commit eefcc076bae9234dd5e252885b2e9344e0ad0dbe
Author: Matthew Finkel <sysrqb(a)torproject.org>
Date: Mon May 17 18:09:09 2021 +0000
Bug 40432: Prevent probing installed applications
---
.../exthandler/nsExternalHelperAppService.cpp | 30 ++++++++++++++++++----
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp
index 0dcc1d3ed6ab..7ff9c5b626a3 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -1002,8 +1002,33 @@ nsresult nsExternalHelperAppService::GetFileTokenForPath(
//////////////////////////////////////////////////////////////////////////////////////////////////////
// begin external protocol service default implementation...
//////////////////////////////////////////////////////////////////////////////////////////////////////
+
+static const char kExternalProtocolPrefPrefix[] =
+ "network.protocol-handler.external.";
+static const char kExternalProtocolDefaultPref[] =
+ "network.protocol-handler.external-default";
+
NS_IMETHODIMP nsExternalHelperAppService::ExternalProtocolHandlerExists(
const char* aProtocolScheme, bool* aHandlerExists) {
+
+ // Replicate the same check performed in LoadURI.
+ // Deny load if the prefs say to do so
+ nsAutoCString externalPref(kExternalProtocolPrefPrefix);
+ externalPref += aProtocolScheme;
+ bool allowLoad = false;
+ *aHandlerExists = false;
+ if (NS_FAILED(Preferences::GetBool(externalPref.get(), &allowLoad))) {
+ // no scheme-specific value, check the default
+ if (NS_FAILED(
+ Preferences::GetBool(kExternalProtocolDefaultPref, &allowLoad))) {
+ return NS_OK; // missing default pref
+ }
+ }
+
+ if (!allowLoad) {
+ return NS_OK; // explicitly denied
+ }
+
nsCOMPtr<nsIHandlerInfo> handlerInfo;
nsresult rv = GetProtocolHandlerInfo(nsDependentCString(aProtocolScheme),
getter_AddRefs(handlerInfo));
@@ -1046,11 +1071,6 @@ NS_IMETHODIMP nsExternalHelperAppService::IsExposedProtocol(
return NS_OK;
}
-static const char kExternalProtocolPrefPrefix[] =
- "network.protocol-handler.external.";
-static const char kExternalProtocolDefaultPref[] =
- "network.protocol-handler.external-default";
-
NS_IMETHODIMP
nsExternalHelperAppService::LoadURI(nsIURI* aURI,
nsIPrincipal* aTriggeringPrincipal,