diff --git a/librpc/idl/netlogon.idl b/librpc/idl/netlogon.idl
index 77c0e7a..832fb3e 100644
--- a/librpc/idl/netlogon.idl
+++ b/librpc/idl/netlogon.idl
@@ -1260,20 +1260,36 @@ interface netlogon
 	} netr_LsaPolicyInformation;
 
 	typedef [public] struct {
-		uint32 dwOSVersionInfoSize;
-		uint32 dwMajorVersion;
-		uint32 dwMinorVersion;
-		uint32 dwBuildNumber;
-		uint32 dwPlatformId;
-		char szCSDVersion[128];
-		uint16 wServicePackMajor;
-		uint16 wServicePackMinor;
+		[value(284)] uint32 OSVersionInfoSize;
+		uint32 MajorVersion;
+		uint32 MinorVersion;
+		uint32 BuildNumber;
+		uint32 PlatformId;
+		[charset(UTF16)] uint16 CSDVersion[128];
+		uint16 ServicePackMajor;
+		uint16 ServicePackMinor;
 		netr_SuiteMask wSuiteMask;
 		netr_ProductType wProductType;
 		uint8 wReserved;
 	} netr_OsVersionInfoEx;
 
 	typedef struct {
+		/* these first 3 values come from the fact windows
+		   actually encodes this structure as a UNICODE_STRING
+		   - see MS-NRPC section 2.2.1.3.9 */
+		[value(284)] uint32 length;
+		[value(0)] uint32 dummy;
+		[value(284)] uint32 size;
+		netr_OsVersionInfoEx os;
+	} netr_os_version;
+
+	typedef struct {
+		[value(os == NULL ? 0 : 142)] uint16 length; /* value is 284 when info != os, otherwise 0 */
+		[value(os == NULL ? 0 : 142)] uint16 size;   /* value is 284 when info != os, otherwise 0 */
+		netr_os_version *os;
+	} netr_os_version_container;
+
+	typedef struct {
 		netr_LsaPolicyInformation lsa_policy;
 		[string,charset(UTF16)] uint16 *dns_hostname;
 		[string,charset(UTF16)] uint16 *sitename;
@@ -1281,7 +1297,7 @@ interface netlogon
 		[string,charset(UTF16)] uint16 *dummy2;
 		[string,charset(UTF16)] uint16 *dummy3;
 		[string,charset(UTF16)] uint16 *dummy4;
-		lsa_BinaryString os_version;
+		netr_os_version_container os_version;
 		lsa_String os_name;
 		lsa_String dummy_string3;
 		lsa_String dummy_string4;
@@ -1357,7 +1373,7 @@ interface netlogon
 		[in,ref]     netr_Authenticator *credential,
 		[in,out,ref] netr_Authenticator *return_authenticator,
 		[in]	     uint32 level,
-		[in,ref,switch_is(level)] netr_WorkstationInfo *query,
+		[in,switch_is(level)] netr_WorkstationInfo query,
 		[out,ref,switch_is(level)] netr_DomainInfo *info
 		);