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.

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index 84afecd0bf436932173986eec84e8f546ebfb150..b03ca59ae4194ec64c9e74513b2edb9e00298250 100644 (file)
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -4733,6 +4733,42 @@ 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)
+{
+#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)
 {

diff --git a/src/event/ngx_event_openssl.h b/src/event/ngx_event_openssl.h
index 4afdfad483ca785acb2236ff96837a16b5708a05..c9e86d9c0c899d82ac938f17e6425883e8f0c9cc 100644 (file)
--- 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_connection_t *c, ngx_pool_t *pool,
     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,

diff --git a/src/http/modules/ngx_http_ssl_module.c b/src/http/modules/ngx_http_ssl_module.c
index c633f34641cfee96d3302096d979854c139158c1..d74d4609435f21cc8b10cbedad42e88627f86abc 100644 (file)
--- 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_vars[] = {
     { 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 },
 

diff --git a/src/stream/ngx_stream_ssl_module.c b/src/stream/ngx_stream_ssl_module.c
index 530fe8b3dc29a35dbc8bc7e00053d709af156c1b..c5308322ac5c62e8f9633f6ce12ac5bb1390f17b 100644 (file)
--- 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_ssl_vars[] = {
     { 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 },