java-topology/docs/tickets/openssl-0002-ciphersuite-cb-quadratic-dedup.md
russell@unturf.com 9934133dcf whitepaper: 312 sites / 151 ecosystems — wave2+3 defect tables and PDF rebuild
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
2026-03-27 15:23:43 -04:00

1.3 KiB

openssl-0002: ciphersuite_cb — O(n²) TLS 1.3 cipher list dedup via linear scan

CWE: CWE-407 (Inefficient Algorithmic Complexity) Severity: LOW (TLS 1.3 has only 5 standard suites; attack surface is config-time) Status: PATCHED File: ssl/ssl_ciph.cciphersuite_cb()

Defect

set_ciphersuites() parses a colon-separated TLS 1.3 cipher string by calling CONF_parse_list(..., ciphersuite_cb, newciphers). CONF_parse_list invokes ciphersuite_cb once per token (O(n) outer iterations). Inside the callback, a duplicate-suppression loop scans all already-added ciphers linearly:

// ssl/ssl_ciph.c:1250
for (int i = 0; i < sk_SSL_CIPHER_num(ciphersuites); ++i)   // O(k) inner
    if (sk_SSL_CIPHER_value(ciphersuites, i)->id == cipher->id)
        return 1;

With n tokens this is O(n²) dedup. Today TLS 1.3 has 5 ciphersuites so practical cost is negligible, but the pattern is wrong and will degrade if the list ever grows (e.g. custom/vendor forks, future RFC additions).

Fix

Replace the linear scan with a uint8_t seen[SSL_MAX_CIPHERS] bitmask indexed by the cipher's position in the static tls13_ciphers table (all IDs are known at compile time). Lookup and mark become O(1).

See patch: defects/openssl/patch/openssl-0002.patch