Srcdoc escaping - #425
Open
vrana wants to merge 2 commits into
Open
Srcdoc escaping#425vrana wants to merge 2 commits into
vrana wants to merge 2 commits into
Conversation
…BC break)
The value of srcdoc is an HTML document: the browser attribute-decodes it and
then parses the result as HTML. Latte escaped it like any other attribute, so
<iframe srcdoc="<p>{$x}</p>"> with $x = '<script>...</script>' rendered
<script>, which decodes to a live <script>. An iframe without sandbox
shares the parent's origin, so this was an XSS.
srcdoc now gets its own html/attr/html context: a value is escaped as HTML text
first and as an attribute second (HtmlHelpers::escapeHtmlAttr). This covers the
static attribute, the dynamic attribute srcdoc={$x}, n:attr and blocks or
templates included into srcdoc.
An Html object is encoded only once, so trusted markup keeps its tags;
previously they were stripped.
BC break: trusted HTML passed as a plain string is now displayed as text. Wrap
it in Latte\Runtime\Html (or use |noescape).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
…ly rendered as HTML
With Feature::MigrationWarnings, a plain srcdoc value that renders as a different
document now than before (it contains '<' or a character reference) triggers
a warning suggesting to wrap trusted HTML in Latte\Runtime\Html. Text such as
'a & b' renders the same document as before and stays quiet; so does an Html
object, whose tags were stripped before and are kept now. |accept silences it.
It covers dynamic attributes (srcdoc={$x}, srcdoc="{$x}") and n:attr. A mixed
value like srcdoc="<p>{$x}</p>" is escaped by code the Escaper emits, which has
no access to feature flags, so it does not warn.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Uh oh!
There was an error while loading. Please reload this page.