// Decrypt finds the first encrypted part of doc, decrypts it using
// privateKey and returns the plaintext of the embedded document.
func Decrypt(privateKey []byte, doc []byte) ([]byte, error) {
startProcessingXML()
defer stopProcessingXML()
keysMngr := C.xmlSecKeysMngrCreate()
if keysMngr == nil {
return nil, popError()
}
defer C.xmlSecKeysMngrDestroy(keysMngr)
if rv := C.xmlSecCryptoAppDefaultKeysMngrInit(keysMngr); rv < 0 {
return nil, popError()
}
key := C.xmlSecCryptoAppKeyLoadMemory(
(*C.xmlSecByte)(unsafe.Pointer(&privateKey[0])),
C.xmlSecSize(len(privateKey)),
C.xmlSecKeyDataFormatPem,
nil, nil, nil)
if key == nil {
return nil, popError()
}
if rv := C.xmlSecCryptoAppDefaultKeysMngrAdoptKey(keysMngr, key); rv < 0 {
return nil, popError()
}
parsedDoc, err := newDoc(doc, nil)
if err != nil {
return nil, err
}
defer closeDoc(parsedDoc)
// create encryption context
encCtx := C.xmlSecEncCtxCreate(keysMngr)
if encCtx == nil {
return nil, popError()
}
defer C.xmlSecEncCtxDestroy(encCtx)
encDataNode := C.xmlSecFindNode(C.xmlDocGetRootElement(parsedDoc),
(*C.xmlChar)(unsafe.Pointer(&C.xmlSecNodeEncryptedData)),
(*C.xmlChar)(unsafe.Pointer(&C.xmlSecEncNs)))
if encDataNode == nil {
return nil, fmt.Errorf("xmlSecFindNode cannot find EncryptedData node")
}
// decrypt the data
if rv := C.xmlSecEncCtxDecrypt(encCtx, encDataNode); rv < 0 {
return nil, popError()
}
encDataNode = nil // the template is inserted in the doc, so we don't own it
return dumpDoc(parsedDoc), nil
}
// XMLSecCryptoAppKeyLoadMemory calls xmlSecCryptoAppKeyLoadMemory to
// load a key from an in memory buffer.
// This function acceses the byte buffer directly, so make sure not
// to touch the buffer from some other goroutine
func XMLSecCryptoAppKeyLoadMemory(buf []byte, format KeyDataFormat) (uintptr, error) {
key := C.xmlSecCryptoAppKeyLoadMemory(
(*C.xmlSecByte)(unsafe.Pointer(&buf[0])),
(C.xmlSecSize)(C.int(len(buf))),
(C.xmlSecKeyDataFormat)(format),
nil,
nil,
nil,
)
if key == nil {
return 0, errors.New("failed to load key")
}
return uintptr(unsafe.Pointer(key)), nil
}
// Sign returns a version of doc signed with key according to
// the XMLDSIG standard. doc is a template document meaning
// that it contains an `http://www.w3.org/2000/09/xmldsig#Signature`
// element whose properties define how and what to sign.
func Sign(key []byte, doc []byte, opts SignatureOptions) ([]byte, error) {
startProcessingXML()
defer stopProcessingXML()
ctx := C.xmlSecDSigCtxCreate(nil)
if ctx == nil {
return nil, errors.New("failed to create signature context")
}
defer C.xmlSecDSigCtxDestroy(ctx)
ctx.signKey = C.xmlSecCryptoAppKeyLoadMemory(
(*C.xmlSecByte)(unsafe.Pointer(&key[0])),
C.xmlSecSize(len(key)),
C.xmlSecKeyDataFormatPem,
nil, nil, nil)
if ctx.signKey == nil {
return nil, errors.New("failed to load pem key")
}
parsedDoc, err := newDoc(doc, opts.XMLID)
if err != nil {
return nil, err
}
defer closeDoc(parsedDoc)
node := C.xmlSecFindNode(C.xmlDocGetRootElement(parsedDoc),
(*C.xmlChar)(unsafe.Pointer(&C.xmlSecNodeSignature)),
(*C.xmlChar)(unsafe.Pointer(&C.xmlSecDSigNs)))
if node == nil {
return nil, errors.New("cannot find start node")
}
if rv := C.xmlSecDSigCtxSign(ctx, node); rv < 0 {
return nil, errors.New("failed to sign")
}
return dumpDoc(parsedDoc), nil
}
// Encrypt encrypts the XML document to publicKey and returns the encrypted
// document.
func Encrypt(publicKey, doc []byte, opts EncryptOptions) ([]byte, error) {
startProcessingXML()
defer stopProcessingXML()
keysMngr := C.xmlSecKeysMngrCreate()
if keysMngr == nil {
return nil, mustPopError()
}
defer C.xmlSecKeysMngrDestroy(keysMngr)
if rv := C.xmlSecCryptoAppDefaultKeysMngrInit(keysMngr); rv < 0 {
return nil, mustPopError()
}
key := C.xmlSecCryptoAppKeyLoadMemory(
(*C.xmlSecByte)(unsafe.Pointer(&publicKey[0])),
C.xmlSecSize(len(publicKey)),
C.xmlSecKeyDataFormatCertPem,
nil, nil, nil)
if key == nil {
return nil, mustPopError()
}
if rv := C.xmlSecCryptoAppKeyCertLoadMemory(key,
(*C.xmlSecByte)(unsafe.Pointer(&publicKey[0])),
C.xmlSecSize(len(publicKey)),
C.xmlSecKeyDataFormatCertPem); rv < 0 {
C.xmlSecKeyDestroy(key)
return nil, mustPopError()
}
if rv := C.xmlSecCryptoAppDefaultKeysMngrAdoptKey(keysMngr, key); rv < 0 {
return nil, mustPopError()
}
parsedDoc, err := newDoc(doc, nil)
if err != nil {
return nil, err
}
defer closeDoc(parsedDoc)
var sessionCipherTransform C.xmlSecTransformId
switch opts.SessionCipher {
case DefaultSessionCipher:
sessionCipherTransform = C.MY_xmlSecTransformAes256CbcId()
case Aes256Cbc:
sessionCipherTransform = C.MY_xmlSecTransformAes256CbcId()
case Aes192Cbc:
sessionCipherTransform = C.MY_xmlSecTransformAes192CbcId()
case Aes128Cbc:
sessionCipherTransform = C.MY_xmlSecTransformAes128CbcId()
case Des3Cbc:
sessionCipherTransform = C.MY_xmlSecTransformDes3CbcId()
default:
return nil, errInvalidAlgorithm
}
// create encryption template to encrypt XML file and replace
// its content with encryption result
encDataNode := C.xmlSecTmplEncDataCreate(parsedDoc, sessionCipherTransform,
nil, (*C.xmlChar)(unsafe.Pointer(&C.xmlSecTypeEncElement)), nil, nil)
if encDataNode == nil {
return nil, mustPopError()
}
defer func() {
if encDataNode != nil {
C.xmlFreeNode(encDataNode)
encDataNode = nil
}
}()
// we want to put encrypted data in the <enc:CipherValue/> node
if C.xmlSecTmplEncDataEnsureCipherValue(encDataNode) == nil {
return nil, mustPopError()
}
// add <dsig:KeyInfo/>
keyInfoNode := C.xmlSecTmplEncDataEnsureKeyInfo(encDataNode, nil)
if keyInfoNode == nil {
return nil, mustPopError()
}
// add <enc:EncryptedKey/> to store the encrypted session key
var cipherTransform C.xmlSecTransformId
switch opts.Cipher {
case DefaultCipher:
cipherTransform = C.MY_xmlSecTransformRsaOaepId()
case RsaOaep:
cipherTransform = C.MY_xmlSecTransformRsaOaepId()
case RsaPkcs1:
cipherTransform = C.MY_xmlSecTransformRsaPkcs1Id()
}
encKeyNode := C.xmlSecTmplKeyInfoAddEncryptedKey(keyInfoNode, cipherTransform, nil, nil, nil)
if encKeyNode == nil {
return nil, mustPopError()
}
// we want to put encrypted key in the <enc:CipherValue/> node
if C.xmlSecTmplEncDataEnsureCipherValue(encKeyNode) == nil {
return nil, mustPopError()
}
// add <dsig:KeyInfo/> and <dsig:KeyName/> nodes to <enc:EncryptedKey/>
keyInfoNode2 := C.xmlSecTmplEncDataEnsureKeyInfo(encKeyNode, nil)
if keyInfoNode2 == nil {
return nil, mustPopError()
}
// Add a DigestMethod element to the encryption method node
{
encKeyMethod := C.xmlSecTmplEncDataGetEncMethodNode(encKeyNode)
var algorithm *C.xmlChar
switch opts.DigestAlgorithm {
case Sha512:
algorithm = constSha512
case Sha384:
algorithm = constSha384
case Sha256:
algorithm = constSha256
case Sha1:
algorithm = constSha1
case DefaultDigestAlgorithm:
algorithm = constSha1
default:
return nil, errInvalidAlgorithm
}
node := C.xmlSecAddChild(encKeyMethod, constDigestMethod, constDsigNamespace)
C.xmlSetProp(node, constAlgorithm, algorithm)
}
// add our certificate to KeyInfoNode
x509dataNode := C.xmlSecTmplKeyInfoAddX509Data(keyInfoNode2)
if x509dataNode == nil {
return nil, mustPopError()
}
if dataNode := C.xmlSecTmplX509DataAddCertificate(x509dataNode); dataNode == nil {
return nil, mustPopError()
}
// create encryption context
var encCtx = C.xmlSecEncCtxCreate(keysMngr)
if encCtx == nil {
return nil, mustPopError()
}
defer C.xmlSecEncCtxDestroy(encCtx)
// generate a key of the appropriate type
switch opts.SessionCipher {
case DefaultSessionCipher:
encCtx.encKey = C.xmlSecKeyGenerate(C.MY_xmlSecKeyDataAesId(), 256,
C.xmlSecKeyDataTypeSession)
case Aes128Cbc:
encCtx.encKey = C.xmlSecKeyGenerate(C.MY_xmlSecKeyDataAesId(), 128,
C.xmlSecKeyDataTypeSession)
case Aes192Cbc:
encCtx.encKey = C.xmlSecKeyGenerate(C.MY_xmlSecKeyDataAesId(), 192,
C.xmlSecKeyDataTypeSession)
case Aes256Cbc:
encCtx.encKey = C.xmlSecKeyGenerate(C.MY_xmlSecKeyDataAesId(), 256,
C.xmlSecKeyDataTypeSession)
case Des3Cbc:
encCtx.encKey = C.xmlSecKeyGenerate(C.MY_xmlSecKeyDataDesId(), 192,
C.xmlSecKeyDataTypeSession)
default:
return nil, errInvalidAlgorithm
}
if encCtx.encKey == nil {
return nil, mustPopError()
}
// encrypt the data
if rv := C.xmlSecEncCtxXmlEncrypt(encCtx, encDataNode, C.xmlDocGetRootElement(parsedDoc)); rv < 0 {
return nil, mustPopError()
}
encDataNode = nil // the template is inserted in the doc, so we don't own it
return dumpDoc(parsedDoc), nil
}
// Verify checks that the signature in doc is valid according
// to the XMLDSIG specification. publicKey is the public part of
// the key used to sign doc. If the signature is not correct,
// this function returns ErrVerificationFailed.
func Verify(publicKey []byte, doc []byte, opts SignatureOptions) error {
startProcessingXML()
defer stopProcessingXML()
keysMngr := C.xmlSecKeysMngrCreate()
if keysMngr == nil {
return mustPopError()
}
defer C.xmlSecKeysMngrDestroy(keysMngr)
if rv := C.xmlSecCryptoAppDefaultKeysMngrInit(keysMngr); rv < 0 {
return mustPopError()
}
key := C.xmlSecCryptoAppKeyLoadMemory(
(*C.xmlSecByte)(unsafe.Pointer(&publicKey[0])),
C.xmlSecSize(len(publicKey)),
C.xmlSecKeyDataFormatCertPem,
nil, nil, nil)
if key == nil {
return mustPopError()
}
if rv := C.xmlSecCryptoAppKeyCertLoadMemory(key,
(*C.xmlSecByte)(unsafe.Pointer(&publicKey[0])),
C.xmlSecSize(len(publicKey)),
C.xmlSecKeyDataFormatCertPem); rv < 0 {
C.xmlSecKeyDestroy(key)
return mustPopError()
}
if rv := C.xmlSecCryptoAppDefaultKeysMngrAdoptKey(keysMngr, key); rv < 0 {
return mustPopError()
}
dsigCtx := C.xmlSecDSigCtxCreate(keysMngr)
if dsigCtx == nil {
return mustPopError()
}
defer C.xmlSecDSigCtxDestroy(dsigCtx)
parsedDoc, err := newDoc(doc, opts.XMLID)
if err != nil {
return err
}
defer closeDoc(parsedDoc)
node := C.xmlSecFindNode(C.xmlDocGetRootElement(parsedDoc),
(*C.xmlChar)(unsafe.Pointer(&C.xmlSecNodeSignature)),
(*C.xmlChar)(unsafe.Pointer(&C.xmlSecDSigNs)))
if node == nil {
return errors.New("cannot find start node")
}
if rv := C.xmlSecDSigCtxVerify(dsigCtx, node); rv < 0 {
return ErrVerificationFailed
}
if dsigCtx.status != xmlSecDSigStatusSucceeded {
return ErrVerificationFailed
}
return nil
}