From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 2 Dec 2019 22:43:15 +0000 (-0800)
Subject: bpo-38945: UU Encoding: Don't let newline in filename corrupt the output format ... 
X-Git-Tag: v3.7.6rc1~18
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=87f2d261ee1c63ed39517355833d087c5a78b4bf;p=thirdparty%2FPython%2Fcpython.git

bpo-38945: UU Encoding: Don't let newline in filename corrupt the output format (GH-17418)

(cherry picked from commit a62ad4730c9b575f140f24074656c0257c86a09a)

Co-authored-by: Matthew Rollings <1211162+stealthcopter@users.noreply.github.com>
---

diff --git a/Lib/encodings/uu_codec.py b/Lib/encodings/uu_codec.py
index 2a5728fb5b74..4e58c62fe9ef 100644
--- a/Lib/encodings/uu_codec.py
+++ b/Lib/encodings/uu_codec.py
@@ -20,6 +20,10 @@ def uu_encode(input, errors='strict', filename='<data>', mode=0o666):
     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 c9f05e5b760d..c8709f7a0d66 100644
--- a/Lib/test/test_uu.py
+++ b/Lib/test/test_uu.py
@@ -136,6 +136,15 @@ class UUTest(unittest.TestCase):
                 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 9b1e5e607207..9f1f37f1a641 100755
--- a/Lib/uu.py
+++ b/Lib/uu.py
@@ -73,6 +73,13 @@ def encode(in_file, out_file, name=None, mode=None, *, backtick=False):
             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 000000000000..1bf6ed567b24
--- /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