Merge pull request #5872 from radarhere/safe_read

This commit is contained in:
Hugo van Kemenade 2021-12-07 15:30:56 +02:00 committed by GitHub
commit 421e7f3c5a
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2 changed files with 19 additions and 4 deletions

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@ -2,7 +2,7 @@ from io import BytesIO
import pytest
from PIL import EpsImagePlugin, Image, ImageFile, features
from PIL import BmpImagePlugin, EpsImagePlugin, Image, ImageFile, _binary, features
from .helper import (
assert_image,
@ -111,6 +111,20 @@ class TestImageFile:
with pytest.raises(OSError):
p.close()
def test_truncated(self):
b = BytesIO(
b"BM000000000000" # head_data
+ _binary.o32le(
ImageFile.SAFEBLOCK + 1 + 4
) # header_size, so BmpImagePlugin will try to read SAFEBLOCK + 1 bytes
+ (
b"0" * ImageFile.SAFEBLOCK
) # only SAFEBLOCK bytes, so that the header is truncated
)
with pytest.raises(OSError) as e:
BmpImagePlugin.BmpImageFile(b)
assert str(e.value) == "Truncated File Read"
@skip_unless_feature("zlib")
def test_truncated_with_errors(self):
with Image.open("Tests/images/truncated_image.png") as im:

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@ -545,12 +545,13 @@ def _safe_read(fp, size):
raise OSError("Truncated File Read")
return data
data = []
while size > 0:
block = fp.read(min(size, SAFEBLOCK))
remaining_size = size
while remaining_size > 0:
block = fp.read(min(remaining_size, SAFEBLOCK))
if not block:
break
data.append(block)
size -= len(block)
remaining_size -= len(block)
if sum(len(d) for d in data) < size:
raise OSError("Truncated File Read")
return b"".join(data)