dom/security/CSPEvalChecker.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/dom/CSPEvalChecker.h"
   8 #include "mozilla/dom/Document.h"
   9 #include "mozilla/dom/WorkerPrivate.h"
  10 #include "mozilla/dom/WorkerRunnable.h"
  11 #include "mozilla/BasePrincipal.h"
  12 #include "mozilla/ErrorResult.h"
  13 #include "nsIParentChannel.h"
  14 #include "nsGlobalWindowInner.h"
  15 #include "nsContentSecurityUtils.h"
  16 #include "nsContentUtils.h"
  17 #include "nsCOMPtr.h"
  18 #include "nsJSUtils.h"
  19
  20 using namespace mozilla;
  21 using namespace mozilla::dom;
  22
  23 namespace {
  24
  25 // We use the subjectPrincipal to assert that eval() is never
  26 // executed in system privileged context.
  27 nsresult CheckInternal(nsIContentSecurityPolicy* aCSP,
  28                        nsICSPEventListener* aCSPEventListener,
  29                        nsIPrincipal* aSubjectPrincipal,
  30                        const nsAString& aExpression,
  31                        const nsAString& aFileNameString, uint32_t aLineNum,
  32                        uint32_t aColumnNum, bool* aAllowed) {
  33   MOZ_ASSERT(NS_IsMainThread());
  34   MOZ_ASSERT(aAllowed);
  35
  36   // The value is set at any "return", but better to have a default value here.
  37   *aAllowed = false;
  38
  39   // This is the non-CSP check for gating eval() use in the SystemPrincipal
  40 #if !defined(ANDROID)
  41   JSContext* cx = nsContentUtils::GetCurrentJSContext();
  42   if (!nsContentSecurityUtils::IsEvalAllowed(
  43           cx, aSubjectPrincipal->IsSystemPrincipal(), aExpression)) {
  44     *aAllowed = false;
  45     return NS_OK;
  46   }
  47 #endif
  48
  49   if (!aCSP) {
  50     *aAllowed = true;
  51     return NS_OK;
  52   }
  53
  54   bool reportViolation = false;
  55   nsresult rv = aCSP->GetAllowsEval(&reportViolation, aAllowed);
  56   if (NS_WARN_IF(NS_FAILED(rv))) {
  57     *aAllowed = false;
  58     return rv;
  59   }
  60
  61   if (reportViolation) {
  62     aCSP->LogViolationDetails(nsIContentSecurityPolicy::VIOLATION_TYPE_EVAL,
  63                               nullptr,  // triggering element
  64                               aCSPEventListener, aFileNameString, aExpression,
  65                               aLineNum, aColumnNum, u""_ns, u""_ns);
  66   }
  67
  68   return NS_OK;
  69 }
  70
  71 class WorkerCSPCheckRunnable final : public WorkerMainThreadRunnable {
  72  public:
  73   WorkerCSPCheckRunnable(WorkerPrivate* aWorkerPrivate,
  74                          const nsAString& aExpression,
  75                          const nsAString& aFileNameString, uint32_t aLineNum,
  76                          uint32_t aColumnNum)
  77       : WorkerMainThreadRunnable(aWorkerPrivate, "CSP Eval Check"_ns),
  78         mExpression(aExpression),
  79         mFileNameString(aFileNameString),
  80         mLineNum(aLineNum),
  81         mColumnNum(aColumnNum),
  82         mEvalAllowed(false) {}
  83
  84   bool MainThreadRun() override {
  85     mResult = CheckInternal(
  86         mWorkerPrivate->GetCsp(), mWorkerPrivate->CSPEventListener(),
  87         mWorkerPrivate->GetLoadingPrincipal(), mExpression, mFileNameString,
  88         mLineNum, mColumnNum, &mEvalAllowed);
  89     return true;
  90   }
  91
  92   nsresult GetResult(bool* aAllowed) {
  93     MOZ_ASSERT(aAllowed);
  94     *aAllowed = mEvalAllowed;
  95     return mResult;
  96   }
  97
  98  private:
  99   const nsString mExpression;
 100   const nsString mFileNameString;
 101   const uint32_t mLineNum;
 102   const uint32_t mColumnNum;
 103   bool mEvalAllowed;
 104   nsresult mResult;
 105 };
 106
 107 }  // namespace
 108
 109 /* static */
 110 nsresult CSPEvalChecker::CheckForWindow(JSContext* aCx,
 111                                         nsGlobalWindowInner* aWindow,
 112                                         const nsAString& aExpression,
 113                                         bool* aAllowEval) {
 114   MOZ_ASSERT(NS_IsMainThread());
 115   MOZ_ASSERT(aWindow);
 116   MOZ_ASSERT(aAllowEval);
 117
 118   // The value is set at any "return", but better to have a default value here.
 119   *aAllowEval = false;
 120
 121   // if CSP is enabled, and setTimeout/setInterval was called with a string,
 122   // disable the registration and log an error
 123   nsCOMPtr<Document> doc = aWindow->GetExtantDoc();
 124   if (!doc) {
 125     // if there's no document, we don't have to do anything.
 126     *aAllowEval = true;
 127     return NS_OK;
 128   }
 129
 130   nsresult rv = NS_OK;
 131
 132   // Get the calling location.
 133   uint32_t lineNum = 0;
 134   uint32_t columnNum = 1;
 135   nsAutoString fileNameString;
 136   if (!nsJSUtils::GetCallingLocation(aCx, fileNameString, &lineNum,
 137                                      &columnNum)) {
 138     fileNameString.AssignLiteral("unknown");
 139   }
 140
 141   nsCOMPtr<nsIContentSecurityPolicy> csp = doc->GetCsp();
 142   rv = CheckInternal(csp, nullptr /* no CSPEventListener for window */,
 143                      doc->NodePrincipal(), aExpression, fileNameString, lineNum,
 144                      columnNum, aAllowEval);
 145   if (NS_WARN_IF(NS_FAILED(rv))) {
 146     *aAllowEval = false;
 147     return rv;
 148   }
 149
 150   return NS_OK;
 151 }
 152
 153 /* static */
 154 nsresult CSPEvalChecker::CheckForWorker(JSContext* aCx,
 155                                         WorkerPrivate* aWorkerPrivate,
 156                                         const nsAString& aExpression,
 157                                         bool* aAllowEval) {
 158   MOZ_ASSERT(aWorkerPrivate);
 159   aWorkerPrivate->AssertIsOnWorkerThread();
 160   MOZ_ASSERT(aAllowEval);
 161
 162   // The value is set at any "return", but better to have a default value here.
 163   *aAllowEval = false;
 164
 165   // Get the calling location.
 166   uint32_t lineNum = 0;
 167   uint32_t columnNum = 1;
 168   nsAutoString fileNameString;
 169   if (!nsJSUtils::GetCallingLocation(aCx, fileNameString, &lineNum,
 170                                      &columnNum)) {
 171     fileNameString.AssignLiteral("unknown");
 172   }
 173
 174   RefPtr<WorkerCSPCheckRunnable> r = new WorkerCSPCheckRunnable(
 175       aWorkerPrivate, aExpression, fileNameString, lineNum, columnNum);
 176   ErrorResult error;
 177   r->Dispatch(Canceling, error);
 178   if (NS_WARN_IF(error.Failed())) {
 179     *aAllowEval = false;
 180     return error.StealNSResult();
 181   }
 182
 183   nsresult rv = r->GetResult(aAllowEval);
 184   if (NS_WARN_IF(NS_FAILED(rv))) {
 185     *aAllowEval = false;
 186     return rv;
 187   }
 188
 189   return NS_OK;
 190 }