SSL: the $ssl_client_escaped_cert variable (ticket #857).

This variable contains URL-encoded client SSL certificate.  In contrast
to $ssl_client_cert, it doesn't depend on deprecated header continuation.
The NGX_ESCAPE_URI_COMPONENT variant of encoding is used, so the resulting
variable can be safely used not only in headers, but also as a request
argument.

The $ssl_client_cert variable should be considered deprecated now.
The $ssl_client_raw_cert variable will be eventually renambed back
to $ssl_client_cert.

src/event/ngx_event_openssl.c

@@ -3662,6 +3662,36 @@ ngx_ssl_get_certificate(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
 }
 
 
+ngx_int_t
+ngx_ssl_get_escaped_certificate(ngx_connection_t *c, ngx_pool_t *pool,
+    ngx_str_t *s)
+{
+    ngx_str_t  cert;
+    uintptr_t  n;
+
+    if (ngx_ssl_get_raw_certificate(c, pool, &cert) != NGX_OK) {
+        return NGX_ERROR;
+    }
+
+    if (cert.len == 0) {
+        s->len = 0;
+        return NGX_OK;
+    }
+
+    n = ngx_escape_uri(NULL, cert.data, cert.len, NGX_ESCAPE_URI_COMPONENT);
+
+    s->len = cert.len + n * 2;
+    s->data = ngx_pnalloc(pool, s->len);
+    if (s->data == NULL) {
+        return NGX_ERROR;
+    }
+
+    ngx_escape_uri(s->data, cert.data, cert.len, NGX_ESCAPE_URI_COMPONENT);
+
+    return NGX_OK;
+}
+
+
 ngx_int_t
 ngx_ssl_get_subject_dn(ngx_connection_t *c, ngx_pool_t *pool, ngx_str_t *s)
 {

src/event/ngx_event_openssl.h

@@ -212,6 +212,8 @@ ngx_int_t ngx_ssl_get_raw_certificate(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);
 ngx_int_t ngx_ssl_get_certificate(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);
+ngx_int_t ngx_ssl_get_escaped_certificate(ngx_connection_t *c, ngx_pool_t *pool,
+    ngx_str_t *s);
 ngx_int_t ngx_ssl_get_subject_dn(ngx_connection_t *c, ngx_pool_t *pool,
     ngx_str_t *s);
 ngx_int_t ngx_ssl_get_issuer_dn(ngx_connection_t *c, ngx_pool_t *pool,

src/http/modules/ngx_http_ssl_module.c

@@ -299,6 +299,10 @@ static ngx_http_variable_t  ngx_http_ssl_vars[] = {
       (uintptr_t) ngx_ssl_get_raw_certificate,
       NGX_HTTP_VAR_CHANGEABLE, 0 },
 
+    { ngx_string("ssl_client_escaped_cert"), NULL, ngx_http_ssl_variable,
+      (uintptr_t) ngx_ssl_get_escaped_certificate,
+      NGX_HTTP_VAR_CHANGEABLE, 0 },
+
     { ngx_string("ssl_client_s_dn"), NULL, ngx_http_ssl_variable,
       (uintptr_t) ngx_ssl_get_subject_dn, NGX_HTTP_VAR_CHANGEABLE, 0 },
 

src/stream/ngx_stream_ssl_module.c

@@ -249,6 +249,10 @@ static ngx_stream_variable_t  ngx_stream_ssl_vars[] = {
       (uintptr_t) ngx_ssl_get_raw_certificate,
       NGX_STREAM_VAR_CHANGEABLE, 0 },
 
+    { ngx_string("ssl_client_escaped_cert"), NULL, ngx_stream_ssl_variable,
+      (uintptr_t) ngx_ssl_get_escaped_certificate,
+      NGX_STREAM_VAR_CHANGEABLE, 0 },
+
     { ngx_string("ssl_client_s_dn"), NULL, ngx_stream_ssl_variable,
       (uintptr_t) ngx_ssl_get_subject_dn, NGX_STREAM_VAR_CHANGEABLE, 0 },