Public bug reported:
The python2 version of pillow in bionic (python-pil 5.1.0-1ubuntu0.6)
included debian/patches/CVE-2021-28675.patch includes has the following:
```
--- a/src/PIL/ImageFile.py
+++ b/src/PIL/ImageFile.py
@@ -522,12 +522,18 @@ def _safe_read(fp, size):
:param fp: File handle. Must implement a <b>read</b> method.
:param size: Number of bytes to read.
- :returns: A string containing up to <i>size</i> bytes of data.
+ :returns: A string containing <i>size</i> bytes of data.
+
+ Raises an OSError if the file is truncated and the read can not be
completed
+
"""
if size <= 0:
return b""
if size <= SAFEBLOCK:
- return fp.read(size)
+ data = fp.read(size)
+ if len(data) < size:
+ raise OSError("Truncated File Read")
+ return data
data = []
while size > 0:
block = fp.read(min(size, SAFEBLOCK))
@@ -535,6 +541,8 @@ def _safe_read(fp, size):
break
data.append(block)
size -= len(block)
+ if sum(len(d) for d in data) < size:
+ raise OSError("Truncated File Read")
return b"".join(data)
```
However, further up in the file in the `feed` method we have:
```
# attempt to open this file
try:
with io.BytesIO(self.data) as fp:
im = Image.open(fp)
except IOError:
# traceback.print_exc()
pass # not enough data
```
In the python3 version of this file the IOError has already been changed
to OSError but not so here.
In my local copy of /usr/lib/python2.7/dist-packages/PIL/ImageFile.py
I've changed line 392 from `except IOError:` to `except (IOError,
OSError):` and I can confirm this has fixed the issues I've been seeing
since the release of 5.1.0-1ubuntu0.6 (tracebacks with
`OSError("Truncated File Read")`).
I've tried running the test suite locally (with `make test`) to submit a
patch, but I'm getting lots of unrelated failures in tests (missing
pytest imports, file comparisons not matching, etc.). Happy to provide
more detail on that if appropriate.
** Affects: pillow (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1933983
Title:
5.1.0-1ubuntu0.6 on bionic (python2) can fail on Parser.feed(data) due
to OSError
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