feat: using sha256 instead of sha1

This commit is contained in:
theexiile1305 2024-12-07 10:16:53 +01:00
parent e56a563286
commit 7e0511407b

390
pkcs7.go
View file

@ -7,6 +7,7 @@ package mail
import (
"bytes"
"crypto"
"crypto/ecdsa"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
@ -18,9 +19,25 @@ import (
"sort"
"time"
_ "crypto/sha1" // for crypto.SHA1
_ "crypto/sha256" // for crypto.SHA256
)
var (
OIDData = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 1}
OIDSignedData = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 2}
OIDAttributeContentType = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 3}
OIDAttributeMessageDigest = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 4}
OIDAttributeSigningTime = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 5}
OIDDigestAlgorithmSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 1}
OIDDigestAlgorithmECDSASHA256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 2}
OIDEncryptionAlgorithmRSASHA256 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 11}
)
// ErrUnsupportedAlgorithm tells you when our quick dev assumptions have failed
var ErrUnsupportedAlgorithm = errors.New("pkcs7: cannot decrypt data: only RSA, DES, DES-EDE3, AES-256-CBC and AES-128-GCM supported")
// PKCS7 Represents a PKCS7 structure
type PKCS7 struct {
Content []byte
@ -30,19 +47,34 @@ type PKCS7 struct {
raw interface{}
}
// GetOnlySigner returns an x509.Certificate for the first signer of the signed
// data payload. If there are more or less than one signer, nil is returned
func (p7 *PKCS7) GetOnlySigner() *x509.Certificate {
if len(p7.Signers) != 1 {
return nil
}
signer := p7.Signers[0]
return getCertFromCertsByIssuerAndSerial(p7.Certificates, signer.IssuerAndSerialNumber)
}
// UnmarshalSignedAttribute decodes a single attribute from the signer info
func (p7 *PKCS7) UnmarshalSignedAttribute(attributeType asn1.ObjectIdentifier, out interface{}) error {
sd, ok := p7.raw.(signedData)
if !ok {
return errors.New("pkcs7: payload is not signedData content")
}
if len(sd.SignerInfos) < 1 {
return errors.New("pkcs7: payload has no signers")
}
attributes := sd.SignerInfos[0].AuthenticatedAttributes
return unmarshalAttribute(attributes, attributeType, out)
}
type contentInfo struct {
ContentType asn1.ObjectIdentifier
Content asn1.RawValue `asn1:"explicit,optional,tag:0"`
}
var (
oidData = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 1}
oidSignedData = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 2}
oidAttributeContentType = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 3}
oidAttributeMessageDigest = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 4}
oidAttributeSigningTime = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 5}
)
type signedData struct {
Version int `asn1:"default:1"`
DigestAlgorithmIdentifiers []pkix.AlgorithmIdentifier `asn1:"set"`
@ -56,6 +88,19 @@ type rawCertificates struct {
Raw asn1.RawContent
}
func (raw rawCertificates) Parse() ([]*x509.Certificate, error) {
if len(raw.Raw) == 0 {
return nil, nil
}
var val asn1.RawValue
if _, err := asn1.Unmarshal(raw.Raw, &val); err != nil {
return nil, err
}
return x509.ParseCertificates(val.Bytes)
}
type attribute struct {
Type asn1.ObjectIdentifier
Value asn1.RawValue `asn1:"set"`
@ -87,96 +132,6 @@ type signerInfo struct {
UnauthenticatedAttributes []attribute `asn1:"optional,tag:1"`
}
func (raw rawCertificates) Parse() ([]*x509.Certificate, error) {
if len(raw.Raw) == 0 {
return nil, nil
}
var val asn1.RawValue
if _, err := asn1.Unmarshal(raw.Raw, &val); err != nil {
return nil, err
}
return x509.ParseCertificates(val.Bytes)
}
func marshalAttributes(attrs []attribute) ([]byte, error) {
encodedAttributes, err := asn1.Marshal(struct {
A []attribute `asn1:"set"`
}{A: attrs})
if err != nil {
return nil, err
}
// Remove the leading sequence octets
var raw asn1.RawValue
if _, err := asn1.Unmarshal(encodedAttributes, &raw); err != nil {
return nil, err
}
return raw.Bytes, nil
}
var (
oidDigestAlgorithmSHA1 = asn1.ObjectIdentifier{1, 3, 14, 3, 2, 26}
oidSignatureSHA1WithRSA = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}
)
func getCertFromCertsByIssuerAndSerial(certs []*x509.Certificate, ias issuerAndSerial) *x509.Certificate {
for _, cert := range certs {
if isCertMatchForIssuerAndSerial(cert, ias) {
return cert
}
}
return nil
}
// GetOnlySigner returns an x509.Certificate for the first signer of the signed
// data payload. If there are more or less than one signer, nil is returned
func (p7 *PKCS7) GetOnlySigner() *x509.Certificate {
if len(p7.Signers) != 1 {
return nil
}
signer := p7.Signers[0]
return getCertFromCertsByIssuerAndSerial(p7.Certificates, signer.IssuerAndSerialNumber)
}
// ErrUnsupportedAlgorithm tells you when our quick dev assumptions have failed
var ErrUnsupportedAlgorithm = errors.New("pkcs7: cannot decrypt data: only RSA, DES, DES-EDE3, AES-256-CBC and AES-128-GCM supported")
func isCertMatchForIssuerAndSerial(cert *x509.Certificate, ias issuerAndSerial) bool {
return cert.SerialNumber.Cmp(ias.SerialNumber) == 0 && bytes.Equal(cert.RawIssuer, ias.IssuerName.FullBytes)
}
func unmarshalAttribute(attrs []attribute, attributeType asn1.ObjectIdentifier, out interface{}) error {
for _, attr := range attrs {
if attr.Type.Equal(attributeType) {
_, err := asn1.Unmarshal(attr.Value.Bytes, out)
return err
}
}
return errors.New("pkcs7: attribute type not in attributes")
}
// UnmarshalSignedAttribute decodes a single attribute from the signer info
func (p7 *PKCS7) UnmarshalSignedAttribute(attributeType asn1.ObjectIdentifier, out interface{}) error {
sd, ok := p7.raw.(signedData)
if !ok {
return errors.New("pkcs7: payload is not signedData content")
}
if len(sd.SignerInfos) < 1 {
return errors.New("pkcs7: payload has no signers")
}
attributes := sd.SignerInfos[0].AuthenticatedAttributes
return unmarshalAttribute(attributes, attributeType, out)
}
// SignedData is an opaque data structure for creating signed data payloads
type SignedData struct {
sd signedData
certs []*x509.Certificate
messageDigest []byte
}
// Attribute represents a key value pair attribute. Value must be marshalable byte
// `encoding/asn1`
type Attribute struct {
@ -187,30 +142,7 @@ type Attribute struct {
// SignerInfoConfig are optional values to include when adding a signer
type SignerInfoConfig struct {
ExtraSignedAttributes []Attribute
}
// newSignedData initializes a SignedData with content
func newSignedData(data []byte) (*SignedData, error) {
content, err := asn1.Marshal(data)
if err != nil {
return nil, err
}
ci := contentInfo{
ContentType: oidData,
Content: asn1.RawValue{Class: 2, Tag: 0, Bytes: content, IsCompound: true},
}
digAlg := pkix.AlgorithmIdentifier{
Algorithm: oidDigestAlgorithmSHA1,
}
h := crypto.SHA1.New()
h.Write(data)
md := h.Sum(nil)
sd := signedData{
ContentInfo: ci,
Version: 1,
DigestAlgorithmIdentifiers: []pkix.AlgorithmIdentifier{digAlg},
}
return &SignedData{sd: sd, messageDigest: md}, nil
ExtraUnsignedAttributes []Attribute
}
type attributes struct {
@ -219,9 +151,9 @@ type attributes struct {
}
// Add adds the attribute, maintaining insertion order
func (attrs *attributes) Add(attrType asn1.ObjectIdentifier, value interface{}) {
attrs.types = append(attrs.types, attrType)
attrs.values = append(attrs.values, value)
func (as *attributes) Add(attrType asn1.ObjectIdentifier, value interface{}) {
as.types = append(as.types, attrType)
as.values = append(as.values, value)
}
type sortableAttribute struct {
@ -231,31 +163,31 @@ type sortableAttribute struct {
type attributeSet []sortableAttribute
func (sa attributeSet) Len() int {
return len(sa)
func (as attributeSet) Len() int {
return len(as)
}
func (sa attributeSet) Less(i, j int) bool {
return bytes.Compare(sa[i].SortKey, sa[j].SortKey) < 0
func (as attributeSet) Less(i, j int) bool {
return bytes.Compare(as[i].SortKey, as[j].SortKey) < 0
}
func (sa attributeSet) Swap(i, j int) {
sa[i], sa[j] = sa[j], sa[i]
func (as attributeSet) Swap(i, j int) {
as[i], as[j] = as[j], as[i]
}
func (sa attributeSet) attributes() []attribute {
attrs := make([]attribute, len(sa))
for i, attr := range sa {
func (as attributeSet) attributes() []attribute {
attrs := make([]attribute, len(as))
for i, attr := range as {
attrs[i] = attr.Attribute
}
return attrs
}
func (attrs *attributes) forMarshaling() ([]attribute, error) {
sortables := make(attributeSet, len(attrs.types))
func (as *attributes) forMarshaling() ([]attribute, error) {
sortables := make(attributeSet, len(as.types))
for i := range sortables {
attrType := attrs.types[i]
attrValue := attrs.values[i]
attrType := as.types[i]
attrValue := as.values[i]
asn1Value, err := asn1.Marshal(attrValue)
if err != nil {
return nil, err
@ -277,12 +209,78 @@ func (attrs *attributes) forMarshaling() ([]attribute, error) {
return sortables.attributes(), nil
}
// addSigner signs attributes about the content and adds certificate to payload
// SignedData is an opaque data structure for creating signed data payloads
type SignedData struct {
sd signedData
certs []*x509.Certificate
data []byte
messageDigest []byte
digestOid asn1.ObjectIdentifier
}
// newSignedData initializes a SignedData with content
func newSignedData(data []byte) (*SignedData, error) {
content, err := asn1.Marshal(data)
if err != nil {
return nil, err
}
ci := contentInfo{
ContentType: OIDData,
Content: asn1.RawValue{Class: 2, Tag: 0, Bytes: content, IsCompound: true},
}
sd := signedData{
ContentInfo: ci,
Version: 1,
}
return &SignedData{sd: sd, data: data, digestOid: OIDDigestAlgorithmSHA256}, nil
}
// addSigner is a wrapper around AddSignerChain() that adds a signer without any parent.
func (sd *SignedData) addSigner(cert *x509.Certificate, pkey crypto.PrivateKey, config SignerInfoConfig) error {
var parents []*x509.Certificate
return sd.addSignerChain(cert, pkey, parents, config)
}
// addSignerChain signs attributes about the content and adds certificates
// and signers infos to the Signed Data. The certificate and private key
// of the end-entity signer are used to issue the signature, and any
// parent of that end-entity that need to be added to the list of
// certifications can be specified in the parents slice.
//
// The signature algorithm used to hash the data is the one of the end-entity
// certificate.
func (sd *SignedData) addSignerChain(ee *x509.Certificate, pkey crypto.PrivateKey, parents []*x509.Certificate, config SignerInfoConfig) error {
// Following RFC 2315, 9.2 SignerInfo type, the distinguished name of
// the issuer of the end-entity signer is stored in the issuerAndSerialNumber
// section of the SignedData.SignerInfo, alongside the serial number of
// the end-entity.
var ias issuerAndSerial
ias.SerialNumber = ee.SerialNumber
if len(parents) == 0 {
// no parent, the issuer is the end-entity cert itself
ias.IssuerName = asn1.RawValue{FullBytes: ee.RawIssuer}
} else {
err := verifyPartialChain(ee, parents)
if err != nil {
return err
}
// the first parent is the issuer
ias.IssuerName = asn1.RawValue{FullBytes: parents[0].RawSubject}
}
sd.sd.DigestAlgorithmIdentifiers = append(sd.sd.DigestAlgorithmIdentifiers,
pkix.AlgorithmIdentifier{Algorithm: sd.digestOid},
)
h := crypto.SHA256.New()
h.Write(sd.data)
sd.messageDigest = h.Sum(nil)
encryptionOid, err := getOIDForEncryptionAlgorithm(pkey, sd.digestOid)
if err != nil {
return err
}
attrs := &attributes{}
attrs.Add(oidAttributeContentType, sd.sd.ContentInfo.ContentType)
attrs.Add(oidAttributeMessageDigest, sd.messageDigest)
attrs.Add(oidAttributeSigningTime, time.Now())
attrs.Add(OIDAttributeContentType, sd.sd.ContentInfo.ContentType)
attrs.Add(OIDAttributeMessageDigest, sd.messageDigest)
attrs.Add(OIDAttributeSigningTime, time.Now().UTC())
for _, attr := range config.ExtraSignedAttributes {
attrs.Add(attr.Type, attr.Value)
}
@ -290,26 +288,32 @@ func (sd *SignedData) addSigner(cert *x509.Certificate, pkey crypto.PrivateKey,
if err != nil {
return err
}
signature, err := signAttributes(finalAttrs, pkey, crypto.SHA1)
unsignedAttrs := &attributes{}
for _, attr := range config.ExtraUnsignedAttributes {
unsignedAttrs.Add(attr.Type, attr.Value)
}
finalUnsignedAttrs, err := unsignedAttrs.forMarshaling()
if err != nil {
return err
}
ias, err := cert2issuerAndSerial(cert)
// create signature of signed attributes
signature, err := signAttributes(finalAttrs, pkey, crypto.SHA256)
if err != nil {
return err
}
signer := signerInfo{
AuthenticatedAttributes: finalAttrs,
DigestAlgorithm: pkix.AlgorithmIdentifier{Algorithm: oidDigestAlgorithmSHA1},
DigestEncryptionAlgorithm: pkix.AlgorithmIdentifier{Algorithm: oidSignatureSHA1WithRSA},
UnauthenticatedAttributes: finalUnsignedAttrs,
DigestAlgorithm: pkix.AlgorithmIdentifier{Algorithm: sd.digestOid},
DigestEncryptionAlgorithm: pkix.AlgorithmIdentifier{Algorithm: encryptionOid},
IssuerAndSerialNumber: ias,
EncryptedDigest: signature,
Version: 1,
}
// create signature of signed attributes
sd.certs = append(sd.certs, cert)
sd.certs = append(sd.certs, ee)
if len(parents) > 0 {
sd.certs = append(sd.certs, parents...)
}
sd.sd.SignerInfos = append(sd.sd.SignerInfos, signer)
return nil
}
@ -322,7 +326,7 @@ func (sd *SignedData) addCertificate(cert *x509.Certificate) {
// detach removes content from the signed data struct to make it a detached signature.
// This must be called right before Finish()
func (sd *SignedData) detach() {
sd.sd.ContentInfo = contentInfo{ContentType: oidData}
sd.sd.ContentInfo = contentInfo{ContentType: OIDData}
}
// finish marshals the content and its signers
@ -333,20 +337,41 @@ func (sd *SignedData) finish() ([]byte, error) {
return nil, err
}
outer := contentInfo{
ContentType: oidSignedData,
ContentType: OIDSignedData,
Content: asn1.RawValue{Class: 2, Tag: 0, Bytes: inner, IsCompound: true},
}
return asn1.Marshal(outer)
}
func cert2issuerAndSerial(cert *x509.Certificate) (issuerAndSerial, error) {
var ias issuerAndSerial
// The issuer RDNSequence has to match exactly the sequence in the certificate
// We cannot use cert.Issuer.ToRDNSequence() here since it mangles the sequence
ias.IssuerName = asn1.RawValue{FullBytes: cert.RawIssuer}
ias.SerialNumber = cert.SerialNumber
// verifyPartialChain checks that a given cert is issued by the first parent in the list,
// then continue down the path. It doesn't require the last parent to be a root CA,
// or to be trusted in any truststore. It simply verifies that the chain provided, albeit
// partial, makes sense.
func verifyPartialChain(cert *x509.Certificate, parents []*x509.Certificate) error {
if len(parents) == 0 {
return fmt.Errorf("pkcs7: zero parents provided to verify the signature of certificate %q", cert.Subject.CommonName)
}
err := cert.CheckSignatureFrom(parents[0])
if err != nil {
return fmt.Errorf("pkcs7: certificate signature from parent is invalid: %w", err)
}
if len(parents) == 1 {
// there is no more parent to check, return
return nil
}
return verifyPartialChain(parents[0], parents[1:])
}
return ias, nil
// getOIDForEncryptionAlgorithm takes the private key type of the signer and
// the OID of a digest algorithm to return the appropriate signerInfo.DigestEncryptionAlgorithm
func getOIDForEncryptionAlgorithm(pkey crypto.PrivateKey, OIDDigestAlg asn1.ObjectIdentifier) (asn1.ObjectIdentifier, error) {
switch pkey.(type) {
case *rsa.PrivateKey:
return OIDEncryptionAlgorithmRSASHA256, nil
case *ecdsa.PrivateKey:
return OIDDigestAlgorithmECDSASHA256, nil
}
return nil, fmt.Errorf("pkcs7: cannot convert encryption algorithm to oid, unknown private key type %T", pkey)
}
// signs the DER encoded form of the attributes with the private key
@ -360,12 +385,12 @@ func signAttributes(attrs []attribute, pkey crypto.PrivateKey, hash crypto.Hash)
hashed := h.Sum(nil)
switch priv := pkey.(type) {
case *rsa.PrivateKey:
return rsa.SignPKCS1v15(rand.Reader, priv, crypto.SHA1, hashed)
return rsa.SignPKCS1v15(rand.Reader, priv, crypto.SHA256, hashed)
}
return nil, ErrUnsupportedAlgorithm
}
// concats and wraps the certificates in the RawValue structure
// concat and wraps the certificates in the RawValue structure
func marshalCertificates(certs []*x509.Certificate) rawCertificates {
var buf bytes.Buffer
for _, cert := range certs {
@ -376,7 +401,7 @@ func marshalCertificates(certs []*x509.Certificate) rawCertificates {
}
// Even though, the tag & length are stripped out during marshalling the
// RawContent, we have to encode it into the RawContent. If its missing,
// RawContent, we have to encode it into the RawContent. If It's missing,
// then `asn1.Marshal()` will strip out the certificate wrapper instead.
func marshalCertificateBytes(certs []byte) (rawCertificates, error) {
val := asn1.RawValue{Bytes: certs, Class: 2, Tag: 0, IsCompound: true}
@ -386,3 +411,42 @@ func marshalCertificateBytes(certs []byte) (rawCertificates, error) {
}
return rawCertificates{Raw: b}, nil
}
func marshalAttributes(attrs []attribute) ([]byte, error) {
encodedAttributes, err := asn1.Marshal(struct {
A []attribute `asn1:"set"`
}{A: attrs})
if err != nil {
return nil, err
}
// Remove the leading sequence octets
var raw asn1.RawValue
if _, err := asn1.Unmarshal(encodedAttributes, &raw); err != nil {
return nil, err
}
return raw.Bytes, nil
}
func getCertFromCertsByIssuerAndSerial(certs []*x509.Certificate, ias issuerAndSerial) *x509.Certificate {
for _, cert := range certs {
if isCertMatchForIssuerAndSerial(cert, ias) {
return cert
}
}
return nil
}
func isCertMatchForIssuerAndSerial(cert *x509.Certificate, ias issuerAndSerial) bool {
return cert.SerialNumber.Cmp(ias.SerialNumber) == 0 && bytes.Equal(cert.RawIssuer, ias.IssuerName.FullBytes)
}
func unmarshalAttribute(attrs []attribute, attributeType asn1.ObjectIdentifier, out interface{}) error {
for _, attr := range attrs {
if attr.Type.Equal(attributeType) {
_, err := asn1.Unmarshal(attr.Value.Bytes, out)
return err
}
}
return errors.New("pkcs7: attribute type not in attributes")
}