From c28f0584ba37cd6b0e9919dcbec652a34a420843 Mon Sep 17 00:00:00 2001

From: Lumir Balhar <lbalhar@redhat.com>

Date: Wed, 28 Aug 2019 14:10:36 +0200

Subject: [PATCH] Backported original patch from:

 https://github.com/rthalley/dnspython/commit/c76aa6ac9969447220c8e807aa1e5640a6c12924

Unicode label escapify was not escapifying special characters. [Issue #339]

---

 dns/name.py        | 57 +++++++++++++++++++++++-----------------------

 tests/test_name.py |  5 ++++

 2 files changed, 34 insertions(+), 28 deletions(-)

diff --git a/dns/name.py b/dns/name.py

index 97e216c..4a064d6 100644

--- a/dns/name.py

+++ b/dns/name.py

@@ -116,20 +116,28 @@ class IDNACodec(object):

     def __init__(self):

         pass

+    def is_idna(self, label):

+        return label.lower().startswith(b'xn--')

+

+    def is_all_ascii(self, label):

+        for c in label:

+            if ord(c) > 0x7f:

+                return False

+        return True

+

     def encode(self, label):

         raise NotImplementedError

     def decode(self, label):

-        # We do not apply any IDNA policy on decode; we just

-        downcased = label.lower()

-        if downcased.startswith(b'xn--'):

+        # We do not apply any IDNA policy on decode.

+        if self.is_idna(label):

             try:

-                label = downcased[4:].decode('punycode')

+                label = label[4:].decode('punycode')

             except Exception as e:

                 raise IDNAException(idna_exception=e)

         else:

             label = maybe_decode(label)

-        return _escapify(label, True)

+        return _escapify(label)

 class IDNA2003Codec(IDNACodec):

@@ -159,7 +167,7 @@ class IDNA2003Codec(IDNACodec):

         if label == b'':

             return u''

         try:

-            return _escapify(encodings.idna.ToUnicode(label), True)

+            return _escapify(encodings.idna.ToUnicode(label))

         except Exception as e:

             raise IDNAException(idna_exception=e)

@@ -197,12 +205,6 @@ class IDNA2008Codec(IDNACodec):

         self.allow_pure_ascii = allow_pure_ascii

         self.strict_decode = strict_decode

-    def is_all_ascii(self, label):

-        for c in label:

-            if ord(c) > 0x7f:

-                return False

-        return True

-

     def encode(self, label):

         if label == '':

             return b''

@@ -227,11 +229,12 @@ class IDNA2008Codec(IDNACodec):

         try:

             if self.uts_46:

                 label = idna.uts46_remap(label, False, False)

-            return _escapify(idna.ulabel(label), True)

+            return _escapify(idna.ulabel(label))

         except idna.IDNAError as e:

             raise IDNAException(idna_exception=e)

 _escaped = bytearray(b'"().;\\@$')

+_escaped_text = '"().;\\@$'

 IDNA_2003_Practical = IDNA2003Codec(False)

 IDNA_2003_Strict = IDNA2003Codec(True)

@@ -242,13 +245,13 @@ IDNA_2008_Strict = IDNA2008Codec(False, False, False, True)

 IDNA_2008_Transitional = IDNA2008Codec(True, True, False, False)

 IDNA_2008 = IDNA_2008_Practical

-def _escapify(label, unicode_mode=False):

+def _escapify(label):

     """Escape the characters in label which need it.

-    @param unicode_mode: escapify only special and whitespace (<= 0x20)

-    characters

     @returns: the escaped string

     @rtype: string"""

-    if not unicode_mode:

+    if isinstance(label, bytes):

+        # Ordinary DNS label mode.  Escape special characters and values

+        # < 0x20 or > 0x7f.

         text = ''

         if isinstance(label, text_type):

             label = label.encode()

@@ -259,19 +262,17 @@ def _escapify(label, unicode_mode=False):

                 text += chr(c)

             else:

                 text += '\\%03d' % c

-        return text.encode()

+        return text

+    # Unicode label mode.  Escape only special characters and values < 0x20

     text = u''

-    if isinstance(label, binary_type):

-        label = label.decode()

     for c in label:

-        if c > u'\x20' and c < u'\x7f':

-            text += c

+        if c in _escaped_text:

+            text += '\\' + c

+        elif c <= '\x20':

+            text += '\\%03d' % ord(c)

         else:

-            if c >= u'\x7f':

-                text += c

-            else:

-                text += u'\\%03d' % ord(c)

+            text += c

     return text

 def _validate_labels(labels):

@@ -519,8 +520,8 @@ class Name(object):

             l = self.labels[:-1]

         else:

             l = self.labels

-        s = b'.'.join(map(_escapify, l))

-        return maybe_decode(s)

+        s = '.'.join(map(_escapify, l))

+        return s

     def to_unicode(self, omit_final_dot=False, idna_codec=None):

         """Convert name to Unicode text format.

diff --git a/tests/test_name.py b/tests/test_name.py

index f2a8773..fa1d3eb 100644

--- a/tests/test_name.py

+++ b/tests/test_name.py

@@ -255,6 +255,11 @@ class NameTestCase(unittest.TestCase):

         t = dns.name.root.to_unicode()

         self.assertEqual(t, '.')

+    def testToText12(self):

+            n = dns.name.from_text(r'a\.b.c')

+            t = n.to_unicode()

+            self.assertEqual(t, r'a\.b.c.')

+

     def testSlice1(self):

         n = dns.name.from_text(r'a.b.c.', origin=None)

         s = n[:]

-- 

2.21.0