Implement XEP-0448: Encryption for stateless file sharing parsing (#463)

https://xmpp.org/extensions/xep-0448.html

Co-authored-by: Jonah Brüchert <jbb@kaidan.im>

8 files changed, 290 insertions, 0 deletions

diff --git a/doc/doap.xml b/doc/doap.xml
index 97826d73..bbad8a58 100644
--- a/doc/doap.xml
+++ b/doc/doap.xml
@@ -579,6 +579,13 @@ SPDX-License-Identifier: CC0-1.0
     </implements>
     <implements>
       <xmpp:SupportedXep>
+        <xmpp:xep rdf:resource='https://xmpp.org/extensions/xep-0448.html'/>
+        <xmpp:status>partial</xmpp:status>
+        <xmpp:version>0.2</xmpp:version>
+        <xmpp:since>1.5</xmpp:since>
+    </implements>
+    <implements>
+      <xmpp:SupportedXep>
         <xmpp:xep rdf:resource='https://xmpp.org/extensions/xep-0450.html'/>
         <xmpp:status>complete</xmpp:status>
         <xmpp:version>0.4</xmpp:version>
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index c719dc3f..fb4273c9 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -161,6 +161,7 @@ set(SOURCE_FILES
     base/QXmppDataFormBase.cpp
     base/QXmppDiscoveryIq.cpp
     base/QXmppElement.cpp
+    base/QXmppEncryptedFileSource.cpp
     base/QXmppEntityTimeIq.cpp
     base/QXmppError.cpp
     base/QXmppFileMetadata.cpp
diff --git a/src/base/QXmppConstants.cpp b/src/base/QXmppConstants.cpp
index 7f58911c..196ee89b 100644
--- a/src/base/QXmppConstants.cpp
+++ b/src/base/QXmppConstants.cpp
@@ -192,5 +192,7 @@ const char *ns_tm = "urn:xmpp:tm:1";
 const char *ns_file_metadata = "urn:xmpp:file:metadata:0";
 // XEP-0447: Stateless file sharing
 const char *ns_sfs = "urn:xmpp:sfs:0";
+// XEP-0448: Encryption for stateless file sharing
+const char *ns_esfs = "urn:xmpp:esfs:0";
 // XEP-0450: Automatic Trust Management (ATM)
 const char *ns_atm = "urn:xmpp:atm:1";
diff --git a/src/base/QXmppConstants_p.h b/src/base/QXmppConstants_p.h
index d040ed27..83521c5a 100644
--- a/src/base/QXmppConstants_p.h
+++ b/src/base/QXmppConstants_p.h
@@ -204,6 +204,8 @@ extern const char *ns_tm;
 extern const char *ns_file_metadata;
 // XEP-0447: Stateless file sharing
 extern const char *ns_sfs;
+// XEP-0448: Encryption for stateless file sharing
+extern const char *ns_esfs;
 // XEP-0450: Automatic Trust Management (ATM)
 extern const char *ns_atm;
 
diff --git a/src/base/QXmppEncryptedFileSource.cpp b/src/base/QXmppEncryptedFileSource.cpp
new file mode 100644
index 00000000..d2c2b592
--- /dev/null
+++ b/src/base/QXmppEncryptedFileSource.cpp
@@ -0,0 +1,157 @@
+// SPDX-FileCopyrightText: 2022 Linus Jahn <lnj@kaidan.im>
+// SPDX-FileCopyrightText: 2022 Jonah Brüchert <jbb@kaidan.im>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "QXmppConstants_p.h"
+#include "QXmppEncryptedFileSource_p.h"
+#include "QXmppHttpFileSource.h"
+
+#include <optional>
+
+#include <QDomElement>
+#include <QXmlStreamWriter>
+
+/// \cond
+static QString cipherToString(QXmppEncryptedFileSource::Cipher cipher)
+{
+    switch (cipher) {
+    case QXmppEncryptedFileSource::Aes128GcmNopadding:
+        return "urn:xmpp:ciphers:aes-128-gcm-nopadding:0";
+    case QXmppEncryptedFileSource::Aes256GcmNopadding:
+        return "urn:xmpp:ciphers:aes-256-gcm-nopadding:0";
+    case QXmppEncryptedFileSource::Aes256CbcPkcs7:
+        return "urn:xmpp:ciphers:aes-256-cbc-pkcs7:0";
+    }
+    Q_UNREACHABLE();
+}
+
+static std::optional<QXmppEncryptedFileSource::Cipher> cipherFromString(const QString &cipher)
+{
+    if (cipher == "urn:xmpp:ciphers:aes-128-gcm-nopadding:0") {
+        return QXmppEncryptedFileSource::Aes128GcmNopadding;
+    } else if (cipher == "urn:xmpp:ciphers:aes-256-gcm-nopadding:0") {
+        return QXmppEncryptedFileSource::Aes256GcmNopadding;
+    } else if (cipher == "urn:xmpp:ciphers:aes-256-cbc-pkcs7:0") {
+        return QXmppEncryptedFileSource::Aes256CbcPkcs7;
+    }
+    return {};
+}
+
+QXmppEncryptedFileSource::QXmppEncryptedFileSource() = default;
+
+QXmppEncryptedFileSource::Cipher QXmppEncryptedFileSource::cipher() const
+{
+    return m_cipher;
+}
+
+void QXmppEncryptedFileSource::setCipher(Cipher newCipher)
+{
+    m_cipher = newCipher;
+}
+
+const QByteArray &QXmppEncryptedFileSource::key() const
+{
+    return m_key;
+}
+
+void QXmppEncryptedFileSource::setKey(const QByteArray &newKey)
+{
+    m_key = newKey;
+}
+
+const QByteArray &QXmppEncryptedFileSource::iv() const
+{
+    return m_iv;
+}
+
+void QXmppEncryptedFileSource::setIv(const QByteArray &newIv)
+{
+    m_iv = newIv;
+}
+
+const QVector<QXmppHash> &QXmppEncryptedFileSource::hashes() const
+{
+    return m_hashes;
+}
+
+void QXmppEncryptedFileSource::setHashes(const QVector<QXmppHash> &newHashes)
+{
+    m_hashes = newHashes;
+}
+
+const QVector<QXmppHttpFileSource> &QXmppEncryptedFileSource::httpSources() const
+{
+    return m_httpSources;
+}
+
+void QXmppEncryptedFileSource::setHttpSources(const QVector<QXmppHttpFileSource> &newHttpSources)
+{
+    m_httpSources = newHttpSources;
+}
+
+bool QXmppEncryptedFileSource::parse(const QDomElement &el)
+{
+    QString cipher = el.attribute(QStringLiteral("cipher"));
+    if (auto parsedCipher = cipherFromString(cipher)) {
+        m_cipher = *parsedCipher;
+    } else {
+        return false;
+    }
+
+    auto keyEl = el.firstChildElement(QStringLiteral("key"));
+    if (keyEl.isNull()) {
+        return false;
+    }
+    m_key = QByteArray::fromBase64(keyEl.text().toUtf8());
+
+    auto ivEl = el.firstChildElement(QStringLiteral("iv"));
+    if (ivEl.isNull()) {
+        return false;
+    }
+    m_iv = QByteArray::fromBase64(ivEl.text().toUtf8());
+
+    for (auto childEl = el.firstChildElement(QStringLiteral("hash"));
+         !childEl.isNull();
+         childEl = childEl.nextSiblingElement(QStringLiteral("hash"))) {
+        QXmppHash hash;
+        if (!hash.parse(childEl)) {
+            return false;
+        }
+        m_hashes.push_back(std::move(hash));
+    }
+
+    auto sourcesEl = el.firstChildElement(QStringLiteral("sources"));
+    if (sourcesEl.isNull()) {
+        return false;
+    }
+    for (auto childEl = sourcesEl.firstChildElement(QStringLiteral("url-data"));
+         !childEl.isNull();
+         childEl = childEl.nextSiblingElement(QStringLiteral("url-data"))) {
+        QXmppHttpFileSource source;
+        source.parse(childEl);
+        m_httpSources.push_back(std::move(source));
+    }
+
+    return true;
+}
+
+void QXmppEncryptedFileSource::toXml(QXmlStreamWriter *writer) const
+{
+    writer->writeStartElement(QStringLiteral("encrypted"));
+    writer->writeDefaultNamespace(ns_esfs);
+    writer->writeAttribute(QStringLiteral("cipher"), cipherToString(m_cipher));
+    writer->writeTextElement(QStringLiteral("key"), m_key.toBase64());
+    writer->writeTextElement(QStringLiteral("iv"), m_iv.toBase64());
+    for (const auto &hash : m_hashes) {
+        hash.toXml(writer);
+    }
+    writer->writeStartElement(QStringLiteral("sources"));
+    writer->writeDefaultNamespace(ns_sfs);
+    for (const auto &source : m_httpSources) {
+        source.toXml(writer);
+    }
+    writer->writeEndElement();
+    writer->writeEndElement();
+}
+/// \endcond
diff --git a/src/base/QXmppEncryptedFileSource_p.h b/src/base/QXmppEncryptedFileSource_p.h
new file mode 100644
index 00000000..21270de2
--- /dev/null
+++ b/src/base/QXmppEncryptedFileSource_p.h
@@ -0,0 +1,59 @@
+// SPDX-FileCopyrightText: 2022 Linus Jahn <lnj@kaidan.im>
+// SPDX-FileCopyrightText: 2022 Jonah Brüchert <jbb@kaidan.im>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#ifndef QXMPPENCRYPTEDFILESOURCE_H
+#define QXMPPENCRYPTEDFILESOURCE_H
+
+#include "QXmppGlobal.h"
+#include "QXmppHash.h"
+#include "QXmppHttpFileSource.h"
+
+#include <QSharedDataPointer>
+#include <QUrl>
+#include <QVector>
+
+class QXmppEncryptedFileSourcePrivate;
+
+// exported for tests
+class QXMPP_EXPORT QXmppEncryptedFileSource
+{
+public:
+    enum Cipher {
+        Aes128GcmNopadding,
+        Aes256GcmNopadding,
+        Aes256CbcPkcs7,
+    };
+
+    QXmppEncryptedFileSource();
+
+    Cipher cipher() const;
+    void setCipher(Cipher newCipher);
+
+    const QByteArray &key() const;
+    void setKey(const QByteArray &newKey);
+
+    const QByteArray &iv() const;
+    void setIv(const QByteArray &newIv);
+
+    const QVector<QXmppHash> &hashes() const;
+    void setHashes(const QVector<QXmppHash> &newHashes);
+
+    const QVector<QXmppHttpFileSource> &httpSources() const;
+    void setHttpSources(const QVector<QXmppHttpFileSource> &newHttpSources);
+
+    /// \cond
+    bool parse(const QDomElement &el);
+    void toXml(QXmlStreamWriter *writer) const;
+    /// \endcond
+
+private:
+    Cipher m_cipher = Aes128GcmNopadding;
+    QByteArray m_key;
+    QByteArray m_iv;
+    QVector<QXmppHash> m_hashes;
+    QVector<QXmppHttpFileSource> m_httpSources;
+};
+
+#endif  // QXMPPENCRYPTEDFILESOURCE_H
diff --git a/src/base/QXmppHash.cpp b/src/base/QXmppHash.cpp
index c246d200..6d1dcb07 100644
--- a/src/base/QXmppHash.cpp
+++ b/src/base/QXmppHash.cpp
@@ -123,6 +123,7 @@ bool QXmppHash::parse(const QDomElement &el)
 #else
         m_hash = QByteArray::fromBase64(el.text().toUtf8());
 #endif
+        return true;
     }
     return false;
 }
diff --git a/tests/qxmppmessage/tst_qxmppmessage.cpp b/tests/qxmppmessage/tst_qxmppmessage.cpp
index 35bf2625..c9eaa786 100644
--- a/tests/qxmppmessage/tst_qxmppmessage.cpp
+++ b/tests/qxmppmessage/tst_qxmppmessage.cpp
@@ -6,6 +6,7 @@
 
 #include "QXmppBitsOfBinaryContentId.h"
 #include "QXmppBitsOfBinaryDataList.h"
+#include "QXmppEncryptedFileSource_p.h"
 #include "QXmppMessage.h"
 #include "QXmppMixInvitation.h"
 #include "QXmppTrustMessageElement.h"
@@ -53,6 +54,7 @@ private slots:
     void testTrustMessageElement();
     void testE2eeFallbackBody();
     void testFileSharing();
+    void testEncryptedFileSource();
 };
 
 void tst_QXmppMessage::testBasic_data()
@@ -1186,5 +1188,64 @@ void tst_QXmppMessage::testFileSharing()
     serializePacket(message1, xml);
 }
 
+void tst_QXmppMessage::testEncryptedFileSource()
+{
+    {
+        QByteArray xml(
+            "<encrypted xmlns='urn:xmpp:esfs:0' cipher='urn:xmpp:ciphers:aes-256-gcm-nopadding:0'>"
+            "<key>SuRJ2agVm/pQbJQlPq/B23Xt1YOOJCcEGJA5HrcYOGQ=</key>"
+            "<iv>T8RDMBaiqn6Ci4Nw</iv>"
+            "<hash xmlns='urn:xmpp:hashes:2' algo='sha3-256'>BgKI2gp2kNCRsARNvhFmw5kFf9BBo2pTbV2D8XHTMWI=</hash>"
+            "<hash xmlns='urn:xmpp:hashes:2' algo='blake2b-256'>id4cnqqy9/ssfCkM4vYSkiXXrlE=</hash>"
+            "<sources xmlns='urn:xmpp:sfs:0'>"
+            "<url-data xmlns='http://jabber.org/protocol/url-data' target='https://download.montague.lit/4a771ac1-f0b2-4a4a-9700-f2a26fa2bb67/encrypted.jpg'/>"
+            "</sources>"
+            "</encrypted>");
+
+        QXmppEncryptedFileSource encryptedSource;
+        parsePacket(encryptedSource, xml);
+        QCOMPARE(encryptedSource.key(), QByteArray::fromBase64("SuRJ2agVm/pQbJQlPq/B23Xt1YOOJCcEGJA5HrcYOGQ="));
+        QCOMPARE(encryptedSource.iv(), QByteArray::fromBase64("T8RDMBaiqn6Ci4Nw"));
+        QCOMPARE(encryptedSource.httpSources().front().url(), QUrl("https://download.montague.lit/4a771ac1-f0b2-4a4a-9700-f2a26fa2bb67/encrypted.jpg"));
+        QCOMPARE(encryptedSource.cipher(), QXmppEncryptedFileSource::Aes256GcmNopadding);
+        QVERIFY(!encryptedSource.hashes().empty());
+        serializePacket(encryptedSource, xml);
+    }
+
+    {
+        QByteArray xml(
+            "<encrypted xmlns='urn:xmpp:esfs:0' cipher='urn:xmpp:ciphers:aes-128-gcm-nopadding:0'>"
+            "<key>SuRJ2agVm/pQbJQlPq/B23Xt1YOOJCcEGJA5HrcYOGQ=</key>"
+            "<iv>T8RDMBaiqn6Ci4Nw</iv>"
+            "<hash xmlns='urn:xmpp:hashes:2' algo='sha3-256'>BgKI2gp2kNCRsARNvhFmw5kFf9BBo2pTbV2D8XHTMWI=</hash>"
+            "<hash xmlns='urn:xmpp:hashes:2' algo='blake2b-256'>id4cnqqy9/ssfCkM4vYSkiXXrlE=</hash>"
+            "<sources xmlns='urn:xmpp:sfs:0'>"
+            "<url-data xmlns='http://jabber.org/protocol/url-data' target='https://download.montague.lit/4a771ac1-f0b2-4a4a-9700-f2a26fa2bb67/encrypted.jpg'/>"
+            "</sources>"
+            "</encrypted>");
+
+        QXmppEncryptedFileSource encryptedSource;
+        parsePacket(encryptedSource, xml);
+        serializePacket(encryptedSource, xml);
+    }
+
+    {
+        QByteArray xml(
+            "<encrypted xmlns='urn:xmpp:esfs:0' cipher='urn:xmpp:ciphers:aes-256-cbc-pkcs7:0'>"
+            "<key>SuRJ2agVm/pQbJQlPq/B23Xt1YOOJCcEGJA5HrcYOGQ=</key>"
+            "<iv>T8RDMBaiqn6Ci4Nw</iv>"
+            "<hash xmlns='urn:xmpp:hashes:2' algo='sha3-256'>BgKI2gp2kNCRsARNvhFmw5kFf9BBo2pTbV2D8XHTMWI=</hash>"
+            "<hash xmlns='urn:xmpp:hashes:2' algo='blake2b-256'>id4cnqqy9/ssfCkM4vYSkiXXrlE=</hash>"
+            "<sources xmlns='urn:xmpp:sfs:0'>"
+            "<url-data xmlns='http://jabber.org/protocol/url-data' target='https://download.montague.lit/4a771ac1-f0b2-4a4a-9700-f2a26fa2bb67/encrypted.jpg'/>"
+            "</sources>"
+            "</encrypted>");
+
+        QXmppEncryptedFileSource encryptedSource;
+        parsePacket(encryptedSource, xml);
+        serializePacket(encryptedSource, xml);
+    }
+}
+
 QTEST_MAIN(tst_QXmppMessage)
 #include "tst_qxmppmessage.moc"