bpo-38945: UU Encoding: Don't let newline in filename corrupt the output format (#17418)
diff --git a/Lib/encodings/uu_codec.py b/Lib/encodings/uu_codec.py
index 2a5728f..4e58c62 100644
--- a/Lib/encodings/uu_codec.py
+++ b/Lib/encodings/uu_codec.py
@@ -20,6 +20,10 @@
read = infile.read
write = outfile.write
+ # Remove newline chars from filename
+ filename = filename.replace('\n','\\n')
+ filename = filename.replace('\r','\\r')
+
# Encode
write(('begin %o %s\n' % (mode & 0o777, filename)).encode('ascii'))
chunk = read(45)
diff --git a/Lib/test/test_uu.py b/Lib/test/test_uu.py
index c9f05e5..c8709f7 100644
--- a/Lib/test/test_uu.py
+++ b/Lib/test/test_uu.py
@@ -136,6 +136,15 @@
decoded = codecs.decode(encodedtext, "uu_codec")
self.assertEqual(decoded, plaintext)
+ def test_newlines_escaped(self):
+ # Test newlines are escaped with uu.encode
+ inp = io.BytesIO(plaintext)
+ out = io.BytesIO()
+ filename = "test.txt\n\roverflow.txt"
+ safefilename = b"test.txt\\n\\roverflow.txt"
+ uu.encode(inp, out, filename)
+ self.assertIn(safefilename, out.getvalue())
+
class UUStdIOTest(unittest.TestCase):
def setUp(self):
diff --git a/Lib/uu.py b/Lib/uu.py
index 9b1e5e6..9f1f37f 100755
--- a/Lib/uu.py
+++ b/Lib/uu.py
@@ -73,6 +73,13 @@
name = '-'
if mode is None:
mode = 0o666
+
+ #
+ # Remove newline chars from name
+ #
+ name = name.replace('\n','\\n')
+ name = name.replace('\r','\\r')
+
#
# Write the data
#
diff --git a/Misc/NEWS.d/next/Security/2019-12-01-22-44-40.bpo-38945.ztmNXc.rst b/Misc/NEWS.d/next/Security/2019-12-01-22-44-40.bpo-38945.ztmNXc.rst
new file mode 100644
index 0000000..1bf6ed5
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2019-12-01-22-44-40.bpo-38945.ztmNXc.rst
@@ -0,0 +1 @@
+Newline characters have been escaped when performing uu encoding to prevent them from overflowing into to content section of the encoded file. This prevents malicious or accidental modification of data during the decoding process.
\ No newline at end of file