+	case privKey.Algo.Algorithm.Equal(oidPublicKeyRSA):
+		key, err = ParsePKCS1PrivateKey(privKey.PrivateKey)
+		if err != nil {
+			return nil, errors.New("x509: failed to parse RSA private key embedded in PKCS#8: " + err.Error())
+		}
+		return key, nil
+
+	case privKey.Algo.Algorithm.Equal(oidPublicKeyECDSA):
+		bytes := privKey.Algo.Parameters.FullBytes
+		namedCurveOID := new(asn1.ObjectIdentifier)
+		if _, err := asn1.Unmarshal(bytes, namedCurveOID); err != nil {
+			namedCurveOID = nil
+		}
+		key, err = parseECPrivateKey(namedCurveOID, privKey.PrivateKey)
+		if err != nil {
+			return nil, errors.New("x509: failed to parse EC private key embedded in PKCS#8: " + err.Error())
+		}
+		return key, nil
+
+	default:
+		return nil, fmt.Errorf("x509: PKCS#8 wrapping contained private key with unknown algorithm: %v", privKey.Algo.Algorithm)
+	}
+}

vendor/github.com/google/certificate-transparency/go/x509/pkix/pkix.go

@@ -0,0 +1,173 @@
+// Copyright 2011 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 pkix contains shared, low level structures used for ASN.1 parsing
+// and serialization of X.509 certificates, CRL and OCSP.
+package pkix
+
+import (
+	// START CT CHANGES
+	"github.com/google/certificate-transparency/go/asn1"
+	// END CT CHANGES
+	"math/big"
+	"time"
+)
+
+// AlgorithmIdentifier represents the ASN.1 structure of the same name. See RFC
+// 5280, section 4.1.1.2.
+type AlgorithmIdentifier struct {
+	Algorithm  asn1.ObjectIdentifier
+	Parameters asn1.RawValue `asn1:"optional"`
+}
+
+type RDNSequence []RelativeDistinguishedNameSET
+
+type RelativeDistinguishedNameSET []AttributeTypeAndValue
+
+// AttributeTypeAndValue mirrors the ASN.1 structure of the same name in
+// http://tools.ietf.org/html/rfc5280#section-4.1.2.4
+type AttributeTypeAndValue struct {
+	Type  asn1.ObjectIdentifier
+	Value interface{}
+}
+
+// Extension represents the ASN.1 structure of the same name. See RFC
+// 5280, section 4.2.
+type Extension struct {
+	Id       asn1.ObjectIdentifier
+	Critical bool `asn1:"optional"`
+	Value    []byte
+}
+
+// Name represents an X.509 distinguished name. This only includes the common
+// elements of a DN.  Additional elements in the name are ignored.
+type Name struct {
+	Country, Organization, OrganizationalUnit []string
+	Locality, Province                        []string
+	StreetAddress, PostalCode                 []string
+	SerialNumber, CommonName                  string
+
+	Names []AttributeTypeAndValue
+}
+
+func (n *Name) FillFromRDNSequence(rdns *RDNSequence) {
+	for _, rdn := range *rdns {
+		if len(rdn) == 0 {
+			continue
+		}
+		atv := rdn[0]
+		n.Names = append(n.Names, atv)
+		value, ok := atv.Value.(string)
+		if !ok {
+			continue
+		}
+
+		t := atv.Type
+		if len(t) == 4 && t[0] == 2 && t[1] == 5 && t[2] == 4 {
+			switch t[3] {
+			case 3:
+				n.CommonName = value
+			case 5:
+				n.SerialNumber = value
+			case 6:
+				n.Country = append(n.Country, value)
+			case 7:
+				n.Locality = append(n.Locality, value)
+			case 8:
+				n.Province = append(n.Province, value)
+			case 9:
+				n.StreetAddress = append(n.StreetAddress, value)
+			case 10:
+				n.Organization = append(n.Organization, value)
+			case 11:
+				n.OrganizationalUnit = append(n.OrganizationalUnit, value)
+			case 17:
+				n.PostalCode = append(n.PostalCode, value)
+			}
+		}
+	}
+}
+
+var (
+	oidCountry            = []int{2, 5, 4, 6}
+	oidOrganization       = []int{2, 5, 4, 10}
+	oidOrganizationalUnit = []int{2, 5, 4, 11}
+	oidCommonName         = []int{2, 5, 4, 3}
+	oidSerialNumber       = []int{2, 5, 4, 5}
+	oidLocality           = []int{2, 5, 4, 7}
+	oidProvince           = []int{2, 5, 4, 8}
+	oidStreetAddress      = []int{2, 5, 4, 9}
+	oidPostalCode         = []int{2, 5, 4, 17}
+)
+
+// appendRDNs appends a relativeDistinguishedNameSET to the given RDNSequence
+// and returns the new value. The relativeDistinguishedNameSET contains an
+// attributeTypeAndValue for each of the given values. See RFC 5280, A.1, and
+// search for AttributeTypeAndValue.
+func appendRDNs(in RDNSequence, values []string, oid asn1.ObjectIdentifier) RDNSequence {
+	if len(values) == 0 {
+		return in
+	}
+
+	s := make([]AttributeTypeAndValue, len(values))
+	for i, value := range values {
+		s[i].Type = oid
+		s[i].Value = value
+	}
+
+	return append(in, s)
+}
+
+func (n Name) ToRDNSequence() (ret RDNSequence) {
+	ret = appendRDNs(ret, n.Country, oidCountry)
+	ret = appendRDNs(ret, n.Organization, oidOrganization)
+	ret = appendRDNs(ret, n.OrganizationalUnit, oidOrganizationalUnit)
+	ret = appendRDNs(ret, n.Locality, oidLocality)
+	ret = appendRDNs(ret, n.Province, oidProvince)
+	ret = appendRDNs(ret, n.StreetAddress, oidStreetAddress)
+	ret = appendRDNs(ret, n.PostalCode, oidPostalCode)
+	if len(n.CommonName) > 0 {
+		ret = appendRDNs(ret, []string{n.CommonName}, oidCommonName)
+	}
+	if len(n.SerialNumber) > 0 {
+		ret = appendRDNs(ret, []string{n.SerialNumber}, oidSerialNumber)
+	}
+
+	return ret
+}
+
+// CertificateList represents the ASN.1 structure of the same name. See RFC
+// 5280, section 5.1. Use Certificate.CheckCRLSignature to verify the
+// signature.
+type CertificateList struct {
+	TBSCertList        TBSCertificateList
+	SignatureAlgorithm AlgorithmIdentifier
+	SignatureValue     asn1.BitString
+}
+
+// HasExpired reports whether now is past the expiry time of certList.
+func (certList *CertificateList) HasExpired(now time.Time) bool {
+	return now.After(certList.TBSCertList.NextUpdate)
+}
+
+// TBSCertificateList represents the ASN.1 structure of the same name. See RFC
+// 5280, section 5.1.
+type TBSCertificateList struct {
+	Raw                 asn1.RawContent
+	Version             int `asn1:"optional,default:2"`
+	Signature           AlgorithmIdentifier
+	Issuer              RDNSequence
+	ThisUpdate          time.Time
+	NextUpdate          time.Time
+	RevokedCertificates []RevokedCertificate `asn1:"optional"`
+	Extensions          []Extension          `asn1:"tag:0,optional,explicit"`
+}
+
+// RevokedCertificate represents the ASN.1 structure of the same name. See RFC
+// 5280, section 5.1.
+type RevokedCertificate struct {
+	SerialNumber   *big.Int
+	RevocationTime time.Time
+	Extensions     []Extension `asn1:"optional"`
+}

vendor/github.com/google/certificate-transparency/go/x509/root.go

@@ -0,0 +1,17 @@
+// 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 "sync"
+
+var (
+	once        sync.Once
+	systemRoots *CertPool
+)
+
+func systemRootsPool() *CertPool {
+	once.Do(initSystemRoots)
+	return systemRoots
+}

vendor/github.com/google/certificate-transparency/go/x509/root_darwin.go

@@ -0,0 +1,83 @@
+// Copyright 2011 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.
+
+// +build darwin,cgo
+
+package x509
+
+/*
+#cgo CFLAGS: -mmacosx-version-min=10.6 -D__MAC_OS_X_VERSION_MAX_ALLOWED=1060
+#cgo LDFLAGS: -framework CoreFoundation -framework Security
+
+#include <CoreFoundation/CoreFoundation.h>
+#include <Security/Security.h>
+
+// FetchPEMRootsCTX509 fetches the system's list of trusted X.509 root certificates.
+//
+// On success it returns 0 and fills pemRoots with a CFDataRef that contains the extracted root
+// certificates of the system. On failure, the function returns -1.
+//
+// Note: The CFDataRef returned in pemRoots must be released (using CFRelease) after
+// we've consumed its content.
+int FetchPEMRootsCTX509(CFDataRef *pemRoots) {
+	if (pemRoots == NULL) {
+		return -1;
+	}
+
+	CFArrayRef certs = NULL;
+	OSStatus err = SecTrustCopyAnchorCertificates(&certs);
+	if (err != noErr) {
+		return -1;
+	}
+
+	CFMutableDataRef combinedData = CFDataCreateMutable(kCFAllocatorDefault, 0);
+	int i, ncerts = CFArrayGetCount(certs);
+	for (i = 0; i < ncerts; i++) {
+		CFDataRef data = NULL;
+		SecCertificateRef cert = (SecCertificateRef)CFArrayGetValueAtIndex(certs, i);
+		if (cert == NULL) {
+			continue;
+		}
+
+		// Note: SecKeychainItemExport is deprecated as of 10.7 in favor of SecItemExport.
+		// Once we support weak imports via cgo we should prefer that, and fall back to this
+		// for older systems.
+		err = SecKeychainItemExport(cert, kSecFormatX509Cert, kSecItemPemArmour, NULL, &data);
+		if (err != noErr) {
+			continue;
+		}
+
+		if (data != NULL) {
+			CFDataAppendBytes(combinedData, CFDataGetBytePtr(data), CFDataGetLength(data));
+			CFRelease(data);
+		}
+	}
+
+	CFRelease(certs);
+
+	*pemRoots = combinedData;
+	return 0;
+}
+*/
+import "C"
+import "unsafe"
+
+func (c *Certificate) systemVerify(opts *VerifyOptions) (chains [][]*Certificate, err error) {
+	return nil, nil
+}
+
+func initSystemRoots() {
+	roots := NewCertPool()
+
+	var data C.CFDataRef = nil
+	err := C.FetchPEMRootsCTX509(&data)
+	if err == -1 {
+		return
+	}
+
+	defer C.CFRelease(C.CFTypeRef(data))
+	buf := C.GoBytes(unsafe.Pointer(C.CFDataGetBytePtr(data)), C.int(C.CFDataGetLength(data)))
+	roots.AppendCertsFromPEM(buf)
+	systemRoots = roots
+}

vendor/github.com/google/certificate-transparency/go/x509/root_plan9.go

@@ -0,0 +1,33 @@
+// 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.
+
+// +build plan9
+
+package x509
+
+import "io/ioutil"
+
+// Possible certificate files; stop after finding one.
+var certFiles = []string{
+	"/sys/lib/tls/ca.pem",
+}
+
+func (c *Certificate) systemVerify(opts *VerifyOptions) (chains [][]*Certificate, err error) {
+	return nil, nil
+}
+
+func initSystemRoots() {
+	roots := NewCertPool()
+	for _, file := range certFiles {
+		data, err := ioutil.ReadFile(file)
+		if err == nil {
+			roots.AppendCertsFromPEM(data)
+			systemRoots = roots
+			return
+		}
+	}
+
+	// All of the files failed to load. systemRoots will be nil which will
+	// trigger a specific error at verification time.
+}

vendor/github.com/google/certificate-transparency/go/x509/root_stub.go

@@ -0,0 +1,14 @@
+// Copyright 2011 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.
+
+// +build darwin,!cgo
+
+package x509
+
+func (c *Certificate) systemVerify(opts *VerifyOptions) (chains [][]*Certificate, err error) {
+	return nil, nil
+}
+
+func initSystemRoots() {
+}

vendor/github.com/google/certificate-transparency/go/x509/root_unix.go

@@ -0,0 +1,37 @@
+// Copyright 2011 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.
+
+// +build dragonfly freebsd linux openbsd netbsd
+
+package x509
+
+import "io/ioutil"
+
+// Possible certificate files; stop after finding one.
+var certFiles = []string{
+	"/etc/ssl/certs/ca-certificates.crt",     // Debian/Ubuntu/Gentoo etc.
+	"/etc/pki/tls/certs/ca-bundle.crt",       // Fedora/RHEL
+	"/etc/ssl/ca-bundle.pem",                 // OpenSUSE
+	"/etc/ssl/cert.pem",                      // OpenBSD
+	"/usr/local/share/certs/ca-root-nss.crt", // FreeBSD/DragonFly
+}
+
+func (c *Certificate) systemVerify(opts *VerifyOptions) (chains [][]*Certificate, err error) {
+	return nil, nil
+}
+
+func initSystemRoots() {
+	roots := NewCertPool()
+	for _, file := range certFiles {
+		data, err := ioutil.ReadFile(file)
+		if err == nil {
+			roots.AppendCertsFromPEM(data)
+			systemRoots = roots
+			return
+		}
+	}
+
+	// All of the files failed to load. systemRoots will be nil which will
+	// trigger a specific error at verification time.
+}

vendor/github.com/google/certificate-transparency/go/x509/root_windows.go

@@ -0,0 +1,229 @@
+// 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 _, intermediate := range opts.Intermediates.certs {
+			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))[:]
+	lastChain := simpleChains[count-1]
+	elements := (*[1 << 20]*syscall.CertChainElement)(unsafe.Pointer(lastChain.Elements))[:]
+	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))[:]
+		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}
+		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: uintptr(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
+}
+
+// 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) {
+	hasDNSName := opts != nil && len(opts.DNSName) > 0
+
+	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))
+
+	// If there's a DNSName set in opts, assume we're verifying
+	// a certificate from a TLS server.
+	if hasDNSName {
+		oids := []*byte{
+			&syscall.OID_PKIX_KP_SERVER_AUTH[0],
+			// Both IE and Chrome allow certificates with
+			// Server Gated Crypto as well. Some certificates
+			// in the wild require them.
+			&syscall.OID_SERVER_GATED_CRYPTO[0],
+			&syscall.OID_SGC_NETSCAPE[0],
+		}
+		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
+	}
+
+	// CertGetCertificateChain will traverse Windows's root stores
+	// in an attempt to build a verified certificate chain.  Once
+	// it has found a verified chain, it stops. MSDN docs on
+	// CERT_CHAIN_CONTEXT:
+	//
+	//   When a CERT_CHAIN_CONTEXT is built, the first simple chain
+	//   begins with an end certificate and ends with a self-signed
+	//   certificate. If that self-signed certificate is not a root
+	//   or otherwise trusted certificate, an attempt is made to
+	//   build a new chain. CTLs are used to create the new chain
+	//   beginning with the self-signed certificate from the original
+	//   chain as the end certificate of the new chain. This process
+	//   continues building additional simple chains until the first
+	//   self-signed certificate is a trusted certificate or until
+	//   an additional simple chain cannot be built.
+	//
+	// The result is that we'll only get a single trusted chain to
+	// return to our caller.
+	var chainCtx *syscall.CertChainContext
+	err = syscall.CertGetCertificateChain(syscall.Handle(0), storeCtx, verifyTime, storeCtx.Store, para, 0, 0, &chainCtx)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.CertFreeCertificateChain(chainCtx)
+
+	err = checkChainTrustStatus(c, chainCtx)
+	if err != nil {
+		return nil, err
+	}
+
+	if hasDNSName {
+		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
+	}
+
+	chains = append(chains, chain)
+
+	return chains, nil
+}
+
+func initSystemRoots() {
+}

vendor/github.com/google/certificate-transparency/go/x509/sec1.go

@@ -0,0 +1,85 @@
+// 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 (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	// START CT CHANGES
+	"github.com/google/certificate-transparency/go/asn1"
+	// START CT CHANGES
+	"errors"
+	"fmt"
+	"math/big"
+)
+
+const ecPrivKeyVersion = 1
+
+// ecPrivateKey reflects an ASN.1 Elliptic Curve Private Key Structure.
+// References:
+//   RFC5915
+//   SEC1 - http://www.secg.org/download/aid-780/sec1-v2.pdf
+// Per RFC5915 the NamedCurveOID is marked as ASN.1 OPTIONAL, however in
+// most cases it is not.
+type ecPrivateKey struct {
+	Version       int
+	PrivateKey    []byte
+	NamedCurveOID asn1.ObjectIdentifier `asn1:"optional,explicit,tag:0"`
+	PublicKey     asn1.BitString        `asn1:"optional,explicit,tag:1"`
+}
+
+// ParseECPrivateKey parses an ASN.1 Elliptic Curve Private Key Structure.
+func ParseECPrivateKey(der []byte) (key *ecdsa.PrivateKey, err error) {
+	return parseECPrivateKey(nil, der)
+}
+
+// MarshalECPrivateKey marshals an EC private key into ASN.1, DER format.
+func MarshalECPrivateKey(key *ecdsa.PrivateKey) ([]byte, error) {
+	oid, ok := oidFromNamedCurve(key.Curve)
+	if !ok {
+		return nil, errors.New("x509: unknown elliptic curve")
+	}
+	return asn1.Marshal(ecPrivateKey{
+		Version:       1,
+		PrivateKey:    key.D.Bytes(),
+		NamedCurveOID: oid,
+		PublicKey:     asn1.BitString{Bytes: elliptic.Marshal(key.Curve, key.X, key.Y)},
+	})
+}
+
+// parseECPrivateKey parses an ASN.1 Elliptic Curve Private Key Structure.
+// The OID for the named curve may be provided from another source (such as
+// the PKCS8 container) - if it is provided then use this instead of the OID
+// that may exist in the EC private key structure.
+func parseECPrivateKey(namedCurveOID *asn1.ObjectIdentifier, der []byte) (key *ecdsa.PrivateKey, err error) {
+	var privKey ecPrivateKey
+	if _, err := asn1.Unmarshal(der, &privKey); err != nil {
+		return nil, errors.New("x509: failed to parse EC private key: " + err.Error())
+	}
+	if privKey.Version != ecPrivKeyVersion {
+		return nil, fmt.Errorf("x509: unknown EC private key version %d", privKey.Version)
+	}
+
+	var curve elliptic.Curve
+	if namedCurveOID != nil {
+		curve = namedCurveFromOID(*namedCurveOID)
+	} else {
+		curve = namedCurveFromOID(privKey.NamedCurveOID)
+	}
+	if curve == nil {
+		return nil, errors.New("x509: unknown elliptic curve")
+	}
+
+	k := new(big.Int).SetBytes(privKey.PrivateKey)
+	if k.Cmp(curve.Params().N) >= 0 {
+		return nil, errors.New("x509: invalid elliptic curve private key value")
+	}
+	priv := new(ecdsa.PrivateKey)
+	priv.Curve = curve
+	priv.D = k
+	priv.X, priv.Y = curve.ScalarBaseMult(privKey.PrivateKey)
+
+	return priv, nil
+}

vendor/github.com/google/certificate-transparency/go/x509/verify.go

@@ -0,0 +1,476 @@
+// Copyright 2011 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 (
+	"fmt"
+	"net"
+	"runtime"
+	"strings"
+	"time"
+	"unicode/utf8"
+)
+
+type InvalidReason int
+
+const (
+	// NotAuthorizedToSign results when a certificate is signed by another
+	// which isn't marked as a CA certificate.
+	NotAuthorizedToSign InvalidReason = iota
+	// Expired results when a certificate has expired, based on the time
+	// given in the VerifyOptions.
+	Expired
+	// CANotAuthorizedForThisName results when an intermediate or root
+	// certificate has a name constraint which doesn't include the name
+	// being checked.
+	CANotAuthorizedForThisName
+	// TooManyIntermediates results when a path length constraint is
+	// violated.
+	TooManyIntermediates
+	// IncompatibleUsage results when the certificate's key usage indicates
+	// that it may only be used for a different purpose.
+	IncompatibleUsage
+)
+
+// CertificateInvalidError results when an odd error occurs. Users of this
+// library probably want to handle all these errors uniformly.
+type CertificateInvalidError struct {
+	Cert   *Certificate
+	Reason InvalidReason
+}
+
+func (e CertificateInvalidError) Error() string {
+	switch e.Reason {
+	case NotAuthorizedToSign:
+		return "x509: certificate is not authorized to sign other certificates"
+	case Expired:
+		return "x509: certificate has expired or is not yet valid"
+	case CANotAuthorizedForThisName:
+		return "x509: a root or intermediate certificate is not authorized to sign in this domain"
+	case TooManyIntermediates:
+		return "x509: too many intermediates for path length constraint"
+	case IncompatibleUsage:
+		return "x509: certificate specifies an incompatible key usage"
+	}
+	return "x509: unknown error"
+}
+
+// HostnameError results when the set of authorized names doesn't match the
+// requested name.
+type HostnameError struct {
+	Certificate *Certificate
+	Host        string
+}
+
+func (h HostnameError) Error() string {
+	c := h.Certificate
+
+	var valid string
+	if ip := net.ParseIP(h.Host); ip != nil {
+		// Trying to validate an IP
+		if len(c.IPAddresses) == 0 {
+			return "x509: cannot validate certificate for " + h.Host + " because it doesn't contain any IP SANs"
+		}
+		for _, san := range c.IPAddresses {
+			if len(valid) > 0 {
+				valid += ", "
+			}
+			valid += san.String()
+		}
+	} else {
+		if len(c.DNSNames) > 0 {
+			valid = strings.Join(c.DNSNames, ", ")
+		} else {
+			valid = c.Subject.CommonName
+		}
+	}
+	return "x509: certificate is valid for " + valid + ", not " + h.Host
+}
+
+// UnknownAuthorityError results when the certificate issuer is unknown
+type UnknownAuthorityError struct {
+	cert *Certificate
+	// hintErr contains an error that may be helpful in determining why an
+	// authority wasn't found.
+	hintErr error
+	// hintCert contains a possible authority certificate that was rejected
+	// because of the error in hintErr.
+	hintCert *Certificate
+}
+
+func (e UnknownAuthorityError) Error() string {
+	s := "x509: certificate signed by unknown authority"
+	if e.hintErr != nil {
+		certName := e.hintCert.Subject.CommonName
+		if len(certName) == 0 {
+			if len(e.hintCert.Subject.Organization) > 0 {
+				certName = e.hintCert.Subject.Organization[0]
+			}
+			certName = "serial:" + e.hintCert.SerialNumber.String()
+		}
+		s += fmt.Sprintf(" (possibly because of %q while trying to verify candidate authority certificate %q)", e.hintErr, certName)
+	}
+	return s
+}
+
+// SystemRootsError results when we fail to load the system root certificates.
+type SystemRootsError struct {
+}
+
+func (e SystemRootsError) Error() string {
+	return "x509: failed to load system roots and no roots provided"
+}
+
+// VerifyOptions contains parameters for Certificate.Verify. It's a structure
+// because other PKIX verification APIs have ended up needing many options.
+type VerifyOptions struct {
+	DNSName           string
+	Intermediates     *CertPool
+	Roots             *CertPool // if nil, the system roots are used
+	CurrentTime       time.Time // if zero, the current time is used
+	DisableTimeChecks bool
+	// KeyUsage specifies which Extended Key Usage values are acceptable.
+	// An empty list means ExtKeyUsageServerAuth. Key usage is considered a
+	// constraint down the chain which mirrors Windows CryptoAPI behaviour,
+	// but not the spec. To accept any key usage, include ExtKeyUsageAny.
+	KeyUsages []ExtKeyUsage
+}
+
+const (
+	leafCertificate = iota
+	intermediateCertificate
+	rootCertificate
+)
+
+// isValid performs validity checks on the c.
+func (c *Certificate) isValid(certType int, currentChain []*Certificate, opts *VerifyOptions) error {
+	if !opts.DisableTimeChecks {
+		now := opts.CurrentTime
+		if now.IsZero() {
+			now = time.Now()
+		}
+		if now.Before(c.NotBefore) || now.After(c.NotAfter) {
+			return CertificateInvalidError{c, Expired}
+		}
+	}
+
+	if len(c.PermittedDNSDomains) > 0 {
+		ok := false
+		for _, domain := range c.PermittedDNSDomains {
+			if opts.DNSName == domain ||
+				(strings.HasSuffix(opts.DNSName, domain) &&
+					len(opts.DNSName) >= 1+len(domain) &&
+					opts.DNSName[len(opts.DNSName)-len(domain)-1] == '.') {
+				ok = true
+				break
+			}
+		}
+
+		if !ok {
+			return CertificateInvalidError{c, CANotAuthorizedForThisName}
+		}
+	}
+
+	// KeyUsage status flags are ignored. From Engineering Security, Peter
+	// Gutmann: A European government CA marked its signing certificates as
+	// being valid for encryption only, but no-one noticed. Another
+	// European CA marked its signature keys as not being valid for
+	// signatures. A different CA marked its own trusted root certificate
+	// as being invalid for certificate signing.  Another national CA
+	// distributed a certificate to be used to encrypt data for the
+	// country’s tax authority that was marked as only being usable for
+	// digital signatures but not for encryption. Yet another CA reversed
+	// the order of the bit flags in the keyUsage due to confusion over
+	// encoding endianness, essentially setting a random keyUsage in
+	// certificates that it issued. Another CA created a self-invalidating
+	// certificate by adding a certificate policy statement stipulating
+	// that the certificate had to be used strictly as specified in the
+	// keyUsage, and a keyUsage containing a flag indicating that the RSA
+	// encryption key could only be used for Diffie-Hellman key agreement.
+
+	if certType == intermediateCertificate && (!c.BasicConstraintsValid || !c.IsCA) {
+		return CertificateInvalidError{c, NotAuthorizedToSign}
+	}
+
+	if c.BasicConstraintsValid && c.MaxPathLen >= 0 {
+		numIntermediates := len(currentChain) - 1
+		if numIntermediates > c.MaxPathLen {
+			return CertificateInvalidError{c, TooManyIntermediates}
+		}
+	}
+
+	return nil
+}
+
+// Verify attempts to verify c by building one or more chains from c to a
+// certificate in opts.Roots, using certificates in opts.Intermediates if
+// needed. If successful, it returns one or more chains where the first
+// element of the chain is c and the last element is from opts.Roots.
+//
+// WARNING: this doesn't do any revocation checking.
+func (c *Certificate) Verify(opts VerifyOptions) (chains [][]*Certificate, err error) {
+	// Use Windows's own verification and chain building.
+	if opts.Roots == nil && runtime.GOOS == "windows" {
+		return c.systemVerify(&opts)
+	}
+
+	if opts.Roots == nil {
+		opts.Roots = systemRootsPool()
+		if opts.Roots == nil {
+			return nil, SystemRootsError{}
+		}
+	}
+
+	err = c.isValid(leafCertificate, nil, &opts)
+	if err != nil {
+		return
+	}
+
+	if len(opts.DNSName) > 0 {
+		err = c.VerifyHostname(opts.DNSName)
+		if err != nil {
+			return
+		}
+	}
+
+	candidateChains, err := c.buildChains(make(map[int][][]*Certificate), []*Certificate{c}, &opts)
+	if err != nil {
+		return
+	}
+
+	keyUsages := opts.KeyUsages
+	if len(keyUsages) == 0 {
+		keyUsages = []ExtKeyUsage{ExtKeyUsageServerAuth}
+	}
+
+	// If any key usage is acceptable then we're done.
+	for _, usage := range keyUsages {
+		if usage == ExtKeyUsageAny {
+			chains = candidateChains
+			return
+		}
+	}
+
+	for _, candidate := range candidateChains {
+		if checkChainForKeyUsage(candidate, keyUsages) {
+			chains = append(chains, candidate)
+		}
+	}
+
+	if len(chains) == 0 {
+		err = CertificateInvalidError{c, IncompatibleUsage}
+	}
+
+	return
+}
+
+func appendToFreshChain(chain []*Certificate, cert *Certificate) []*Certificate {
+	n := make([]*Certificate, len(chain)+1)
+	copy(n, chain)
+	n[len(chain)] = cert
+	return n
+}
+
+func (c *Certificate) buildChains(cache map[int][][]*Certificate, currentChain []*Certificate, opts *VerifyOptions) (chains [][]*Certificate, err error) {
+	possibleRoots, failedRoot, rootErr := opts.Roots.findVerifiedParents(c)
+	for _, rootNum := range possibleRoots {
+		root := opts.Roots.certs[rootNum]
+		err = root.isValid(rootCertificate, currentChain, opts)
+		if err != nil {
+			continue
+		}
+		chains = append(chains, appendToFreshChain(currentChain, root))
+	}
+
+	possibleIntermediates, failedIntermediate, intermediateErr := opts.Intermediates.findVerifiedParents(c)
+nextIntermediate:
+	for _, intermediateNum := range possibleIntermediates {
+		intermediate := opts.Intermediates.certs[intermediateNum]
+		for _, cert := range currentChain {
+			if cert == intermediate {
+				continue nextIntermediate
+			}
+		}
+		err = intermediate.isValid(intermediateCertificate, currentChain, opts)
+		if err != nil {
+			continue
+		}
+		var childChains [][]*Certificate
+		childChains, ok := cache[intermediateNum]
+		if !ok {
+			childChains, err = intermediate.buildChains(cache, appendToFreshChain(currentChain, intermediate), opts)
+			cache[intermediateNum] = childChains
+		}
+		chains = append(chains, childChains...)
+	}
+
+	if len(chains) > 0 {
+		err = nil
+	}
+
+	if len(chains) == 0 && err == nil {
+		hintErr := rootErr
+		hintCert := failedRoot
+		if hintErr == nil {
+			hintErr = intermediateErr
+			hintCert = failedIntermediate
+		}
+		err = UnknownAuthorityError{c, hintErr, hintCert}
+	}
+
+	return
+}
+
+func matchHostnames(pattern, host string) bool {
+	if len(pattern) == 0 || len(host) == 0 {
+		return false
+	}
+
+	patternParts := strings.Split(pattern, ".")
+	hostParts := strings.Split(host, ".")
+
+	if len(patternParts) != len(hostParts) {
+		return false
+	}
+
+	for i, patternPart := range patternParts {
+		if patternPart == "*" {
+			continue
+		}
+		if patternPart != hostParts[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+// toLowerCaseASCII returns a lower-case version of in. See RFC 6125 6.4.1. We use
+// an explicitly ASCII function to avoid any sharp corners resulting from
+// performing Unicode operations on DNS labels.
+func toLowerCaseASCII(in string) string {
+	// If the string is already lower-case then there's nothing to do.
+	isAlreadyLowerCase := true
+	for _, c := range in {
+		if c == utf8.RuneError {
+			// If we get a UTF-8 error then there might be
+			// upper-case ASCII bytes in the invalid sequence.
+			isAlreadyLowerCase = false
+			break
+		}
+		if 'A' <= c && c <= 'Z' {
+			isAlreadyLowerCase = false
+			break
+		}
+	}
+
+	if isAlreadyLowerCase {
+		return in
+	}
+
+	out := []byte(in)
+	for i, c := range out {
+		if 'A' <= c && c <= 'Z' {
+			out[i] += 'a' - 'A'
+		}
+	}
+	return string(out)
+}
+
+// VerifyHostname returns nil if c is a valid certificate for the named host.
+// Otherwise it returns an error describing the mismatch.
+func (c *Certificate) VerifyHostname(h string) error {
+	// IP addresses may be written in [ ].
+	candidateIP := h
+	if len(h) >= 3 && h[0] == '[' && h[len(h)-1] == ']' {
+		candidateIP = h[1 : len(h)-1]
+	}
+	if ip := net.ParseIP(candidateIP); ip != nil {
+		// We only match IP addresses against IP SANs.
+		// https://tools.ietf.org/html/rfc6125#appendix-B.2
+		for _, candidate := range c.IPAddresses {
+			if ip.Equal(candidate) {
+				return nil
+			}
+		}
+		return HostnameError{c, candidateIP}
+	}
+
+	lowered := toLowerCaseASCII(h)
+
+	if len(c.DNSNames) > 0 {
+		for _, match := range c.DNSNames {
+			if matchHostnames(toLowerCaseASCII(match), lowered) {
+				return nil
+			}
+		}
+		// If Subject Alt Name is given, we ignore the common name.
+	} else if matchHostnames(toLowerCaseASCII(c.Subject.CommonName), lowered) {
+		return nil
+	}
+
+	return HostnameError{c, h}
+}
+
+func checkChainForKeyUsage(chain []*Certificate, keyUsages []ExtKeyUsage) bool {
+	usages := make([]ExtKeyUsage, len(keyUsages))
+	copy(usages, keyUsages)
+
+	if len(chain) == 0 {
+		return false
+	}
+
+	usagesRemaining := len(usages)
+
+	// We walk down the list and cross out any usages that aren't supported
+	// by each certificate. If we cross out all the usages, then the chain
+	// is unacceptable.
+
+	for i := len(chain) - 1; i >= 0; i-- {
+		cert := chain[i]
+		if len(cert.ExtKeyUsage) == 0 && len(cert.UnknownExtKeyUsage) == 0 {
+			// The certificate doesn't have any extended key usage specified.
+			continue
+		}
+
+		for _, usage := range cert.ExtKeyUsage {
+			if usage == ExtKeyUsageAny {
+				// The certificate is explicitly good for any usage.
+				continue
+			}
+		}
+
+		const invalidUsage ExtKeyUsage = -1
+
+	NextRequestedUsage:
+		for i, requestedUsage := range usages {
+			if requestedUsage == invalidUsage {
+				continue
+			}
+
+			for _, usage := range cert.ExtKeyUsage {
+				if requestedUsage == usage {
+					continue NextRequestedUsage
+				} else if requestedUsage == ExtKeyUsageServerAuth &&
+					(usage == ExtKeyUsageNetscapeServerGatedCrypto ||
+						usage == ExtKeyUsageMicrosoftServerGatedCrypto) {
+					// In order to support COMODO
+					// certificate chains, we have to
+					// accept Netscape or Microsoft SGC
+					// usages as equal to ServerAuth.
+					continue NextRequestedUsage
+				}
+			}
+
+			usages[i] = invalidUsage
+			usagesRemaining--
+			if usagesRemaining == 0 {
+				return false
+			}
+		}
+	}
+
+	return true
+}