Files
openswarm/openswarm-edge/app/sandbox.py
T

91 lines
3.5 KiB
Python

"""Sandboxed Python runner for published apps' backend.py compute.
VENDORED from backend/apps/outputs/executor.py (the desktop App Builder runtime).
Keep the subprocess hardening in sync with that file; this is the same
data-shaping sandbox, just running in the edge instead of on the desktop. The
static gate it runs on every call lives in the vendored app/code_safety.py. Pure
compute only: no network, no disk, no subprocess, no secrets. Safe to run
multi-tenant on one machine because nothing here can reach shared state."""
from __future__ import annotations
import asyncio
import json
import os
import sys
import tempfile
from dataclasses import dataclass
from app.code_safety import ALLOWED_MODULES, validate_code_safety
TIMEOUT_SECONDS = 30
def _minimal_env() -> dict:
return {
"PYTHONDONTWRITEBYTECODE": "1",
"LANG": os.environ.get("LANG", "C.UTF-8"),
"LC_ALL": os.environ.get("LC_ALL", "C.UTF-8"),
"PYTHONUTF8": "1",
"PYTHONIOENCODING": "utf-8",
}
@dataclass
class ComputeResult:
result: dict
stdout: str
async def run_backend(code: str, input_data: dict) -> ComputeResult:
"""Validate + execute user backend code in a hardened subprocess. The code
reads `input_data` (a global dict) and assigns a global `result` dict."""
validate_code_safety(code)
preamble = (
"import json, sys, io, builtins\n"
"p_stdout = sys.stdout\n"
"p_capture = io.StringIO()\n"
"sys.stdout = p_capture\n"
"input_data = json.loads(sys.stdin.read())\n"
"result = {}\n"
# Warm the allowlist BEFORE scrubbing builtins: half the stdlib borrows the builtins the scrub deletes while it loads (tokenize does `from builtins import open`, taking `import dataclasses` with it). Then the module handles go, because leaving `sys` bound hands gate-passing code a live `sys.modules['os']` with no import statement in sight.
f"for p_name in {tuple(sorted(ALLOWED_MODULES))!r}:\n"
" try: __import__(p_name)\n"
" except ImportError: pass\n"
"for p_name in ('open','input','breakpoint','exit','quit'):\n"
" try: delattr(builtins, p_name)\n"
" except AttributeError: pass\n"
"del sys, io, builtins, p_name\n"
)
postamble = (
"\np_stdout.write(json.dumps({\"__stdout__\": p_capture.getvalue(), \"__result__\": result}))\n"
)
wrapper = preamble + code + postamble
with tempfile.TemporaryDirectory(prefix="osw-edge-exec-") as workdir:
proc = await asyncio.create_subprocess_exec(
sys.executable, "-c", wrapper,
stdin=asyncio.subprocess.PIPE,
stdout=asyncio.subprocess.PIPE,
stderr=asyncio.subprocess.PIPE,
cwd=workdir,
env=_minimal_env(),
)
try:
stdout, stderr = await asyncio.wait_for(
proc.communicate(input=json.dumps(input_data).encode()),
timeout=TIMEOUT_SECONDS,
)
except asyncio.TimeoutError:
proc.kill()
await proc.wait()
raise RuntimeError(f"compute timed out after {TIMEOUT_SECONDS}s")
if proc.returncode != 0:
raise RuntimeError(f"compute failed: {stderr.decode(errors='replace').strip()[:500]}")
try:
parsed = json.loads(stdout.decode())
except json.JSONDecodeError:
raise RuntimeError("compute did not return valid JSON")
return ComputeResult(result=parsed.get("__result__", {}), stdout=parsed.get("__stdout__", ""))