Implement XEP-0384: OMEMO Encryption v0.8

This implements XEP-0384 in version v0.8 with a manager and storage
classes to be user-implemented for persistant storage.

The license of the code is LGPL-2.1-or-later as usual.  However since
libomemo-c (libsignal-protocol-c) is GPL-3.0, the built binary is always
licensed under GPL-3.0.  Having our code LGPL licensed will make it
avoids relicensing in the future in case we port it to an LGPL
compatible omemo library.

Closes #133.

Co-authored-by: Linus Jahn <lnj@kaidan.im>

5 files changed, 25 insertions, 7 deletions

diff --git a/src/base/QXmppConstants.cpp b/src/base/QXmppConstants.cpp
index 29b3862c..7864d229 100644
--- a/src/base/QXmppConstants.cpp
+++ b/src/base/QXmppConstants.cpp
@@ -170,6 +170,8 @@ const char *ns_spoiler = "urn:xmpp:spoiler:0";
 const char *ns_omemo = "eu.siacs.conversations.axolotl";
 const char *ns_omemo_1 = "urn:xmpp:omemo:1";
 const char *ns_omemo_2 = "urn:xmpp:omemo:2";
+const char *ns_omemo_2_bundles = "urn:xmpp:omemo:2:bundles";
+const char *ns_omemo_2_devices = "urn:xmpp:omemo:2:devices";
 // XEP-0405: Mediated Information eXchange (MIX): Participant Server Requirements
 const char *ns_mix_pam = "urn:xmpp:mix:pam:1";
 const char *ns_mix_roster = "urn:xmpp:mix:roster:0";
diff --git a/src/base/QXmppConstants_p.h b/src/base/QXmppConstants_p.h
index 6583cfdb..3bfff544 100644
--- a/src/base/QXmppConstants_p.h
+++ b/src/base/QXmppConstants_p.h
@@ -182,6 +182,8 @@ extern const char *ns_spoiler;
 extern const char *ns_omemo;
 extern const char *ns_omemo_1;
 extern const char *ns_omemo_2;
+extern const char *ns_omemo_2_bundles;
+extern const char *ns_omemo_2_devices;
 // XEP-0405: Mediated Information eXchange (MIX): Participant Server Requirements
 extern const char *ns_mix_pam;
 extern const char *ns_mix_roster;
diff --git a/src/base/QXmppMessage.cpp b/src/base/QXmppMessage.cpp
index d583fd7e..2f0fb5fe 100644
--- a/src/base/QXmppMessage.cpp
+++ b/src/base/QXmppMessage.cpp
@@ -11,8 +11,10 @@
 #include "QXmppConstants_p.h"
 #include "QXmppGlobal_p.h"
 #include "QXmppMixInvitation.h"
+#ifdef BUILD_OMEMO
 #include "QXmppOmemoElement_p.h"
 #include "QXmppOmemoEnvelope_p.h"
+#endif
 #include "QXmppTrustMessageElement.h"
 #include "QXmppUtils.h"
 
@@ -136,10 +138,10 @@ public:
     // XEP-0382: Spoiler messages
     bool isSpoiler;
     QString spoilerHint;
-
+#ifdef BUILD_OMEMO
     // XEP-0384: OMEMO Encryption
     std::optional<QXmppOmemoElement> omemoElement;
-
+#endif
     // XEP-0407: Mediated Information eXchange (MIX): Miscellaneous Capabilities
     std::optional<QXmppMixInvitation> mixInvitation;
 
@@ -1078,6 +1080,8 @@ void QXmppMessage::setSpoilerHint(const QString &spoilerHint)
         d->isSpoiler = true;
 }
 
+#ifdef BUILD_OMEMO
+/// \cond
 ///
 /// Returns an included OMEMO element as defined by \xep{0384, OMEMO Encryption}.
 ///
@@ -1097,6 +1101,8 @@ void QXmppMessage::setOmemoElement(const std::optional<QXmppOmemoElement> &omemo
 {
     d->omemoElement = omemoElement;
 }
+/// \endcond
+#endif
 
 ///
 /// Returns an included \xep{0369}: Mediated Information eXchange (MIX)
@@ -1297,6 +1303,7 @@ bool QXmppMessage::parseExtension(const QDomElement &element, QXmpp::SceMode sce
             d->encryptionName = element.attribute(QStringLiteral("name"));
             return true;
         }
+#ifdef BUILD_OMEMO
         // XEP-0384: OMEMO Encryption
         if (QXmppOmemoElement::isOmemoElement(element)) {
             QXmppOmemoElement omemoElement;
@@ -1304,6 +1311,7 @@ bool QXmppMessage::parseExtension(const QDomElement &element, QXmpp::SceMode sce
             d->omemoElement = omemoElement;
             return true;
         }
+#endif
         // XEP-0428: Fallback Indication
         if (checkElement(element, QStringLiteral("fallback"), ns_fallback_indication)) {
             d->isFallback = true;
@@ -1523,10 +1531,12 @@ void QXmppMessage::serializeExtensions(QXmlStreamWriter *writer, QXmpp::SceMode
             writer->writeEndElement();
         }
 
+#ifdef BUILD_OMEMO
         // XEP-0384: OMEMO Encryption
         if (d->omemoElement) {
             d->omemoElement->toXml(writer);
         }
+#endif
 
         // XEP-0428: Fallback Indication
         if (d->isFallback) {
diff --git a/src/base/QXmppMessage.h b/src/base/QXmppMessage.h
index e9d442c1..ba6917c4 100644
--- a/src/base/QXmppMessage.h
+++ b/src/base/QXmppMessage.h
@@ -18,7 +18,9 @@
 class QXmppMessagePrivate;
 class QXmppBitsOfBinaryDataList;
 class QXmppMixInvitation;
+#ifdef BUILD_OMEMO
 class QXmppOmemoElement;
+#endif
 class QXmppTrustMessageElement;
 
 ///
@@ -232,10 +234,6 @@ public:
     QString spoilerHint() const;
     void setSpoilerHint(const QString &);
 
-    // XEP-0384: OMEMO Encryption
-    std::optional<QXmppOmemoElement> omemoElement() const;
-    void setOmemoElement(const std::optional<QXmppOmemoElement> &omemoElement);
-
     // XEP-0407: Mediated Information eXchange (MIX): Miscellaneous Capabilities
     std::optional<QXmppMixInvitation> mixInvitation() const;
     void setMixInvitation(const std::optional<QXmppMixInvitation> &mixInvitation);
@@ -249,6 +247,12 @@ public:
     void setTrustMessageElement(const std::optional<QXmppTrustMessageElement> &trustMessageElement);
 
     /// \cond
+#ifdef BUILD_OMEMO
+    // XEP-0384: OMEMO Encryption
+    std::optional<QXmppOmemoElement> omemoElement() const;
+    void setOmemoElement(const std::optional<QXmppOmemoElement> &omemoElement);
+#endif
+
     void parse(const QDomElement &element) override final;
     virtual void parse(const QDomElement &element, QXmpp::SceMode);
     void toXml(QXmlStreamWriter *writer) const override final;
diff --git a/src/base/QXmppOmemoData.cpp b/src/base/QXmppOmemoData.cpp
index 33215d67..dd99eefd 100644
--- a/src/base/QXmppOmemoData.cpp
+++ b/src/base/QXmppOmemoData.cpp
@@ -247,7 +247,7 @@ QByteArray QXmppOmemoDeviceBundle::signedPublicPreKeySignature() const
 }
 
 ///
-/// Returns the signature of the public pre key that is signed.
+/// Sets the signature of the public pre key that is signed.
 ///
 /// \param signature signature of the signed public pre key
 ///