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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
// vim: ft=cpp tw=78 sw=4 et ts=8
/* 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/. */

/*
 * Implementation of the "@mozilla.org/layout/content-policy;1" contract.
 */

#include "mozilla/Logging.h"

#include "nsISupports.h"
#include "nsXPCOM.h"
#include "nsContentPolicyUtils.h"
#include "mozilla/dom/nsCSPService.h"
#include "nsContentPolicy.h"
#include "nsIURI.h"
#include "nsIDocShell.h"
#include "nsIDOMElement.h"
#include "nsIDOMNode.h"
#include "nsIDOMWindow.h"
#include "nsITabChild.h"
#include "nsIContent.h"
#include "nsIImageLoadingContent.h"
#include "nsILoadContext.h"
#include "nsCOMArray.h"
#include "nsContentUtils.h"
#include "mozilla/dom/nsMixedContentBlocker.h"
#include "nsIContentSecurityPolicy.h"
#include "mozilla/dom/TabGroup.h"
#include "mozilla/TaskCategory.h"

using mozilla::LogLevel;

NS_IMPL_ISUPPORTS(nsContentPolicy, nsIContentPolicy)

static mozilla::LazyLogModule gConPolLog("nsContentPolicy");

nsresult NS_NewContentPolicy(nsIContentPolicy **aResult) {
  *aResult = new nsContentPolicy;
  NS_ADDREF(*aResult);
  return NS_OK;
}

nsContentPolicy::nsContentPolicy()
    : mPolicies(NS_CONTENTPOLICY_CATEGORY),
      mMixedContentBlocker(do_GetService(NS_MIXEDCONTENTBLOCKER_CONTRACTID)),
      mCSPService(do_GetService(CSPSERVICE_CONTRACTID)) {}

nsContentPolicy::~nsContentPolicy() {}

#ifdef DEBUG
#define WARN_IF_URI_UNINITIALIZED(uri, name)            \
  PR_BEGIN_MACRO                                        \
  if ((uri)) {                                          \
    nsAutoCString spec;                                 \
    (uri)->GetAsciiSpec(spec);                          \
    if (spec.IsEmpty()) {                               \
      NS_WARNING(name " is uninitialized, fix caller"); \
    }                                                   \
  }                                                     \
  PR_END_MACRO

#else  // ! defined(DEBUG)

#define WARN_IF_URI_UNINITIALIZED(uri, name)

#endif  // defined(DEBUG)

inline nsresult nsContentPolicy::CheckPolicy(
    CPMethod policyMethod, nsContentPolicyType contentType,
    nsIURI *contentLocation, nsIURI *requestingLocation,
    nsISupports *requestingContext, const nsACString &mimeType,
    nsISupports *extra, nsIPrincipal *requestPrincipal, int16_t *decision) {
  // sanity-check passed-through parameters
  NS_PRECONDITION(decision, "Null out pointer");
  WARN_IF_URI_UNINITIALIZED(contentLocation, "Request URI");
  WARN_IF_URI_UNINITIALIZED(requestingLocation, "Requesting URI");

#ifdef DEBUG
  {
    nsCOMPtr<nsIDOMNode> node(do_QueryInterface(requestingContext));
    nsCOMPtr<nsIDOMWindow> window(do_QueryInterface(requestingContext));
    nsCOMPtr<nsITabChild> tabChild(do_QueryInterface(requestingContext));
    NS_ASSERTION(!requestingContext || node || window || tabChild,
                 "Context should be a DOM node, DOM window or a tabChild!");
  }
#endif

  /*
   * There might not be a requestinglocation. This can happen for
   * iframes with an image as src. Get the uri from the dom node.
   * See bug 254510
   */
  if (!requestingLocation) {
    nsCOMPtr<nsIDocument> doc;
    nsCOMPtr<nsIContent> node = do_QueryInterface(requestingContext);
    if (node) {
      doc = node->OwnerDoc();
    }
    if (!doc) {
      doc = do_QueryInterface(requestingContext);
    }
    if (doc) {
      requestingLocation = doc->GetDocumentURI();
    }
  }

  nsContentPolicyType externalType =
      nsContentUtils::InternalContentPolicyTypeToExternal(contentType);

  /*
   * Enumerate mPolicies and ask each of them, taking the logical AND of
   * their permissions.
   */
  nsresult rv;
  const nsCOMArray<nsIContentPolicy> &entries = mPolicies.GetCachedEntries();

  nsCOMPtr<nsPIDOMWindowOuter> window;
  if (nsCOMPtr<nsINode> node = do_QueryInterface(requestingContext)) {
    window = node->OwnerDoc()->GetWindow();
  } else {
    window = do_QueryInterface(requestingContext);
  }

  if (requestPrincipal) {
    nsCOMPtr<nsIContentSecurityPolicy> csp;
    requestPrincipal->GetCsp(getter_AddRefs(csp));
    if (csp && window) {
      csp->EnsureEventTarget(
          window->EventTargetFor(mozilla::TaskCategory::Other));
    }
  }

  int32_t count = entries.Count();
  for (int32_t i = 0; i < count; i++) {
    /* check the appropriate policy */
    // Send internal content policy type to CSP and mixed content blocker
    nsContentPolicyType type = externalType;
    if (mMixedContentBlocker == entries[i] || mCSPService == entries[i]) {
      type = contentType;
    }
    rv = (entries[i]->*policyMethod)(type, contentLocation, requestingLocation,
                                     requestingContext, mimeType, extra,
                                     requestPrincipal, decision);

    if (NS_SUCCEEDED(rv) && NS_CP_REJECTED(*decision)) {
      // If we are blocking an image, we have to let the
      // ImageLoadingContent know that we blocked the load.
      if (externalType == nsIContentPolicy::TYPE_IMAGE ||
          externalType == nsIContentPolicy::TYPE_IMAGESET) {
        nsCOMPtr<nsIImageLoadingContent> img =
            do_QueryInterface(requestingContext);
        if (img) {
          img->SetBlockedRequest(*decision);
        }
      }
      /* policy says no, no point continuing to check */
      return NS_OK;
    }
  }

  // everyone returned failure, or no policies: sanitize result
  *decision = nsIContentPolicy::ACCEPT;
  return NS_OK;
}

// uses the parameters from ShouldXYZ to produce and log a message
// logType must be a literal string constant
#define LOG_CHECK(logType)                                                     \
  PR_BEGIN_MACRO                                                               \
  /* skip all this nonsense if the call failed or logging is disabled */       \
  if (NS_SUCCEEDED(rv) && MOZ_LOG_TEST(gConPolLog, LogLevel::Debug)) {         \
    const char *resultName;                                                    \
    if (decision) {                                                            \
      resultName = NS_CP_ResponseName(*decision);                              \
    } else {                                                                   \
      resultName = "(null ptr)";                                               \
    }                                                                          \
    MOZ_LOG(                                                                   \
        gConPolLog, LogLevel::Debug,                                           \
        ("Content Policy: " logType ": <%s> <Ref:%s> result=%s",               \
         contentLocation ? contentLocation->GetSpecOrDefault().get() : "None", \
         requestingLocation ? requestingLocation->GetSpecOrDefault().get()     \
                            : "None",                                          \
         resultName));                                                         \
  }                                                                            \
  PR_END_MACRO

NS_IMETHODIMP
nsContentPolicy::ShouldLoad(uint32_t contentType, nsIURI *contentLocation,
                            nsIURI *requestingLocation,
                            nsISupports *requestingContext,
                            const nsACString &mimeType, nsISupports *extra,
                            nsIPrincipal *requestPrincipal, int16_t *decision) {
  // ShouldProcess does not need a content location, but we do
  NS_PRECONDITION(contentLocation, "Must provide request location");
  nsresult rv =
      CheckPolicy(&nsIContentPolicy::ShouldLoad, contentType, contentLocation,
                  requestingLocation, requestingContext, mimeType, extra,
                  requestPrincipal, decision);
  LOG_CHECK("ShouldLoad");

  return rv;
}

NS_IMETHODIMP
nsContentPolicy::ShouldProcess(uint32_t contentType, nsIURI *contentLocation,
                               nsIURI *requestingLocation,
                               nsISupports *requestingContext,
                               const nsACString &mimeType, nsISupports *extra,
                               nsIPrincipal *requestPrincipal,
                               int16_t *decision) {
  nsresult rv =
      CheckPolicy(&nsIContentPolicy::ShouldProcess, contentType,
                  contentLocation, requestingLocation, requestingContext,
                  mimeType, extra, requestPrincipal, decision);
  LOG_CHECK("ShouldProcess");

  return rv;
}