Stabality improvements

see CHANGELOG
SubconsciousCompute · Dec 20, 2022 · cf2fc75 · cf2fc75
1 parent 9414821
commit cf2fc75
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Showing 5 changed files with 32 additions and 11 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,8 @@
+# v0.6.0
+
+- Fix issue of floating point operations in kernel driver
+- Performance improvements
+
 # v0.5.5
 
 - Upgrade `C` standard to `C11`

diff --git a/Cargo.toml b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "fsfilter-rs"
-version = "0.5.5"
+version = "0.6.0"
 edition = "2021"
 authors = ["sn99 <[email protected]>"]
 description = "A rust library to monitor filesystem and more in windows"

diff --git a/minifilter/snFilter/ShanonEntropy.cpp b/minifilter/snFilter/ShanonEntropy.cpp
@@ -1,5 +1,3 @@
-// #pragma warning(disable : 28110)
-
 #include "ShanonEntropy.h"
 
 constexpr DOUBLE M_LOG2E = 1.4426950408889634;
@@ -17,10 +15,8 @@ _Kernel_float_used_ DOUBLE shannonEntropy(PUCHAR buffer, size_t size)
         bucketByteVals[buffer[i]]++;
     }
 
-    KFLOATING_SAVE SaveState;
     __try
     {
-        KeSaveFloatingPointState(&SaveState);
         for (ULONG i = 0; i < MAX_BYTE_SIZE; i++)
         {
             if (bucketByteVals[i] != 0)
@@ -33,7 +29,7 @@ _Kernel_float_used_ DOUBLE shannonEntropy(PUCHAR buffer, size_t size)
     }
     __finally
     {
-        KeRestoreFloatingPointState(&SaveState);
     }
+
     return entropy;
 }
diff --git a/minifilter/snFilter/snFilter.cpp b/minifilter/snFilter/snFilter.cpp
@@ -574,7 +574,14 @@ FSProcessPreOperartion(_Inout_ PFLT_CALLBACK_DATA Data, _In_ PCFLT_RELATED_OBJEC
 
         __try
         {
-            newItem->Entropy = shannonEntropy((PUCHAR)writeBuffer, newItem->MemSizeUsed);
+            KFLOATING_SAVE SaveState;
+            NTSTATUS Status = KeSaveFloatingPointState(&SaveState);
+            if (NT_SUCCESS(Status))
+            {
+                newItem->Entropy = shannonEntropy((PUCHAR)writeBuffer, newItem->MemSizeUsed);
+            }
+
+            KeRestoreFloatingPointState(&SaveState);
             newItem->isEntropyCalc = TRUE;
         }
         __except (EXCEPTION_EXECUTE_HANDLER)
@@ -936,7 +943,14 @@ FSProcessPostReadIrp(_Inout_ PFLT_CALLBACK_DATA Data, _In_ PCFLT_RELATED_OBJECTS
     // we catch EXCEPTION_EXECUTE_HANDLER so to prevent crash when calculating
     __try
     {
-        entry->data.Entropy = shannonEntropy((PUCHAR)ReadBuffer, Data->IoStatus.Information);
+
+        KFLOATING_SAVE SaveState;
+        NTSTATUS Status = KeSaveFloatingPointState(&SaveState);
+        if (NT_SUCCESS(Status))
+        {
+            entry->data.Entropy = shannonEntropy((PUCHAR)ReadBuffer, Data->IoStatus.Information);
+        }
+        KeRestoreFloatingPointState(&SaveState);
         entry->data.isEntropyCalc = TRUE;
     }
     __except (EXCEPTION_EXECUTE_HANDLER)
@@ -976,7 +990,13 @@ FLT_POSTOP_CALLBACK_STATUS FSProcessPostReadSafe(_Inout_ PFLT_CALLBACK_DATA Data
             {
                 if (entry != nullptr)
                 {
-                    entry->data.Entropy = shannonEntropy((PUCHAR)ReadBuffer, Data->IoStatus.Information);
+                    KFLOATING_SAVE SaveState;
+                    NTSTATUS Status = KeSaveFloatingPointState(&SaveState);
+                    if (NT_SUCCESS(Status))
+                    {
+                        entry->data.Entropy = shannonEntropy((PUCHAR)ReadBuffer, Data->IoStatus.Information);
+                    }
+                    KeRestoreFloatingPointState(&SaveState);
                     entry->data.MemSizeUsed = Data->IoStatus.Information;
                     entry->data.isEntropyCalc = TRUE;
                 }

diff --git a/minifilter/snFilter/snFilter.vcxproj b/minifilter/snFilter/snFilter.vcxproj
@@ -39,7 +39,7 @@
     <ConfigurationType>Driver</ConfigurationType>
     <DriverType>WDM</DriverType>
     <PreferredToolArchitecture>x64</PreferredToolArchitecture>
-    <Driver_SpectreMitigation>Spectre</Driver_SpectreMitigation>
+    <Driver_SpectreMitigation>false</Driver_SpectreMitigation>
     <WholeProgramOptimization>true</WholeProgramOptimization>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
@@ -49,7 +49,7 @@
     <ConfigurationType>Driver</ConfigurationType>
     <DriverType>WDM</DriverType>
     <WholeProgramOptimization>true</WholeProgramOptimization>
-    <Driver_SpectreMitigation>Spectre</Driver_SpectreMitigation>
+    <Driver_SpectreMitigation>false</Driver_SpectreMitigation>
     <PreferredToolArchitecture>x64</PreferredToolArchitecture>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />