From 62b3b461ec59b9b3ecd47d92b036d403359d229d Mon Sep 17 00:00:00 2001
From: Nicolas Werner <nicolas.werner@hotmail.de>
Date: Sun, 12 Jun 2022 19:09:07 +0200
Subject: [PATCH] Fix comparison for glare algorithm
---
src/encryption/DeviceVerificationFlow.cpp | 9 +++++----
src/encryption/DeviceVerificationFlow.h | 5 ++++-
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/src/encryption/DeviceVerificationFlow.cpp b/src/encryption/DeviceVerificationFlow.cpp
index 32473522c..cc12bb9bf 100644
--- a/src/encryption/DeviceVerificationFlow.cpp
+++ b/src/encryption/DeviceVerificationFlow.cpp
@@ -15,6 +15,7 @@
#include <QDateTime>
#include <QTimer>
#include <iostream>
+#include <tuple>
static constexpr int TIMEOUT = 2 * 60 * 1000; // 2 minutes
@@ -569,10 +570,10 @@ DeviceVerificationFlow::handleStartMessage(const mtx::events::msg::KeyVerificati
this->canonical_json = nlohmann::json(msg);
else {
// resolve glare
- if (utils::localUser().toStdString() > this->toClient.to_string() &&
- http::client()->device_id() > this->deviceId.toStdString()) {
- // treat this as if the user with the smaller mxid and deviceid was the sender of
- // "start"
+ if (std::tuple(this->toClient.to_string(), this->deviceId.toStdString()) <
+ std::tuple(utils::localUser().toStdString(), http::client()->device_id())) {
+ // treat this as if the user with the smaller mxid or smaller deviceid (if the mxid
+ // was the same) was the sender of "start"
this->canonical_json = nlohmann::json(msg);
this->sender = false;
}
diff --git a/src/encryption/DeviceVerificationFlow.h b/src/encryption/DeviceVerificationFlow.h
index e980d2ec3..1955fab31 100644
--- a/src/encryption/DeviceVerificationFlow.h
+++ b/src/encryption/DeviceVerificationFlow.h
@@ -37,7 +37,7 @@ using sas_ptr = std::unique_ptr<mtx::crypto::SAS>;
* && | n | | |
* no canonical_json | a | (m.key.verification.start) | | waitingForKeys
* | l |<--------------------------------| Not sending to prevent the glare resolve| && no commitment
- * | | | | && no canonical_json
+ * | | | (1) | && no canonical_json
* | | m.key.verification.start | |
* waitForOtherAccept | |-------------------------------->| (IF NOT ALREADY ASKED, |
* && | | | ASK FOR VERIFICATION REQUEST) | promptStartVerify, if not accepted
@@ -57,6 +57,9 @@ using sas_ptr = std::unique_ptr<mtx::crypto::SAS>;
* | | | |
* success/fail | | m.key.verification.done | | success/fail
* | |<------------------------------->| |
+ *
+ * (1) Sometimes the other side does send this start. In this case we run the glare algorithm and send an accept only if
+ * We are the bigger mxid and deviceid (since we discard our start message). <- GLARE RESOLUTION
*/
// clang-format on
class DeviceVerificationFlow : public QObject
--
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