From 6f1c7c97a337a080f177f489fd50cc1810b60fe7 Mon Sep 17 00:00:00 2001
From: Michael Katz <45770613+microkatz@users.noreply.github.com>
Date: Tue, 26 Apr 2022 10:33:16 -0700
Subject: Check success of StringFromCLSID before printing string (#1) (#716)

* Check success of StringFromCLSID before printing string
* initialized wchar ptr to null
---
 avstream/samplemft0/Mft0.cpp | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/avstream/samplemft0/Mft0.cpp b/avstream/samplemft0/Mft0.cpp
index 044a4e71..e714d46f 100644
--- a/avstream/samplemft0/Mft0.cpp
+++ b/avstream/samplemft0/Mft0.cpp
@@ -298,7 +298,7 @@ STDMETHODIMP CMft0::GetInputAvailableType(
     IUnknown *pUnk = NULL;
     IMFAttributes *pSourceAttributes = NULL;
     UINT32 uiSourceStreamId = 0;
-    wchar_t *pszName;
+    wchar_t *pszName = NULL;
 
     EnterCriticalSection(&m_critSec);
 
@@ -321,8 +321,7 @@ STDMETHODIMP CMft0::GetInputAvailableType(
             } else if(m_stStreamType == PINNAME_IMAGE) {
                 wprintf(L"Stream type: PINNAME_IMAGE\n");
             } else {
-                StringFromCLSID(m_stStreamType, &pszName);
-                if(pszName){
+                if(SUCCEEDED(StringFromCLSID(m_stStreamType, &pszName)) && pszName){
                     wprintf(L"Stream type: %s\n", pszName);
                     CoTaskMemFree(pszName);
                 }
@@ -349,7 +348,7 @@ STDMETHODIMP CMft0::GetOutputAvailableType(
     IUnknown *pUnk = NULL;
     IMFAttributes *pSourceAttributes = NULL;
     UINT32 uiSourceStreamId = 0;
-    wchar_t *pszName;
+    wchar_t *pszName = NULL;
 
     EnterCriticalSection(&m_critSec);
 
@@ -370,8 +369,10 @@ STDMETHODIMP CMft0::GetOutputAvailableType(
             } else if(m_stStreamType == PINNAME_IMAGE) {
                 wprintf(L"Stream type: PINNAME_IMAGE\n");
             } else {
-                StringFromCLSID(m_stStreamType, &pszName);
-                wprintf(L"Stream type: %s\n", pszName);
+                if (SUCCEEDED(StringFromCLSID(m_stStreamType, &pszName)) && pszName) {
+                    wprintf(L"Stream type: %s\n", pszName);
+                    CoTaskMemFree(pszName);
+                }
             }
             CHK_LOG_BRK((m_stStreamType == PINNAME_VIDEO_PREVIEW || m_stStreamType == PINNAME_VIDEO_CAPTURE) ? S_OK : E_UNEXPECTED);
             CHK_LOG_BRK(GenerateMFMediaTypeListFromDevice(uiSourceStreamId));
-- 
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