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-rw-r--r--dom/base/nsDataDocumentContentPolicy.cpp177
1 files changed, 177 insertions, 0 deletions
diff --git a/dom/base/nsDataDocumentContentPolicy.cpp b/dom/base/nsDataDocumentContentPolicy.cpp
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+++ b/dom/base/nsDataDocumentContentPolicy.cpp
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+/* -*- 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/. */
+
+/*
+ * Content policy implementation that prevents all loads of images,
+ * subframes, etc from documents loaded as data (eg documents loaded
+ * via XMLHttpRequest).
+ */
+
+#include "nsContentPolicyUtils.h"
+#include "nsContentUtils.h"
+#include "nsDataDocumentContentPolicy.h"
+#include "nsNetUtil.h"
+#include "nsIProtocolHandler.h"
+#include "nsScriptSecurityManager.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/ScopeExit.h"
+#include "nsINode.h"
+#include "nsIURI.h"
+
+using namespace mozilla;
+
+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(nsIURI* aContentLocation,
+ nsILoadInfo* aLoadInfo,
+ const nsACString& aMimeGuess,
+ int16_t* aDecision) {
+ auto setBlockingReason = mozilla::MakeScopeExit([&]() {
+ if (NS_CP_REJECTED(*aDecision)) {
+ NS_SetRequestBlockingReason(
+ aLoadInfo, nsILoadInfo::BLOCKING_REASON_CONTENT_POLICY_DATA_DOCUMENT);
+ }
+ });
+
+ ExtContentPolicyType contentType = aLoadInfo->GetExternalContentPolicyType();
+ nsCOMPtr<nsISupports> requestingContext = aLoadInfo->GetLoadingContext();
+
+ *aDecision = nsIContentPolicy::ACCEPT;
+ // Look for the document. In most cases, requestingContext is a node.
+ nsCOMPtr<mozilla::dom::Document> doc;
+ nsCOMPtr<nsINode> node = do_QueryInterface(requestingContext);
+ if (node) {
+ doc = node->OwnerDoc();
+ } else {
+ if (nsCOMPtr<nsPIDOMWindowOuter> window =
+ do_QueryInterface(requestingContext)) {
+ doc = window->GetDoc();
+ }
+ }
+
+ // DTDs are always OK to load
+ if (!doc || contentType == ExtContentPolicy::TYPE_DTD) {
+ return NS_OK;
+ }
+
+ if (doc->IsLoadedAsData()) {
+ bool allowed = [&] {
+ if (!doc->IsStaticDocument()) {
+ // If not a print/print preview doc, then nothing else is allowed for
+ // data documents.
+ return false;
+ }
+ // Let static (print/print preview) documents to load fonts and
+ // images.
+ switch (contentType) {
+ case ExtContentPolicy::TYPE_IMAGE:
+ case ExtContentPolicy::TYPE_IMAGESET:
+ case ExtContentPolicy::TYPE_FONT:
+ case ExtContentPolicy::TYPE_UA_FONT:
+ // This one is a bit sketchy, but nsObjectLoadingContent takes care of
+ // only getting here if it is an image.
+ case ExtContentPolicy::TYPE_OBJECT:
+ return true;
+ default:
+ return false;
+ }
+ }();
+
+ if (!allowed) {
+ *aDecision = nsIContentPolicy::REJECT_TYPE;
+ return NS_OK;
+ }
+ }
+
+ mozilla::dom::Document* 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();
+ nsAutoCString sourceSpec;
+ requestingPrincipal->GetAsciiSpec(sourceSpec);
+ nsAutoCString targetSpec;
+ aContentLocation->GetAsciiSpec(targetSpec);
+ nsScriptSecurityManager::ReportError(
+ "ExternalDataError", sourceSpec, targetSpec,
+ requestingPrincipal->OriginAttributesRef().mPrivateBrowsingId > 0);
+ }
+ } else if ((contentType == ExtContentPolicy::TYPE_IMAGE ||
+ contentType == ExtContentPolicy::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 (contentType == ExtContentPolicy::TYPE_OBJECT ||
+ contentType == ExtContentPolicy::TYPE_DOCUMENT ||
+ contentType == ExtContentPolicy::TYPE_SUBDOCUMENT ||
+ contentType == ExtContentPolicy::TYPE_SCRIPT ||
+ contentType == ExtContentPolicy::TYPE_XSLT ||
+ contentType == ExtContentPolicy::TYPE_FETCH ||
+ contentType == ExtContentPolicy::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(nsIURI* aContentLocation,
+ nsILoadInfo* aLoadInfo,
+ const nsACString& aMimeGuess,
+ int16_t* aDecision) {
+ return ShouldLoad(aContentLocation, aLoadInfo, aMimeGuess, aDecision);
+}