commit 4b7123f235465f26052ea0dfaeebb590a3f31e0f Author: Kathy Brade brade@pearlcrescent.com Date: Tue Jun 28 15:13:05 2016 -0400

Bug 19273: Avoid JavaScript patching of the external app helper dialog.

Before launching an external application, broadcast an "external-app-requested" observer service notification to allow other modules, including extensions, a chance to cancel the launch. --- .../exthandler/nsExternalHelperAppService.cpp | 34 +++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp index 2843299..5ca4e8b 100644 --- a/uriloader/exthandler/nsExternalHelperAppService.cpp +++ b/uriloader/exthandler/nsExternalHelperAppService.cpp @@ -41,6 +41,7 @@ #include "nsThreadUtils.h" #include "nsAutoPtr.h" #include "nsIMutableArray.h" +#include "nsISupportsPrimitives.h" // for nsISupportsPRBool

// used to access our datastore of user-configured helper applications #include "nsIHandlerService.h" @@ -480,6 +481,22 @@ static nsresult GetDownloadDirectory(nsIFile **_directory, return NS_OK; }

+static nsresult shouldCancel(bool *aShouldCancel) +{ + NS_ENSURE_ARG_POINTER(aShouldCancel); + + nsCOMPtr<nsISupportsPRBool> cancelObj = + do_CreateInstance(NS_SUPPORTS_PRBOOL_CONTRACTID); + cancelObj->SetData(false); + nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService(); + if (!obs) + return NS_ERROR_FAILURE; + + obs->NotifyObservers(cancelObj, "external-app-requested", nullptr); + cancelObj->GetData(aShouldCancel); + return NS_OK; +} + /** * Structure for storing extension->type mappings. * @see defaultMimeEntries @@ -762,6 +779,14 @@ NS_IMETHODIMP nsExternalHelperAppService::DoContent(const nsACString& aMimeConte aForceSave, aWindowContext, aStreamListener); }

+ // Give other modules, including extensions, a chance to cancel. + bool doCancel = false; + nsresult rv = shouldCancel(&doCancel); + NS_ENSURE_SUCCESS(rv, rv); + if (doCancel) { + return NS_ERROR_FAILURE; + } + nsAutoString fileName; nsAutoCString fileExtension; uint32_t reason = nsIHelperAppLauncherDialog::REASON_CANTHANDLE; @@ -798,7 +823,6 @@ NS_IMETHODIMP nsExternalHelperAppService::DoContent(const nsACString& aMimeConte nsAutoCString query;

// We only care about the query for HTTP and HTTPS URLs - nsresult rv; bool isHTTP, isHTTPS; rv = uri->SchemeIs("http", &isHTTP); if (NS_FAILED(rv)) { @@ -1058,6 +1082,14 @@ nsExternalHelperAppService::LoadURI(nsIURI *aURI, return NS_OK; // explicitly denied }

+ // Give other modules, including extensions, a chance to cancel. + bool doCancel = false; + rv = shouldCancel(&doCancel); + NS_ENSURE_SUCCESS(rv, rv); + if (doCancel) { + return NS_OK; + } + nsCOMPtr<nsIHandlerInfo> handler; rv = GetProtocolHandlerInfo(scheme, getter_AddRefs(handler)); NS_ENSURE_SUCCESS(rv, rv);