From 899cd5595ddc145672e1697fca9b6cf0e7c84b22 Mon Sep 17 00:00:00 2001
From: Bill Zissimopoulos <billziss@navimatics.com>
Date: Mon, 1 Jun 2020 23:11:33 -0700
Subject: [PATCH] sys: FspIsNtDdiVersionAvailable

---
 src/sys/driver.c |  6 ++--
 src/sys/driver.h |  1 +
 src/sys/util.c   | 71 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 3 deletions(-)

diff --git a/src/sys/driver.c b/src/sys/driver.c
index 66eb90b6..f430deb8 100644
--- a/src/sys/driver.c
+++ b/src/sys/driver.c
@@ -237,7 +237,7 @@ static VOID FspDriverMultiVersionInitialize(VOID)
 #pragma prefast(suppress:30035, "FspDriverMultiVersionInitialize is called from DriverEntry")
     ExInitializeDriverRuntime(DrvRtPoolNxOptIn);
 
-    if (RtlIsNtDdiVersionAvailable(NTDDI_WIN7))
+    if (FspIsNtDdiVersionAvailable(NTDDI_WIN7))
     {
         UNICODE_STRING Name;
 
@@ -246,10 +246,10 @@ static VOID FspDriverMultiVersionInitialize(VOID)
             (FSP_MV_CcCoherencyFlushAndPurgeCache *)(UINT_PTR)MmGetSystemRoutineAddress(&Name);
     }
 
-    if (RtlIsNtDdiVersionAvailable(NTDDI_WIN8))
+    if (FspIsNtDdiVersionAvailable(NTDDI_WIN8))
         FspMvMdlMappingNoWrite = MdlMappingNoWrite;
 
-    if (RtlIsNtDdiVersionAvailable(0x0A000005/*NTDDI_WIN10_RS4*/))
+    if (FspIsNtDdiVersionAvailable(NTDDI_WIN10_RS4))
         FspHasReparsePointCaseSensitivityFix = TRUE;
 }
 
diff --git a/src/sys/driver.h b/src/sys/driver.h
index f87f1bb9..2eaee33f 100644
--- a/src/sys/driver.h
+++ b/src/sys/driver.h
@@ -503,6 +503,7 @@ NTSTATUS FspUuid5Make(const UUID *Namespace, const VOID *Buffer, ULONG Size, UUI
 /* utility */
 PVOID FspAllocatePoolMustSucceed(POOL_TYPE PoolType, SIZE_T Size, ULONG Tag);
 PVOID FspAllocateIrpMustSucceed(CCHAR StackSize);
+BOOLEAN FspIsNtDdiVersionAvailable(ULONG RequestedVersion);
 NTSTATUS FspCreateGuid(GUID *Guid);
 NTSTATUS FspGetDeviceObjectPointer(PUNICODE_STRING ObjectName, ACCESS_MASK DesiredAccess,
     PULONG PFileNameIndex, PFILE_OBJECT *PFileObject, PDEVICE_OBJECT *PDeviceObject);
diff --git a/src/sys/util.c b/src/sys/util.c
index cf85c517..0ba7db1d 100644
--- a/src/sys/util.c
+++ b/src/sys/util.c
@@ -21,6 +21,7 @@
 
 #include <sys/driver.h>
 
+BOOLEAN FspIsNtDdiVersionAvailable(ULONG Version);
 NTSTATUS FspCreateGuid(GUID *Guid);
 NTSTATUS FspGetDeviceObjectPointer(PUNICODE_STRING ObjectName, ACCESS_MASK DesiredAccess,
     PULONG PFileNameIndex, PFILE_OBJECT *PFileObject, PDEVICE_OBJECT *PDeviceObject);
@@ -132,6 +133,7 @@ PVOID FspIrpHookContext(PVOID Context);
 NTSTATUS FspIrpHookNext(PDEVICE_OBJECT DeviceObject, PIRP Irp, PVOID Context);
 
 #ifdef ALLOC_PRAGMA
+#pragma alloc_text(PAGE, FspIsNtDdiVersionAvailable)
 #pragma alloc_text(PAGE, FspCreateGuid)
 #pragma alloc_text(PAGE, FspGetDeviceObjectPointer)
 #pragma alloc_text(PAGE, FspRegistryGetValue)
@@ -223,6 +225,75 @@ PVOID FspAllocateIrpMustSucceed(CCHAR StackSize)
     }
 }
 
+BOOLEAN FspIsNtDdiVersionAvailable(ULONG RequestedVersion)
+{
+    PAGED_CODE();
+
+    static ULONG Version;
+
+    if (0 == Version)
+    {
+        RTL_OSVERSIONINFOEXW VersionInfo;
+        ULONG TempVersion;
+
+        RtlZeroMemory(&VersionInfo, sizeof VersionInfo);
+        VersionInfo.dwOSVersionInfoSize = sizeof VersionInfo;
+        RtlGetVersion((PVOID)&VersionInfo);
+
+        TempVersion =
+            ((UINT8)VersionInfo.dwMajorVersion << 24) |
+            ((UINT8)VersionInfo.dwMinorVersion << 16) |
+            ((UINT8)VersionInfo.wServicePackMajor << 8);
+
+        if (10 <= VersionInfo.dwMajorVersion)
+        {
+            /* see https://docs.microsoft.com/en-us/windows/release-information/ */
+            static struct
+            {
+                ULONG BuildNumber;
+                ULONG Subver;
+            } Builds[] =
+            {
+                { 10240, SUBVER(NTDDI_WIN10) },
+                { 10586, SUBVER(NTDDI_WIN10_TH2) },
+                { 14393, SUBVER(NTDDI_WIN10_RS1) },
+                { 15063, SUBVER(NTDDI_WIN10_RS2) },
+                { 16299, SUBVER(NTDDI_WIN10_RS3) },
+                { 17134, SUBVER(NTDDI_WIN10_RS4) },
+                { 17763, SUBVER(NTDDI_WIN10_RS5) },
+                { 18362, SUBVER(NTDDI_WIN10_19H1) },
+                { 18363, SUBVER(NTDDI_WIN10_19H1) },
+                { 19041, 9 },
+                { (ULONG)-1, 10 },
+            };
+            int Lo = 0, Hi = sizeof Builds / sizeof Builds[0] - 1, Mi;
+
+            while (Lo <= Hi)
+            {
+                Mi = (unsigned)(Lo + Hi) >> 1;
+
+                if (Builds[Mi].BuildNumber < VersionInfo.dwBuildNumber)
+                    Lo = Mi + 1;
+                else if (Builds[Mi].BuildNumber > VersionInfo.dwBuildNumber)
+                    Hi = Mi - 1;
+                else
+                {
+                    Lo = Mi;
+                    break;
+                }
+            }
+            Mi = Lo;
+
+            TempVersion |= (UINT8)Builds[Mi].Subver;
+        }
+
+        /* thread-safe because multiple threads will compute same value */
+        InterlockedExchange((PVOID)&Version, TempVersion);
+    }
+
+    return RequestedVersion <= Version;
+}
+
 NTSTATUS FspCreateGuid(GUID *Guid)
 {
     PAGED_CODE();