changeset 7973:3443c02ca1d1

SSL: $ssl_curve (ticket #2135). The variable contains a negotiated curve used for the handshake key exchange process. Known curves are listed by their names, unknown ones are shown in hex. Note that for resumed sessions in TLSv1.2 and older protocols, $ssl_curve contains the curve used during the initial handshake, while in TLSv1.3 it contains the curve used during the session resumption (see the SSL_get_negotiated_group manual page for details). The variable is only meaningful when using OpenSSL 3.0 and above. With older versions the variable is empty.
author Sergey Kandaurov <pluknet@nginx.com>
date Mon, 01 Nov 2021 18:09:34 +0300
parents 284f03d6f154
children 555533169506
files src/event/ngx_event_openssl.c src/event/ngx_event_openssl.h src/http/modules/ngx_http_ssl_module.c src/stream/ngx_stream_ssl_module.c
diffstat 4 files changed, 44 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -4734,6 +4734,42 @@ ngx_ssl_get_ciphers(ngx_connection_t *c,
 
 
 ngx_int_t
+ngx_ssl_get_curve(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
+{
+#ifdef SSL_get_negotiated_group
+
+    int  nid;
+
+    nid = SSL_get_negotiated_group(c->ssl->connection);
+
+    if (nid != NID_undef) {
+
+        if ((nid & TLSEXT_nid_unknown) == 0) {
+            s->len = ngx_strlen(OBJ_nid2sn(nid));
+            s->data = (u_char *) OBJ_nid2sn(nid);
+            return NGX_OK;
+        }
+
+        s->len = sizeof("0x0000") - 1;
+
+        s->data = ngx_pnalloc(pool, s->len);
+        if (s->data == NULL) {
+            return NGX_ERROR;
+        }
+
+        ngx_sprintf(s->data, "0x%04xd", nid & 0xffff);
+
+        return NGX_OK;
+    }
+
+#endif
+
+    s->len = 0;
+    return NGX_OK;
+}
+
+
+ngx_int_t
 ngx_ssl_get_curves(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
 {
 #ifdef SSL_CTRL_GET_CURVES
--- a/src/event/ngx_event_openssl.h
+++ b/src/event/ngx_event_openssl.h
@@ -256,6 +256,8 @@ ngx_int_t ngx_ssl_get_cipher_name(ngx_co
     ngx_str_t *s);
 ngx_int_t ngx_ssl_get_ciphers(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);
+ngx_int_t ngx_ssl_get_curve(ngx_connection_t *c, ngx_pool_t *pool,
+    ngx_str_t *s);
 ngx_int_t ngx_ssl_get_curves(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);
 ngx_int_t ngx_ssl_get_session_id(ngx_connection_t *c, ngx_pool_t *pool,
--- a/src/http/modules/ngx_http_ssl_module.c
+++ b/src/http/modules/ngx_http_ssl_module.c
@@ -342,6 +342,9 @@ static ngx_http_variable_t  ngx_http_ssl
     { ngx_string("ssl_ciphers"), NULL, ngx_http_ssl_variable,
       (uintptr_t) ngx_ssl_get_ciphers, NGX_HTTP_VAR_CHANGEABLE, 0 },
 
+    { ngx_string("ssl_curve"), NULL, ngx_http_ssl_variable,
+      (uintptr_t) ngx_ssl_get_curve, NGX_HTTP_VAR_CHANGEABLE, 0 },
+
     { ngx_string("ssl_curves"), NULL, ngx_http_ssl_variable,
       (uintptr_t) ngx_ssl_get_curves, NGX_HTTP_VAR_CHANGEABLE, 0 },
 
--- a/src/stream/ngx_stream_ssl_module.c
+++ b/src/stream/ngx_stream_ssl_module.c
@@ -269,6 +269,9 @@ static ngx_stream_variable_t  ngx_stream
     { ngx_string("ssl_ciphers"), NULL, ngx_stream_ssl_variable,
       (uintptr_t) ngx_ssl_get_ciphers, NGX_STREAM_VAR_CHANGEABLE, 0 },
 
+    { ngx_string("ssl_curve"), NULL, ngx_stream_ssl_variable,
+      (uintptr_t) ngx_ssl_get_curve, NGX_STREAM_VAR_CHANGEABLE, 0 },
+
     { ngx_string("ssl_curves"), NULL, ngx_stream_ssl_variable,
       (uintptr_t) ngx_ssl_get_curves, NGX_STREAM_VAR_CHANGEABLE, 0 },