python-lxml/0003-Fix-CVE-2021-28957.patch

40 lines
1.4 KiB
Diff

diff --git a/src/lxml/html/defs.py b/src/lxml/html/defs.py
index b21a113..e40c808 100644
--- a/src/lxml/html/defs.py
+++ b/src/lxml/html/defs.py
@@ -21,6 +21,8 @@ link_attrs = frozenset([
'usemap',
# Not standard:
'dynsrc', 'lowsrc',
+ # HTML5 formaction
+ 'formaction'
])
# Not in the HTML 4 spec:
diff --git a/src/lxml/html/tests/test_clean.py b/src/lxml/html/tests/test_clean.py
index a193d99..87b7220 100644
--- a/src/lxml/html/tests/test_clean.py
+++ b/src/lxml/html/tests/test_clean.py
@@ -68,6 +68,21 @@ class CleanerTest(unittest.TestCase):
s = lxml.html.fromstring('<invalid tag>child</another>')
self.assertEqual('child', clean_html(s).text_content())
+ def test_formaction_attribute_in_button_input(self):
+ # The formaction attribute overrides the form's action and should be
+ # treated as a malicious link attribute
+ html = ('<form id="test"><input type="submit" formaction="javascript:alert(1)"></form>'
+ '<button form="test" formaction="javascript:alert(1)">X</button>')
+ expected = ('<div><form id="test"><input type="submit" formaction=""></form>'
+ '<button form="test" formaction="">X</button></div>')
+ cleaner = Cleaner(
+ forms=False,
+ safe_attrs_only=False,
+ )
+ self.assertEqual(
+ expected,
+ cleaner.clean_html(html))
+
def test_suite():
suite = unittest.TestSuite()