summaryrefslogtreecommitdiff
path: root/ebics/src/main/kotlin/XMLUtil.kt
blob: b602adc04216b433f32756ab6d934481d1475685 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
/*
 * This file is part of LibEuFin.
 * Copyright (C) 2024 Taler Systems S.A.

 * LibEuFin is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation; either version 3, or
 * (at your option) any later version.

 * LibEuFin is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General
 * Public License for more details.

 * You should have received a copy of the GNU Affero General Public
 * License along with LibEuFin; see the file COPYING.  If not, see
 * <http://www.gnu.org/licenses/>
 */

package tech.libeufin.ebics

import io.ktor.http.*
import org.slf4j.Logger
import org.slf4j.LoggerFactory
import org.w3c.dom.Document
import org.w3c.dom.Node
import org.w3c.dom.NodeList
import org.w3c.dom.ls.LSInput
import org.w3c.dom.ls.LSResourceResolver
import org.xml.sax.ErrorHandler
import org.xml.sax.InputSource
import org.xml.sax.SAXException
import org.xml.sax.SAXParseException
import java.io.*
import java.security.PrivateKey
import java.security.PublicKey
import java.security.interfaces.RSAPrivateCrtKey
import javax.xml.XMLConstants
import javax.xml.crypto.*
import javax.xml.crypto.dom.DOMURIReference
import javax.xml.crypto.dsig.*
import javax.xml.crypto.dsig.dom.DOMSignContext
import javax.xml.crypto.dsig.dom.DOMValidateContext
import javax.xml.crypto.dsig.spec.C14NMethodParameterSpec
import javax.xml.crypto.dsig.spec.TransformParameterSpec
import javax.xml.namespace.NamespaceContext
import javax.xml.parsers.DocumentBuilderFactory
import javax.xml.transform.OutputKeys
import javax.xml.transform.Source
import javax.xml.transform.TransformerFactory
import javax.xml.transform.dom.DOMSource
import javax.xml.transform.stream.StreamResult
import javax.xml.transform.stream.StreamSource
import javax.xml.validation.SchemaFactory
import javax.xml.validation.Validator
import javax.xml.xpath.XPath
import javax.xml.xpath.XPathConstants
import javax.xml.xpath.XPathFactory

private val logger: Logger = LoggerFactory.getLogger("libeufin-xml")

/**
 * This URI dereferencer allows handling the resource reference used for
 * XML signatures in EBICS.
 */
private class EbicsSigUriDereferencer : URIDereferencer {
    override fun dereference(myRef: URIReference?, myCtx: XMLCryptoContext?): Data {
        if (myRef !is DOMURIReference)
            throw Exception("invalid type")
        if (myRef.uri != "#xpointer(//*[@authenticate='true'])")
            throw Exception("invalid EBICS XML signature URI: '${myRef.uri}'")
        val xp: XPath = XPathFactory.newInstance().newXPath()
        val nodeSet = xp.compile("//*[@authenticate='true']/descendant-or-self::node()").evaluate(
            myRef.here.ownerDocument, XPathConstants.NODESET
        )
        if (nodeSet !is NodeList)
            throw Exception("invalid type")
        if (nodeSet.length <= 0) {
            throw Exception("no nodes to sign")
        }
        val nodeList = ArrayList<Node>()
        for (i in 0 until nodeSet.length) {
            val node = nodeSet.item(i)
            nodeList.add(node)
        }
        return NodeSetData { nodeList.iterator() }
    }
}

/**
 * Helpers for dealing with XML in EBICS.
 */
object XMLUtil {
    fun convertDomToBytes(document: Document): ByteArray {
        val w = ByteArrayOutputStream()
        val transformer = TransformerFactory.newInstance().newTransformer()
        transformer.setOutputProperty(OutputKeys.STANDALONE, "yes")
        transformer.transform(DOMSource(document), StreamResult(w))
        return w.toByteArray()
    }

    /**
     * Convert a node to a string without the XML declaration or
     * indentation.
     */
    fun convertNodeToString(node: Node): String {
        /* Make Transformer.  */
        val tf = TransformerFactory.newInstance()
        val t = tf.newTransformer()
        t.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes")
        /* Make string writer.  */
        val sw = StringWriter()
        /* Extract string.  */
        t.transform(DOMSource(node), StreamResult(sw))
        return sw.toString()
    }

    /** Parse [xml] into a XML DOM */
    fun parseIntoDom(xml: InputStream): Document {
        val factory = DocumentBuilderFactory.newInstance().apply {
            isNamespaceAware = true
        }
        val builder = factory.newDocumentBuilder()
        return xml.use { 
            builder.parse(InputSource(it))
        }
    }

    /**
     * Sign an EBICS document with the authentication and identity signature.
     */
    fun signEbicsDocument(
        doc: Document,
        signingPriv: PrivateKey,
        withEbics3: Boolean = false
    ) {
        val ns = if (withEbics3) "urn:org:ebics:H005" else "urn:org:ebics:H004"
        val authSigNode = XPathFactory.newInstance().newXPath()
            .evaluate("/*[1]/$ns:AuthSignature", doc, XPathConstants.NODE)
        if (authSigNode !is Node)
            throw java.lang.Exception("no AuthSignature")
        val fac = XMLSignatureFactory.getInstance("DOM")
        val c14n = fac.newTransform(CanonicalizationMethod.INCLUSIVE, null as TransformParameterSpec?)
        val ref: Reference =
            fac.newReference(
                "#xpointer(//*[@authenticate='true'])",
                fac.newDigestMethod(DigestMethod.SHA256, null),
                listOf(c14n),
                null,
                null
            )
        val canon: CanonicalizationMethod =
            fac.newCanonicalizationMethod(CanonicalizationMethod.INCLUSIVE, null as C14NMethodParameterSpec?)
        val signatureMethod = fac.newSignatureMethod("http://www.w3.org/2001/04/xmldsig-more#rsa-sha256", null)
        val si: SignedInfo = fac.newSignedInfo(canon, signatureMethod, listOf(ref))
        val sig: XMLSignature = fac.newXMLSignature(si, null)
        val dsc = DOMSignContext(signingPriv, authSigNode)
        dsc.defaultNamespacePrefix = "ds"
        dsc.uriDereferencer = EbicsSigUriDereferencer()
        dsc.setProperty("javax.xml.crypto.dsig.cacheReference", true)
        sig.sign(dsc)
        val innerSig = authSigNode.firstChild
        while (innerSig.hasChildNodes()) {
            authSigNode.appendChild(innerSig.firstChild)
        }
        authSigNode.removeChild(innerSig)
    }

    fun verifyEbicsDocument(
        doc: Document,
        signingPub: PublicKey,
        withEbics3: Boolean = false
    ): Boolean {
        val doc2: Document = doc.cloneNode(true) as Document
        val ns = if (withEbics3) "urn:org:ebics:H005" else "urn:org:ebics:H004"
        val authSigNode = XPathFactory.newInstance().newXPath()
            .evaluate("/*[1]/$ns:AuthSignature", doc2, XPathConstants.NODE)
        if (authSigNode !is Node)
            throw java.lang.Exception("no AuthSignature")
        val sigEl = doc2.createElementNS("http://www.w3.org/2000/09/xmldsig#", "ds:Signature")
        authSigNode.parentNode.insertBefore(sigEl, authSigNode)
        while (authSigNode.hasChildNodes()) {
            sigEl.appendChild(authSigNode.firstChild)
        }
        authSigNode.parentNode.removeChild(authSigNode)
        val fac = XMLSignatureFactory.getInstance("DOM")
        val dvc = DOMValidateContext(signingPub, sigEl)
        dvc.setProperty("javax.xml.crypto.dsig.cacheReference", true)
        dvc.uriDereferencer = EbicsSigUriDereferencer()
        val sig = fac.unmarshalXMLSignature(dvc)
        // FIXME: check that parameters are okay!
        val valResult = sig.validate(dvc)
        sig.signedInfo.references[0].validate(dvc)
        return valResult
    }

    fun getNodeFromXpath(doc: Document, query: String): Node {
        val xpath = XPathFactory.newInstance().newXPath()
        val ret = xpath.evaluate(query, doc, XPathConstants.NODE)
            ?: throw EbicsProtocolError(HttpStatusCode.NotFound, "Unsuccessful XPath query string: $query")
        return ret as Node
    }

    fun getStringFromXpath(doc: Document, query: String): String {
        val xpath = XPathFactory.newInstance().newXPath()
        val ret = xpath.evaluate(query, doc, XPathConstants.STRING) as String
        if (ret.isEmpty()) {
            throw EbicsProtocolError(HttpStatusCode.NotFound, "Unsuccessful XPath query string: $query")
        }
        return ret
    }
}