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"
using namespace mozilla;
/* Keeps track of whether or not CSP is enabled */
bool CSPService::sCSPEnabled = true;
static LazyLogModule gCspPRLog("CSP");
CSPService::CSPService()
{
Preferences::AddBoolVarCache(&sCSPEnabled, "security.csp.enable");
}
CSPService::~CSPService()
{
mAppStatusCache.Clear();
}
NS_IMPL_ISUPPORTS(CSPService, nsIContentPolicy, nsIChannelEventSink)
// Helper function to identify protocols and content types not subject to CSP.
bool
subjectToCSP(nsIURI* aURI, nsContentPolicyType aContentType) {
// 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 false;
}
// 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 into
// the category underneath and also "javascript:" which is not
// subject to CSP content loading rules.
rv = aURI->SchemeIs("about", &match);
if (NS_SUCCEEDED(rv) && match) {
return false;
}
rv = aURI->SchemeIs("javascript", &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:
// 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;
}
// 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)
{
if (!aContentLocation) {
return NS_ERROR_FAILURE;
}
if (MOZ_LOG_TEST(gCspPRLog, LogLevel::Debug)) {
MOZ_LOG(gCspPRLog, LogLevel::Debug,
("CSPService::ShouldLoad called for %s",
aContentLocation->GetSpecOrDefault().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
// or type 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, aContentType)) {
return NS_OK;
}
// Find a principal to retrieve the CSP from. If we don't have a context node
// (because, for instance, the load originates in a service worker), or the
// requesting principal's CSP overrides our document CSP, use the request
// principal. Otherwise, use the document principal.
nsCOMPtr<nsINode> node(do_QueryInterface(aRequestContext));
nsCOMPtr<nsIPrincipal> principal;
if (!node || (aRequestPrincipal &&
BasePrincipal::Cast(aRequestPrincipal)->OverridesCSP(node->NodePrincipal()))) {
principal = aRequestPrincipal;
} else {
principal = node->NodePrincipal();
}
if (!principal) {
// if we can't query a principal, then there is nothing to do.
return NS_OK;
}
nsresult rv = NS_OK;
// 1) Apply speculate CSP for preloads
bool isPreload = nsContentUtils::IsPreloadType(aContentType);
if (isPreload) {
nsCOMPtr<nsIContentSecurityPolicy> preloadCsp;
rv = principal->GetPreloadCsp(getter_AddRefs(preloadCsp));
NS_ENSURE_SUCCESS(rv, rv);
if (preloadCsp) {
// obtain the enforcement decision
// (don't pass aExtra, we use that slot for redirects)
rv = preloadCsp->ShouldLoad(aContentType,
aContentLocation,
aRequestOrigin,
aRequestContext,
aMimeTypeGuess,
nullptr, // aExtra
aDecision);
NS_ENSURE_SUCCESS(rv, rv);
// if the preload policy already denied the load, then there
// is no point in checking the real policy
if (NS_CP_REJECTED(*aDecision)) {
return NS_OK;
}
}
}
// 2) Apply actual CSP to all loads
nsCOMPtr<nsIContentSecurityPolicy> csp;
rv = principal->GetCsp(getter_AddRefs(csp));
NS_ENSURE_SUCCESS(rv, rv);
if (csp) {
// obtain the enforcement decision
// (don't pass aExtra, we use that slot for redirects)
rv = csp->ShouldLoad(aContentType,
aContentLocation,
aRequestOrigin,
aRequestContext,
aMimeTypeGuess,
nullptr,
aDecision);
NS_ENSURE_SUCCESS(rv, rv);
}
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)
{
if (!aContentLocation) {
return NS_ERROR_FAILURE;
}
if (MOZ_LOG_TEST(gCspPRLog, LogLevel::Debug)) {
MOZ_LOG(gCspPRLog, LogLevel::Debug,
("CSPService::ShouldProcess called for %s",
aContentLocation->GetSpecOrDefault().get()));
}
// ShouldProcess is only relevant to TYPE_OBJECT, so let's convert the
// internal contentPolicyType to the mapping external one.
// If it is not TYPE_OBJECT, we can return at this point.
// Note that we should still pass the internal contentPolicyType
// (aContentType) to ShouldLoad().
uint32_t policyType =
nsContentUtils::InternalContentPolicyTypeToExternal(aContentType);
if (policyType != nsIContentPolicy::TYPE_OBJECT) {
*aDecision = nsIContentPolicy::ACCEPT;
return NS_OK;
}
return ShouldLoad(aContentType,
aContentLocation,
aRequestOrigin,
aRequestContext,
aMimeTypeGuess,
aExtra,
aRequestPrincipal,
aDecision);
}
/* nsIChannelEventSink implementation */
NS_IMETHODIMP
CSPService::AsyncOnChannelRedirect(nsIChannel *oldChannel,
nsIChannel *newChannel,
uint32_t flags,
nsIAsyncVerifyRedirectCallback *callback)
{
net::nsAsyncRedirectAutoCallback autoCallback(callback);
nsCOMPtr<nsIURI> newUri;
nsresult rv = newChannel->GetURI(getter_AddRefs(newUri));
NS_ENSURE_SUCCESS(rv, rv);
nsCOMPtr<nsILoadInfo> loadInfo = oldChannel->GetLoadInfo();
// if no loadInfo on the channel, nothing for us to do
if (!loadInfo) {
return NS_OK;
}
// 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()
nsContentPolicyType policyType = loadInfo->InternalContentPolicyType();
if (!sCSPEnabled || !subjectToCSP(newUri, policyType)) {
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));
if (NS_FAILED(rv)) {
autoCallback.DontCallback();
oldChannel->Cancel(NS_ERROR_DOM_BAD_URI);
return rv;
}
bool isPreload = nsContentUtils::IsPreloadType(policyType);
/* On redirect, if the content policy is a preload type, rejecting the preload
* results in the load silently failing, so we convert preloads to the actual
* type. See Bug 1219453.
*/
policyType =
nsContentUtils::InternalContentPolicyTypeToExternalOrWorker(policyType);
int16_t aDecision = nsIContentPolicy::ACCEPT;
// 1) Apply speculative CSP for preloads
if (isPreload) {
nsCOMPtr<nsIContentSecurityPolicy> preloadCsp;
loadInfo->LoadingPrincipal()->GetPreloadCsp(getter_AddRefs(preloadCsp));
if (preloadCsp) {
// Pass originalURI as aExtra to indicate the redirect
preloadCsp->ShouldLoad(policyType, // load type per nsIContentPolicy (uint32_t)
newUri, // nsIURI
nullptr, // nsIURI
nullptr, // nsISupports
EmptyCString(), // ACString - MIME guess
originalUri, // aExtra
&aDecision);
// if the preload policy already denied the load, then there
// is no point in checking the real policy
if (NS_CP_REJECTED(aDecision)) {
autoCallback.DontCallback();
oldChannel->Cancel(NS_ERROR_DOM_BAD_URI);
return NS_BINDING_FAILED;
}
}
}
// 2) Apply actual CSP to all loads
nsCOMPtr<nsIContentSecurityPolicy> csp;
loadInfo->LoadingPrincipal()->GetCsp(getter_AddRefs(csp));
if (csp) {
// Pass originalURI as aExtra to indicate the redirect
csp->ShouldLoad(policyType, // load type per nsIContentPolicy (uint32_t)
newUri, // nsIURI
nullptr, // nsIURI
nullptr, // nsISupports
EmptyCString(), // ACString - MIME guess
originalUri, // aExtra
&aDecision);
}
// if ShouldLoad doesn't accept the load, cancel the request
if (!NS_CP_ACCEPTED(aDecision)) {
autoCallback.DontCallback();
oldChannel->Cancel(NS_ERROR_DOM_BAD_URI);
return NS_BINDING_FAILED;
}
return NS_OK;
}