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Author SHA1 Message Date
dgtlmoon af035d2775 Bumping tests 2026-05-11 17:24:50 +02:00
dgtlmoon 08d30c6f22 HTML hygiene fix/improvement (Dont allow unescaped HTML to become real HTML in notifications) 2026-05-11 16:58:30 +02:00
dgtlmoon ab19cb3e4f Fixing GHSA-vwgh-2hvh-4xm5 — substring match in the shared_diff_access, improve access control to shared diff access (#4130) 2026-05-11 14:43:27 +02:00
dgtlmoon 68ea3b2ac5 Notifications - Escape only the diff variables before Jinja2 renders them into the template ( Stop breaking custom HTML for plaintext pages on HTML notifications) #4121 (#4123)
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2026-05-05 18:46:58 +02:00
6 changed files with 229 additions and 20 deletions
+11 -1
View File
@@ -3,6 +3,16 @@ from functools import wraps
from flask import current_app, redirect, request
from loguru import logger
# Endpoints exempt from auth when `shared_diff_access` is enabled.
# Must be exact endpoint names — substring matching (GHSA-vwgh-2hvh-4xm5)
# let the state-changing `/diff/<uuid>/extract` endpoints slip through
# because their names share the `diff_history_page` prefix.
SHARED_DIFF_READ_ONLY_ENDPOINTS = frozenset({
'ui.ui_diff.diff_history_page',
'ui.ui_diff.processor_asset',
'ui.ui_diff.download_patch',
})
def login_optionally_required(func):
"""
If password authentication is enabled, verify the user is logged in.
@@ -20,7 +30,7 @@ def login_optionally_required(func):
has_password_enabled = datastore.data['settings']['application'].get('password') or os.getenv("SALTED_PASS", False)
# Permitted
if request.endpoint and 'diff_history_page' in request.endpoint and datastore.data['settings']['application'].get('shared_diff_access'):
if request.endpoint in SHARED_DIFF_READ_ONLY_ENDPOINTS and datastore.data['settings']['application'].get('shared_diff_access'):
return func(*args, **kwargs)
elif request.method in flask_login.config.EXEMPT_METHODS:
return func(*args, **kwargs)
+2 -2
View File
@@ -414,7 +414,7 @@ def _jinja2_filter_sanitize_tag_class(tag_title):
return sanitized if sanitized else 'tag'
# Import login_optionally_required from auth_decorator
from changedetectionio.auth_decorator import login_optionally_required
from changedetectionio.auth_decorator import SHARED_DIFF_READ_ONLY_ENDPOINTS, login_optionally_required
# When nobody is logged in Flask-Login's current_user is set to an AnonymousUser object.
class User(flask_login.UserMixin):
@@ -541,7 +541,7 @@ def changedetection_app(config=None, datastore_o=None):
# Permitted
elif request.endpoint and 'login' in request.endpoint:
return None
elif request.endpoint and 'diff_history_page' in request.endpoint and datastore.data['settings']['application'].get('shared_diff_access'):
elif request.endpoint in SHARED_DIFF_READ_ONLY_ENDPOINTS and datastore.data['settings']['application'].get('shared_diff_access'):
return None
elif request.method in flask_login.config.EXEMPT_METHODS:
return None
+11 -8
View File
@@ -382,14 +382,17 @@ def process_notification(n_object: NotificationContextData, datastore):
n_object['llm_summary'] = _llm_change_summary or (n_object.get('_llm_result') or {}).get('summary', '')
n_object['llm_intent'] = n_object.get('_llm_intent', '')
# Re #3529: diff content from text/plain pages may contain raw '<' chars that break HTML emails.
# Escape only the diff variables before Jinja2 renders them into the template, so the user's
# own HTML in the notification body (e.g. <a href="{{watch_url}}">) is never touched.
# Diff placemarkers (e.g. @removed_PLACEMARKER_OPEN) contain no HTML chars so they survive
# html_escape and are still replaced with <span> tags by apply_service_tweaks later.
watch_mime_type = n_object.get('watch_mime_type')
if (watch_mime_type and 'text/' in watch_mime_type.lower() and 'html' not in watch_mime_type.lower()
and 'html' in requested_output_format):
# Escape diff/snapshot variables before Jinja renders them into an HTML notification.
# GHSA-q8xq-qg4x-wphg: inscriptis decodes HTML entities when converting text/html
# pages to snapshot text, so a page that visibly displays "&lt;a href...&gt;" yields
# literal "<a href...>" in the snapshot — which would otherwise render as live
# markup in HTML emails / Telegram (parse_mode=html) / Discord embeds, letting a
# watched page inject phishing links into the operator's notification channel.
# Also covers #3529 — raw '<' chars from text/plain pages breaking HTML email layout.
# The operator's own template HTML (e.g. <a href="{{watch_url}}">) is outside the
# variable values so it stays untouched. Diff placemarkers contain no HTML chars,
# so they survive escape and are still replaced with <span> tags later.
if 'html' in requested_output_format:
from markupsafe import escape as html_escape
_page_content_keys = {'raw_diff', 'current_snapshot', 'prev_snapshot', 'triggered_text'}
for key in [k for k in notification_parameters if k.startswith('diff') or k in _page_content_keys]:
@@ -108,7 +108,9 @@ def test_check_notification_email_formats_default_HTML(client, live_server, meas
html_content = html_part.get_content()
assert 'some text<br>' in html_content # We converted \n from the notification body
assert 'fallback-body<br>' in html_content # kept the original <br>
assert '(added) So let\'s see what happens.<br>' in html_content # the html part
# GHSA-q8xq-qg4x-wphg: apostrophes in diff content are escaped (&#39;) for HTML notifications.
# Renders as ' in the recipient's email client; only the byte-source differs.
assert '(added) So let&#39;s see what happens.<br>' in html_content # the html part
delete_all_watches(client)
@@ -452,7 +454,8 @@ def test_check_notification_email_formats_default_Text_override_HTML(client, liv
html_part = parts[1]
assert html_part.get_content_type() == 'text/html'
html_content = html_part.get_content()
assert '(removed) So let\'s see what happens.' in html_content # the html part
# GHSA-q8xq-qg4x-wphg: apostrophes in diff content are escaped (&#39;) for HTML notifications.
assert '(removed) So let&#39;s see what happens.' in html_content # the html part
assert '&lt;!DOCTYPE html' not in html_content
assert '<!DOCTYPE html' in html_content # Our original template is working correctly
@@ -792,5 +795,6 @@ def test_check_html_notification_with_apprise_format_is_html(client, live_server
html_content = html_part.get_content()
assert 'some text<br>' in html_content # We converted \n from the notification body
assert 'fallback-body<br>' in html_content # kept the original <br>
assert '(added) So let\'s see what happens.<br>' in html_content # the html part
# GHSA-q8xq-qg4x-wphg: apostrophes in diff content are escaped (&#39;) for HTML notifications.
assert '(added) So let&#39;s see what happens.<br>' in html_content # the html part
delete_all_watches(client)
@@ -48,6 +48,32 @@ def test_check_access_control(app, client, live_server, measure_memory_usage, da
res = c.get(url_for("ui.ui_diff.diff_history_page", uuid="first"))
assert b'Random content' in res.data
# GHSA-vwgh-2hvh-4xm5: shared_diff_access only covers the read-only
# diff page — the extract endpoints (which run an attacker-supplied
# regex against history and write a CSV to disk) must still require
# auth even when the share flag is enabled.
res = c.get(url_for("ui.ui_diff.diff_history_page_extract_GET", uuid="first"))
assert res.status_code == 302, "Extract form GET must redirect to login for anonymous users"
assert b'/login' in res.data or b'login' in res.headers.get('Location', '').encode()
res = c.post(
url_for("ui.ui_diff.diff_history_page_extract_POST", uuid="first"),
data={"extract_regex": ".*", "extract_submit_button": "Extract as CSV"},
)
assert res.status_code == 302, "Extract POST must redirect to login for anonymous users"
assert b'login' in res.headers.get('Location', '').encode()
# But sub-resources the diff page legitimately loads should still pass the gate.
# download_patch is linked from diff.html — anonymous viewers must be able to fetch it.
# (We don't care about the body here, just that auth doesn't block it.)
res = c.get(url_for("ui.ui_diff.download_patch", uuid="first"))
assert res.status_code != 302, "download_patch must be reachable for shared diff viewers"
# processor_asset (used for screenshots embedded in image_ssim_diff watches) must also be reachable.
# For a text watch the processor has no such asset so 404 is fine — what matters is no auth redirect.
res = c.get(url_for("ui.ui_diff.processor_asset", uuid="first", asset_name="before"))
assert res.status_code != 302, "processor_asset must be reachable for shared diff viewers"
# access to assets should work (check_authentication)
res = c.get(url_for('static_content', group='js', filename='jquery-3.6.0.min.js'))
assert res.status_code == 200
+172 -6
View File
@@ -638,9 +638,11 @@ def test_html_color_notifications(client, live_server, measure_memory_usage, dat
def _test_custom_html_in_notification_body_not_escaped(client, datastore_path, content_type=None):
"""
#4121 - Custom HTML in the notification body (e.g. <a href="{{watch_url}}">) must NOT be
HTML-escaped regardless of the watched page's content-type. Only raw diff content from
text/plain pages needs escaping (to prevent raw '<' chars breaking HTML email rendering).
#4121 - The operator's own HTML in the notification body template (e.g.
<a href="{{watch_url}}">) must survive unescaped regardless of the watched page's
Content-Type. The escape pass in handler.py only touches the variable *values*
(diff/snapshot content from the page see GHSA-q8xq-qg4x-wphg) it leaves the
surrounding template HTML alone.
"""
set_original_response(datastore_path=datastore_path)
@@ -693,10 +695,174 @@ def _test_custom_html_in_notification_body_not_escaped(client, datastore_path, c
def test_plaintext_watch_custom_html_in_notification_body_not_escaped(client, live_server, measure_memory_usage, datastore_path):
# text/plain: diff content may contain raw '<' chars — those must be escaped, but NOT the user's template HTML
# Diff/snapshot values are escaped for HTML notifications (covered by
# test_html_watch_diff_content_escaped_in_html_notification). What this test
# locks in is that the *surrounding* template HTML is left alone in every case.
_test_custom_html_in_notification_body_not_escaped(client, datastore_path, content_type="text/plain")
# text/html: HTML processor strips tags before diffing, no escaping needed, user's template HTML must be preserved
_test_custom_html_in_notification_body_not_escaped(client, datastore_path, content_type="text/html")
# no MIME type (None): same as HTML case, user's template HTML must be preserved
_test_custom_html_in_notification_body_not_escaped(client, datastore_path, content_type=None)
def test_html_watch_diff_content_escaped_in_html_notification(client, live_server, measure_memory_usage, datastore_path):
"""
GHSA-q8xq-qg4x-wphg diff/snapshot content from the watched page must be
HTML-escaped before it is rendered into an HTML-format notification, regardless
of the watched page's Content-Type.
Inscriptis (used to convert text/html pages to snapshot text) decodes HTML
entities so a page that visibly displays "&lt;a href=...&gt;" produces snapshot
text containing literal "<a href=...>". The previous gate at handler.py:391
only escaped when watch_mime_type matched 'text/' and not 'html', which let
that decoded markup through to HTML emails / Telegram (parse_mode=html) /
Discord embeds, where it renders as a real clickable link i.e. an attacker
who controls a watched page can inject phishing links into the operator's
trusted notification channel.
"""
from .util import write_test_file_and_sync
if os.path.isfile(os.path.join(datastore_path, "notification.txt")):
os.unlink(os.path.join(datastore_path, "notification.txt"))
# Baseline: an innocuous text/html page.
baseline_html = "<html><body><p>nothing to see here</p></body></html>"
write_test_file_and_sync(os.path.join(datastore_path, "endpoint-content.txt"), baseline_html)
test_notification_url = url_for('test_notification_endpoint', _external=True).replace('http://', 'post://')
# Pass content_type=text/html so the watch records 'text/html' as its content-type
# — this is the branch the previous gate skipped escaping for.
test_url = url_for('test_endpoint', _external=True, content_type='text/html')
# HTML-format notification body that embeds the snapshot directly. Operators do this
# when they want the full changed content in the alert (e.g. an email digest).
res = client.post(
url_for("settings.settings_page"),
data={
"application-fetch_backend": "html_requests",
"application-minutes_between_check": 180,
"application-notification_body": 'Watch had changes:\n{{current_snapshot}}',
"application-notification_format": "html",
"application-notification_urls": test_notification_url,
"application-notification_title": "Change detected",
},
follow_redirects=True
)
assert b'Settings updated' in res.data
res = client.post(
url_for("ui.ui_views.form_quick_watch_add"),
data={"url": test_url, "tags": ''},
follow_redirects=True
)
assert b"Watch added" in res.data
wait_for_all_checks(client)
# Now flip the page to something whose *visible* text contains entity-encoded
# angle brackets — exactly the pattern a forum / pastebin / code-sample site uses
# to display literal HTML on the page. Inscriptis will decode &lt;/&gt; back to
# literal < / > in the stored snapshot.
attacker_html = (
'<html><body><pre>'
'&lt;a href="https://attacker.example/payment"&gt;ACTION REQUIRED&lt;/a&gt;'
'&lt;img src="https://attacker.example/track" width="1" height="1"&gt;'
'</pre></body></html>'
)
write_test_file_and_sync(os.path.join(datastore_path, "endpoint-content.txt"), attacker_html)
res = client.get(url_for("ui.form_watch_checknow"), follow_redirects=True)
assert b'Queued 1 watch for rechecking.' in res.data
wait_for_all_checks(client)
wait_for_notification_endpoint_output(datastore_path=datastore_path)
with open(os.path.join(datastore_path, "notification.txt"), 'r') as f:
body = f.read()
# Sanity: the snapshot really did contain the decoded markup (otherwise the test
# would pass for the wrong reason). The escaped form must appear somewhere.
assert '&lt;a href=' in body or '&amp;lt;a href=' in body, \
f"Expected escaped attacker markup in notification body, got: {body!r}"
# The bug: a live <a href="https://attacker..."> ends up in the HTML notification.
assert '<a href="https://attacker.example/payment"' not in body, \
f"Diff content from text/html page was NOT escaped — phishing link reached HTML notification: {body!r}"
assert '<img src="https://attacker.example/track"' not in body, \
f"Diff content from text/html page was NOT escaped — tracking pixel reached HTML notification: {body!r}"
client.get(url_for("ui.form_delete", uuid="all"), follow_redirects=True)
def test_source_url_diff_content_escaped_in_html_notification(client, live_server, measure_memory_usage, datastore_path):
"""
GHSA-q8xq-qg4x-wphg companion to the inscriptis test. `source:`-prefixed
URLs short-circuit the HTMLtext step (processor.py:509-511) and store the
raw HTML body verbatim as the snapshot. That gives an attacker who controls
a watched page a *direct* injection path no entity-encoding tricks needed,
any live `<a>` / `<img>` / `<script>` on the page lands straight into
current_snapshot / raw_diff. The escape pass must catch this too.
"""
from .util import write_test_file_and_sync
if os.path.isfile(os.path.join(datastore_path, "notification.txt")):
os.unlink(os.path.join(datastore_path, "notification.txt"))
# Baseline: innocuous raw HTML.
baseline_html = "<html><body><p>nothing to see here</p></body></html>"
write_test_file_and_sync(os.path.join(datastore_path, "endpoint-content.txt"), baseline_html)
test_notification_url = url_for('test_notification_endpoint', _external=True).replace('http://', 'post://')
# `source:` prefix → raw HTML body is stored as-is in the snapshot (no inscriptis).
test_url = 'source:' + url_for('test_endpoint', _external=True, content_type='text/html')
res = client.post(
url_for("settings.settings_page"),
data={
"application-fetch_backend": "html_requests",
"application-minutes_between_check": 180,
"application-notification_body": 'Watch had changes:\n{{current_snapshot}}',
"application-notification_format": "html",
"application-notification_urls": test_notification_url,
"application-notification_title": "Change detected",
},
follow_redirects=True
)
assert b'Settings updated' in res.data
res = client.post(
url_for("ui.ui_views.form_quick_watch_add"),
data={"url": test_url, "tags": ''},
follow_redirects=True
)
assert b"Watch added" in res.data
wait_for_all_checks(client)
# Modified page contains LIVE HTML directly — no entity encoding. With source:
# this lands in the snapshot verbatim.
attacker_html = (
'<html><body>'
'<a href="https://attacker.example/payment">ACTION REQUIRED</a>'
'<img src="https://attacker.example/track" width="1" height="1">'
'</body></html>'
)
write_test_file_and_sync(os.path.join(datastore_path, "endpoint-content.txt"), attacker_html)
res = client.get(url_for("ui.form_watch_checknow"), follow_redirects=True)
assert b'Queued 1 watch for rechecking.' in res.data
wait_for_all_checks(client)
wait_for_notification_endpoint_output(datastore_path=datastore_path)
with open(os.path.join(datastore_path, "notification.txt"), 'r') as f:
body = f.read()
# Sanity: snapshot really did carry the markup through. Escaped form must show up.
assert '&lt;a href=' in body or '&amp;lt;a href=' in body, \
f"Expected escaped attacker markup in notification body, got: {body!r}"
assert '<a href="https://attacker.example/payment"' not in body, \
f"source: URL raw HTML was NOT escaped — phishing link reached HTML notification: {body!r}"
assert '<img src="https://attacker.example/track"' not in body, \
f"source: URL raw HTML was NOT escaped — tracking pixel reached HTML notification: {body!r}"
client.get(url_for("ui.form_delete", uuid="all"), follow_redirects=True)