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bpo-35907, CVE-2019-9948: urllib rejects local_file:// scheme #13474

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Merged
merged 1 commit into from
May 22, 2019
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bpo-35907, CVE-2019-9948: urllib rejects local_file:// scheme #13474

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13 changes: 13 additions & 0 deletions Lib/test/test_urllib.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1481,6 +1481,19 @@ def test_urlopener_retrieve_remote(self):
filename, _ = urllib.request.URLopener().retrieve(url)
self.assertEqual(os.path.splitext(filename)[1], ".txt")

@support.ignore_warnings(category=DeprecationWarning)
def test_local_file_open(self):
# bpo-35907, CVE-2019-9948: urllib must reject local_file:// scheme
class DummyURLopener(urllib.request.URLopener):
def open_local_file(self, url):
return url
for url in ('local_file://example', 'local-file://example'):
self.assertRaises(OSError, urllib.request.urlopen, url)
self.assertRaises(OSError, urllib.request.URLopener().open, url)
self.assertRaises(OSError, urllib.request.URLopener().retrieve, url)
self.assertRaises(OSError, DummyURLopener().open, url)
self.assertRaises(OSError, DummyURLopener().retrieve, url)


# Just commented them out.
# Can't really tell why keep failing in windows and sparc.
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2 changes: 1 addition & 1 deletion Lib/urllib/request.py
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Expand Up @@ -1745,7 +1745,7 @@ def open(self, fullurl, data=None):
name = 'open_' + urltype
self.type = urltype
name = name.replace('-', '_')
if not hasattr(self, name):
if not hasattr(self, name) or name == 'open_local_file':
if proxy:
return self.open_unknown_proxy(proxy, fullurl, data)
else:
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Security/2019-05-21-23-20-18.bpo-35907.NC_zNK.rst
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@@ -0,0 +1,2 @@
CVE-2019-9948: Avoid file reading as disallowing the unnecessary URL scheme in
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@gpshead gpshead May 22, 2019 •
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This text doesn't make sense as written. "as disallowing the unnecessary URL scheme" says nothing. WHAT url scheme did we just break our users applications by refusing to support? Those need to be listed in the NEWS entry.

CVE-2019-9948: Drop support for the unintended local_file:// URL scheme in ...

``URLopener().open()`` ``URLopener().retrieve()`` of :mod:`urllib.request`.