gecko-dev/dom/security/nsCSPService.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/. */
#include "mozilla/Logging.h"
#include "nsString.h"
#include "nsCOMPtr.h"
#include "nsIURI.h"
#include "nsIPrincipal.h"
#include "nsIObserver.h"
#include "nsIContent.h"
#include "nsCSPService.h"
#include "nsIContentSecurityPolicy.h"
#include "nsError.h"
#include "nsIAsyncVerifyRedirectCallback.h"
#include "nsAsyncRedirectVerifyHelper.h"
#include "mozilla/Preferences.h"
#include "nsIScriptError.h"
#include "nsContentUtils.h"
#include "nsContentPolicyUtils.h"
#include "nsPrincipal.h"
using namespace mozilla;
/* Keeps track of whether or not CSP is enabled */
bool CSPService::sCSPEnabled = true;
static PRLogModuleInfo* gCspPRLog;
CSPService::CSPService()
{
Preferences::AddBoolVarCache(&sCSPEnabled, "security.csp.enable");
if (!gCspPRLog)
gCspPRLog = PR_NewLogModule("CSP");
}
CSPService::~CSPService()
{
mAppStatusCache.Clear();
}
NS_IMPL_ISUPPORTS(CSPService, nsIContentPolicy, nsIChannelEventSink)
// Helper function to identify protocols not subject to CSP.
bool
subjectToCSP(nsIURI* aURI) {
// The three protocols: data:, blob: and filesystem: share the same
// protocol flag (URI_IS_LOCAL_RESOURCE) with other protocols, like
// chrome:, resource:, moz-icon:, but those three protocols get
// special attention in CSP and are subject to CSP, hence we have
// to make sure those protocols are subject to CSP, see:
// http://www.w3.org/TR/CSP2/#source-list-guid-matching
bool match = false;
nsresult rv = aURI->SchemeIs("data", &match);
if (NS_SUCCEEDED(rv) && match) {
return true;
}
rv = aURI->SchemeIs("blob", &match);
if (NS_SUCCEEDED(rv) && match) {
return true;
}
rv = aURI->SchemeIs("filesystem", &match);
if (NS_SUCCEEDED(rv) && match) {
return true;
}
// finally we have to whitelist "about:" which does not fall in
// any of the two categories underneath but is not subject to CSP.
rv = aURI->SchemeIs("about", &match);
if (NS_SUCCEEDED(rv) && match) {
return false;
}
// Other protocols are not subject to CSP and can be whitelisted:
// * URI_IS_LOCAL_RESOURCE
// e.g. chrome:, data:, blob:, resource:, moz-icon:
// * URI_INHERITS_SECURITY_CONTEXT
// e.g. javascript:
//
// Please note that it should be possible for websites to
// whitelist their own protocol handlers with respect to CSP,
// hence we use protocol flags to accomplish that.
rv = NS_URIChainHasFlags(aURI, nsIProtocolHandler::URI_IS_LOCAL_RESOURCE, &match);
if (NS_SUCCEEDED(rv) && match) {
return false;
}
rv = NS_URIChainHasFlags(aURI, nsIProtocolHandler::URI_INHERITS_SECURITY_CONTEXT, &match);
if (NS_SUCCEEDED(rv) && match) {
return false;
}
// all other protocols are subject To CSP.
return true;
}
/* nsIContentPolicy implementation */
NS_IMETHODIMP
CSPService::ShouldLoad(uint32_t aContentType,
nsIURI *aContentLocation,
nsIURI *aRequestOrigin,
nsISupports *aRequestContext,
const nsACString &aMimeTypeGuess,
nsISupports *aExtra,
nsIPrincipal *aRequestPrincipal,
int16_t *aDecision)
{
MOZ_ASSERT(aContentType ==
nsContentUtils::InternalContentPolicyTypeToExternalOrPreload(aContentType),
"We should only see external content policy types or preloads here.");
if (!aContentLocation) {
return NS_ERROR_FAILURE;
}
if (MOZ_LOG_TEST(gCspPRLog, LogLevel::Debug)) {
nsAutoCString location;
aContentLocation->GetSpec(location);
MOZ_LOG(gCspPRLog, LogLevel::Debug,
("CSPService::ShouldLoad called for %s", location.get()));
}
// default decision, CSP can revise it if there's a policy to enforce
*aDecision = nsIContentPolicy::ACCEPT;
// No need to continue processing if CSP is disabled or if the protocol
// is *not* subject to CSP.
// Please note, the correct way to opt-out of CSP using a custom
// protocolHandler is to set one of the nsIProtocolHandler flags
// that are whitelistet in subjectToCSP()
if (!sCSPEnabled || !subjectToCSP(aContentLocation)) {
return NS_OK;
}
// These content types are not subject to CSP content policy checks:
// TYPE_CSP_REPORT -- csp can't block csp reports
// TYPE_REFRESH -- never passed to ShouldLoad (see nsIContentPolicy.idl)
// TYPE_DOCUMENT -- used for frame-ancestors
if (aContentType == nsIContentPolicy::TYPE_CSP_REPORT ||
aContentType == nsIContentPolicy::TYPE_REFRESH ||
aContentType == nsIContentPolicy::TYPE_DOCUMENT) {
return NS_OK;
}
// ----- THIS IS A TEMPORARY FAST PATH FOR CERTIFIED APPS. -----
// ----- PLEASE REMOVE ONCE bug 925004 LANDS. -----
// Cache the app status for this origin.
uint16_t status = nsIPrincipal::APP_STATUS_NOT_INSTALLED;
nsAutoCString sourceOrigin;
if (aRequestPrincipal && aRequestOrigin) {
aRequestOrigin->GetPrePath(sourceOrigin);
if (!mAppStatusCache.Get(sourceOrigin, &status)) {
aRequestPrincipal->GetAppStatus(&status);
mAppStatusCache.Put(sourceOrigin, status);
}
}
if (status == nsIPrincipal::APP_STATUS_CERTIFIED) {
// The CSP for certified apps is :
// "default-src * data: blob:; script-src 'self'; object-src 'none'; style-src 'self' app://theme.gaiamobile.org:*"
// That means we can optimize for this case by:
// - loading same origin scripts and stylesheets, and stylesheets from the
// theme url space.
// - never loading objects.
// - accepting everything else.
switch (aContentType) {
case nsIContentPolicy::TYPE_SCRIPT:
case nsIContentPolicy::TYPE_STYLESHEET:
{
// Whitelist the theme resources.
auto themeOrigin = Preferences::GetCString("b2g.theme.origin");
nsAutoCString contentOrigin;
aContentLocation->GetPrePath(contentOrigin);
if (!(sourceOrigin.Equals(contentOrigin) ||
(themeOrigin && themeOrigin.Equals(contentOrigin)))) {
*aDecision = nsIContentPolicy::REJECT_SERVER;
}
}
break;
case nsIContentPolicy::TYPE_OBJECT:
*aDecision = nsIContentPolicy::REJECT_SERVER;
break;
default:
*aDecision = nsIContentPolicy::ACCEPT;
}
// Only cache and return if we are successful. If not, we want the error
// to be reported, and thus fallback to the slow path.
if (*aDecision == nsIContentPolicy::ACCEPT) {
return NS_OK;
}
}
// ----- END OF TEMPORARY FAST PATH FOR CERTIFIED APPS. -----
// find the principal of the document that initiated this request and see
// if it has a CSP policy object
nsCOMPtr<nsINode> node(do_QueryInterface(aRequestContext));
nsCOMPtr<nsIPrincipal> principal;
nsCOMPtr<nsIContentSecurityPolicy> csp;
if (node) {
principal = node->NodePrincipal();
principal->GetCsp(getter_AddRefs(csp));
if (csp) {
if (MOZ_LOG_TEST(gCspPRLog, LogLevel::Debug)) {
uint32_t numPolicies = 0;
nsresult rv = csp->GetPolicyCount(&numPolicies);
if (NS_SUCCEEDED(rv)) {
for (uint32_t i=0; i<numPolicies; i++) {
nsAutoString policy;
csp->GetPolicy(i, policy);
MOZ_LOG(gCspPRLog, LogLevel::Debug,
("Document has CSP[%d]: %s", i,
NS_ConvertUTF16toUTF8(policy).get()));
}
}
}
// obtain the enforcement decision
// (don't pass aExtra, we use that slot for redirects)
csp->ShouldLoad(aContentType,
aContentLocation,
aRequestOrigin,
aRequestContext,
aMimeTypeGuess,
nullptr,
aDecision);
}
}
else if (MOZ_LOG_TEST(gCspPRLog, LogLevel::Debug)) {
nsAutoCString uriSpec;
aContentLocation->GetSpec(uriSpec);
MOZ_LOG(gCspPRLog, LogLevel::Debug,
("COULD NOT get nsINode for location: %s", uriSpec.get()));
}
return NS_OK;
}
NS_IMETHODIMP
CSPService::ShouldProcess(uint32_t aContentType,
nsIURI *aContentLocation,
nsIURI *aRequestOrigin,
nsISupports *aRequestContext,
const nsACString &aMimeTypeGuess,
nsISupports *aExtra,
nsIPrincipal *aRequestPrincipal,
int16_t *aDecision)
{
MOZ_ASSERT(aContentType ==
nsContentUtils::InternalContentPolicyTypeToExternalOrPreload(aContentType),
"We should only see external content policy types or preloads here.");
if (!aContentLocation)
return NS_ERROR_FAILURE;
*aDecision = nsIContentPolicy::ACCEPT;
return NS_OK;
}
/* nsIChannelEventSink implementation */
NS_IMETHODIMP
CSPService::AsyncOnChannelRedirect(nsIChannel *oldChannel,
nsIChannel *newChannel,
uint32_t flags,
nsIAsyncVerifyRedirectCallback *callback)
{
nsAsyncRedirectAutoCallback autoCallback(callback);
nsCOMPtr<nsIURI> newUri;
nsresult rv = newChannel->GetURI(getter_AddRefs(newUri));
NS_ENSURE_SUCCESS(rv, rv);
// No need to continue processing if CSP is disabled or if the protocol
// is *not* subject to CSP.
// Please note, the correct way to opt-out of CSP using a custom
// protocolHandler is to set one of the nsIProtocolHandler flags
// that are whitelistet in subjectToCSP()
if (!sCSPEnabled || !subjectToCSP(newUri)) {
return NS_OK;
}
nsCOMPtr<nsILoadInfo> loadInfo;
rv = oldChannel->GetLoadInfo(getter_AddRefs(loadInfo));
// if no loadInfo on the channel, nothing for us to do
if (!loadInfo) {
return NS_OK;
}
// Get the LoadingPrincipal and CSP from the loadInfo
nsCOMPtr<nsIContentSecurityPolicy> csp;
rv = loadInfo->LoadingPrincipal()->GetCsp(getter_AddRefs(csp));
NS_ENSURE_SUCCESS(rv, rv);
// if there is no CSP, nothing for us to do
if (!csp) {
return NS_OK;
}
/* Since redirecting channels don't call into nsIContentPolicy, we call our
* Content Policy implementation directly when redirects occur using the
* information set in the LoadInfo when channels are created.
*
* We check if the CSP permits this host for this type of load, if not,
* we cancel the load now.
*/
nsCOMPtr<nsIURI> originalUri;
rv = oldChannel->GetOriginalURI(getter_AddRefs(originalUri));
NS_ENSURE_SUCCESS(rv, rv);
nsContentPolicyType policyType =
nsContentUtils::InternalContentPolicyTypeToExternal(loadInfo->GetContentPolicyType());
int16_t aDecision = nsIContentPolicy::ACCEPT;
csp->ShouldLoad(policyType, // load type per nsIContentPolicy (uint32_t)
newUri, // nsIURI
nullptr, // nsIURI
nullptr, // nsISupports
EmptyCString(), // ACString - MIME guess
originalUri, // aMimeTypeGuess
&aDecision);
if (newUri && MOZ_LOG_TEST(gCspPRLog, LogLevel::Debug)) {
nsAutoCString newUriSpec("None");
newUri->GetSpec(newUriSpec);
MOZ_LOG(gCspPRLog, LogLevel::Debug,
("CSPService::AsyncOnChannelRedirect called for %s",
newUriSpec.get()));
}
if (aDecision == 1) {
MOZ_LOG(gCspPRLog, LogLevel::Debug,
("CSPService::AsyncOnChannelRedirect ALLOWING request."));
}
else {
MOZ_LOG(gCspPRLog, LogLevel::Debug,
("CSPService::AsyncOnChannelRedirect CANCELLING request."));
}
// if ShouldLoad doesn't accept the load, cancel the request
if (!NS_CP_ACCEPTED(aDecision)) {
autoCallback.DontCallback();
return NS_BINDING_FAILED;
}
return NS_OK;
}