clients: add a helper function to get required openconnect VPN secrets

OpenConnect needs three secrets - COOKIE, HOST and FINGERPRINT. They can be
obtained by authenticating to the server. This can be performed by running
"openconnect --authenticate <host>" and the three values are printed to stdout.

Note that the function may (probably will) interactively ask user for
his credentials.

Alternatively, it would be possible to dlopen() libopenconnect and call its
functions. However, as that would be more complicated and would also require
implementing functionality that openconnect simply does for free for us, it is
not worth it, I think.

clients/common/nm-vpn-helpers.c

@@ -29,6 +29,7 @@
 #include <gmodule.h>
 
 #include "nm-default.h"
+#include "nm-utils.h"
 #include "nm-vpn-helpers.h"
 
 #include "nm-macros-internal.h"
@@ -137,3 +138,80 @@ nm_vpn_get_secret_names (const char *vpn_type)
 	return NULL;
 }
 
+static gboolean
+_extract_variable_value (char *line, const char *tag, char **value)
+{
+	char *p1, *p2;
+
+	if (g_str_has_prefix (line, tag)) {
+		p1 = line + strlen (tag);
+		p2 = line + strlen (line) - 1;
+		if ((*p1 == '\'' || *p1 == '"') && (*p1 == *p2)) {
+			p1++;
+			*p2 = '\0';
+		}
+		if (value)
+			*value = g_strdup (p1);
+		return TRUE;
+	}
+	return FALSE;
+}
+
+gboolean
+nm_vpn_openconnect_authenticate_helper (const char *host,
+                                        char **cookie,
+                                        char **gateway,
+                                        char **gwcert,
+                                        int *status,
+                                        GError **error)
+{
+	char *output = NULL;
+	gboolean ret;
+	char **strv = NULL, **iter;
+	char *argv[4];
+	const char *path;
+	const char *const DEFAULT_PATHS[] = {
+		"/sbin/",
+		"/usr/sbin/",
+		"/usr/local/sbin/",
+		"/bin/",
+		"/usr/bin/",
+		"/usr/local/bin/",
+		NULL,
+	};
+
+	path = nm_utils_file_search_in_paths ("openconnect", "/usr/sbin/openconnect", DEFAULT_PATHS,
+	                                      G_FILE_TEST_IS_EXECUTABLE, NULL, NULL, error);
+	if (!path)
+		return FALSE;
+
+	argv[0] = (char *) path;
+	argv[1] = "--authenticate";
+	argv[2] = (char *) host;
+	argv[3] = NULL;
+
+	ret = g_spawn_sync (NULL, argv, NULL,
+	                    G_SPAWN_SEARCH_PATH | G_SPAWN_CHILD_INHERITS_STDIN,
+	                    NULL, NULL,  &output, NULL,
+	                    status, error);
+
+	if (!ret)
+		return FALSE;
+
+	/* Parse output and set cookie, gateway and gwcert
+	 * output example:
+	 * COOKIE='loremipsum'
+	 * HOST='1.2.3.4'
+	 * FINGERPRINT='sha1:32bac90cf09a722e10ecc1942c67fe2ac8c21e2e'
+	 */
+	strv = g_strsplit_set (output ? output : "", "\r\n", 0);
+	for (iter = strv; iter && *iter; iter++) {
+		_extract_variable_value (*iter, "COOKIE=", cookie);
+		_extract_variable_value (*iter, "HOST=", gateway);
+		_extract_variable_value (*iter, "FINGERPRINT=", gwcert);
+	}
+	g_strfreev (strv);
+
+	return TRUE;
+}
+

clients/common/nm-vpn-helpers.h

@@ -36,4 +36,11 @@ gboolean nm_vpn_supports_ipv6 (NMConnection *connection);
 
 const VpnPasswordName * nm_vpn_get_secret_names (const char *vpn_type);
 
+gboolean nm_vpn_openconnect_authenticate_helper (const char *host,
+                                                 char **cookie,
+                                                 char **gateway,
+                                                 char **gwcert,
+                                                 int *status,
+                                                 GError **error);
+
 #endif  /* __NM_VPN_HELPERS_H__ */