dom/base/FragmentOrElement.h
author Kris Maglione <maglione.k@gmail.com>
Wed, 24 Jan 2018 14:56:48 -0800
changeset 454546 64737c752ac4af4766ad6f82720818521f3aca24
parent 454456 49ae9160211d8b60cdd0ac7d99c80fc4cef15272
permissions -rw-r--r--
Bug 1432966: Sanitize HTML fragments created for chrome-privileged documents. r=bz f=gijs a=jcristau This is a short-term solution to our inability to apply CSP to chrome-privileged documents. Ideally, we should be preventing all inline script execution in chrome-privileged documents, since the reprecussions of XSS in chrome documents are much worse than in content documents. Unfortunately, that's not possible in the near term because a) we don't support CSP in system principal documents at all, and b) we rely heavily on inline JS in our static XUL. This stop-gap solution at least prevents some of the most common vectors of XSS attack, by automatically sanitizing any HTML fragment created for a chrome-privileged document. MozReview-Commit-ID: 5w17celRFr

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * Base class for all element classes as well as nsDocumentFragment.  This
 * provides an implementation of nsIDOMNode, implements nsIContent, provides
 * utility methods for subclasses, and so forth.
 */

#ifndef FragmentOrElement_h___
#define FragmentOrElement_h___

#include "mozilla/Attributes.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/UniquePtr.h"
#include "nsAttrAndChildArray.h"          // member
#include "nsCycleCollectionParticipant.h" // NS_DECL_CYCLE_*
#include "nsIContent.h"                   // base class
#include "nsIWeakReference.h"             // base class
#include "nsNodeUtils.h"                  // class member nsNodeUtils::CloneNodeImpl
#include "nsIHTMLCollection.h"
#include "nsDataHashtable.h"
#include "nsXBLBinding.h"

class ContentUnbinder;
class nsContentList;
class nsLabelsNodeList;
class nsDOMAttributeMap;
class nsDOMTokenList;
class nsIControllers;
class nsICSSDeclaration;
class nsIDocument;
class nsDOMStringMap;
class nsIURI;

namespace mozilla {
class DeclarationBlock;
namespace dom {
struct CustomElementData;
class Element;
} // namespace dom
} // namespace mozilla

/**
 * A class that implements nsIWeakReference
 */

class nsNodeWeakReference final : public nsIWeakReference
{
public:
  explicit nsNodeWeakReference(nsINode* aNode)
    : nsIWeakReference(aNode)
  {
  }

  // nsISupports
  NS_DECL_ISUPPORTS

  // nsIWeakReference
  NS_DECL_NSIWEAKREFERENCE
  virtual size_t SizeOfOnlyThis(mozilla::MallocSizeOf aMallocSizeOf) const override;

  void NoticeNodeDestruction()
  {
    mObject = nullptr;
  }

private:
  ~nsNodeWeakReference();
};

/**
 * Tearoff to use for nodes to implement nsISupportsWeakReference
 */
class nsNodeSupportsWeakRefTearoff final : public nsISupportsWeakReference
{
public:
  explicit nsNodeSupportsWeakRefTearoff(nsINode* aNode)
    : mNode(aNode)
  {
  }

  // nsISupports
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  // nsISupportsWeakReference
  NS_DECL_NSISUPPORTSWEAKREFERENCE

  NS_DECL_CYCLE_COLLECTION_CLASS(nsNodeSupportsWeakRefTearoff)

private:
  ~nsNodeSupportsWeakRefTearoff() {}

  nsCOMPtr<nsINode> mNode;
};

/**
 * A generic base class for DOM elements, implementing many nsIContent,
 * nsIDOMNode and nsIDOMElement methods.
 */
namespace mozilla {
namespace dom {

class ShadowRoot;

class FragmentOrElement : public nsIContent
{
public:
  explicit FragmentOrElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
  explicit FragmentOrElement(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_ADDSIZEOFEXCLUDINGTHIS

  // nsINode interface methods
  virtual uint32_t GetChildCount() const override;
  virtual nsIContent *GetChildAt_Deprecated(uint32_t aIndex) const override;
  virtual int32_t IndexOf(const nsINode* aPossibleChild) const override;
  virtual nsresult InsertChildAt(nsIContent* aKid, uint32_t aIndex,
                                 bool aNotify) override;
  virtual void RemoveChildAt_Deprecated(uint32_t aIndex, bool aNotify) override;
  virtual void RemoveChildNode(nsIContent* aKid, bool aNotify) override;
  virtual void GetTextContentInternal(nsAString& aTextContent,
                                      mozilla::OOMReporter& aError) override;
  virtual void SetTextContentInternal(const nsAString& aTextContent,
                                      nsIPrincipal* aSubjectPrincipal,
                                      mozilla::ErrorResult& aError) override;

  // nsIContent interface methods
  virtual already_AddRefed<nsINodeList> GetChildren(uint32_t aFilter) override;
  virtual const nsTextFragment *GetText() override;
  virtual uint32_t TextLength() const override;
  virtual nsresult SetText(const char16_t* aBuffer, uint32_t aLength,
                           bool aNotify) override;
  // Need to implement this here too to avoid hiding.
  nsresult SetText(const nsAString& aStr, bool aNotify)
  {
    return SetText(aStr.BeginReading(), aStr.Length(), aNotify);
  }
  virtual nsresult AppendText(const char16_t* aBuffer, uint32_t aLength,
                              bool aNotify) override;
  virtual bool TextIsOnlyWhitespace() override;
  virtual bool ThreadSafeTextIsOnlyWhitespace() const override;
  virtual bool HasTextForTranslation() override;
  virtual void AppendTextTo(nsAString& aResult) override;
  MOZ_MUST_USE
  virtual bool AppendTextTo(nsAString& aResult, const mozilla::fallible_t&) override;
  virtual nsXBLBinding* DoGetXBLBinding() const override;
  virtual bool IsLink(nsIURI** aURI) const override;

  virtual void DestroyContent() override;
  virtual void SaveSubtreeState() override;

  nsIHTMLCollection* Children();
  uint32_t ChildElementCount()
  {
    return Children()->Length();
  }

  /**
   * Sets the IsElementInStyleScope flag on each element in the subtree rooted
   * at this node, including any elements reachable through shadow trees.
   *
   * @param aInStyleScope The flag value to set.
   */
  void SetIsElementInStyleScopeFlagOnSubtree(bool aInStyleScope);

public:
  /**
   * If there are listeners for DOMNodeInserted event, fires the event on all
   * aNodes
   */
  static void FireNodeInserted(nsIDocument* aDoc,
                               nsINode* aParent,
                               nsTArray<nsCOMPtr<nsIContent> >& aNodes);

  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS(FragmentOrElement)

  /**
   * Fire a DOMNodeRemoved mutation event for all children of this node
   */
  void FireNodeRemovedForChildren();

  virtual bool OwnedOnlyByTheDOMTree() override
  {
    uint32_t rc = mRefCnt.get();
    if (GetParent()) {
      --rc;
    }
    rc -= mAttrsAndChildren.ChildCount();
    return rc == 0;
  }

  virtual bool IsPurple() override
  {
    return mRefCnt.IsPurple();
  }

  virtual void RemovePurple() override
  {
    mRefCnt.RemovePurple();
  }

  static void ClearContentUnbinder();
  static bool CanSkip(nsINode* aNode, bool aRemovingAllowed);
  static bool CanSkipInCC(nsINode* aNode);
  static bool CanSkipThis(nsINode* aNode);
  static void RemoveBlackMarkedNode(nsINode* aNode);
  static void MarkNodeChildren(nsINode* aNode);
  static void InitCCCallbacks();
  static void MarkUserData(void* aObject, nsAtom* aKey, void* aChild,
                           void *aData);

  /**
   * Is the HTML local name a void element?
   */
  static bool IsHTMLVoid(nsAtom* aLocalName);
protected:
  virtual ~FragmentOrElement();

  /**
   * Copy attributes and state to another element
   * @param aDest the object to copy to
   */
  nsresult CopyInnerTo(FragmentOrElement* aDest, bool aPreallocateChildren);

public:
  /**
   * There are a set of DOM- and scripting-specific instance variables
   * that may only be instantiated when a content object is accessed
   * through the DOM. Rather than burn actual slots in the content
   * objects for each of these instance variables, we put them off
   * in a side structure that's only allocated when the content is
   * accessed through the DOM.
   */

  class nsExtendedDOMSlots final : public nsIContent::nsExtendedContentSlots
  {
  public:
    nsExtendedDOMSlots();
    ~nsExtendedDOMSlots() final;

    void Traverse(nsCycleCollectionTraversalCallback&) final override;
    void Unlink() final override;

    /**
     * SMIL Overridde style rules (for SMIL animation of CSS properties)
     * @see Element::GetSMILOverrideStyle
     */
    nsCOMPtr<nsICSSDeclaration> mSMILOverrideStyle;

    /**
     * Holds any SMIL override style declaration for this element.
     */
    RefPtr<mozilla::DeclarationBlock> mSMILOverrideStyleDeclaration;

    /**
    * The controllers of the XUL Element.
    */
    nsCOMPtr<nsIControllers> mControllers;

    /**
     * An object implementing the .labels property for this element.
     */
    RefPtr<nsLabelsNodeList> mLabelsList;

    /**
     * ShadowRoot bound to the element.
     */
    RefPtr<ShadowRoot> mShadowRoot;

    /**
     * XBL binding installed on the element.
     */
    RefPtr<nsXBLBinding> mXBLBinding;

    /**
     * Web components custom element data.
     */
    RefPtr<CustomElementData> mCustomElementData;

    /**
     * For XUL to hold either frameloader or opener.
     */
    nsCOMPtr<nsISupports> mFrameLoaderOrOpener;

  };

  class nsDOMSlots final : public nsIContent::nsContentSlots
  {
  public:
    nsDOMSlots();
    ~nsDOMSlots() final;

    void Traverse(nsCycleCollectionTraversalCallback&) final override;
    void Unlink() final override;

    size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

    /**
     * The .style attribute (an interface that forwards to the actual
     * style rules)
     * @see nsGenericHTMLElement::GetStyle
     */
    nsCOMPtr<nsICSSDeclaration> mStyle;

    /**
     * The .dataset attribute.
     * @see nsGenericHTMLElement::GetDataset
     */
    nsDOMStringMap* mDataset; // [Weak]

    /**
     * @see Element::Attributes
     */
    RefPtr<nsDOMAttributeMap> mAttributeMap;

    /**
     * An object implementing the .children property for this element.
     */
    RefPtr<nsContentList> mChildrenList;

    /**
     * An object implementing the .classList property for this element.
     */
    RefPtr<nsDOMTokenList> mClassList;
  };

protected:
  void GetMarkup(bool aIncludeSelf, nsAString& aMarkup);
  void SetInnerHTMLInternal(const nsAString& aInnerHTML, ErrorResult& aError,
                            bool aNeverSanitize = false);

  // Override from nsINode
  nsIContent::nsContentSlots* CreateSlots() override
  {
    return new nsDOMSlots();
  }

  nsIContent::nsExtendedContentSlots* CreateExtendedSlots() final override
  {
    return new nsExtendedDOMSlots();
  }

  nsDOMSlots* DOMSlots()
  {
    return static_cast<nsDOMSlots*>(Slots());
  }

  nsDOMSlots *GetExistingDOMSlots() const
  {
    return static_cast<nsDOMSlots*>(GetExistingSlots());
  }

  nsExtendedDOMSlots* ExtendedDOMSlots()
  {
    return static_cast<nsExtendedDOMSlots*>(ExtendedContentSlots());
  }

  const nsExtendedDOMSlots* GetExistingExtendedDOMSlots() const
  {
    return static_cast<const nsExtendedDOMSlots*>(
      GetExistingExtendedContentSlots());
  }

  nsExtendedDOMSlots* GetExistingExtendedDOMSlots()
  {
    return static_cast<nsExtendedDOMSlots*>(GetExistingExtendedContentSlots());
  }

  /**
   * Calls SetIsElementInStyleScopeFlagOnSubtree for each shadow tree attached
   * to this node, which is assumed to be an Element.
   *
   * @param aInStyleScope The IsElementInStyleScope flag value to set.
   */
  void SetIsElementInStyleScopeFlagOnShadowTree(bool aInStyleScope);

  friend class ::ContentUnbinder;
  /**
   * Array containing all attributes and children for this element
   */
  nsAttrAndChildArray mAttrsAndChildren;
};

} // namespace dom
} // namespace mozilla

#define NS_ELEMENT_INTERFACE_TABLE_TO_MAP_SEGUE                               \
    if (NS_SUCCEEDED(rv))                                                     \
      return rv;                                                              \
                                                                              \
    rv = FragmentOrElement::QueryInterface(aIID, aInstancePtr);               \
    NS_INTERFACE_TABLE_TO_MAP_SEGUE

#endif /* FragmentOrElement_h___ */