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Browse - programming tips - win32 permissive security attributes

Date: 2008aug22
Platform: win32

Q.  How can I make a SECURITY_ATTRIBUTES that allows anybody to use my resource?

A.  Use this CreateNullDacl() to create it.

BOOL CreateNullDacl(SECURITY_ATTRIBUTES *sa)
{
	PSECURITY_DESCRIPTOR		pSD; 

	if (sa == NULL) return FALSE;

	pSD = (PSECURITY_DESCRIPTOR) LocalAlloc(LPTR, SECURITY_DESCRIPTOR_MIN_LENGTH); 
	if (pSD == NULL) return FALSE;

	if (!InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION)) return FALSE;

	// Add a null DACL to the security descriptor. 
	if (!SetSecurityDescriptorDacl(pSD, TRUE, (PACL) NULL, FALSE))
		return TRUE;

	sa->nLength = sizeof(SECURITY_ATTRIBUTES); 
	sa->lpSecurityDescriptor = pSD;
	sa->bInheritHandle = TRUE; 

	return TRUE;
}

void FreeNullDacl(SECURITY_ATTRIBUTES *sa)
{
	if (sa == NULL) return;

	if (sa->lpSecurityDescriptor)
	{
		LocalFree(sa->lpSecurityDescriptor);
		sa->lpSecurityDescriptor = NULL;
	}
}

void ExampleUse()
{
	SECURITY_ATTRIBUTES 		sa;
	HANDLE				hMutex;

	CreateNullDacl(&sa);

	hMutex = CreateMutex(&sa, FALSE, "my.mutex");
	// Everyone can use this mutex
}

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