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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
/*
* Content policy implementation that prevents all loads of images,
* subframes, etc from documents loaded as data (eg documents loaded
* via XMLHttpRequest).
*/
#include "nsContentUtils.h"
#include "nsDataDocumentContentPolicy.h"
#include "nsNetUtil.h"
#include "nsIProtocolHandler.h"
#include "nsScriptSecurityManager.h"
#include "nsIDocument.h"
#include "nsINode.h"
#include "nsIDOMWindow.h"
#include "nsIURI.h"
NS_IMPL_ISUPPORTS(nsDataDocumentContentPolicy, nsIContentPolicy)
// Helper method for ShouldLoad()
// Checks a URI for the given flags. Returns true if the URI has the flags,
// and false if not (or if we weren't able to tell).
static bool
HasFlags(nsIURI* aURI, uint32_t aURIFlags)
{
bool hasFlags;
nsresult rv = NS_URIChainHasFlags(aURI, aURIFlags, &hasFlags);
return NS_SUCCEEDED(rv) && hasFlags;
}
// If you change DataDocumentContentPolicy, make sure to check that
// CHECK_PRINCIPAL_AND_DATA in nsContentPolicyUtils is still valid.
// nsContentPolicyUtils may not pass all the parameters to ShouldLoad.
NS_IMETHODIMP
nsDataDocumentContentPolicy::ShouldLoad(uint32_t aContentType,
nsIURI *aContentLocation,
nsIURI *aRequestingLocation,
nsISupports *aRequestingContext,
const nsACString &aMimeGuess,
nsISupports *aExtra,
nsIPrincipal *aRequestPrincipal,
int16_t *aDecision)
{
MOZ_ASSERT(aContentType == nsContentUtils::InternalContentPolicyTypeToExternal(aContentType),
"We should only see external content policy types here.");
*aDecision = nsIContentPolicy::ACCEPT;
// Look for the document. In most cases, aRequestingContext is a node.
nsCOMPtr<nsIDocument> doc;
nsCOMPtr<nsINode> node = do_QueryInterface(aRequestingContext);
if (node) {
doc = node->OwnerDoc();
} else {
if (nsCOMPtr<nsPIDOMWindowOuter> window = do_QueryInterface(aRequestingContext)) {
doc = window->GetDoc();
}
}
// DTDs are always OK to load
if (!doc || aContentType == nsIContentPolicy::TYPE_DTD) {
return NS_OK;
}
// Nothing else is OK to load for data documents
if (doc->IsLoadedAsData()) {
// ...but let static (print/print preview) documents to load fonts.
if (!doc->IsStaticDocument() || aContentType != nsIContentPolicy::TYPE_FONT) {
*aDecision = nsIContentPolicy::REJECT_TYPE;
return NS_OK;
}
}
nsIDocument* docToCheckForImage = doc->GetDisplayDocument();
if (!docToCheckForImage) {
docToCheckForImage = doc;
}
if (docToCheckForImage->IsBeingUsedAsImage()) {
// We only allow SVG images to load content from URIs that are local and
// also satisfy one of the following conditions:
// - URI inherits security context, e.g. data URIs
// OR
// - URI loadable by subsumers, e.g. blob URIs
// Any URI that doesn't meet these requirements will be rejected below.
if (!(HasFlags(aContentLocation,
nsIProtocolHandler::URI_IS_LOCAL_RESOURCE) &&
(HasFlags(aContentLocation,
nsIProtocolHandler::URI_INHERITS_SECURITY_CONTEXT) ||
HasFlags(aContentLocation,
nsIProtocolHandler::URI_LOADABLE_BY_SUBSUMERS)))) {
*aDecision = nsIContentPolicy::REJECT_TYPE;
// Report error, if we can.
if (node) {
nsIPrincipal* requestingPrincipal = node->NodePrincipal();
RefPtr<nsIURI> principalURI;
nsresult rv =
requestingPrincipal->GetURI(getter_AddRefs(principalURI));
if (NS_SUCCEEDED(rv) && principalURI) {
nsScriptSecurityManager::ReportError(
nullptr, NS_LITERAL_STRING("ExternalDataError"), principalURI,
aContentLocation);
}
}
} else if ((aContentType == nsIContentPolicy::TYPE_IMAGE ||
aContentType == nsIContentPolicy::TYPE_IMAGESET) &&
doc->GetDocumentURI()) {
// Check for (& disallow) recursive image-loads
bool isRecursiveLoad;
nsresult rv = aContentLocation->EqualsExceptRef(doc->GetDocumentURI(),
&isRecursiveLoad);
if (NS_FAILED(rv) || isRecursiveLoad) {
NS_WARNING("Refusing to recursively load image");
*aDecision = nsIContentPolicy::REJECT_TYPE;
}
}
return NS_OK;
}
// Allow all loads for non-resource documents
if (!doc->IsResourceDoc()) {
return NS_OK;
}
// For resource documents, blacklist some load types
if (aContentType == nsIContentPolicy::TYPE_OBJECT ||
aContentType == nsIContentPolicy::TYPE_DOCUMENT ||
aContentType == nsIContentPolicy::TYPE_SUBDOCUMENT ||
aContentType == nsIContentPolicy::TYPE_SCRIPT ||
aContentType == nsIContentPolicy::TYPE_XSLT ||
aContentType == nsIContentPolicy::TYPE_FETCH ||
aContentType == nsIContentPolicy::TYPE_WEB_MANIFEST) {
*aDecision = nsIContentPolicy::REJECT_TYPE;
}
// If you add more restrictions here, make sure to check that
// CHECK_PRINCIPAL_AND_DATA in nsContentPolicyUtils is still valid.
// nsContentPolicyUtils may not pass all the parameters to ShouldLoad
return NS_OK;
}
NS_IMETHODIMP
nsDataDocumentContentPolicy::ShouldProcess(uint32_t aContentType,
nsIURI *aContentLocation,
nsIURI *aRequestingLocation,
nsISupports *aRequestingContext,
const nsACString &aMimeGuess,
nsISupports *aExtra,
nsIPrincipal *aRequestPrincipal,
int16_t *aDecision)
{
return ShouldLoad(aContentType, aContentLocation, aRequestingLocation,
aRequestingContext, aMimeGuess, aExtra, aRequestPrincipal,
aDecision);
}
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