windows: add GetExplicitEntriesFromAcl

windows/security_windows.go

@@ -1122,6 +1122,7 @@ type OBJECTS_AND_NAME struct {
 //sys	SetSecurityInfo(handle Handle, objectType SE_OBJECT_TYPE, securityInformation SECURITY_INFORMATION, owner *SID, group *SID, dacl *ACL, sacl *ACL) = advapi32.SetSecurityInfo
 //sys	getNamedSecurityInfo(objectName string, objectType SE_OBJECT_TYPE, securityInformation SECURITY_INFORMATION, owner **SID, group **SID, dacl **ACL, sacl **ACL, sd **SECURITY_DESCRIPTOR) (ret error) = advapi32.GetNamedSecurityInfoW
 //sys	SetNamedSecurityInfo(objectName string, objectType SE_OBJECT_TYPE, securityInformation SECURITY_INFORMATION, owner *SID, group *SID, dacl *ACL, sacl *ACL) (ret error) = advapi32.SetNamedSecurityInfoW
+//sys	getExplicitEntriesFromAclW(acl *ACL, countAccessEntries *uint32, accessEntries *EXPLICIT_ACCESS) (ret error) = advapi32.GetExplicitEntriesFromAclW
 
 //sys	buildSecurityDescriptor(owner *TRUSTEE, group *TRUSTEE, countAccessEntries uint32, accessEntries *EXPLICIT_ACCESS, countAuditEntries uint32, auditEntries *EXPLICIT_ACCESS, oldSecurityDescriptor *SECURITY_DESCRIPTOR, sizeNewSecurityDescriptor *uint32, newSecurityDescriptor **SECURITY_DESCRIPTOR) (ret error) = advapi32.BuildSecurityDescriptorW
 //sys	initializeSecurityDescriptor(absoluteSD *SECURITY_DESCRIPTOR, revision uint32) (err error) = advapi32.InitializeSecurityDescriptor
@@ -1374,6 +1375,30 @@ func GetNamedSecurityInfo(objectName string, objectType SE_OBJECT_TYPE, security
 	return winHeapSD.copySelfRelativeSecurityDescriptor(), nil
 }
 
+// GetExplicitEntriesFromAcl queries the explicit entries from a given ACL
+func GetExplicitEntriesFromAcl(acl *ACL) ([]EXPLICIT_ACCESS, error) {
+	var entries *EXPLICIT_ACCESS
+	var size uint32
+	err := getExplicitEntriesFromAclW(
+		acl,
+		size,
+		entries,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	defer LocalFree((Handle)(unsafe.Pointer(entries)))
+
+	var accesses []EXPLICIT_ACCESS
+	for i := 0; i < int(size); i++ {
+		accesses = append(accesses, *entries)
+		entries = (*EXPLICIT_ACCESS)(unsafe.Pointer((uintptr(unsafe.Pointer(entries)) + unsafe.Sizeof(*entries))))
+	}
+
+	return accesses, nil
+}
+
 // BuildSecurityDescriptor makes a new security descriptor using the input trustees, explicit access lists, and
 // prior security descriptor to be merged, any of which can be nil, returning the self-relative security descriptor
 // result on the Go heap.