From e383b00ff83c99bdf37c3cef37a3bd1da79ef911 Mon Sep 17 00:00:00 2001
From: Jordan Doyle <jordan@doyle.la>
Date: Sun, 8 Jan 2023 19:24:21 +0000
Subject: [PATCH] Return an error if a client attempts to authenticate again

---
 src/client.rs     |  8 ++++++--
 src/connection.rs | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/client.rs b/src/client.rs
index 073ba9d..1d015f6 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -12,7 +12,7 @@ use tracing::{debug, error, info_span, instrument, warn, Instrument, Span};
 
 use crate::{
     channel::Channel,
-    connection::{InitiatedConnection, MessageSink},
+    connection::{InitiatedConnection, MessageSink, SaslAlreadyAuthenticated},
     messages::{
         Broadcast, ChannelFetchTopic, ChannelInvite, ChannelJoin, ChannelKickUser, ChannelList,
         ChannelMemberList, ChannelMessage, ChannelPart, ChannelUpdateTopic, FetchClientDetails,
@@ -569,7 +569,11 @@ impl StreamHandler<Result<irc_proto::Message, ProtocolError>> for Client {
             Command::BOTSERV(_) => {}
             Command::HOSTSERV(_) => {}
             Command::MEMOSERV(_) => {}
-            Command::AUTHENTICATE(_) => {}
+            Command::AUTHENTICATE(_) => {
+                self.writer.write(
+                    SaslAlreadyAuthenticated(self.connection.nick.to_string()).into_message(),
+                );
+            }
             Command::ACCOUNT(_) => {}
             Command::METADATA(_, _, _) => {}
             Command::MONITOR(_, _) => {}
diff --git a/src/connection.rs b/src/connection.rs
index 1c3293c..774ba76 100644
--- a/src/connection.rs
+++ b/src/connection.rs
@@ -343,6 +343,26 @@ impl FromStr for AuthStrategy {
     }
 }
 
+/// Returned to the client if they try to call AUTHENTICATE again after negotiation.
+pub struct SaslAlreadyAuthenticated(pub String);
+
+impl SaslAlreadyAuthenticated {
+    #[must_use]
+    pub fn into_message(self) -> Message {
+        Message {
+            tags: None,
+            prefix: None,
+            command: Command::Response(
+                Response::ERR_SASLALREADY,
+                vec![
+                    self.0,
+                    "You have already authenticated using SASL".to_string(),
+                ],
+            ),
+        }
+    }
+}
+
 /// Returned to the client when an invalid SASL strategy is attempted.
 pub struct SaslStrategyUnsupported(String);
 
--
libgit2 1.7.2