// Sign the given context with the given private key - which is a PEM or hsm: key
// A hsm: key is a urn 'key' that points to a specific key/action in a goeleven interface to a HSM
// See https://github.com/wayf-dk/goeleven
func (xp *Xp) Sign(context *C.xmlNode, privatekey, pw, cert, algo string) (err error) {
contextHash := Hash(algos[algo].algo, xp.C14n(context))
contextDigest := base64.StdEncoding.EncodeToString(contextHash)
signaturexml := `<ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
<ds:SignedInfo>
<ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
<ds:SignatureMethod Algorithm=""/>
<ds:Reference URI="">
<ds:Transforms>
<ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/>
<ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
</ds:Transforms>
<ds:DigestMethod Algorithm=""/>
<ds:DigestValue></ds:DigestValue>
</ds:Reference>
</ds:SignedInfo>
<ds:SignatureValue></ds:SignatureValue>
</ds:Signature>`
signature := C.xmlNewDocFragment(xp.doc)
var res C.xmlNodePtr
buf := ([]byte)(signaturexml)
C.xmlParseBalancedChunkMemory(xp.doc, nil, nil, 0, (*C.xmlChar)(&buf[0]), &res)
C.xmlAddChildList(signature, res)
C.xmlAddNextSibling(C.xmlFirstElementChild(context), signature)
id := xp.Query1(context, "@ID")
signedInfo := xp.QueryDashP(signature, `ds:Signature/ds:SignedInfo[1]`, "", nil)
xp.QueryDashP(signedInfo, `ds:SignatureMethod[1]/@Algorithm`, algos[algo].signature, nil)
xp.QueryDashP(signedInfo, `ds:Reference/@URI`, "#"+id, nil)
xp.QueryDashP(signedInfo, `ds:Reference/ds:DigestMethod[1]/@Algorithm`, algos[algo].digest, nil)
xp.QueryDashP(signedInfo, `ds:Reference/ds:DigestValue[1]`, contextDigest, nil)
signedInfoC14n := xp.C14n(signedInfo)
digest := Hash(algos[algo].algo, signedInfoC14n)
var signaturevalue []byte
if strings.HasPrefix(privatekey, "hsm:") {
signaturevalue, err = signGoEleven(digest, privatekey, algo)
} else {
signaturevalue, err = signGo(digest, privatekey, pw, algo)
}
signatureval := base64.StdEncoding.EncodeToString(signaturevalue)
xp.QueryDashP(signature, `ds:Signature/ds:SignatureValue`, signatureval, nil)
xp.QueryDashP(signature, `ds:Signature/ds:KeyInfo/ds:X509Data/ds:X509Certificate`, cert, nil)
// log.Println(xp.Pp())
return
}
// Decrypt decrypts the context using the given privatekey
func (xp *Xp) Decrypt(context *C.xmlNode, privatekey *rsa.PrivateKey) (decryptedAssertion *C.xmlNode) {
// for now just use what we send ourselves ...
encryptedkey := xp.Query1(context, "./xenc:EncryptedData/ds:KeyInfo/xenc:EncryptedKey/xenc:CipherData/xenc:CipherValue")
encryptedkeybyte, _ := base64.StdEncoding.DecodeString(encryptedkey)
sessionkey, _ := rsa.DecryptOAEP(sha1.New(), rand.Reader, privatekey, encryptedkeybyte, nil)
encryptedassertion := xp.Query1(context, "./xenc:EncryptedData/xenc:CipherData/xenc:CipherValue")
encryptedassertionbyte, _ := base64.StdEncoding.DecodeString(encryptedassertion)
assertion := decryptAES([]byte(sessionkey), encryptedassertionbyte)
assertion = append(assertion, 0)
var res C.xmlNodePtr
decryptedAssertion = C.xmlNewDocFragment(xp.doc)
C.xmlParseBalancedChunkMemory(xp.doc, nil, nil, 0, (*C.xmlChar)(&assertion[0]), &res)
C.xmlAddChildList(decryptedAssertion, res)
C.xmlReplaceNode(context, decryptedAssertion)
C.xmlReconciliateNs(xp.doc, decryptedAssertion)
return
}
// Encrypt the context with the given publickey
// Hardcoded to aes256-cbc for the symetric part and
// rsa-oaep-mgf1p and sha1 for the rsa part
func (xp *Xp) Encrypt(context *C.xmlNode, publickey *rsa.PublicKey) {
template := []byte(`<saml:EncryptedAssertion xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
<xenc:EncryptedData Type="http://www.w3.org/2001/04/xmlenc#Element">
<xenc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes256-cbc" />
<ds:KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<xenc:EncryptedKey >
<xenc:EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p">
<ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
</xenc:EncryptionMethod>
<xenc:CipherData>
<xenc:CipherValue>encryptedsessionkey</xenc:CipherValue>
</xenc:CipherData>
</xenc:EncryptedKey>
</ds:KeyInfo>
<xenc:CipherData>
<xenc:CipherValue>encryptedassertion</xenc:CipherValue>
</xenc:CipherData>
</xenc:EncryptedData>
</saml:EncryptedAssertion>`)
var res C.xmlNodePtr
encryptedAssertion := C.xmlNewDocFragment(xp.doc)
C.xmlParseBalancedChunkMemory(xp.doc, nil, nil, 0, (*C.xmlChar)(&template[0]), &res)
C.xmlAddChildList(encryptedAssertion, res)
//sessionkey, ciphertext := encryptAES([]byte(xp.C14n(context)))
sessionkey, ciphertext := encryptAES([]byte(xp.Dump2(context)))
sessionkey, err := rsa.EncryptOAEP(sha1.New(), rand.Reader, publickey, sessionkey, nil)
if err != nil {
panic(err)
}
ec := xp.QueryDashP(encryptedAssertion, `saml:EncryptedAssertion/xenc:EncryptedData`, "", nil)
xp.QueryDashP(ec, `ds:KeyInfo/xenc:EncryptedKey/xenc:CipherData/xenc:CipherValue`, base64.StdEncoding.EncodeToString(sessionkey), nil)
xp.QueryDashP(ec, `xenc:CipherData/xenc:CipherValue`, base64.StdEncoding.EncodeToString(ciphertext), nil)
C.xmlReplaceNode(context, encryptedAssertion)
}