Implement async. comm. with Python interpreter

Creating, destroying and communicationg with the interpreter subprocess
is now handled by a thread attached to PythonSession. Interpreter is
sandboxed using libseccomp.

1 files changed, 40 insertions, 0 deletions

diff --git a/python/interpreter.py b/python/interpreter.py
new file mode 100755
index 0000000..87de3aa
--- /dev/null
+++ b/python/interpreter.py
@@ -0,0 +1,40 @@
+#!/usr/bin/python3
+
+import code
+import sys
+
+import seccomp
+
+f = seccomp.SyscallFilter(defaction=seccomp.KILL)
+# Necessary for Python.
+f.add_rule(seccomp.ALLOW, "exit_group")
+f.add_rule(seccomp.ALLOW, "rt_sigaction")
+f.add_rule(seccomp.ALLOW, "brk")
+
+# Mostly harmless.
+f.add_rule(seccomp.ALLOW, "mprotect")
+
+# Allow reading from stdin and writing to stdout/stderr.
+f.add_rule(seccomp.ALLOW, "read", seccomp.Arg(0, seccomp.EQ, sys.stdin.fileno()))
+f.add_rule(seccomp.ALLOW, "write", seccomp.Arg(0, seccomp.EQ, sys.stdout.fileno()))
+f.add_rule(seccomp.ALLOW, "write", seccomp.Arg(0, seccomp.EQ, sys.stderr.fileno()))
+
+f.add_rule(seccomp.ALLOW, "ioctl")
+f.add_rule(seccomp.ALLOW, "mmap")
+f.add_rule(seccomp.ALLOW, "munmap")
+
+# Needed for finding source code for exceptions.
+f.add_rule(seccomp.ALLOW, "stat")
+f.add_rule(seccomp.ALLOW, "open", seccomp.Arg(1, seccomp.MASKED_EQ, 0x3, 0))
+f.add_rule(seccomp.ALLOW, "fcntl")
+f.add_rule(seccomp.ALLOW, "fstat")
+f.add_rule(seccomp.ALLOW, "lseek")
+f.add_rule(seccomp.ALLOW, "read")
+f.add_rule(seccomp.ALLOW, "close")
+
+# Needed for code.InteractiveConsole.
+f.add_rule(seccomp.ALLOW, "access")
+f.add_rule(seccomp.ALLOW, "select")
+f.load()
+
+code.interact(banner='')