From abd5ff08ca3102e3763253436e2f4da839defa39 Mon Sep 17 00:00:00 2001
From: David Florness <david@florness.com>
Date: Sun, 17 Jan 2021 18:14:07 -0500
Subject: [PATCH] Ensure elections exist before using them

---
 election/msg.go | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/election/msg.go b/election/msg.go
index 5148466..dbf7194 100644
--- a/election/msg.go
+++ b/election/msg.go
@@ -110,7 +110,11 @@ func OnJoinElectionMessage(source mautrix.EventSource, evt *event.Event, electio
 		return
 	}
 	input := new(big.Int).SetBytes(bytes)
-	el := elections.Get(content.CreateEventId)
+	el, exists := elections.GetOk(content.CreateEventId)
+	if !exists {
+		log.Warnf("ignoring %s's join since the election doesn't exist", evt.Sender)
+		return
+	}
 	el.Lock()
 	defer el.Unlock()
 	if el.Started {
@@ -135,7 +139,11 @@ func OnStartElectionMessage(source mautrix.EventSource, evt *event.Event, electi
 		return
 	}
 	// TODO ensure election exists
-	el := elections.Get(content.CreateEventId)
+	el, exists := elections.GetOk(content.CreateEventId)
+	if !exists {
+		log.Warnf("ignoring %s's election start since the election doesn't exist", evt.Sender)
+		return
+	}
 	el.Lock()
 	defer el.Unlock()
 	if evt.Sender != el.Creator {
@@ -149,7 +157,7 @@ func OnStartElectionMessage(source mautrix.EventSource, evt *event.Event, electi
 func OnEvalMessage(source mautrix.EventSource, evt *event.Event, elections *ElectionsMap, localVoter *LocalVoter) {
 	content, ok := evt.Content.Parsed.(*EvalMessageContent)
 	if !ok {
-		log.Warn("ignoring eval message since we couldn't cast message content to EvalMessageContent")
+		log.Warn("ignoring %s's eval message since we couldn't cast message content to EvalMessageContent", evt.Sender)
 		return
 	}
 	encodedEncryptedOutput, ok := content.Outputs[localVoter.UserID]
@@ -159,13 +167,21 @@ func OnEvalMessage(source mautrix.EventSource, evt *event.Event, elections *Elec
 	}
 	encryptedOutput, err := base64.StdEncoding.DecodeString(encodedEncryptedOutput)
 	if err != nil {
-		log.Errorf("couldn't decode encrypted output: %s", err)
+		log.Errorf("couldn't decode %s's encrypted output: %s", evt.Sender, err)
+		return
+	}
+	el, exists := elections.GetOk(content.CreateEventId)
+	if !exists {
+		log.Warnf("ignoring %s's eval message since the election doesn't exist", evt.Sender)
 		return
 	}
-	el := elections.Get(content.CreateEventId)
 	el.Lock()
 	defer el.Unlock()
-	voter := el.Voters[evt.Sender]
+	voter, exists := el.Voters[evt.Sender]
+	if !exists {
+		log.Warnf("ignoring %s's eval message since they are not a voter", evt.Sender)
+		return
+	}
 
 	var decryptNonce [24]byte
 	copy(decryptNonce[:], encryptedOutput[:24])
-- 
2.38.4