diff --git a/Tests/test_imagefile.py b/Tests/test_imagefile.py index 1ee68492630..069ae7e5ac8 100644 --- a/Tests/test_imagefile.py +++ b/Tests/test_imagefile.py @@ -118,6 +118,26 @@ def test_safeblock(self) -> None: assert_image_equal(im1, im2) + def test_tile_size(self) -> None: + with open("Tests/images/hopper.tif", "rb") as im_fp: + data = im_fp.read() + + reads = [] + + class FP(BytesIO): + def read(self, size: int | None = None) -> bytes: + reads.append(size) + return super().read(size) + + fp = FP(data) + with Image.open(fp) as im: + assert len(im.tile) == 7 + + im.load() + + # Despite multiple tiles, assert only one tile caused a read of maxblock size + assert reads.count(im.decodermaxblock) == 1 + def test_raise_oserror(self) -> None: with pytest.warns(DeprecationWarning): with pytest.raises(OSError): diff --git a/src/PIL/ImageFile.py b/src/PIL/ImageFile.py index 9836cd68884..72a195e42fa 100644 --- a/src/PIL/ImageFile.py +++ b/src/PIL/ImageFile.py @@ -263,7 +263,7 @@ def load(self) -> Image.core.PixelAccess | None: self.tile, lambda tile: (tile[0], tile[1], tile[3]) ) ] - for decoder_name, extents, offset, args in self.tile: + for i, (decoder_name, extents, offset, args) in enumerate(self.tile): seek(offset) decoder = Image._getdecoder( self.mode, decoder_name, args, self.decoderconfig @@ -276,8 +276,13 @@ def load(self) -> Image.core.PixelAccess | None: else: b = prefix while True: + read_bytes = self.decodermaxblock + if i + 1 < len(self.tile): + next_offset = self.tile[i + 1].offset + if next_offset > offset: + read_bytes = next_offset - offset try: - s = read(self.decodermaxblock) + s = read(read_bytes) except (IndexError, struct.error) as e: # truncated png/gif if LOAD_TRUNCATED_IMAGES: