[aandrejevic] 61056: [FAST486] Implement privilege checks when loading the code selector.

Author: aandrejevic
Date: Wed Nov 20 10:43:12 2013
New Revision: 61056

URL: http://svn.reactos.org/svn/reactos?rev=61056&view=rev
Log:
[FAST486]
Implement privilege checks when loading the code selector.

Modified:
    branches/ntvdm/lib/fast486/common.inl

Modified: branches/ntvdm/lib/fast486/common.inl
URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/lib/fast486/common.inl?rev...
==============================================================================
--- branches/ntvdm/lib/fast486/common.inl	[iso-8859-1] (original)
+++ branches/ntvdm/lib/fast486/common.inl	[iso-8859-1] Wed Nov 20 10:43:12 2013
@@ -430,36 +430,85 @@
             if (!GdtEntry.SystemType)
             {
                 /* This is a special descriptor */
-                Fast486Exception(State, FAST486_EXCEPTION_GP);
+                Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
                 return FALSE;
             }

if (GdtEntry.Executable || !GdtEntry.ReadWrite)
             {
-                Fast486Exception(State, FAST486_EXCEPTION_GP);
+                Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
                 return FALSE;
             }

if ((GET_SEGMENT_RPL(Selector) != Fast486GetCurrentPrivLevel(State))
                 || (GET_SEGMENT_RPL(Selector) != GdtEntry.Dpl))
             {
+                Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
+                return FALSE;
+            }
+
+            if (!GdtEntry.Present)
+            {
+                Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_SS, Selector);
+                return FALSE;
+            }
+        }
+        else if (Segment == FAST486_REG_CS)
+        {
+            /* Loading the code segment */
+
+            if (GET_SEGMENT_INDEX(Selector) == 0)
+            {
                 Fast486Exception(State, FAST486_EXCEPTION_GP);
                 return FALSE;
             }

-            if (!GdtEntry.Present)
-            {
-                Fast486Exception(State, FAST486_EXCEPTION_SS);
-                return FALSE;
-            }
-        }
-        else if (Segment == FAST486_REG_CS)
-        {
-            /* Loading the code segment */
-            // TODO: Implement security checks, call gates, etc...
-
-            /* Update CPL */
-            State->Cpl = GET_SEGMENT_RPL(Selector);
+            if (GdtEntry.SystemType)
+            {
+                // TODO: Call/interrupt/task gates NOT IMPLEMENTED!
+                UNIMPLEMENTED;
+            }
+            else
+            {
+                if (!GdtEntry.Present)
+                {
+                    Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_NP, Selector);
+                    return FALSE;
+                }
+
+                if (!GdtEntry.Executable)
+                {
+                    Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
+                    return FALSE;
+                }
+
+                if (GdtEntry.DirConf)
+                {
+                    /* Conforming Code Segment */
+
+                    if (GdtEntry.Dpl > Fast486GetCurrentPrivLevel(State))
+                    {
+                        /* Must be accessed from lower-privileged code */
+                        Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
+                        return FALSE;
+                    }
+                }
+                else
+                {
+                    /* Regular code segment */
+
+                    if ((GET_SEGMENT_RPL(Selector) > Fast486GetCurrentPrivLevel(State))
+                        || (Fast486GetCurrentPrivLevel(State) != GdtEntry.Dpl))
+                    {
+                        Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
+                        return FALSE;
+                    }
+
+                }
+
+                /* Update CPL */
+                State->Cpl = GET_SEGMENT_RPL(Selector);
+            }
         }
         else
         {
@@ -468,20 +517,20 @@
             if (!GdtEntry.SystemType)
             {
                 /* This is a special descriptor */
-                Fast486Exception(State, FAST486_EXCEPTION_GP);
+                Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
                 return FALSE;
             }

if ((GET_SEGMENT_RPL(Selector) > GdtEntry.Dpl)
                 || (Fast486GetCurrentPrivLevel(State) > GdtEntry.Dpl))
             {
-                Fast486Exception(State, FAST486_EXCEPTION_GP);
+                Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_GP, Selector);
                 return FALSE;
             }

if (!GdtEntry.Present)
             {
-                Fast486Exception(State, FAST486_EXCEPTION_NP);
+                Fast486ExceptionWithErrorCode(State, FAST486_EXCEPTION_NP, Selector);
                 return FALSE;
             }
         }