Add a basic seccomp2 syscall filter on Linux

It's controlled by the new Sandbox argument.  Right now, it's rather
coarse-grained, it's Linux-only, and it may break some features.

1 files changed, 55 insertions, 0 deletions

diff --git a/src/common/sandbox.h b/src/common/sandbox.h
new file mode 100644
index 000000000..bd6f0cfb4
--- /dev/null
+++ b/src/common/sandbox.h
@@ -0,0 +1,55 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2013, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file sandbox.h
+ * \brief Header file for sandbox.c.
+ **/
+
+#ifndef SANDBOX_H_
+#define SANDBOX_H_
+
+#ifndef SYS_SECCOMP
+
+/**
+ * Used by SIGSYS signal handler to check if the signal was issued due to a
+ * seccomp2 filter violation.
+ */
+#define SYS_SECCOMP 1
+
+#endif
+
+/**
+ * Linux definitions
+ */
+#ifdef __linux__
+
+#define __USE_GNU
+#include <sys/ucontext.h>
+
+/**
+ * Linux 32 bit definitions
+ */
+#if defined(__i386__)
+
+#define REG_SYSCALL REG_EAX
+
+/**
+ * Linux 64 bit definitions
+ */
+#elif defined(__x86_64__)
+
+#define REG_SYSCALL REG_RAX
+
+#endif
+
+#endif // __linux__
+
+void sandbox_set_debugging_fd(int fd);
+int tor_global_sandbox(void);
+
+#endif /* SANDBOX_H_ */
+