1 files changed, 247 insertions, 0 deletions
diff --git a/dom/security/FramingChecker.cpp b/dom/security/FramingChecker.cpp
new file mode 100644
index 0000000000..7b473b0764
--- /dev/null
+++ b/dom/security/FramingChecker.cpp
@@ -0,0 +1,247 @@
+/* -*- 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/. */
+
+#include "FramingChecker.h"
+#include "nsCharSeparatedTokenizer.h"
+#include "nsContentUtils.h"
+#include "nsCSPUtils.h"
+#include "nsDocShell.h"
+#include "nsHttpChannel.h"
+#include "nsContentSecurityUtils.h"
+#include "nsGlobalWindowOuter.h"
+#include "nsIChannel.h"
+#include "nsIConsoleReportCollector.h"
+#include "nsIContentSecurityPolicy.h"
+#include "nsIScriptError.h"
+#include "nsNetUtil.h"
+#include "nsQueryObject.h"
+#include "nsTArray.h"
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/dom/nsCSPUtils.h"
+#include "mozilla/dom/LoadURIOptionsBinding.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+#include "mozilla/NullPrincipal.h"
+#include "mozilla/net/HttpBaseChannel.h"
+
+#include "nsIObserverService.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+/* static */
+void FramingChecker::ReportError(const char* aMessageTag,
+                                 nsIHttpChannel* aChannel, nsIURI* aURI,
+                                 const nsAString& aPolicy) {
+  MOZ_ASSERT(aChannel);
+  MOZ_ASSERT(aURI);
+
+  nsCOMPtr<net::HttpBaseChannel> httpChannel = do_QueryInterface(aChannel);
+  if (!httpChannel) {
+    return;
+  }
+
+  // Get the URL spec
+  nsAutoCString spec;
+  nsresult rv = aURI->GetAsciiSpec(spec);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  nsTArray<nsString> params;
+  params.AppendElement(aPolicy);
+  params.AppendElement(NS_ConvertUTF8toUTF16(spec));
+
+  httpChannel->AddConsoleReport(nsIScriptError::errorFlag, "X-Frame-Options"_ns,
+                                nsContentUtils::eSECURITY_PROPERTIES, spec, 0,
+                                0, nsDependentCString(aMessageTag), params);
+}
+
+/* static */
+bool FramingChecker::CheckOneFrameOptionsPolicy(nsIHttpChannel* aHttpChannel,
+                                                const nsAString& aPolicy) {
+  nsCOMPtr<nsIURI> uri;
+  aHttpChannel->GetURI(getter_AddRefs(uri));
+
+  // return early if header does not have one of the values with meaning
+  if (!aPolicy.LowerCaseEqualsLiteral("deny") &&
+      !aPolicy.LowerCaseEqualsLiteral("sameorigin")) {
+    ReportError("XFrameOptionsInvalid", aHttpChannel, uri, aPolicy);
+    return true;
+  }
+
+  // If the X-Frame-Options value is SAMEORIGIN, then the top frame in the
+  // parent chain must be from the same origin as this document.
+  bool checkSameOrigin = aPolicy.LowerCaseEqualsLiteral("sameorigin");
+
+  nsCOMPtr<nsILoadInfo> loadInfo = aHttpChannel->LoadInfo();
+  RefPtr<mozilla::dom::BrowsingContext> ctx;
+  loadInfo->GetBrowsingContext(getter_AddRefs(ctx));
+
+  while (ctx) {
+    nsCOMPtr<nsIPrincipal> principal;
+    // Generally CheckOneFrameOptionsPolicy is consulted from within the
+    // DocumentLoadListener in the parent process. For loads of type object
+    // and embed it's called from the Document in the content process.
+    // After Bug 1646899 we should be able to remove that branching code for
+    // querying the principal.
+    if (XRE_IsParentProcess()) {
+      WindowGlobalParent* window = ctx->Canonical()->GetCurrentWindowGlobal();
+      if (window) {
+        // Using the URI of the Principal and not the document because e.g.
+        // window.open inherits the principal and hence the URI of the
+        // opening context needed for same origin checks.
+        principal = window->DocumentPrincipal();
+      }
+    } else if (nsPIDOMWindowOuter* windowOuter = ctx->GetDOMWindow()) {
+      principal = nsGlobalWindowOuter::Cast(windowOuter)->GetPrincipal();
+    }
+
+    if (principal && principal->IsSystemPrincipal()) {
+      return true;
+    }
+
+    if (checkSameOrigin) {
+      bool isPrivateWin = false;
+      bool isSameOrigin = false;
+      if (principal) {
+        isPrivateWin = principal->OriginAttributesRef().mPrivateBrowsingId > 0;
+        principal->IsSameOrigin(uri, isPrivateWin, &isSameOrigin);
+      }
+      // one of the ancestors is not same origin as this document
+      if (!isSameOrigin) {
+        ReportError("XFrameOptionsDeny", aHttpChannel, uri, aPolicy);
+        return false;
+      }
+    }
+    ctx = ctx->GetParent();
+  }
+
+  // If the value of the header is DENY, and the previous condition is
+  // not met (current docshell is not the top docshell), prohibit the
+  // load.
+  if (aPolicy.LowerCaseEqualsLiteral("deny")) {
+    ReportError("XFrameOptionsDeny", aHttpChannel, uri, aPolicy);
+    return false;
+  }
+
+  return true;
+}
+
+// Ignore x-frame-options if CSP with frame-ancestors exists
+static bool ShouldIgnoreFrameOptions(nsIChannel* aChannel,
+                                     nsIContentSecurityPolicy* aCSP) {
+  NS_ENSURE_TRUE(aChannel, false);
+  if (!aCSP) {
+    return false;
+  }
+
+  bool enforcesFrameAncestors = false;
+  aCSP->GetEnforcesFrameAncestors(&enforcesFrameAncestors);
+  if (!enforcesFrameAncestors) {
+    // if CSP does not contain frame-ancestors, then there
+    // is nothing to do here.
+    return false;
+  }
+
+  // log warning to console that xfo is ignored because of CSP
+  nsCOMPtr<nsILoadInfo> loadInfo = aChannel->LoadInfo();
+  uint64_t innerWindowID = loadInfo->GetInnerWindowID();
+  bool privateWindow = !!loadInfo->GetOriginAttributes().mPrivateBrowsingId;
+  AutoTArray<nsString, 2> params = {u"x-frame-options"_ns,
+                                    u"frame-ancestors"_ns};
+  CSP_LogLocalizedStr("IgnoringSrcBecauseOfDirective", params,
+                      u""_ns,  // no sourcefile
+                      u""_ns,  // no scriptsample
+                      0,       // no linenumber
+                      0,       // no columnnumber
+                      nsIScriptError::warningFlag,
+                      "IgnoringSrcBecauseOfDirective"_ns, innerWindowID,
+                      privateWindow);
+
+  return true;
+}
+
+// Check if X-Frame-Options permits this document to be loaded as a
+// subdocument. This will iterate through and check any number of
+// X-Frame-Options policies in the request (comma-separated in a header,
+// multiple headers, etc).
+/* static */
+bool FramingChecker::CheckFrameOptions(nsIChannel* aChannel,
+                                       nsIContentSecurityPolicy* aCsp) {
+  if (!aChannel) {
+    return true;
+  }
+
+  nsCOMPtr<nsILoadInfo> loadInfo = aChannel->LoadInfo();
+  ExtContentPolicyType contentType = loadInfo->GetExternalContentPolicyType();
+
+  // xfo check only makes sense for subdocument and object loads, if this is
+  // not a load of such type, there is nothing to do here.
+  if (contentType != ExtContentPolicy::TYPE_SUBDOCUMENT &&
+      contentType != ExtContentPolicy::TYPE_OBJECT) {
+    return true;
+  }
+
+  // xfo checks are ignored in case CSP frame-ancestors is present,
+  // if so, there is nothing to do here.
+  if (ShouldIgnoreFrameOptions(aChannel, aCsp)) {
+    return true;
+  }
+
+  nsCOMPtr<nsIHttpChannel> httpChannel;
+  nsresult rv = nsContentSecurityUtils::GetHttpChannelFromPotentialMultiPart(
+      aChannel, getter_AddRefs(httpChannel));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return true;
+  }
+
+  // xfo can only hang off an httpchannel, if this is not an httpChannel
+  // then there is nothing to do here.
+  if (!httpChannel) {
+    return true;
+  }
+
+  // ignore XFO checks on channels that will be redirected
+  uint32_t responseStatus;
+  rv = httpChannel->GetResponseStatus(&responseStatus);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return true;
+  }
+  if (mozilla::net::nsHttpChannel::IsRedirectStatus(responseStatus)) {
+    return true;
+  }
+
+  nsAutoCString xfoHeaderCValue;
+  Unused << httpChannel->GetResponseHeader("X-Frame-Options"_ns,
+                                           xfoHeaderCValue);
+  NS_ConvertUTF8toUTF16 xfoHeaderValue(xfoHeaderCValue);
+
+  // if no header value, there's nothing to do.
+  if (xfoHeaderValue.IsEmpty()) {
+    return true;
+  }
+
+  // iterate through all the header values (usually there's only one, but can
+  // be many.  If any want to deny the load, deny the load.
+  nsCharSeparatedTokenizer tokenizer(xfoHeaderValue, ',');
+  while (tokenizer.hasMoreTokens()) {
+    const nsAString& tok = tokenizer.nextToken();
+    if (!CheckOneFrameOptionsPolicy(httpChannel, tok)) {
+      // if xfo blocks the load we are notifying observers for
+      // testing purposes because there is no event to gather
+      // what an iframe load was blocked or not.
+      nsCOMPtr<nsIURI> uri;
+      httpChannel->GetURI(getter_AddRefs(uri));
+      nsCOMPtr<nsIObserverService> observerService =
+          mozilla::services::GetObserverService();
+      nsAutoString policy(tok);
+      observerService->NotifyObservers(uri, "xfo-on-violate-policy",
+                                       policy.get());
+      return false;
+    }
+  }
+  return true;
+}