island: Move file_has_expected_permissions() to file_utils.py

Rename to `has_expected_permissions()` as
`file_has_expected_permissions()` is now reduntant.

Add unit tests

monkey/monkey_island/cc/server_utils/file_utils.py

@@ -3,3 +3,10 @@ import os
 
 def expand_path(path: str) -> str:
     return os.path.expandvars(os.path.expanduser(path))
+
+
+def has_expected_permissions(path: str, expected_permissions: int) -> bool:
+    file_mode = os.stat(path).st_mode
+    file_permissions = file_mode & 0o777
+
+    return file_permissions == expected_permissions

monkey/monkey_island/cc/services/utils/file_handling.py

@@ -1,6 +1,7 @@
 import os
 
 from common.utils.exceptions import InsecurePermissionsError
+from monkey_island.cc.server_utils.file_utils import has_expected_permissions
 
 
 def ensure_file_existence(file: str) -> None:
@@ -9,14 +10,7 @@ def ensure_file_existence(file: str) -> None:
 
 
 def ensure_file_permissions(file: str) -> None:
-    if not file_has_expected_permissions(path=file, expected_permissions="0o400"):
+    if not has_expected_permissions(path=file, expected_permissions="0o400"):
         raise InsecurePermissionsError(
             f"{file} has insecure permissions. Required permissions: 400. Exiting."
         )
-
-
-def file_has_expected_permissions(path: str, expected_permissions: str) -> bool:
-    file_mode = os.stat(path).st_mode
-    file_permissions = oct(file_mode & 0o777)
-
-    return file_permissions == expected_permissions

monkey/tests/unit_tests/monkey_island/cc/server_utils/test_file_utils.py

@@ -1,5 +1,7 @@
 import os
 
+import pytest
+
 from monkey_island.cc.server_utils import file_utils
 
 
@@ -15,3 +17,28 @@ def test_expand_vars(patched_home_env):
     expected_path = os.path.join(patched_home_env, "test")
 
     assert file_utils.expand_path(input_path) == expected_path
+
+
+@pytest.mark.skipif(os.name != "posix", reason="Tests Posix (not Windows) permissions.")
+def test_has_expected_permissions_true(tmpdir):
+    file_name = f"{tmpdir}/test"
+
+    create_empty_file(file_name)
+    os.chmod(file_name, 0o754)
+
+    assert file_utils.has_expected_permissions(file_name, 0o754)
+
+
+@pytest.mark.skipif(os.name != "posix", reason="Tests Posix (not Windows) permissions.")
+def test_has_expected_permissions_false(tmpdir):
+    file_name = f"{tmpdir}/test"
+
+    create_empty_file(file_name)
+    os.chmod(file_name, 0o755)
+
+    assert not file_utils.has_expected_permissions(file_name, 0o700)
+
+
+def create_empty_file(file_name):
+    with open(file_name, "w"):
+        pass