From 8254e707b6ba5a3069ebaf70cf3bc5bacaa5fb16 Mon Sep 17 00:00:00 2001
From: Arthur Hanson <worldnomad@gmail.com>
Date: Thu, 11 Jan 2024 06:31:32 -0800
Subject: [PATCH] 12851 replace bleach with nh3 (#14767)

* 12851 replace bleach with nh3

* Move tags & attributes lists to constants.py

---------

Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com>
---
 base_requirements.txt         |  8 ++++----
 netbox/utilities/constants.py | 24 ++++++++++++++++++++++++
 netbox/utilities/utils.py     | 30 ++++++------------------------
 requirements.txt              |  2 +-
 4 files changed, 35 insertions(+), 29 deletions(-)

diff --git a/base_requirements.txt b/base_requirements.txt
index 0c7e54b13..87a3066c4 100644
--- a/base_requirements.txt
+++ b/base_requirements.txt
@@ -1,7 +1,3 @@
-# HTML sanitizer
-# https://github.com/mozilla/bleach/blob/main/CHANGES
-bleach
-
 # The Python web framework on which NetBox is built
 # https://docs.djangoproject.com/en/stable/releases/
 Django<5.1
@@ -108,6 +104,10 @@ mkdocstrings[python-legacy]
 # https://github.com/netaddr/netaddr/blob/master/CHANGELOG
 netaddr
 
+# Python bindings to the ammonia HTML sanitization library.
+# https://github.com/messense/nh3
+nh3
+
 # Fork of PIL (Python Imaging Library) for image processing
 # https://github.com/python-pillow/Pillow/blob/main/CHANGES.rst
 Pillow
diff --git a/netbox/utilities/constants.py b/netbox/utilities/constants.py
index 345894065..c7c26f6b3 100644
--- a/netbox/utilities/constants.py
+++ b/netbox/utilities/constants.py
@@ -69,3 +69,27 @@ CSV_DELIMITERS = {
     'semicolon': ';',
     'tab': '\t',
 }
+
+
+#
+# HTML allowed tags & attributes
+#
+
+HTML_ALLOWED_TAGS = {
+    "a", "b", "blockquote", "br", "code", "dd", "del", "div", "dl", "dt", "em", "h1", "h2", "h3", "h4", "h5", "h6",
+    "hr", "i", "img", "li", "ol", "p", "pre", "strong", "table", "tbody", "td", "th", "thead", "tr", "ul"
+}
+
+HTML_ALLOWED_ATTRIBUTES = {
+    "a": {"href", "title"},
+    "div": {"class"},
+    "h1": {"id"},
+    "h2": {"id"},
+    "h3": {"id"},
+    "h4": {"id"},
+    "h5": {"id"},
+    "h6": {"id"},
+    "img": {"alt", "src", "title"},
+    "td": {"align"},
+    "th": {"align"},
+}
diff --git a/netbox/utilities/utils.py b/netbox/utilities/utils.py
index f3f8c7c50..ca05c35bb 100644
--- a/netbox/utilities/utils.py
+++ b/netbox/utilities/utils.py
@@ -1,11 +1,11 @@
 import datetime
 import decimal
 import json
+import nh3
 import re
 from decimal import Decimal
 from itertools import count, groupby
 
-import bleach
 from django.contrib.contenttypes.models import ContentType
 from django.core import serializers
 from django.db.models import Count, ManyToOneRel, OuterRef, Subquery
@@ -24,6 +24,7 @@ from netbox.config import get_config
 from netbox.plugins import PluginConfig
 from urllib.parse import urlencode
 from utilities.constants import HTTP_REQUEST_META_SAFE_COPY
+from .constants import HTML_ALLOWED_ATTRIBUTES, HTML_ALLOWED_TAGS
 
 
 def title(value):
@@ -511,30 +512,11 @@ def clean_html(html, schemes):
     Sanitizes HTML based on a whitelist of allowed tags and attributes.
     Also takes a list of allowed URI schemes.
     """
-
-    ALLOWED_TAGS = {
-        "div", "pre", "code", "blockquote", "del",
-        "hr", "h1", "h2", "h3", "h4", "h5", "h6",
-        "ul", "ol", "li", "p", "br",
-        "strong", "em", "a", "b", "i", "img",
-        "table", "thead", "tbody", "tr", "th", "td",
-        "dl", "dt", "dd",
-    }
-
-    ALLOWED_ATTRIBUTES = {
-        "div": ['class'],
-        "h1": ["id"], "h2": ["id"], "h3": ["id"], "h4": ["id"], "h5": ["id"], "h6": ["id"],
-        "a": ["href", "title"],
-        "img": ["src", "title", "alt"],
-        "th": ["align"],
-        "td": ["align"],
-    }
-
-    return bleach.clean(
+    return nh3.clean(
         html,
-        tags=ALLOWED_TAGS,
-        attributes=ALLOWED_ATTRIBUTES,
-        protocols=schemes
+        tags=HTML_ALLOWED_TAGS,
+        attributes=HTML_ALLOWED_ATTRIBUTES,
+        url_schemes=set(schemes)
     )
 
 
diff --git a/requirements.txt b/requirements.txt
index 788a22f9c..cc733d4b9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,3 @@
-bleach==6.1.0
 Django==5.0.1
 django-cors-headers==4.3.1
 django-debug-toolbar==4.2.0
@@ -24,6 +23,7 @@ Markdown==3.5.1
 mkdocs-material==9.5.3
 mkdocstrings[python-legacy]==0.24.0
 netaddr==0.9.0
+nh3==0.2.15
 Pillow==10.1.0
 psycopg[binary,pool]==3.1.16
 PyYAML==6.0.1