path: root/netwerk/base/nsChannelClassifier.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "nsChannelClassifier.h"

#include "mozIThirdPartyUtil.h"
#include "nsCharSeparatedTokenizer.h"
#include "nsContentUtils.h"
#include "nsICacheEntry.h"
#include "nsICachingChannel.h"
#include "nsIChannel.h"
#include "nsIDocShell.h"
#include "nsIDocument.h"
#include "nsIDOMDocument.h"
#include "nsIHttpChannelInternal.h"
#include "nsIIOService.h"
#include "nsILoadContext.h"
#include "nsIParentChannel.h"
#include "nsIPermissionManager.h"
#include "nsIProtocolHandler.h"
#include "nsIScriptError.h"
#include "nsIScriptSecurityManager.h"
#include "nsISecureBrowserUI.h"
#include "nsISecurityEventSink.h"
#include "nsIURL.h"
#include "nsIWebProgressListener.h"
#include "nsNetUtil.h"
#include "nsPIDOMWindow.h"
#include "nsXULAppAPI.h"

#include "mozilla/ErrorNames.h"
#include "mozilla/Logging.h"
#include "mozilla/Preferences.h"

namespace mozilla {
namespace net {

//
// MOZ_LOG=nsChannelClassifier:5
//
static LazyLogModule gChannelClassifierLog("nsChannelClassifier");

#undef LOG
#define LOG(args)     MOZ_LOG(gChannelClassifierLog, LogLevel::Debug, args)
#define LOG_ENABLED() MOZ_LOG_TEST(gChannelClassifierLog, LogLevel::Debug)

NS_IMPL_ISUPPORTS(nsChannelClassifier,
                  nsIURIClassifierCallback)

nsChannelClassifier::nsChannelClassifier()
  : mIsAllowListed(false),
    mSuspendedChannel(false)
{
}

void
nsChannelClassifier::Start(nsIChannel *aChannel)
{
  mChannel = aChannel;

  nsresult rv = StartInternal();
  if (NS_FAILED(rv)) {
    // If we aren't getting a callback for any reason, assume a good verdict and
    // make sure we resume the channel if necessary.
    OnClassifyComplete(NS_OK);
  }
}

nsresult
nsChannelClassifier::StartInternal()
{
    // Should only be called in the parent process.
    MOZ_ASSERT(XRE_IsParentProcess());

    // Don't bother to run the classifier on a load that has already failed.
    // (this might happen after a redirect)
    nsresult status;
    mChannel->GetStatus(&status);
    if (NS_FAILED(status))
        return status;

    // Don't bother to run the classifier on a cached load that was
    // previously classified as good.
    if (HasBeenClassified(mChannel)) {
        return NS_ERROR_UNEXPECTED;
    }

    nsCOMPtr<nsIURI> uri;
    nsresult rv = mChannel->GetURI(getter_AddRefs(uri));
    NS_ENSURE_SUCCESS(rv, rv);

    // Don't bother checking certain types of URIs.
    bool hasFlags;
    rv = NS_URIChainHasFlags(uri,
                             nsIProtocolHandler::URI_DANGEROUS_TO_LOAD,
                             &hasFlags);
    NS_ENSURE_SUCCESS(rv, rv);
    if (hasFlags) return NS_ERROR_UNEXPECTED;

    rv = NS_URIChainHasFlags(uri,
                             nsIProtocolHandler::URI_IS_LOCAL_FILE,
                             &hasFlags);
    NS_ENSURE_SUCCESS(rv, rv);
    if (hasFlags) return NS_ERROR_UNEXPECTED;

    rv = NS_URIChainHasFlags(uri,
                             nsIProtocolHandler::URI_IS_UI_RESOURCE,
                             &hasFlags);
    NS_ENSURE_SUCCESS(rv, rv);
    if (hasFlags) return NS_ERROR_UNEXPECTED;

    rv = NS_URIChainHasFlags(uri,
                             nsIProtocolHandler::URI_IS_LOCAL_RESOURCE,
                             &hasFlags);
    NS_ENSURE_SUCCESS(rv, rv);
    if (hasFlags) return NS_ERROR_UNEXPECTED;

    // Skip whitelisted hostnames.
    nsAutoCString whitelisted;
    Preferences::GetCString("urlclassifier.skipHostnames", &whitelisted);
    if (!whitelisted.IsEmpty()) {
      ToLowerCase(whitelisted);
      LOG(("nsChannelClassifier[%p]:StartInternal whitelisted hostnames = %s",
           this, whitelisted.get()));
      if (IsHostnameWhitelisted(uri, whitelisted)) {
        return NS_ERROR_UNEXPECTED;
      }
    }

    nsCOMPtr<nsIURIClassifier> uriClassifier =
        do_GetService(NS_URICLASSIFIERSERVICE_CONTRACTID, &rv);
    if (rv == NS_ERROR_FACTORY_NOT_REGISTERED ||
        rv == NS_ERROR_NOT_AVAILABLE) {
        // no URI classifier, ignore this failure.
        return NS_ERROR_NOT_AVAILABLE;
    }
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIScriptSecurityManager> securityManager =
        do_GetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID, &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIPrincipal> principal;
    rv = securityManager->GetChannelURIPrincipal(mChannel, getter_AddRefs(principal));
    NS_ENSURE_SUCCESS(rv, rv);

    bool expectCallback;

    if (LOG_ENABLED()) {
      nsCOMPtr<nsIURI> principalURI;
      principal->GetURI(getter_AddRefs(principalURI));
      LOG(("nsChannelClassifier[%p]: Classifying principal %s on channel with "
           "uri %s", this, principalURI->GetSpecOrDefault().get(),
           uri->GetSpecOrDefault().get()));
    }
    rv = uriClassifier->Classify(principal, false, this, &expectCallback);
    if (NS_FAILED(rv)) {
        return rv;
    }

    if (expectCallback) {
        // Suspend the channel, it will be resumed when we get the classifier
        // callback.
        rv = mChannel->Suspend();
        if (NS_FAILED(rv)) {
            // Some channels (including nsJSChannel) fail on Suspend.  This
            // shouldn't be fatal, but will prevent malware from being
            // blocked on these channels.
            LOG(("nsChannelClassifier[%p]: Couldn't suspend channel", this));
            return rv;
        }

        mSuspendedChannel = true;
        LOG(("nsChannelClassifier[%p]: suspended channel %p",
             this, mChannel.get()));
    } else {
        LOG(("nsChannelClassifier[%p]: not expecting callback", this));
        return NS_ERROR_FAILURE;
    }

    return NS_OK;
}

bool
nsChannelClassifier::IsHostnameWhitelisted(nsIURI *aUri,
                                           const nsACString &aWhitelisted)
{
  nsAutoCString host;
  nsresult rv = aUri->GetHost(host);
  if (NS_FAILED(rv) || host.IsEmpty()) {
    return false;
  }
  ToLowerCase(host);

  nsCCharSeparatedTokenizer tokenizer(aWhitelisted, ',');
  while (tokenizer.hasMoreTokens()) {
    const nsCSubstring& token = tokenizer.nextToken();
    if (token.Equals(host)) {
      LOG(("nsChannelClassifier[%p]:StartInternal skipping %s (whitelisted)",
           this, host.get()));
      return true;
    }
  }

  return false;
}

// Note in the cache entry that this URL was classified, so that future
// cached loads don't need to be checked.
void
nsChannelClassifier::MarkEntryClassified(nsresult status)
{
    // Should only be called in the parent process.
    MOZ_ASSERT(XRE_IsParentProcess());

    if (mIsAllowListed) {
        return;
    }

    if (LOG_ENABLED()) {
      nsAutoCString errorName;
      GetErrorName(status, errorName);
      nsCOMPtr<nsIURI> uri;
      mChannel->GetURI(getter_AddRefs(uri));
      nsAutoCString spec;
      uri->GetAsciiSpec(spec);
      LOG(("nsChannelClassifier::MarkEntryClassified[%s] %s",
           errorName.get(), spec.get()));
    }

    nsCOMPtr<nsICachingChannel> cachingChannel = do_QueryInterface(mChannel);
    if (!cachingChannel) {
        return;
    }

    nsCOMPtr<nsISupports> cacheToken;
    cachingChannel->GetCacheToken(getter_AddRefs(cacheToken));
    if (!cacheToken) {
        return;
    }

    nsCOMPtr<nsICacheEntry> cacheEntry =
        do_QueryInterface(cacheToken);
    if (!cacheEntry) {
        return;
    }

    cacheEntry->SetMetaDataElement("necko:classified",
                                   NS_SUCCEEDED(status) ? "1" : nullptr);
}

bool
nsChannelClassifier::HasBeenClassified(nsIChannel *aChannel)
{
    // Should only be called in the parent process.
    MOZ_ASSERT(XRE_IsParentProcess());

    nsCOMPtr<nsICachingChannel> cachingChannel =
        do_QueryInterface(aChannel);
    if (!cachingChannel) {
        return false;
    }

    // Only check the tag if we are loading from the cache without
    // validation.
    bool fromCache;
    if (NS_FAILED(cachingChannel->IsFromCache(&fromCache)) || !fromCache) {
        return false;
    }

    nsCOMPtr<nsISupports> cacheToken;
    cachingChannel->GetCacheToken(getter_AddRefs(cacheToken));
    if (!cacheToken) {
        return false;
    }

    nsCOMPtr<nsICacheEntry> cacheEntry =
        do_QueryInterface(cacheToken);
    if (!cacheEntry) {
        return false;
    }

    nsXPIDLCString tag;
    cacheEntry->GetMetaDataElement("necko:classified", getter_Copies(tag));
    return tag.EqualsLiteral("1");
}

//static
bool
nsChannelClassifier::SameLoadingURI(nsIDocument *aDoc, nsIChannel *aChannel)
{
  nsCOMPtr<nsIURI> docURI = aDoc->GetDocumentURI();
  nsCOMPtr<nsILoadInfo> channelLoadInfo = aChannel->GetLoadInfo();
  if (!channelLoadInfo || !docURI) {
    return false;
  }

  nsCOMPtr<nsIPrincipal> channelLoadingPrincipal = channelLoadInfo->LoadingPrincipal();
  if (!channelLoadingPrincipal) {
    // TYPE_DOCUMENT loads will not have a channelLoadingPrincipal. But top level
    // loads should not be blocked by Tracking Protection, so we will return
    // false
    return false;
  }
  nsCOMPtr<nsIURI> channelLoadingURI;
  channelLoadingPrincipal->GetURI(getter_AddRefs(channelLoadingURI));
  if (!channelLoadingURI) {
    return false;
  }
  bool equals = false;
  nsresult rv = docURI->EqualsExceptRef(channelLoadingURI, &equals);
  return NS_SUCCEEDED(rv) && equals;
}

NS_IMETHODIMP
nsChannelClassifier::OnClassifyComplete(nsresult aErrorCode)
{
    // Should only be called in the parent process.
    MOZ_ASSERT(XRE_IsParentProcess());

    if (mSuspendedChannel) {
      nsAutoCString errorName;
      if (LOG_ENABLED()) {
        GetErrorName(aErrorCode, errorName);
        LOG(("nsChannelClassifier[%p]:OnClassifyComplete %s (suspended channel)",
             this, errorName.get()));
      }
      MarkEntryClassified(aErrorCode);

      if (NS_FAILED(aErrorCode)) {
        if (LOG_ENABLED()) {
          nsCOMPtr<nsIURI> uri;
          mChannel->GetURI(getter_AddRefs(uri));
          LOG(("nsChannelClassifier[%p]: cancelling channel %p for %s "
               "with error code %s", this, mChannel.get(),
               uri->GetSpecOrDefault().get(), errorName.get()));
        }

        mChannel->Cancel(aErrorCode);
      }
      LOG(("nsChannelClassifier[%p]: resuming channel %p from "
           "OnClassifyComplete", this, mChannel.get()));
      mChannel->Resume();
    }

    mChannel = nullptr;

    return NS_OK;
}

} // namespace net
} // namespace mozilla