A customer noted that
the
SetPrivateObjectSecurity
function
updates a pointer provided by the
ObjectsSecurityDescriptor
parameter.
Since it may allocate a new security descriptor,
that means that it needs to deallocate the old one.
But what function does it use to free the old one?
After all,
the allocation function must match the deallocation function.
Similarly, how should the new security descriptor be freed?
(I say "similarly" because the two answers had better be the same!)
The system allocates and frees the security descriptor from the
proess heap,
as reported by the
GetProcessHeap
function.
The allocation function is HeapAlloc
and the deallication function is HeapFree
.
That means that the security descriptor you pass in must have
been allocated with
SecurityDescriptor = HeapAlloc(GetProcessHeap(), flags, size);
and then you pass the pointer like this:
SetPrivateObjectSecurity(..., &SecurityDescriptor, ...); // or SetPrivateObjectSecurityEx(..., &SecurityDescriptor, ...);
and after the
SetPrivateObjectSecurity
function is done, you must free the memory with
HeapFree(GetProcessHeap(), SecurityDescriptor);
I wrote this post the same day that I submitted the change request to add this essential information to the documentation. We'll see who wins.