From 3057e6e9ad3ccb0be5cd1546697871cfec4d1fa3 Mon Sep 17 00:00:00 2001 From: Maxim Dounin Date: Wed, 12 Oct 2022 20:14:43 +0300 Subject: [PATCH] SSL: explicit clearing of expired sessions. This reduces lifetime of session keying material in server's memory, and therefore can be beneficial from forward secrecy point of view. --- src/event/ngx_event_openssl.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c index 24b17f985..ec4aa8f59 100644 --- a/src/event/ngx_event_openssl.c +++ b/src/event/ngx_event_openssl.c @@ -4031,6 +4031,8 @@ ngx_ssl_get_cached_session(ngx_ssl_conn_t *ssl_conn, ngx_rbtree_delete(&cache->session_rbtree, node); + ngx_explicit_memzero(sess_id->session, sess_id->len); + #if (NGX_PTR_SIZE == 8) ngx_slab_free_locked(shpool, sess_id->session); #endif @@ -4120,6 +4122,8 @@ ngx_ssl_remove_session(SSL_CTX *ssl, ngx_ssl_session_t *sess) ngx_rbtree_delete(&cache->session_rbtree, node); + ngx_explicit_memzero(sess_id->session, sess_id->len); + #if (NGX_PTR_SIZE == 8) ngx_slab_free_locked(shpool, sess_id->session); #endif @@ -4168,6 +4172,8 @@ ngx_ssl_expire_sessions(ngx_ssl_session_cache_t *cache, ngx_rbtree_delete(&cache->session_rbtree, &sess_id->node); + ngx_explicit_memzero(sess_id->session, sess_id->len); + #if (NGX_PTR_SIZE == 8) ngx_slab_free_locked(shpool, sess_id->session); #endif