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>

6 files changed, 222 insertions, 0 deletions

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;
 }