Remove max_file_size option

It breaks dotnet, and it was not secure anyways; quotas are a better
replacement.

Author: prandla

cms/conf.py

@@ -98,8 +98,6 @@ class FSQuotaSettings:
 @dataclass()
 class SandboxConfig:
     sandbox_implementation: str = "isolate"
-    # Max size of each writable file during an evaluation step, in KiB.
-    max_file_size: int = 1024 * 1024  # 1 GiB
     fs_quota: FSQuotaSettings | None = None
     # Max processes, CPU time (s), memory (KiB) for compilation runs.
     compilation_sandbox_max_processes: int = 1000

cms/grading/Sandbox.py

@@ -265,7 +265,6 @@ def __init__(
         self.preserve_env = False  # -e
         self.inherit_env: list[str] = []  # -E
         self.set_env: dict[str, str] = {}  # -E
-        self.fsize: int | None = None  # -f
         self.stdin_file: str | int | None = None  # -i
         self.stdout_file: str | int | None = None  # -o
         self.stderr_file: str | int | None = None  # -r
@@ -801,9 +800,6 @@ def build_box_options(self) -> list[str]:
             res += ["--env=%s" % var]
         for var, value in self.set_env.items():
             res += ["--env=%s=%s" % (var, value)]
-        if self.fsize is not None:
-            # Isolate wants file size as KiB.
-            res += ["--fsize=%d" % (self.fsize // 1024)]
         if isinstance(self.stdin_file, str):
             res += ["--stdin=%s" % self.inner_absolute_path(self.stdin_file)]
         if self.stack_space is not None:

cms/grading/steps/evaluation.py

@@ -196,9 +196,6 @@ def evaluation_step_before_run(
     else:
         sandbox.address_space = None
 
-    # config.sandbox.max_file_size is in KiB
-    sandbox.fsize = config.sandbox.max_file_size * 1024
-
     sandbox.stdin_file = stdin_redirect
     sandbox.stdout_file = stdout_redirect
     sandbox.stderr_file = "stderr.txt"

cmstestsuite/Tests.py

@@ -520,13 +520,6 @@
          languages=(LANG_C,),
          checks=[CheckOverallScore(0, 100)]),
 
-    # Write a huge file
-
-    Test('write-big-fileio',
-         task=batch_fileio, filenames=['write-big-fileio.%l'],
-         languages=(LANG_C,),
-         checks=[CheckOverallScore(0, 100)]),
-
 ]
 
 # TODO figure out a better way to enable/disable this.........

cmstestsuite/code/write-big-fileio.c

@@ -79,12 +79,6 @@ twophase_commit = false
 
 
 [sandbox]
-# Do not allow contestants' solutions to write files bigger than this
-# size (expressed in KB; defaults to 1 GB).
-# Note that this alone isn't secure; solutions can create multiple files
-# in the sandbox.
-max_file_size = 1_048_576
-
 # If these are set, enforce a filesystem quota on sandboxes. Note that:
 # (1) The file system that stores isolate boxes (box_root in isolate's
 #     config file) must have quota accounting enabled (for a tmpfs,