Store reroute.py

diff --git a/linux/reroute.py b/linux/reroute.py
new file mode 100755 (executable)
index 0000000..db1a16a
--- /dev/null
+++ b/linux/reroute.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+
+DESCRIPTION = """
+This script runs a command with a different network configuration using firejail.
+
+THIS MIGHT BE UNSAFE. USE AT YOUR OWN CAUTION:
+
+* Input might not be correctly validated.
+* Use of firejail might not be correct.
+"""
+
+import argparse
+import pathlib
+import shlex
+import subprocess
+import tempfile
+import textwrap
+
+
+def main():
+    parser = argparse.ArgumentParser(description=DESCRIPTION)
+
+    parser.add_argument("network_interface")
+    parser.add_argument("dns")
+    parser.add_argument("gateway")
+    parser.add_argument("ip")
+    parser.add_argument("command", nargs="+")
+
+    parser.add_argument("--route", nargs="*", help="destination,gateway")
+
+    args = parser.parse_args()
+
+    routes = "".join([_make_route(r) for r in args.route])
+
+    command = shlex.join(args.command)
+
+    with tempfile.TemporaryDirectory() as tempdir:
+        script = pathlib.Path(tempdir) / "script"
+
+        script.write_text(textwrap.dedent(
+            f"""
+            #!/bin/sh
+
+            {routes}
+            {command}
+            """
+        ).lstrip())
+        script.chmod(0o555)
+        command = ["sudo", "firejail", f"--net={args.network_interface}", f"--dns={args.dns}", f"--defaultgw={args.gateway}", f"--ip={args.ip}", f"--whitelist={script}", "--", script]
+
+        subprocess.run(command, check=True)
+
+
+def _make_route(argument):
+    destination, gateway = argument.split(",")
+    return shlex.join(["ip", "route", "add", destination, "via", gateway, "dev", "eth0"])
+
+if __name__ == "__main__":
+    main()