Merge pull request #1366 from uploadcare/fix-truncated-regression-from-master

Pillow fails to load truncated images with LOAD_TRUNCATED_IMAGES

PIL/ImageFile.py

@@ -33,7 +33,7 @@ import io
 import logging
 import os
 import sys
-# import traceback
+import struct
 
 logger = logging.getLogger(__name__)
 
@@ -101,7 +101,8 @@ class ImageFile(Image.Image):
         except (IndexError,  # end of data
                 TypeError,  # end of data (ord)
                 KeyError,  # unsupported mode
-                EOFError) as v:  # got header but not the first frame
+                EOFError,  # got header but not the first frame
+                struct.error) as v:
             logger.exception("%s")
             raise SyntaxError(v)
 
@@ -204,11 +205,11 @@ class ImageFile(Image.Image):
                 while True:
                     try:
                         s = read(self.decodermaxblock)
-                    except IndexError as ie:  # truncated png/gif
+                    except (IndexError, struct.error):  # truncated png/gif
                         if LOAD_TRUNCATED_IMAGES:
                             break
                         else:
-                            raise IndexError(ie)
+                            raise IOError("image file is truncated")
 
                     if not s and not d.handles_eof:  # truncated jpeg
                         self.tile = []

Tests/test_imagefile.py

@@ -79,12 +79,11 @@ class TestImageFile(PillowTestCase):
         self.assertEqual((48, 48), p.image.size)
 
     def test_safeblock(self):
-
-        im1 = hopper()
-
         if "zip_encoder" not in codecs:
             self.skipTest("PNG (zlib) encoder not available")
 
+        im1 = hopper()
+
         try:
             ImageFile.SAFEBLOCK = 1
             im2 = fromstring(tostring(im1, "PNG"))
@@ -96,6 +95,25 @@ class TestImageFile(PillowTestCase):
     def test_raise_ioerror(self):
         self.assertRaises(IOError, lambda: ImageFile.raise_ioerror(1))
 
+    def test_truncated_with_errors(self):
+        if "zip_encoder" not in codecs:
+            self.skipTest("PNG (zlib) encoder not available")
+
+        im = Image.open("Tests/images/truncated_image.png")
+        with self.assertRaises(IOError):
+            im.load()
+
+    def test_truncated_without_errors(self):
+        if "zip_encoder" not in codecs:
+            self.skipTest("PNG (zlib) encoder not available")
+
+        im = Image.open("Tests/images/truncated_image.png")
+
+        ImageFile.LOAD_TRUNCATED_IMAGES = True
+        try:
+            im.load()
+        finally:
+            ImageFile.LOAD_TRUNCATED_IMAGES = False
 
 if __name__ == '__main__':
     unittest.main()