diff --git a/sdk/include/ndk/rtltypes.h b/sdk/include/ndk/rtltypes.h
index fdda1203a8c..b255260fd24 100644
--- a/sdk/include/ndk/rtltypes.h
+++ b/sdk/include/ndk/rtltypes.h
@@ -1391,6 +1391,15 @@ typedef struct _RTL_PERTHREAD_CURDIR
     PVOID Environment;
 } RTL_PERTHREAD_CURDIR, *PRTL_PERTHREAD_CURDIR;
 
+typedef struct _RTL_ACE_DATA
+{
+    UCHAR AceType;
+    UCHAR InheritFlags;
+    UCHAR AceFlags;
+    ACCESS_MASK Mask;
+    PSID *Sid;
+} RTL_ACE_DATA, *PRTL_ACE_DATA;
+
 //
 // Private State structure for RtlAcquirePrivilege/RtlReleasePrivilege
 //
diff --git a/sdk/lib/rtl/security.c b/sdk/lib/rtl/security.c
index 564bf24de61..8c6144ea917 100644
--- a/sdk/lib/rtl/security.c
+++ b/sdk/lib/rtl/security.c
@@ -391,7 +391,7 @@ Cleanup1:
  */
 NTSTATUS
 NTAPI
-RtlCreateAndSetSD(IN PVOID AceData,
+RtlCreateAndSetSD(IN PRTL_ACE_DATA AceData,
                   IN ULONG AceCount,
                   IN PSID OwnerSid OPTIONAL,
                   IN PSID GroupSid OPTIONAL,
@@ -556,7 +556,7 @@ RtlNewInstanceSecurityObject(IN BOOLEAN ParentDescriptorChanged,
  */
 NTSTATUS
 NTAPI
-RtlCreateUserSecurityObject(IN PVOID AceData,
+RtlCreateUserSecurityObject(IN PRTL_ACE_DATA AceData,
                             IN ULONG AceCount,
                             IN PSID OwnerSid,
                             IN PSID GroupSid,