Andrew Eikum : mfplat: Allow NULL length pointer in IMFAttributes::GetAllocatedString.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: ca10760d2e7ea4f8718741592fd639f589247e53
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=ca10760d2e7ea4f8718741592fd639f589247e53

Author: Andrew Eikum <aeikum at codeweavers.com>
Date:   Mon May  9 10:56:29 2022 -0500

mfplat: Allow NULL length pointer in IMFAttributes::GetAllocatedString.

Signed-off-by: Andrew Eikum <aeikum at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/mfplat/main.c         | 3 ++-
 dlls/mfplat/tests/mfplat.c | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/dlls/mfplat/main.c b/dlls/mfplat/main.c
index cee052defeb..08195bca448 100644
--- a/dlls/mfplat/main.c
+++ b/dlls/mfplat/main.c
@@ -2670,7 +2670,8 @@ HRESULT attributes_GetAllocatedString(struct attributes *attributes, REFGUID key
     if (SUCCEEDED(hr))
     {
         *value = attrval.pwszVal;
-        *length = lstrlenW(*value);
+        if (length)
+            *length = lstrlenW(*value);
     }
 
     return hr;
diff --git a/dlls/mfplat/tests/mfplat.c b/dlls/mfplat/tests/mfplat.c
index 8d21f2ed60e..8f18fcb293d 100644
--- a/dlls/mfplat/tests/mfplat.c
+++ b/dlls/mfplat/tests/mfplat.c
@@ -1638,6 +1638,11 @@ static void test_attributes(void)
     ok(hr == S_OK, "Failed to get string length, hr %#lx.\n", hr);
     ok(string_length == lstrlenW(stringW), "Unexpected length %u.\n", string_length);
 
+    hr = IMFAttributes_GetAllocatedString(attributes, &DUMMY_GUID1, &string, NULL);
+    ok(hr == S_OK, "Failed to get allocated string, hr %#lx.\n", hr);
+    ok(!lstrcmpW(string, stringW), "Unexpected string %s.\n", wine_dbgstr_w(string));
+    CoTaskMemFree(string);
+
     string_length = 0xdeadbeef;
     hr = IMFAttributes_GetAllocatedString(attributes, &DUMMY_GUID1, &string, &string_length);
     ok(hr == S_OK, "Failed to get allocated string, hr %#lx.\n", hr);