harden: connclass clone-cap at register, ws control-frame limits, uuid recycle-skip, json-escape extjwt/filehost claims, metadata value/key caps, cloak numeric-dotted leak, relaymsg remote-nick, rpc set_oper block validation, isupport 13-token split, multi-hop privmsg routing, connectdelay=0

src/link.rs

@@ -79,6 +79,7 @@ impl Server {
     /// Mint the next network-wide UID for a local user: our SID + 6 base-26 chars
     /// (e.g. `0AAAAAAAB`).
     pub fn next_uuid(&mut self) -> String {
+        loop {
             let mut x = self.uuid_counter;
             self.uuid_counter += 1;
             let mut suffix = [b'A'; 6];
@@ -86,11 +87,17 @@ impl Server {
                 *c = b'A' + (x % 26) as u8;
                 x /= 26;
             }
-        format!(
+            let uuid = format!(
                 "{}{}",
                 self.sid,
                 std::str::from_utf8(&suffix).unwrap_or("AAAAAA")
-        )
+            );
+            // after 26^6 mints the counter wraps and could re-issue a still-live id;
+            // skip any that's in use so uuids stay unique
+            if !self.uuid_local.contains_key(&uuid) && !self.remote_users.contains_key(&uuid) {
+                return uuid;
+            }
+        }
     }
 
     /// Register a new server-link connection. An **outbound** link introduces
@@ -966,6 +973,9 @@ impl Server {
                 .map(|u| u.nick.clone())
                 .unwrap_or_default();
             self.send(dst, format!(":{prefix} {cmd} {nick} :{text}"));
+        } else {
+            // a remote target reached via another link (multi-hop) — forward onward
+            self.forward_to_target(&target, msg, via);
         }
     }
 

src/modules/cloak.rs

@@ -99,7 +99,13 @@ pub fn cloak_host(key: &str, host: &str) -> String {
         format!("{alpha}.{beta}.{gamma}{IP_SUFFIX}")
     } else {
         let parts: Vec<&str> = host.split('.').filter(|p| !p.is_empty()).collect();
-        if parts.len() >= 3 {
+        // reveal the registered domain suffix only for a real hostname (its TLD has a
+        // letter); a numeric dotted string that slipped past the IP parsers is fully
+        // cloaked so no octets leak in cleartext
+        let real_host = parts
+            .last()
+            .is_some_and(|t| t.bytes().any(|b| b.is_ascii_alphabetic()));
+        if parts.len() >= 3 && real_host {
             let suffix = parts[parts.len() - 2..].join(".");
             format!("{}.{suffix}", label(key, host, 8))
         } else {

src/modules/connclass.rs

@@ -386,6 +386,18 @@ pub fn on_register(s: &mut Server, uid: Uid) -> AuthOutcome {
     else {
         return AuthOutcome::Proceed;
     };
+    // enforce per-IP clone caps here too: a class matched only by a host mask isn't
+    // picked at connect, so `assign` never got to check them
+    if let Some(max) = class.localmax {
+        if local_clones(s, &ip, &class.name, uid) >= max {
+            return AuthOutcome::Reject("Too many connections from your address".into());
+        }
+    }
+    if let Some(max) = class.globalmax {
+        if global_clones(s, &ip, uid) >= max {
+            return AuthOutcome::Reject("Too many connections from your address".into());
+        }
+    }
     // cheap cert check before the (possibly slow) password verify
     if class.ssl_trusted && !has_cert {
         return AuthOutcome::Reject("Your connection class requires a client certificate".into());

src/modules/extjwt.rs

@@ -42,6 +42,23 @@ fn json_arr(chars: impl IntoIterator<Item = char>) -> String {
     format!("[{}]", items.join(","))
 }
 
+/// Escape a string for embedding in a JSON string literal.
+fn json_esc(s: &str) -> String {
+    let mut o = String::with_capacity(s.len());
+    for c in s.chars() {
+        match c {
+            '"' => o.push_str("\\\""),
+            '\\' => o.push_str("\\\\"),
+            '\n' => o.push_str("\\n"),
+            '\r' => o.push_str("\\r"),
+            '\t' => o.push_str("\\t"),
+            c if (c as u32) < 0x20 => o.push_str(&format!("\\u{:04x}", c as u32)),
+            c => o.push(c),
+        }
+    }
+    o
+}
+
 pub fn commands() -> Vec<Box<dyn Command>> {
     vec![Box::new(ExtJwt)]
 }
@@ -106,15 +123,19 @@ impl Command for ExtJwt {
                     v
                 })
                 .unwrap_or_default();
-            chan_claims = format!(",\"channel\":\"{target}\",\"cmodes\":{}", json_arr(cmodes));
+            chan_claims = format!(
+                ",\"channel\":\"{}\",\"cmodes\":{}",
+                json_esc(&target),
+                json_arr(cmodes)
+            );
         }
 
         let claims = format!(
             "{{\"exp\":{},\"iss\":\"{}\",\"sub\":\"{}\",\"account\":\"{}\",\"umodes\":{}{}}}",
             now() + duration,
-            s.name,
+            json_esc(&s.name),
-            nick,
+            json_esc(&nick),
-            account,
+            json_esc(&account),
             umodes,
             chan_claims
         );

src/modules/filehost.rs

@@ -50,6 +50,24 @@ fn file_type(filename: &str) -> &'static str {
     }
 }
 
+/// Escape a string for embedding in a JSON string literal (the tag carries JSON,
+/// so a `"`/`\` in the url or filename would otherwise break it).
+fn json_esc(v: &str) -> String {
+    let mut o = String::with_capacity(v.len());
+    for c in v.chars() {
+        match c {
+            '"' => o.push_str("\\\""),
+            '\\' => o.push_str("\\\\"),
+            '\n' => o.push_str("\\n"),
+            '\r' => o.push_str("\\r"),
+            '\t' => o.push_str("\\t"),
+            c if (c as u32) < 0x20 => o.push_str(&format!("\\u{:04x}", c as u32)),
+            c => o.push(c),
+        }
+    }
+    o
+}
+
 /// IRCv3 message-tag value escape (JSON is full of spaces, which would split the line).
 fn escape_tag(v: &str) -> String {
     let mut out = String::with_capacity(v.len());
@@ -114,8 +132,8 @@ impl Module for FileHost {
             let filename = &url[files_prefix.len().min(url.len())..];
             let meta = format!(
                 "{{\"url\":\"{}\",\"filename\":\"{}\",\"type\":\"{}\"}}",
-                url,
+                json_esc(url),
-                filename,
+                json_esc(filename),
                 file_type(filename)
             );
             // fold the metadata onto this message's relayed tag block (message-tags

src/modules/metadata.rs

@@ -144,10 +144,22 @@ impl Command for MetadataCmd {
                     return CmdResult::Fail;
                 };
                 let value = params.get(3).cloned(); // no value => delete the key
+                let maxval = s.conf_num("metadata_maxvalue", 512usize);
+                let maxkeys = s.conf_num("metadata_maxkeys", 32usize);
                 {
                     let st = s.ext.get_or_insert_with::<MetaStore>(MetaStore::default);
                     match &value {
                         Some(v) => {
+                            // bound value length and per-target key count so a client
+                            // can't grow the store without limit
+                            let cur = st.0.get(&key);
+                            let overlong = v.len() > maxval;
+                            let too_many = cur.map(|m| m.len() >= maxkeys && !m.contains_key(&mkey))
+                                .unwrap_or(false);
+                            if overlong || too_many {
+                                s.fail(uid, "METADATA", "KEY_INVALID", "value too long or too many keys");
+                                return CmdResult::Fail;
+                            }
                             st.0.entry(key.clone())
                                 .or_default()
                                 .insert(mkey.clone(), v.clone());

src/modules/relaymsg.rs

@@ -56,7 +56,7 @@ impl Command for RelayMsg {
             );
             return CmdResult::Fail;
         }
-        if s.find_nick(nick).is_some() {
+        if s.find_nick(nick).is_some() || s.remote_nick.contains_key(&nick.to_ascii_lowercase()) {
             return bad(s, "RELAYMSG spoofed nick is already in use");
         }
         if nick.chars().any(|c| FORBIDDEN.contains(c)) {

src/modules/restrictcommands.rs

@@ -147,8 +147,9 @@ impl Module for RestrictCommands {
                 return ModResult::Passthru;
             }
         }
-        // connect-delay: allowed once connected long enough
+        // connect-delay: allowed once connected long enough (0 = no delay, so the
-        if r.connectdelay > 0 && now().saturating_sub(signon) >= r.connectdelay {
+        // command is allowed immediately)
+        if now().saturating_sub(signon) >= r.connectdelay {
             return ModResult::Passthru;
         }
 

src/modules/rpc/user.rs

@@ -134,7 +134,17 @@ pub fn handle(s: &mut Server, action: &str, params: &str) -> Result<String, RpcE
             let uid = resolve(s, params).ok_or_else(|| RpcError::not_found("no such user"))?;
             let oper = json::get_str(params, "oper").or_else(|| json::get_str(params, "type"));
             match oper {
-                Some(name) if !name.is_empty() => s.oper_up(uid),
+                Some(name) if !name.is_empty() => {
+                    // apply the named oper block's level; reject an unknown name rather
+                    // than silently opering with defaults
+                    match s.opers.iter().find(|o| o.0 == name).map(|o| o.2) {
+                        Some(level) => {
+                            s.oper_up(uid);
+                            crate::modules::operlevels::set(s, uid, level);
+                        }
+                        None => return Err(RpcError::invalid_params("no such oper block")),
+                    }
+                }
                 _ => svs_set_user_modes(s, uid, "-o"), // de-oper
             }
             Ok(obj(&[("result", "true".into())]))

src/server.rs

@@ -716,17 +716,22 @@ impl Server {
         // config-overridable (see modules::customprefix)
         let include_oper = self.conf_bool("operprefix", false) || self.conf_bool("ojoin", false);
         let prefix = crate::modules::customprefix::isupport(include_oper);
-        let mut lines = vec![format!(
+        let mut tokens: Vec<String> = format!(
             "CHANTYPES=# PREFIX={prefix} CHANMODES=beIgXw,k,lfjFLHBJdK,ACDGMNOPQRSTUcimnprstuz EXTBAN=,Gbcgjmnrsy WATCH={maxwatch} MONITOR={maxmon} SILENCE={maxsil} CALLERID=g WHOX CHATHISTORY={chathist} MSGREFTYPES=timestamp,msgid UTF8ONLY CASEMAPPING=ascii NICKLEN={maxnick} CHANNELLEN={maxchan} NETWORK={}",
             self.network
-        )];
+        )
+        .split(' ')
+        .map(String::from)
+        .collect();
         if let Some(tok) = crate::modules::network_icon::isupport(self) {
-            lines.push(tok);
+            tokens.push(tok);
         }
         if let Some(tok) = crate::modules::filehost::isupport(self) {
-            lines.push(tok);
+            tokens.push(tok);
         }
-        lines
+        // at most 13 tokens per 005 line (the RFC-suggested cap) so strict clients
+        // don't truncate trailing tokens
+        tokens.chunks(13).map(|c| c.join(" ")).collect()
     }
 
     /// Emit the ISUPPORT numerics to `uid`. When `batched` (the client negotiated

src/websocket.rs

@@ -326,6 +326,13 @@ fn io_loop<S: WsStream>(
                         Ok(Some((frame, consumed))) => {
                             acc.drain(..consumed);
                             match frame.opcode {
+                                // RFC 6455 §5.5: control frames must be ≤125 bytes and
+                                // never fragmented — drop the connection otherwise
+                                OP_CLOSE | OP_PING | OP_PONG
+                                    if !frame.fin || frame.payload.len() > 125 =>
+                                {
+                                    return
+                                }
                                 OP_CLOSE => return,
                                 OP_PING => {
                                     let _ = stream.write_all(&encode(OP_PONG, &frame.payload));