1 files changed, 86 insertions, 0 deletions
diff --git a/jail/preload.c b/jail/preload.c
new file mode 100644
index 0000000..97ac44d
--- /dev/null
+++ b/jail/preload.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2015 John Crispin <blogic@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <dlfcn.h>
+#include <syslog.h>
+
+#include "seccomp.h"
+#include "../preload.h"
+
+static main_t __main__;
+
+static int __preload_main__(int argc, char **argv, char **envp)
+{
+	uid_t uid = getuid();
+	char *env_file = getenv("SECCOMP_FILE");
+
+	if (uid) {
+		INFO("preload-seccomp: %s: not root, cannot install seccomp filter\n", *argv);
+		return -1;
+	}
+
+	if (install_syscall_filter(*argv, env_file))
+		return -1;
+
+	unsetenv("LD_PRELOAD");
+	unsetenv("SECCOMP_FILE");
+
+	return (*__main__)(argc, argv, envp);
+}
+
+int __libc_start_main(main_t main,
+			int argc,
+			char **argv,
+			ElfW(auxv_t) *auxvec,
+			__typeof (main) init,
+			void (*fini) (void),
+			void (*rtld_fini) (void),
+			void *stack_end)
+{
+	start_main_t __start_main__;
+
+	__start_main__ = dlsym(RTLD_NEXT, "__libc_start_main");
+	if (!__start_main__)
+		INFO("failed to find __libc_start_main %s\n", dlerror());
+
+	__main__ = main;
+
+	return (*__start_main__)(__preload_main__, argc, argv, auxvec,
+		init, fini, rtld_fini, stack_end);
+}
+
+void __uClibc_main(main_t main,
+			int argc,
+			char **argv,
+			void (*app_init)(void),
+			void (*app_fini)(void),
+			void (*rtld_fini)(void),
+			void *stack_end attribute_unused)
+{
+	uClibc_main __start_main__;
+
+	__start_main__ = dlsym(RTLD_NEXT, "__uClibc_main");
+	if (!__start_main__)
+		INFO("failed to find __uClibc_main %s\n", dlerror());
+
+	__main__ = main;
+
+	return (*__start_main__)(__preload_main__, argc, argv,
+		app_init, app_fini, rtld_fini, stack_end);
+}