diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index 8f5ea31..9935fb0 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -2504,32 +2504,22 @@
 ngx_ssl_get_session_id(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
 {
     int           len;
-    u_char       *p, *buf;
+    u_char       *buf;
     SSL_SESSION  *sess;
 
     sess = SSL_get0_session(c->ssl->connection);
 
-    len = i2d_SSL_SESSION(sess, NULL);
-
-    buf = ngx_alloc(len, c->log);
-    if (buf == NULL) {
-        return NGX_ERROR;
-    }
+    buf = sess->session_id;
+    len = sess->session_id_length;
 
     s->len = 2 * len;
     s->data = ngx_pnalloc(pool, 2 * len);
     if (s->data == NULL) {
-        ngx_free(buf);
         return NGX_ERROR;
     }
 
-    p = buf;
-    i2d_SSL_SESSION(sess, &p);
-
     ngx_hex_dump(s->data, buf, len);
 
-    ngx_free(buf);
-
     return NGX_OK;
 }