ntdll: Catch exceptions when accessing the application provided pointer

[André Hentschel]

Fixes the UpdateInstaller.exe from "WSUS Offline Update 7.2 - Generator" (wsusoffline.net) with a wow64 setup
see also http://trac.wsusoffline.net/trac.fcgi/browser/trunk/client/UpdateInstaller.au3

it's more or less a try2, last year i sent a version using __TRY, but 2cd062831dd4c1b8d59fd0f8be505b1348c1cbee from Dan inspired me to do it that way.

---
 dlls/ntdll/directory.c       |    2 ++
 dlls/ntdll/tests/directory.c |    5 +++++
 2 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/dlls/ntdll/directory.c b/dlls/ntdll/directory.c
index c8fff6b..28b0ab3 100644
--- a/dlls/ntdll/directory.c
+++ b/dlls/ntdll/directory.c
@@ -3022,6 +3022,8 @@ NTSTATUS WINAPI RtlWow64EnableFsRedirection( BOOLEAN enable )
 NTSTATUS WINAPI RtlWow64EnableFsRedirectionEx( ULONG disable, ULONG *old_value )
 {
     if (!is_wow64) return STATUS_NOT_IMPLEMENTED;
+    if (((ULONG_PTR)old_value >> 16) == 0) return STATUS_ACCESS_VIOLATION;
+
     *old_value = !ntdll_get_thread_data()->wow64_redir;
     ntdll_get_thread_data()->wow64_redir = !disable;
     return STATUS_SUCCESS;
diff --git a/dlls/ntdll/tests/directory.c b/dlls/ntdll/tests/directory.c
index c74bf34..d6b886a 100644
--- a/dlls/ntdll/tests/directory.c
+++ b/dlls/ntdll/tests/directory.c
@@ -287,6 +287,11 @@ static void test_redirection(void)
     ok( !status, "RtlWow64EnableFsRedirectionEx failed status %x\n", status );
     ok( !cur, "RtlWow64EnableFsRedirectionEx got %u\n", cur );
 
+    status = pRtlWow64EnableFsRedirectionEx( TRUE, NULL );
+    ok( status == STATUS_ACCESS_VIOLATION, "RtlWow64EnableFsRedirectionEx failed with status %x\n", status );
+    status = pRtlWow64EnableFsRedirectionEx( TRUE, (void*)1 );
+    ok( status == STATUS_ACCESS_VIOLATION, "RtlWow64EnableFsRedirectionEx failed with status %x\n", status );
+
     status = pRtlWow64EnableFsRedirection( FALSE );
     ok( !status, "RtlWow64EnableFsRedirectionEx failed status %x\n", status );
     status = pRtlWow64EnableFsRedirectionEx( FALSE, &cur );
-- 
1.7.4.1


-- 

Best Regards, André Hentschel