russell@unturf.com
9934133dcf
Add 88 new defect entries to HIGH and MEDIUM tables:
HIGH: mysql-0001/0002, mariadb-0001, redis-0001/0002, valkey-0001/0002, openvpn-0001,
vlc-0001, prometheus-0001, otel-collector-0001, cockroachdb-0001..0004,
tidb-0001..0008, kubernetes-0001/0002, go-0001, kotlin-0002, scala-0001,
allegro5-0001, sdl2-0001, grafana-0001, clickhouse-0001, duckdb-0001,
mongodb-0001, envoy-0001, istio-0001, cilium-0001, linkerd2-0001,
linux-0001/0002/0003, tor-0002/0003, curl-0001, julia-0001, lua-0001,
perl5-0001, nats-0001, spring-0003/0004, tomcat-0001, onos-0002, odl-0002
MEDIUM: helm-0001, mariadb-0002, openssl-0001/0002, memcached-0001,
cassandra-0001..0004, flink-0001, storm-0001/0002, zookeeper-0001..0003,
pip-0001, gradle-0001, nginx-0001, haproxy-0001, caddy-0001, varnish-0001,
ffmpeg-0001, gstreamer-0001, raylib-0001, love2d-0001, php-0001/0002,
r-source-0001, cpython-0002, ruby-0001, rabbitmq-0003/0004, activemq-0001,
ovs-0001, onos-0003, odl-0002, jetty-0001
PDF: 976K
62 lines
2.2 KiB
Markdown
62 lines
2.2 KiB
Markdown
# tomcat-0001: ReplicationValve cross-context session dedup — ArrayList.contains() O(n²)
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**Target:** Apache Tomcat
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**File:** `java/org/apache/catalina/ha/tcp/ReplicationValve.java`
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**CWE:** CWE-407 — Inefficient Algorithmic Complexity
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**Severity:** MEDIUM
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**Status:** PATCHED
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## Description
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`ReplicationValve.registerReplicationSession()` accumulates cross-context
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`DeltaSession` objects in a `ThreadLocal<ArrayList<DeltaSession>>`. For each
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incoming session it checks membership with `sessions.contains(session)` before
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adding, where `sessions` is `ArrayList<DeltaSession>`.
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In Portlet-style deployments the comment in the code explicitly notes that
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"the Portlet API can include a lot of fragments from same or different
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applications with session changes." Each call to `registerReplicationSession()`
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does a full linear scan of the growing list — O(n) per call — producing
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O(n²) total work when n sessions are registered for a single request.
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```java
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// ReplicationValve.java line 80, 265-275
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protected final ThreadLocal<ArrayList<DeltaSession>> crossContextSessions = new ThreadLocal<>();
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public void registerReplicationSession(DeltaSession session) {
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List<DeltaSession> sessions = crossContextSessions.get();
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if (sessions != null) {
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if (!sessions.contains(session)) { // O(n) scan per call → O(n²) total
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sessions.add(session);
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}
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}
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}
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```
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## Fix
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Replace `ArrayList<DeltaSession>` with `LinkedHashSet<DeltaSession>` in the
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`ThreadLocal` initialiser. `Set.add()` is idempotent so the `contains()` guard
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is unnecessary and can be removed entirely.
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```java
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protected final ThreadLocal<LinkedHashSet<DeltaSession>> crossContextSessions = new ThreadLocal<>();
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public void registerReplicationSession(DeltaSession session) {
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LinkedHashSet<DeltaSession> sessions = crossContextSessions.get();
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if (sessions != null) {
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sessions.add(session); // O(1) — Set deduplicates automatically
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}
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}
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```
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Callers that iterate `sessions` (lines 394, 422) are unaffected — `LinkedHashSet`
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is `Iterable` and preserves insertion order.
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## Patch
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`defects/tomcat/patch/tomcat-0001.patch`
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## Unit Test
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`defects/tomcat/unit/TomcatReplicationValveTest.java`
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