diff --git a/Lib/tarfile.py b/Lib/tarfile.py index e3747e9c79c..0f9d1dade18 100644 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -760,9 +760,8 @@ class _FileInFile(object): self.map_index = 0 length = min(size, stop - self.position) if data: - self.fileobj.seek(offset) - block = self.fileobj.read(stop - start) - buf += block[self.position - start:self.position + length] + self.fileobj.seek(offset + (self.position - start)) + buf += self.fileobj.read(length) else: buf += NUL * length size -= length diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 94ef61c0ce7..68e094d5dbc 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -419,6 +419,22 @@ class StreamReadTest(CommonReadTest): mode="r|" + def test_read_through(self): + # Issue #11224: A poorly designed _FileInFile.read() method + # caused seeking errors with stream tar files. + for tarinfo in self.tar: + if not tarinfo.isreg(): + continue + fobj = self.tar.extractfile(tarinfo) + while True: + try: + buf = fobj.read(512) + except tarfile.StreamError: + self.fail("simple read-through using TarFile.extractfile() failed") + if not buf: + break + fobj.close() + def test_fileobj_regular_file(self): tarinfo = self.tar.next() # get "regtype" (can't use getmember) fobj = self.tar.extractfile(tarinfo) diff --git a/Misc/NEWS b/Misc/NEWS index a3a246ceb81..9dcd309312b 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -27,6 +27,10 @@ Core and Builtins Library ------- +- Issue #11224: Fixed a regression in tarfile that affected the file-like + objects returned by TarFile.extractfile() regarding performance, memory + consumption and failures with the stream interface. + - Issue #10924: Adding salt and Modular Crypt Format to crypt library. Moved old C wrapper to _crypt, and added a Python wrapper with enhanced salt generation and simpler API for password generation.