From e26118af2e572431541fca58d6c372ac5a3cfdf6 Mon Sep 17 00:00:00 2001 From: Sergey Kandaurov Date: Tue, 15 Jul 2025 15:55:26 +0400 Subject: [PATCH] SSL: disabled certificate compression by default with OpenSSL. Certificate compression is supported since OpenSSL 3.2, it is enabled automatically as negotiated in a TLSv1.3 handshake. Using certificate compression and decompression in runtime may be suboptimal in terms of CPU and memory consumption in certain typical scenarios, hence it is disabled by default on both server and client sides. It can be enabled with ssl_conf_command and similar directives in upstream as appropriate, for example: ssl_conf_command Options RxCertificateCompression; ssl_conf_command Options TxCertificateCompression; Compressing server certificates requires additional support, this is addressed separately. --- src/event/ngx_event_openssl.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c index ff604c562..0c23c3f2f 100644 --- a/src/event/ngx_event_openssl.c +++ b/src/event/ngx_event_openssl.c @@ -387,6 +387,11 @@ ngx_ssl_create(ngx_ssl_t *ssl, ngx_uint_t protocols, void *data) SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_COMPRESSION); #endif +#ifdef SSL_OP_NO_TX_CERTIFICATE_COMPRESSION + SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_TX_CERTIFICATE_COMPRESSION); + SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_RX_CERTIFICATE_COMPRESSION); +#endif + #ifdef SSL_OP_NO_ANTI_REPLAY SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_ANTI_REPLAY); #endif