Allow setting a binary_path when calling /eval

3 files changed, 16 insertions, 6 deletions

diff --git a/config/snekbox.cfg b/config/snekbox.cfg
index b405521..33cd9e9 100644
--- a/config/snekbox.cfg
+++ b/config/snekbox.cfg
@@ -103,8 +103,3 @@ cgroup_pids_max: 6
 cgroup_pids_mount: "/sys/fs/cgroup/pids"
 
 iface_no_lo: true
-
-exec_bin {
-    path: "/lang/python/default/bin/python"
-    arg: ""
-}
diff --git a/snekbox/api/resources/eval.py b/snekbox/api/resources/eval.py
index 55bba98..98babc9 100644
--- a/snekbox/api/resources/eval.py
+++ b/snekbox/api/resources/eval.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import logging
+from pathlib import Path
 
 import falcon
 from falcon.media.validators.jsonschema import validate
@@ -43,6 +44,7 @@ class EvalResource:
                     "required": ["path"],
                 },
             },
+            "binary_path": {"type": "string"},
         },
         "anyOf": [
             {"required": ["input"]},
@@ -122,10 +124,21 @@ class EvalResource:
         if "input" in body:
             body.setdefault("args", ["-c"])
             body["args"].append(body["input"])
+
+        binary_path = body.get("binary_path")
+        if binary_path:
+            binary_path = Path(binary_path)
+            if (
+                not binary_path.resolve().as_posix().startswith("/lang/")
+                or not binary_path.is_file()
+            ):
+                raise falcon.HTTPBadRequest(title="binary_path file is invalid")
+
         try:
             result = self.nsjail.python3(
                 py_args=body["args"],
                 files=[FileAttachment.from_dict(file) for file in body.get("files", [])],
+                binary_path=binary_path,
             )
         except ParsingError as e:
             raise falcon.HTTPBadRequest(title="Request file is invalid", description=str(e))
diff --git a/tests/test_nsjail.py b/tests/test_nsjail.py
index dde20bc..2d21ad3 100644
--- a/tests/test_nsjail.py
+++ b/tests/test_nsjail.py
@@ -26,6 +26,8 @@ class NsJailTests(unittest.TestCase):
         # Hard-coded because it's non-trivial to parse the mount options.
         self.shm_mount_size = 40 * Size.MiB
 
+        self.default_binary_path = "/lang/python/default/bin/python"
+
     def eval_code(self, code: str):
         return self.nsjail.python3(["-c", code])
 
@@ -547,7 +549,7 @@ class NsJailTests(unittest.TestCase):
         for args, expected in cases:
             with self.subTest(args=args):
                 result = self.nsjail.python3(py_args=args)
-                idx = result.args.index(self.nsjail.config.exec_bin.path)
+                idx = result.args.index(self.default_binary_path)
                 self.assertEqual(result.args[idx + 1 :], expected)
                 self.assertEqual(result.returncode, 0)