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crypto/x509: support certificate creation.

R=rsc
CC=golang-dev
https://golang.org/cl/212041
This commit is contained in:
Adam Langley 2010-02-19 10:55:41 -05:00
parent 55828cee94
commit 32c3c95339
2 changed files with 280 additions and 2 deletions

View File

@ -12,6 +12,7 @@ import (
"crypto/rsa"
"crypto/sha1"
"hash"
"io"
"os"
"strings"
"time"
@ -69,6 +70,21 @@ func ParsePKCS1PrivateKey(der []byte) (key *rsa.PrivateKey, err os.Error) {
return
}
// MarshalPKCS1PrivateKey converts a private key to ASN.1 DER encoded form.
func MarshalPKCS1PrivateKey(key *rsa.PrivateKey) []byte {
priv := pkcs1PrivateKey{
Version: 1,
N: asn1.RawValue{Tag: 2, Bytes: key.PublicKey.N.Bytes()},
E: key.PublicKey.E,
D: asn1.RawValue{Tag: 2, Bytes: key.D.Bytes()},
P: asn1.RawValue{Tag: 2, Bytes: key.P.Bytes()},
Q: asn1.RawValue{Tag: 2, Bytes: key.Q.Bytes()},
}
b, _ := asn1.MarshalToMemory(priv)
return b
}
// These structures reflect the ASN.1 structure of X.509 certificates.:
type certificate struct {
@ -86,8 +102,8 @@ type tbsCertificate struct {
Validity validity
Subject rdnSequence
PublicKey publicKeyInfo
UniqueId asn1.BitString "optional,explicit,tag:1"
SubjectUniqueId asn1.BitString "optional,explicit,tag:2"
UniqueId asn1.BitString "optional,tag:1"
SubjectUniqueId asn1.BitString "optional,tag:2"
Extensions []extension "optional,explicit,tag:3"
}
@ -188,6 +204,64 @@ func (n *Name) fillFromRDNSequence(rdns *rdnSequence) {
}
}
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}
oidLocatity = []int{2, 5, 4, 7}
oidProvince = []int{2, 5, 4, 8}
oidStreetAddress = []int{2, 5, 4, 9}
oidPostalCode = []int{2, 5, 4, 17}
)
func (n Name) toRDNSequence() (ret rdnSequence) {
ret = make([]relativeDistinguishedNameSET, 9 /* maximum number of elements */ )
i := 0
if len(n.Country) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidCountry, n.Country}}
i++
}
if len(n.Organization) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidOrganization, n.Organization}}
i++
}
if len(n.OrganizationalUnit) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidOrganizationalUnit, n.OrganizationalUnit}}
i++
}
if len(n.CommonName) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidCommonName, n.CommonName}}
i++
}
if len(n.SerialNumber) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidSerialNumber, n.SerialNumber}}
i++
}
if len(n.Locality) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidLocatity, n.Locality}}
i++
}
if len(n.Province) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidProvince, n.Province}}
i++
}
if len(n.StreetAddress) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidStreetAddress, n.StreetAddress}}
i++
}
if len(n.PostalCode) > 0 {
ret[i] = []attributeTypeAndValue{attributeTypeAndValue{oidPostalCode, n.PostalCode}}
i++
}
// Adding another RDN here? Remember to update the maximum number of
// elements in the make() at the top of the function.
return ret[0:i]
}
func getSignatureAlgorithmFromOID(oid []int) SignatureAlgorithm {
if len(oid) == 7 && oid[0] == 1 && oid[1] == 2 && oid[2] == 840 &&
oid[3] == 113549 && oid[4] == 1 && oid[5] == 1 {
@ -589,3 +663,157 @@ func ParseCertificates(asn1Data []byte) ([]*Certificate, os.Error) {
return ret, nil
}
func reverseBitsInAByte(in byte) byte {
b1 := in>>4 | in<<4
b2 := b1>>2&0x33 | b1<<2&0xcc
b3 := b2>>1&0x55 | b2<<1&0xaa
return b3
}
var (
oidExtensionSubjectKeyId = []int{2, 5, 29, 14}
oidExtensionKeyUsage = []int{2, 5, 29, 15}
oidExtensionAuthorityKeyId = []int{2, 5, 29, 35}
oidExtensionBasicConstraints = []int{2, 5, 29, 19}
oidExtensionSubjectAltName = []int{2, 5, 29, 17}
)
func buildExtensions(template *Certificate) (ret []extension, err os.Error) {
ret = make([]extension, 5 /* maximum number of elements. */ )
n := 0
if template.KeyUsage != 0 {
ret[n].Id = oidExtensionKeyUsage
ret[n].Critical = true
var a [2]byte
a[0] = reverseBitsInAByte(byte(template.KeyUsage))
a[1] = reverseBitsInAByte(byte(template.KeyUsage >> 8))
l := 1
if a[1] != 0 {
l = 2
}
ret[n].Value, err = asn1.MarshalToMemory(asn1.BitString{Bytes: a[0:l], BitLength: l * 8})
if err != nil {
return
}
n++
}
if template.BasicConstraintsValid {
ret[n].Id = oidExtensionBasicConstraints
ret[n].Value, err = asn1.MarshalToMemory(basicConstraints{template.IsCA, template.MaxPathLen})
ret[n].Critical = true
if err != nil {
return
}
n++
}
if len(template.SubjectKeyId) > 0 {
ret[n].Id = oidExtensionSubjectKeyId
ret[n].Value, err = asn1.MarshalToMemory(template.SubjectKeyId)
if err != nil {
return
}
n++
}
if len(template.AuthorityKeyId) > 0 {
ret[n].Id = oidExtensionAuthorityKeyId
ret[n].Value, err = asn1.MarshalToMemory(authKeyId{template.AuthorityKeyId})
if err != nil {
return
}
n++
}
if len(template.DNSNames) > 0 {
ret[n].Id = oidExtensionSubjectAltName
rawValues := make([]asn1.RawValue, len(template.DNSNames))
for i, name := range template.DNSNames {
rawValues[i] = asn1.RawValue{Tag: 2, Class: 2, Bytes: strings.Bytes(name)}
}
ret[n].Value, err = asn1.MarshalToMemory(rawValues)
if err != nil {
return
}
n++
}
// Adding another extension here? Remember to update the maximum number
// of elements in the make() at the top of the function.
return ret[0:n], nil
}
var (
oidSHA1WithRSA = []int{1, 2, 840, 113549, 1, 1, 5}
oidRSA = []int{1, 2, 840, 113549, 1, 1, 1}
)
// CreateSelfSignedCertificate creates a new certificate based on
// a template. The following members of template are used: SerialNumber,
// Subject, NotBefore, NotAfter, KeyUsage, BasicConstraintsValid, IsCA,
// MaxPathLen, SubjectKeyId, DNSNames.
//
// The certificate is signed by parent. If parent is equal to template then the
// certificate is self-signed.
//
// The returned slice is the certificate in DER encoding.
func CreateCertificate(rand io.Reader, template, parent *Certificate, priv *rsa.PrivateKey) (cert []byte, err os.Error) {
asn1PublicKey, err := asn1.MarshalToMemory(rsaPublicKey{
N: asn1.RawValue{Tag: 2, Bytes: priv.PublicKey.N.Bytes()},
E: priv.PublicKey.E,
})
if err != nil {
return
}
if len(template.SubjectKeyId) > 0 && len(parent.SubjectKeyId) > 0 {
template.AuthorityKeyId = parent.SubjectKeyId
}
extensions, err := buildExtensions(template)
if err != nil {
return
}
encodedPublicKey := asn1.BitString{BitLength: len(asn1PublicKey) * 8, Bytes: asn1PublicKey}
c := tbsCertificate{
Version: 3,
SerialNumber: asn1.RawValue{Bytes: template.SerialNumber, Tag: 2},
SignatureAlgorithm: algorithmIdentifier{oidSHA1WithRSA},
Issuer: parent.Subject.toRDNSequence(),
Validity: validity{template.NotBefore, template.NotAfter},
Subject: template.Subject.toRDNSequence(),
PublicKey: publicKeyInfo{algorithmIdentifier{oidRSA}, encodedPublicKey},
Extensions: extensions,
}
tbsCertContents, err := asn1.MarshalToMemory(c)
if err != nil {
return
}
c.Raw = tbsCertContents
h := sha1.New()
h.Write(tbsCertContents)
digest := h.Sum()
signature, err := rsa.SignPKCS1v15(rand, priv, rsa.HashSHA1, digest)
if err != nil {
return
}
cert, err = asn1.MarshalToMemory(certificate{
c,
algorithmIdentifier{oidSHA1WithRSA},
asn1.BitString{Bytes: signature, BitLength: len(signature) * 8},
})
return
}

View File

@ -9,9 +9,11 @@ import (
"crypto/rsa"
"encoding/hex"
"encoding/pem"
"os"
"reflect"
"strings"
"testing"
"time"
)
func TestParsePKCS1PrivateKey(t *testing.T) {
@ -142,3 +144,51 @@ var certBytes = "308203223082028ba00302010202106edf0d9499fd4533dd1297fc42a93be13
"e9e83994dcab72792f06bfab8170c4a8edea5334edef1e53d906c7562bd15cf4d18a8eb42bb137" +
"9048084225c53e8acb7feb6f04d16dc574a2f7a27c7b603c77cd0ece48027f012fb69b37e02a2a" +
"36dcd585d6ace53f546f961e05af"
func TestCreateSelfSignedCertificate(t *testing.T) {
urandom, err := os.Open("/dev/urandom", os.O_RDONLY, 0)
if err != nil {
t.Errorf("failed to open /dev/urandom")
}
block, _ := pem.Decode(strings.Bytes(pemPrivateKey))
priv, err := ParsePKCS1PrivateKey(block.Bytes)
if err != nil {
t.Errorf("Failed to parse private key: %s", err)
return
}
template := Certificate{
SerialNumber: []byte{1},
Subject: Name{
CommonName: "test.example.com",
Organization: "Acme Co",
},
NotBefore: time.SecondsToUTC(1000),
NotAfter: time.SecondsToUTC(100000),
SubjectKeyId: []byte{1, 2, 3, 4},
KeyUsage: KeyUsageCertSign,
BasicConstraintsValid: true,
IsCA: true,
DNSNames: []string{"test.example.com"},
}
derBytes, err := CreateCertificate(urandom, &template, &template, priv)
if err != nil {
t.Errorf("Failed to create certificate: %s", err)
return
}
cert, err := ParseCertificate(derBytes)
if err != nil {
t.Errorf("Failed to parse certificate: %s", err)
return
}
err = cert.CheckSignatureFrom(cert)
if err != nil {
t.Errorf("Signature verification failed: %s", err)
return
}
}