diff --git a/ntoskrnl/ex/event.c b/ntoskrnl/ex/event.c
index 0f7d6d3bbd0..e30420f65bb 100644
--- a/ntoskrnl/ex/event.c
+++ b/ntoskrnl/ex/event.c
@@ -333,7 +333,8 @@ NtQueryEvent(IN HANDLE EventHandle,
                                          EventInformationLength,
                                          ReturnLength,
                                          NULL,
-                                         PreviousMode);
+                                         PreviousMode,
+                                         TRUE);
     if(!NT_SUCCESS(Status))
     {
         /* Invalid buffers */
diff --git a/ntoskrnl/ex/mutant.c b/ntoskrnl/ex/mutant.c
index ff5772beff2..bab471c6173 100644
--- a/ntoskrnl/ex/mutant.c
+++ b/ntoskrnl/ex/mutant.c
@@ -243,7 +243,8 @@ NtQueryMutant(IN HANDLE MutantHandle,
                                          MutantInformationLength,
                                          ResultLength,
                                          NULL,
-                                         PreviousMode);
+                                         PreviousMode,
+                                         TRUE);
     if(!NT_SUCCESS(Status))
     {
         DPRINT("NtQueryMutant() failed, Status: 0x%x\n", Status);
diff --git a/ntoskrnl/ex/sem.c b/ntoskrnl/ex/sem.c
index 8a1810d5db7..29c622814ff 100644
--- a/ntoskrnl/ex/sem.c
+++ b/ntoskrnl/ex/sem.c
@@ -239,7 +239,8 @@ NtQuerySemaphore(IN HANDLE SemaphoreHandle,
                                          SemaphoreInformationLength,
                                          ReturnLength,
                                          NULL,
-                                         PreviousMode);
+                                         PreviousMode,
+                                         TRUE);
     if (!NT_SUCCESS(Status))
     {
         /* Invalid buffers */
diff --git a/ntoskrnl/ex/timer.c b/ntoskrnl/ex/timer.c
index 129881dc5d9..0ce7af03156 100644
--- a/ntoskrnl/ex/timer.c
+++ b/ntoskrnl/ex/timer.c
@@ -536,7 +536,8 @@ NtQueryTimer(IN HANDLE TimerHandle,
                                          TimerInformationLength,
                                          ReturnLength,
                                          NULL,
-                                         PreviousMode);
+                                         PreviousMode,
+                                         TRUE);
     if (!NT_SUCCESS(Status)) return Status;
 
     /* Get the Timer Object */
diff --git a/ntoskrnl/include/internal/probe.h b/ntoskrnl/include/internal/probe.h
index f02af658779..b819718f5ae 100644
--- a/ntoskrnl/include/internal/probe.h
+++ b/ntoskrnl/include/internal/probe.h
@@ -63,7 +63,8 @@ DefaultQueryInfoBufferCheck(ULONG Class,
                             ULONG BufferLength,
                             PULONG ReturnLength,
                             PULONG_PTR ReturnLengthPtr,
-                            KPROCESSOR_MODE PreviousMode)
+                            KPROCESSOR_MODE PreviousMode,
+                            BOOLEAN CompleteProbing)
 {
     NTSTATUS Status = STATUS_SUCCESS;
 
@@ -90,9 +91,18 @@ DefaultQueryInfoBufferCheck(ULONG Class,
                 {
                     if (Buffer != NULL)
                     {
-                        ProbeForWrite(Buffer,
-                                      BufferLength,
-                                      ClassList[Class].AlignmentQUERY);
+                        if (!CompleteProbing)
+                        {
+                            ProbeForRead(Buffer,
+                                         BufferLength,
+                                         ClassList[Class].AlignmentQUERY);
+                        }
+                        else
+                        {
+                            ProbeForWrite(Buffer,
+                                          BufferLength,
+                                          ClassList[Class].AlignmentQUERY);
+                        }
                     }
 
                     if (ReturnLength != NULL)
diff --git a/ntoskrnl/include/internal/ps_i.h b/ntoskrnl/include/internal/ps_i.h
index 0f0a58e968f..85de26d8814 100644
--- a/ntoskrnl/include/internal/ps_i.h
+++ b/ntoskrnl/include/internal/ps_i.h
@@ -19,7 +19,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         PROCESS_BASIC_INFORMATION,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessQuotaLimits */
@@ -27,7 +27,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         QUOTA_LIMITS,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessIoCounters */
@@ -35,7 +35,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         IO_COUNTERS,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessVmCounters */
@@ -51,7 +51,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         KERNEL_USER_TIMES,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessBasePriority */
@@ -59,7 +59,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         KPRIORITY,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ProcessRaisePriority */
@@ -67,7 +67,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ProcessDebugPort */
@@ -75,7 +75,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         HANDLE,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessExceptionPort */
@@ -83,7 +83,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         HANDLE,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ProcessAccessToken */
@@ -91,7 +91,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         PROCESS_ACCESS_TOKEN,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ProcessLdtInformation */
@@ -99,7 +99,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         PROCESS_LDT_INFORMATION,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessLdtSize */
@@ -107,7 +107,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         PROCESS_LDT_SIZE,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ProcessDefaultHardErrorMode */
@@ -115,7 +115,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessIoPortHandlers */
@@ -123,7 +123,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         UCHAR,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ProcessPooledUsageAndLimits */
@@ -131,7 +131,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         POOLED_USAGE_AND_LIMITS,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessWorkingSetWatch */
@@ -139,7 +139,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         PROCESS_WS_WATCH_INFORMATION,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET | ICIF_SET_SIZE_VARIABLE
     ),
 
     /* ProcessUserModeIOPL */
@@ -147,17 +147,17 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         UCHAR,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ProcessEnableAlignmentFaultFixup */
     IQS
     (
-        CHAR,
+        BOOLEAN,
         CHAR,
         BOOLEAN,
-        UCHAR,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        CHAR,
+        ICIF_SET
     ),
 
     /* ProcessPriorityClass */
@@ -167,7 +167,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
         ULONG,
         PROCESS_PRIORITY_CLASS,
         CHAR,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessWx86Information */
@@ -175,7 +175,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessHandleCount */
@@ -183,7 +183,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessAffinityMask */
@@ -191,7 +191,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         KAFFINITY,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ProcessPriorityBoost */
@@ -199,7 +199,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessDeviceMap */
@@ -209,7 +209,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
         ULONG,
         RTL_FIELD_TYPE(PROCESS_DEVICEMAP_INFORMATION, Set),
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessSessionInformation */
@@ -217,7 +217,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         PROCESS_SESSION_INFORMATION,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessForegroundInformation */
@@ -226,8 +226,8 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
         CHAR,
         CHAR,
         BOOLEAN,
-        UCHAR,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        CHAR,
+        ICIF_SET
     ),
 
     /* ProcessWow64Information */
@@ -235,7 +235,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessImageFileName */
@@ -251,7 +251,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessBreakOnTermination */
@@ -259,7 +259,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessDebugObjectHandle */
@@ -267,7 +267,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         HANDLE,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessDebugFlags */
@@ -275,17 +275,17 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessHandleTracing */
     IQS
     (
         PROCESS_HANDLE_TRACING_QUERY,
-        CHAR,
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ULONG,
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessIoPriority */
@@ -301,7 +301,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ProcessTlsInformation */
@@ -317,7 +317,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessImageInformation */
@@ -325,7 +325,7 @@ static const INFORMATION_CLASS_INFO PsProcessInfoClass[] =
     (
         SECTION_IMAGE_INFORMATION,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ProcessCycleTime */
@@ -411,7 +411,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         THREAD_BASIC_INFORMATION,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ThreadTimes */
@@ -419,7 +419,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         KERNEL_USER_TIMES,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ThreadPriority */
@@ -427,7 +427,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         KPRIORITY,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ThreadBasePriority */
@@ -435,7 +435,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         LONG,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ThreadAffinityMask */
@@ -443,7 +443,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         KAFFINITY,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ThreadImpersonationToken */
@@ -451,7 +451,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         HANDLE,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ThreadDescriptorTableEntry is only implemented in x86 as well as the descriptor entry */
@@ -461,7 +461,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
         (
             DESCRIPTOR_TABLE_ENTRY,
             ULONG,
-            ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+            ICIF_QUERY
         ),
     #else
         IQS_NONE,
@@ -474,7 +474,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
         CHAR,
         BOOLEAN,
         UCHAR,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ThreadEventPair_Reusable */
@@ -492,7 +492,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
         ULONG,
         ULONG_PTR,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ThreadZeroTlsCell */
@@ -500,7 +500,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         ULONG_PTR,
         ULONG,
-        ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ThreadPerformanceCount */
@@ -508,7 +508,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         LARGE_INTEGER,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ThreadAmILastThread */
@@ -516,7 +516,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ThreadIdealProcessor */
@@ -524,7 +524,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         ULONG_PTR,
         ULONG,
-        ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ThreadPriorityBoost */
@@ -534,7 +534,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
         ULONG,
         ULONG_PTR,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ThreadSetTlsArrayAddress */
@@ -550,7 +550,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ThreadHideFromDebugger */
@@ -566,7 +566,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_SET | ICIF_SIZE_VARIABLE
+        ICIF_QUERY | ICIF_SET
     ),
 
     /* ThreadSwitchLegacyState */
@@ -574,7 +574,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_SET | ICIF_SET_SIZE_VARIABLE
+        ICIF_SET
     ),
 
     /* ThreadIsTerminated */
@@ -582,7 +582,7 @@ static const INFORMATION_CLASS_INFO PsThreadInfoClass[] =
     (
         ULONG,
         ULONG,
-        ICIF_QUERY | ICIF_QUERY_SIZE_VARIABLE
+        ICIF_QUERY
     ),
 
     /* ThreadLastSystemCall */
diff --git a/ntoskrnl/include/ntoskrnl.h b/ntoskrnl/include/ntoskrnl.h
index a6ac78b4827..643562e60f0 100644
--- a/ntoskrnl/include/ntoskrnl.h
+++ b/ntoskrnl/include/ntoskrnl.h
@@ -124,6 +124,9 @@ C_ASSERT(MAX_WIN32_PATH == MAX_PATH);
 #include "internal/probe.h"
 #include "resource.h"
 
+/* Internal Ps alignment probing header */
+#include "internal/ps_i.h"
+
 #ifdef _MSC_VER
 # pragma section("INITDATA", read,write,discard)
 #endif
diff --git a/ntoskrnl/io/iomgr/iocomp.c b/ntoskrnl/io/iomgr/iocomp.c
index df883d476a5..41457a66574 100644
--- a/ntoskrnl/io/iomgr/iocomp.c
+++ b/ntoskrnl/io/iomgr/iocomp.c
@@ -399,7 +399,8 @@ NtQueryIoCompletion(IN  HANDLE IoCompletionHandle,
                                          IoCompletionInformationLength,
                                          ResultLength,
                                          NULL,
-                                         PreviousMode);
+                                         PreviousMode,
+                                         TRUE);
     if (!NT_SUCCESS(Status)) return Status;
 
     /* Get the Object */
diff --git a/ntoskrnl/ps/query.c b/ntoskrnl/ps/query.c
index 895c2db5d0d..5c28b03d068 100644
--- a/ntoskrnl/ps/query.c
+++ b/ntoskrnl/ps/query.c
@@ -86,26 +86,20 @@ NtQueryInformationProcess(
     ULONG Flags;
     PAGED_CODE();
 
-    /* Check for user-mode caller */
-    if (PreviousMode != KernelMode)
+    /* Verify Information Class validity */
+    Status = DefaultQueryInfoBufferCheck(ProcessInformationClass,
+                                         PsProcessInfoClass,
+                                         RTL_NUMBER_OF(PsProcessInfoClass),
+                                         ProcessInformation,
+                                         ProcessInformationLength,
+                                         ReturnLength,
+                                         NULL,
+                                         PreviousMode,
+                                         FALSE);
+    if (!NT_SUCCESS(Status))
     {
-        /* Prepare to probe parameters */
-        _SEH2_TRY
-        {
-            /* Probe the buffer */
-            ProbeForRead(ProcessInformation,
-                         ProcessInformationLength,
-                         sizeof(ULONG));
-
-            /* Probe the return length if required */
-            if (ReturnLength) ProbeForWriteUlong(ReturnLength);
-        }
-        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
-        {
-            /* Return the exception code */
-            _SEH2_YIELD(return _SEH2_GetExceptionCode());
-        }
-        _SEH2_END;
+        DPRINT1("NtQueryInformationProcess(): Information verification class failed! (Status -> 0x%lx, ProcessInformationClass -> %lx)\n", Status, ProcessInformationClass);
+        return Status;
     }
 
     if (((ProcessInformationClass == ProcessCookie) ||
@@ -794,6 +788,13 @@ NtQueryInformationProcess(
         /* Per-process security cookie */
         case ProcessCookie:
 
+            if (ProcessInformationLength != sizeof(ULONG))
+            {
+                /* Length size wrong, bail out */
+                Status = STATUS_INFO_LENGTH_MISMATCH;
+                break;
+            }
+
             /* Get the current process and cookie */
             Process = PsGetCurrentProcess();
             Cookie = Process->Cookie;
@@ -1131,15 +1132,17 @@ NtSetInformationProcess(IN HANDLE ProcessHandle,
     PAGED_CODE();
 
     /* Verify Information Class validity */
-#if 0
     Status = DefaultSetInfoBufferCheck(ProcessInformationClass,
                                        PsProcessInfoClass,
                                        RTL_NUMBER_OF(PsProcessInfoClass),
                                        ProcessInformation,
                                        ProcessInformationLength,
                                        PreviousMode);
-    if (!NT_SUCCESS(Status)) return Status;
-#endif
+    if (!NT_SUCCESS(Status))
+    {
+        DPRINT1("NtSetInformationProcess(): Information verification class failed! (Status -> 0x%lx, ProcessInformationClass -> %lx)\n", Status, ProcessInformationClass);
+        return Status;
+    }
 
     /* Check what class this is */
     Access = PROCESS_SET_INFORMATION;
@@ -1846,7 +1849,7 @@ NtSetInformationProcess(IN HANDLE ProcessHandle,
         case ProcessEnableAlignmentFaultFixup:
 
             /* Check buffer length */
-            if (ProcessInformationLength != sizeof(ULONG))
+            if (ProcessInformationLength != sizeof(BOOLEAN))
             {
                 Status = STATUS_INFO_LENGTH_MISMATCH;
                 break;
@@ -2036,15 +2039,17 @@ NtSetInformationThread(IN HANDLE ThreadHandle,
     PAGED_CODE();
 
     /* Verify Information Class validity */
-#if 0
     Status = DefaultSetInfoBufferCheck(ThreadInformationClass,
                                        PsThreadInfoClass,
                                        RTL_NUMBER_OF(PsThreadInfoClass),
                                        ThreadInformation,
                                        ThreadInformationLength,
                                        PreviousMode);
-    if (!NT_SUCCESS(Status)) return Status;
-#endif
+    if (!NT_SUCCESS(Status))
+    {
+        DPRINT1("NtSetInformationThread(): Information verification class failed! (Status -> 0x%lx, ThreadInformationClass -> %lx)\n", Status, ThreadInformationClass);
+        return Status;
+    }
 
     /* Check what kind of information class this is */
     switch (ThreadInformationClass)
@@ -2634,26 +2639,20 @@ NtQueryInformationThread(IN HANDLE ThreadHandle,
     ULONG ThreadTerminated;
     PAGED_CODE();
 
-    /* Check if we were called from user mode */
-    if (PreviousMode != KernelMode)
+    /* Verify Information Class validity */
+    Status = DefaultQueryInfoBufferCheck(ThreadInformationClass,
+                                         PsThreadInfoClass,
+                                         RTL_NUMBER_OF(PsThreadInfoClass),
+                                         ThreadInformation,
+                                         ThreadInformationLength,
+                                         ReturnLength,
+                                         NULL,
+                                         PreviousMode,
+                                         FALSE);
+    if (!NT_SUCCESS(Status))
     {
-        /* Enter SEH */
-        _SEH2_TRY
-        {
-            /* Probe the buffer */
-            ProbeForWrite(ThreadInformation,
-                          ThreadInformationLength,
-                          sizeof(ULONG));
-
-            /* Probe the return length if required */
-            if (ReturnLength) ProbeForWriteUlong(ReturnLength);
-        }
-        _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
-        {
-            /* Return the exception code */
-            _SEH2_YIELD(return _SEH2_GetExceptionCode());
-        }
-        _SEH2_END;
+        DPRINT1("NtQueryInformationThread(): Information verification class failed! (Status -> 0x%lx , ThreadInformationClass -> %lx)\n", Status, ThreadInformationClass);
+        return Status;
     }
 
     /* Check what class this is */
diff --git a/ntoskrnl/se/token.c b/ntoskrnl/se/token.c
index eb67cda7486..256e4b31d4c 100644
--- a/ntoskrnl/se/token.c
+++ b/ntoskrnl/se/token.c
@@ -2400,7 +2400,8 @@ NtQueryInformationToken(
                                          TokenInformationLength,
                                          ReturnLength,
                                          NULL,
-                                         PreviousMode);
+                                         PreviousMode,
+                                         TRUE);
     if (!NT_SUCCESS(Status))
     {
         DPRINT("NtQueryInformationToken() failed, Status: 0x%x\n", Status);
diff --git a/sdk/include/ndk/pstypes.h b/sdk/include/ndk/pstypes.h
index 53e76516eed..3a47b04a560 100644
--- a/sdk/include/ndk/pstypes.h
+++ b/sdk/include/ndk/pstypes.h
@@ -911,18 +911,6 @@ typedef struct _POOLED_USAGE_AND_LIMITS
     SIZE_T PagefileLimit;
 } POOLED_USAGE_AND_LIMITS, *PPOOLED_USAGE_AND_LIMITS;
 
-typedef struct _PROCESS_LDT_INFORMATION
-{
-    ULONG Start;
-    ULONG Length;
-    LDT_ENTRY LdtEntries[ANYSIZE_ARRAY];
-} PROCESS_LDT_INFORMATION, *PPROCESS_LDT_INFORMATION;
-
-typedef struct _PROCESS_LDT_SIZE
-{
-    ULONG Length;
-} PROCESS_LDT_SIZE, *PPROCESS_LDT_SIZE;
-
 typedef struct _PROCESS_WS_WATCH_INFORMATION
 {
     PVOID FaultingPc;
@@ -951,6 +939,18 @@ typedef struct _PROCESS_HANDLE_TRACING_QUERY
 
 #endif
 
+typedef struct _PROCESS_LDT_INFORMATION
+{
+    ULONG Start;
+    ULONG Length;
+    LDT_ENTRY LdtEntries[ANYSIZE_ARRAY];
+} PROCESS_LDT_INFORMATION, *PPROCESS_LDT_INFORMATION;
+
+typedef struct _PROCESS_LDT_SIZE
+{
+    ULONG Length;
+} PROCESS_LDT_SIZE, *PPROCESS_LDT_SIZE;
+
 typedef struct _PROCESS_PRIORITY_CLASS
 {
     BOOLEAN Foreground;