diff --git a/django/utils/text.py b/django/utils/text.py index a6172c41b0..f221747f6f 100644 --- a/django/utils/text.py +++ b/django/utils/text.py @@ -27,8 +27,8 @@ def capfirst(x): # Set up regular expressions -re_words = re.compile(r'<.*?>|((?:\w[-\w]*|&.*?;)+)', re.U | re.S) -re_chars = re.compile(r'<.*?>|(.)', re.U | re.S) +re_words = re.compile(r'<[^>]+?>|([^<>\s]+)', re.S) +re_chars = re.compile(r'<[^>]+?>|(.)', re.S) re_tag = re.compile(r'<(/)?(\S+?)(?:(\s*/)|\s.*?)?>', re.S) re_newlines = re.compile(r'\r\n|\r') # Used in normalize_newlines re_camel_case = re.compile(r'(((?<=[a-z])[A-Z])|([A-Z](?![A-Z]|$)))') diff --git a/docs/releases/1.11.23.txt b/docs/releases/1.11.23.txt index 9a3ab7cbc9..6058bb8a81 100644 --- a/docs/releases/1.11.23.txt +++ b/docs/releases/1.11.23.txt @@ -5,3 +5,17 @@ Django 1.11.23 release notes *August 1, 2019* Django 1.11.23 fixes security issues in 1.11.22. + +CVE-2019-14232: Denial-of-service possibility in ``django.utils.text.Truncator`` +================================================================================ + +If ``django.utils.text.Truncator``'s ``chars()`` and ``words()`` methods +were passed the ``html=True`` argument, they were extremely slow to evaluate +certain inputs due to a catastrophic backtracking vulnerability in a regular +expression. The ``chars()`` and ``words()`` methods are used to implement the +:tfilter:`truncatechars_html` and :tfilter:`truncatewords_html` template +filters, which were thus vulnerable. + +The regular expressions used by ``Truncator`` have been simplified in order to +avoid potential backtracking issues. As a consequence, trailing punctuation may +now at times be included in the truncated output. diff --git a/tests/template_tests/filter_tests/test_truncatewords_html.py b/tests/template_tests/filter_tests/test_truncatewords_html.py index aec2abf2d4..3c73442fbe 100644 --- a/tests/template_tests/filter_tests/test_truncatewords_html.py +++ b/tests/template_tests/filter_tests/test_truncatewords_html.py @@ -19,13 +19,13 @@ class FunctionTests(SimpleTestCase): def test_truncate2(self): self.assertEqual( truncatewords_html('

one two - three
four
five

', 4), - '

one two - three
four ...

', + '

one two - three ...

', ) def test_truncate3(self): self.assertEqual( truncatewords_html('

one two - three
four
five

', 5), - '

one two - three
four
five

', + '

one two - three
four ...

', ) def test_truncate4(self): diff --git a/tests/utils_tests/test_text.py b/tests/utils_tests/test_text.py index 50d1805e86..bfc1b4efc4 100644 --- a/tests/utils_tests/test_text.py +++ b/tests/utils_tests/test_text.py @@ -88,6 +88,16 @@ class TestUtilsText(SimpleTestCase): # lazy strings are handled correctly self.assertEqual(text.Truncator(lazystr('The quick brown fox')).chars(12), 'The quick...') + def test_truncate_chars_html(self): + perf_test_values = [ + (('', None), + ('&' * 50000, '&' * 7 + '...'), + ('_X<<<<<<<<<<<>', None), + ] + for value, expected in perf_test_values: + truncator = text.Truncator(value) + self.assertEqual(expected if expected else value, truncator.chars(10, html=True)) + def test_truncate_words(self): truncator = text.Truncator('The quick brown fox jumped over the lazy dog.') self.assertEqual('The quick brown fox jumped over the lazy dog.', truncator.words(10)) @@ -137,11 +147,16 @@ class TestUtilsText(SimpleTestCase): truncator = text.Truncator('Buenos días! ¿Cómo está?') self.assertEqual('Buenos días! ¿Cómo...', truncator.words(3, '...', html=True)) truncator = text.Truncator('

I <3 python, what about you?

') - self.assertEqual('

I <3 python...

', truncator.words(3, '...', html=True)) + self.assertEqual('

I <3 python,...

', truncator.words(3, '...', html=True)) - re_tag_catastrophic_test = ('' - truncator = text.Truncator(re_tag_catastrophic_test) - self.assertEqual(re_tag_catastrophic_test, truncator.words(500, html=True)) + perf_test_values = [ + ('', + '&' * 50000, + '_X<<<<<<<<<<<>', + ] + for value in perf_test_values: + truncator = text.Truncator(value) + self.assertEqual(value, truncator.words(50, html=True)) def test_wrap(self): digits = '1234 67 9'