Validate downloaded file integrity and raise ValueError on hash mismatch

monai/apps/utils.py

@@ -220,17 +220,16 @@ def download_url(
         HTTPError: See urllib.request.urlretrieve.
         ContentTooShortError: See urllib.request.urlretrieve.
         IOError: See urllib.request.urlretrieve.
-        RuntimeError: When the hash validation of the ``url`` downloaded file fails.
-
+        ValueError: When the hash validation of the ``url`` downloaded file fails.
     """
     if not filepath:
         filepath = Path(".", _basename(url)).resolve()
         logger.info(f"Default downloading to '{filepath}'")
     filepath = Path(filepath)
     if filepath.exists():
         if not check_hash(filepath, hash_val, hash_type):
-            raise RuntimeError(
-                f"{hash_type} check of existing file failed: filepath={filepath}, expected {hash_type}={hash_val}."
+            raise ValueError(
+                f"{hash_type} hash check of existing file failed: filepath={filepath}, expected {hash_type}={hash_val}."
             )
         logger.info(f"File exists: {filepath}, skipped downloading.")
         return
@@ -260,18 +259,20 @@ def download_url(
                 raise RuntimeError(
                     f"Download of file from {url} to {filepath} failed due to network issue or denied permission."
                 )
+            if not check_hash(tmp_name, hash_val, hash_type):
+                raise ValueError(
+                    f"{hash_type} hash check of downloaded file failed: URL={url}, "
+                    f"filepath={filepath}, expected {hash_type}={hash_val}, "
+                    f"The file may be corrupted or tampered with. "
+                    "Please retry the download or verify the source."
+                )
             file_dir = filepath.parent
             if file_dir:
                 os.makedirs(file_dir, exist_ok=True)
             shutil.move(f"{tmp_name}", f"{filepath}")  # copy the downloaded to a user-specified cache.
     except (PermissionError, NotADirectoryError):  # project-monai/monai issue #3613 #3757 for windows
         pass
     logger.info(f"Downloaded: {filepath}")
-    if not check_hash(filepath, hash_val, hash_type):
-        raise RuntimeError(
-            f"{hash_type} check of downloaded file failed: URL={url}, "
-            f"filepath={filepath}, expected {hash_type}={hash_val}."
-        )
 
 
 def _extract_zip(filepath, output_dir):

tests/apps/test_download_and_extract.py

@@ -42,10 +42,10 @@ def test_actions(self):
         with self.assertLogs(logger="monai.apps", level="ERROR"):
             try:
                 download_url(url, filepath, wrong_md5)
-            except (ContentTooShortError, HTTPError, RuntimeError) as e:
-                if isinstance(e, RuntimeError):
+            except (ContentTooShortError, HTTPError, ValueError, RuntimeError) as e:
+                if isinstance(e, ValueError):
                     # FIXME: skip MD5 check as current downloading method may fail
-                    self.assertTrue(str(e).startswith("md5 check"))
+                    self.assertIn("hash check", str(e))
                 return  # skipping this test due the network connection errors
 
         try:

tests/test_utils.py

@@ -79,7 +79,7 @@
     "unexpected EOF",  # incomplete download
     "network issue",
     "gdown dependency",  # gdown not installed
-    "md5 check",
+    "hash check",  # check hash value of downloaded file
     "limit",  # HTTP Error 503: Egress is over the account limit
     "authenticate",
     "timed out",  # urlopen error [Errno 110] Connection timed out
@@ -182,6 +182,39 @@ def skip_if_downloading_fails():
             raise unittest.SkipTest(f"Error while downloading: {rt_e}") from rt_e  # incomplete download
 
         raise rt_e
+    except ValueError as v_e:
+        if "hash check" in str(v_e):
+            raise unittest.SkipTest(f"Hash value error while downloading: {v_e}") from v_e
+
+        raise v_e
+
+
+SAMPLE_TIFF = "https://huggingface.co/datasets/MONAI/testing_data/resolve/main/CMU-1.tiff"
+SAMPLE_TIFF_HASH = "73a7e89bc15576587c3d68e55d9bf92f09690280166240b48ff4b48230b13bcd"
+SAMPLE_TIFF_HASH_TYPE = "sha256"
+
+
+class TestDownloadUrl(unittest.TestCase):
+    """Exercise ``download_url`` success and hash-mismatch paths."""
+
+    def test_download_url(self):
+        """
+        Download a sample TIFF and validate hash handling.
+        """
+        with tempfile.TemporaryDirectory() as tempdir:
+            model_path = os.path.join(tempdir, "model.tiff")
+
+            with skip_if_downloading_fails():
+                download_url(
+                    url=SAMPLE_TIFF, filepath=model_path, hash_val=SAMPLE_TIFF_HASH, hash_type=SAMPLE_TIFF_HASH_TYPE
+                )
+
+            # Verify file exists before testing hash mismatch
+            if not os.path.exists(model_path):
+                self.skipTest("File was not downloaded successfully")
+
+            with self.assertRaises(ValueError):
+                download_url(url=SAMPLE_TIFF, filepath=model_path, hash_val="0" * 64, hash_type=SAMPLE_TIFF_HASH_TYPE)
 
 
 SAMPLE_TIFF = "https://huggingface.co/datasets/MONAI/testing_data/resolve/main/CMU-1.tiff"