# ./pullrev.sh 1869842
http://svn.apache.org/viewvc?view=revision&revision=1869842

--- httpd-2.4.48/modules/ssl/ssl_engine_config.c.r1869842
+++ httpd-2.4.48/modules/ssl/ssl_engine_config.c
@@ -75,6 +75,10 @@
     mc->stapling_refresh_mutex = NULL;
 #endif
 
+#ifdef HAVE_OPENSSL_KEYLOG
+    mc->keylog_file = NULL;
+#endif
+
     apr_pool_userdata_set(mc, SSL_MOD_CONFIG_KEY,
                           apr_pool_cleanup_null,
                           pool);
--- httpd-2.4.48/modules/ssl/ssl_engine_init.c.r1869842
+++ httpd-2.4.48/modules/ssl/ssl_engine_init.c
@@ -445,6 +445,28 @@
     init_bio_methods();
 #endif
 
+#ifdef HAVE_OPENSSL_KEYLOG
+    {
+        const char *logfn = getenv("SSLKEYLOGFILE");
+
+        if (logfn) {
+            rv = apr_file_open(&mc->keylog_file, logfn,
+                               APR_FOPEN_CREATE|APR_FOPEN_WRITE|APR_FOPEN_APPEND|APR_FOPEN_LARGEFILE,
+                               APR_FPROT_UREAD|APR_FPROT_UWRITE,
+                               mc->pPool);
+            if (rv) {
+                ap_log_error(APLOG_MARK, APLOG_NOTICE, rv, s, APLOGNO(10226)
+                             "Could not open log file '%s' configured via SSLKEYLOGFILE",
+                             logfn);
+                return rv;
+            }
+
+            ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s, APLOGNO(10227)
+                         "Init: Logging SSL private key material to %s", logfn);
+        }
+    }
+#endif
+    
     return OK;
 }
 
@@ -806,6 +828,12 @@
      * https://github.com/openssl/openssl/issues/7178 */
     SSL_CTX_clear_mode(ctx, SSL_MODE_AUTO_RETRY);
 #endif
+
+#ifdef HAVE_OPENSSL_KEYLOG
+    if (mctx->sc->mc->keylog_file) {
+        SSL_CTX_set_keylog_callback(ctx, modssl_callback_keylog);
+    }
+#endif
     
     return APR_SUCCESS;
 }
--- httpd-2.4.48/modules/ssl/ssl_engine_kernel.c.r1869842
+++ httpd-2.4.48/modules/ssl/ssl_engine_kernel.c
@@ -2822,3 +2822,17 @@
 }
 
 #endif /* HAVE_SRP */
+
+
+#ifdef HAVE_OPENSSL_KEYLOG
+/* Callback used with SSL_CTX_set_keylog_callback. */
+void modssl_callback_keylog(const SSL *ssl, const char *line)
+{
+    conn_rec *conn = SSL_get_app_data(ssl);
+    SSLSrvConfigRec *sc = mySrvConfig(conn->base_server);
+
+    if (sc && sc->mc->keylog_file) {
+        apr_file_printf(sc->mc->keylog_file, "%s\n", line);
+    }
+}
+#endif
--- httpd-2.4.48/modules/ssl/ssl_private.h.r1869842
+++ httpd-2.4.48/modules/ssl/ssl_private.h
@@ -252,6 +252,10 @@
 #endif
 #endif
 
+#if OPENSSL_VERSION_NUMBER >= 0x10101000L && !defined(LIBRESSL_VERSION_NUMBER)
+#define HAVE_OPENSSL_KEYLOG
+#endif
+
 /* mod_ssl headers */
 #include "ssl_util_ssl.h"
 
@@ -620,6 +624,11 @@
     apr_global_mutex_t   *stapling_cache_mutex;
     apr_global_mutex_t   *stapling_refresh_mutex;
 #endif
+
+#ifdef HAVE_OPENSSL_KEYLOG
+    /* Used for logging if SSLKEYLOGFILE is set at startup. */
+    apr_file_t      *keylog_file;
+#endif
 } SSLModConfigRec;
 
 /** Structure representing configured filenames for certs and keys for
@@ -979,6 +988,11 @@
 int          ssl_callback_SRPServerParams(SSL *, int *, void *);
 #endif
 
+#ifdef HAVE_OPENSSL_KEYLOG
+/* Callback used with SSL_CTX_set_keylog_callback. */
+void         modssl_callback_keylog(const SSL *ssl, const char *line);
+#endif
+
 /**  I/O  */
 void         ssl_io_filter_init(conn_rec *, request_rec *r, SSL *);
 void         ssl_io_filter_register(apr_pool_t *);