package/python-markdown2: fix CVE-2020-11888

python-markdown2 through 2.3.8 allows XSS because element names are
mishandled unless a \w+ match succeeds. For example, an attack might use
elementname@ or elementname- with an onclick attribute.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
This commit is contained in:
Fabrice Fontaine 2020-05-11 21:22:37 +02:00 committed by Peter Korsgaard
parent 2f3fc10587
commit 544007dcc4
3 changed files with 89 additions and 0 deletions

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@ -0,0 +1,53 @@
From 9144d0fc5d5249cc4d81287ee79091806e6dde52 Mon Sep 17 00:00:00 2001
From: Gareth Simpson <gareth.simpson@zoodigital.com>
Date: Fri, 1 May 2020 19:31:21 +0100
Subject: [PATCH] Fix for issue 348 - incomplete tags with punctuation after as
part of the tag name are a source of XSS
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[Retrieved from:
https://github.com/trentm/python-markdown2/commit/9144d0fc5d5249cc4d81287ee79091806e6dde52]
---
lib/markdown2.py | 2 +-
test/tm-cases/issue348_incomplete_tag.html | 1 +
test/tm-cases/issue348_incomplete_tag.opts | 1 +
test/tm-cases/issue348_incomplete_tag.text | 1 +
4 files changed, 4 insertions(+), 1 deletion(-)
create mode 100644 test/tm-cases/issue348_incomplete_tag.html
create mode 100644 test/tm-cases/issue348_incomplete_tag.opts
create mode 100644 test/tm-cases/issue348_incomplete_tag.text
diff --git a/lib/markdown2.py b/lib/markdown2.py
index 3a5d5d9..636bf07 100755
--- a/lib/markdown2.py
+++ b/lib/markdown2.py
@@ -2164,7 +2164,7 @@ def _encode_amps_and_angles(self, text):
text = self._naked_gt_re.sub('&gt;', text)
return text
- _incomplete_tags_re = re.compile("<(/?\w+[\s/]+?)")
+ _incomplete_tags_re = re.compile("<(/?\w+?(?!://).?[\s/]+?)")
def _encode_incomplete_tags(self, text):
if self.safe_mode not in ("replace", "escape"):
diff --git a/test/tm-cases/issue348_incomplete_tag.html b/test/tm-cases/issue348_incomplete_tag.html
new file mode 100644
index 0000000..46059cc
--- /dev/null
+++ b/test/tm-cases/issue348_incomplete_tag.html
@@ -0,0 +1 @@
+<p>&lt;lol@/ //id="pwn"//onclick="alert(1)"//<strong>abc</strong></p>
diff --git a/test/tm-cases/issue348_incomplete_tag.opts b/test/tm-cases/issue348_incomplete_tag.opts
new file mode 100644
index 0000000..ad487c0
--- /dev/null
+++ b/test/tm-cases/issue348_incomplete_tag.opts
@@ -0,0 +1 @@
+{"safe_mode": "escape"}
diff --git a/test/tm-cases/issue348_incomplete_tag.text b/test/tm-cases/issue348_incomplete_tag.text
new file mode 100644
index 0000000..bb4a0de
--- /dev/null
+++ b/test/tm-cases/issue348_incomplete_tag.text
@@ -0,0 +1 @@
+<lol@/ //id="pwn"//onclick="alert(1)"//**abc**

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@ -0,0 +1,32 @@
From 0c0543846fa54281e2269b0bff841a0b9ffe23fe Mon Sep 17 00:00:00 2001
From: Gareth Simpson <gareth.simpson@zoodigital.com>
Date: Sat, 2 May 2020 21:22:36 +0100
Subject: [PATCH] Better fix for issue 348
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[Retrieved from:
https://github.com/trentm/python-markdown2/commit/0c0543846fa54281e2269b0bff841a0b9ffe23fe]
---
lib/markdown2.py | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/lib/markdown2.py b/lib/markdown2.py
index 636bf07..be86502 100755
--- a/lib/markdown2.py
+++ b/lib/markdown2.py
@@ -2164,11 +2164,14 @@ def _encode_amps_and_angles(self, text):
text = self._naked_gt_re.sub('&gt;', text)
return text
- _incomplete_tags_re = re.compile("<(/?\w+?(?!://).?[\s/]+?)")
+ _incomplete_tags_re = re.compile("<(/?\w+?(?!\w).+?[\s/]+?)")
def _encode_incomplete_tags(self, text):
if self.safe_mode not in ("replace", "escape"):
return text
+
+ if text.endswith(">"):
+ return text # this is not an incomplete tag, this is a link in the form <http://x.y.z>
return self._incomplete_tags_re.sub("&lt;\\1", text)

View file

@ -11,4 +11,8 @@ PYTHON_MARKDOWN2_SETUP_TYPE = setuptools
PYTHON_MARKDOWN2_LICENSE = MIT
PYTHON_MARKDOWN2_LICENSE_FILES = LICENSE.txt
# 0001-Fix-for-issue-348-incomplete-tags-with-punctuation-after-as-part-of.patch
# 0002-Better-fix-for-issue-348.patch
PYTHON_MARKDOWN2_IGNORE_CVES += CVE-2020-11888
$(eval $(python-package))