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LibWeb: Verify that a node has styled properties in its styled accessors

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For example, it's possible to access Node::computed_values() on a node
that neither has style nor a parent with style. This ultimately results
in a null pointer dereference when we return parent()->computed_values()
as a fallback. This can be a little tricky to track down due to these
functions being inlined, so add an explicit verification.
This commit is contained in:
Timothy Flynn 2023-04-27 09:03:49 -04:00 • committed by Andreas Kling
parent d053cb6fae
commit 8f0b7fa370
1 changed files with 12 additions and 0 deletions
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12
Userland/Libraries/LibWeb/Layout/Node.h
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@ -71,6 +71,7 @@ public:
DeprecatedString debug_description() const;
bool has_style() const { return m_has_style; }
bool has_style_or_parent_with_style() const;
virtual bool can_have_children() const { return true; }
@ -233,8 +234,15 @@ private:
template<>
inline bool Node::fast_is<NodeWithStyleAndBoxModelMetrics>() const { return is_node_with_style_and_box_model_metrics(); }
inline bool Node::has_style_or_parent_with_style() const
{
return m_has_style || (parent() != nullptr && parent()->has_style_or_parent_with_style());
}
inline Gfx::Font const& Node::font() const
{
VERIFY(has_style_or_parent_with_style());
if (m_has_style)
return static_cast<NodeWithStyle const*>(this)->font();
return parent()->font();
@ -247,6 +255,8 @@ inline Gfx::Font const& Node::scaled_font(PaintContext& context) const
inline const CSS::ImmutableComputedValues& Node::computed_values() const
{
VERIFY(has_style_or_parent_with_style());
if (m_has_style)
return static_cast<NodeWithStyle const*>(this)->computed_values();
return parent()->computed_values();
@ -254,6 +264,8 @@ inline const CSS::ImmutableComputedValues& Node::computed_values() const
inline CSSPixels Node::line_height() const
{
VERIFY(has_style_or_parent_with_style());
if (m_has_style)
return static_cast<NodeWithStyle const*>(this)->line_height();
return parent()->line_height();