Michael Stefaniuc : dmloader: Avoid a crash on a NULL string pointer.

[Alexandre Julliard]

Module: wine
Branch: stable
Commit: 863a496cef8066623b43cc8b135daf0846145944
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=863a496cef8066623b43cc8b13...

Author: Michael Stefaniuc 
Date:   Thu Apr 27 19:15:27 2017 +0200

dmloader: Avoid a crash on a NULL string pointer.

Signed-off-by: Michael Stefaniuc 
Signed-off-by: Alexandre Julliard 
(cherry picked from commit ed6ee0f815518a7bbb3942dbc49f157a57970db1)
Signed-off-by: Michael Stefaniuc

---

dlls/dmloader/loader.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/dlls/dmloader/loader.c b/dlls/dmloader/loader.c
index 0822891..d644abb 100644
--- a/dlls/dmloader/loader.c
+++ b/dlls/dmloader/loader.c
@@ -536,12 +536,16 @@ static HRESULT WINAPI IDirectMusicLoaderImpl_ScanDirectory(IDirectMusicLoader8 *
    WCHAR wszSearchString[MAX_PATH];
    WCHAR *p;
    HRESULT result;
-	TRACE("(%p, %s, %p, %p)\n", This, debugstr_dmguid(rguidClass), pwzFileExtension, pwzScanFileName);
+        TRACE("(%p, %s, %s, %s)\n", This, debugstr_dmguid(rguidClass), debugstr_w(pwzFileExtension),
+                        debugstr_w(pwzScanFileName));
    if (IsEqualGUID (rguidClass, &GUID_DirectMusicAllTypes) || !DMUSIC_IsValidLoadableClass(rguidClass)) {
    	ERR(": rguidClass invalid CLSID\n");
    	return REGDB_E_CLASSNOTREG;
    }
-	
+
+        if (!pwzFileExtension)
+                return S_FALSE;
+
    /* get search path for given class */
    DMUSIC_GetLoaderSettings (iface, rguidClass, wszSearchString, NULL);