branch update for HEAD-2003021201

[reactos.git] / ntoskrnl / ldr / loader.c

diff --git a/ntoskrnl/ldr/loader.c b/ntoskrnl/ldr/loader.c
index ff215f9..960db41 100644 (file)
--- a/ntoskrnl/ldr/loader.c
+++ b/ntoskrnl/ldr/loader.c
@@ -828,6 +828,40 @@ LdrGetModuleObject(PUNICODE_STRING ModuleName)
 
 /*  ----------------------------------------------  PE Module support */
 
+static BOOL
+PageNeedsWriteAccess(PVOID PageStart,
+                     PVOID DriverBase,
+                     PIMAGE_FILE_HEADER PEFileHeader,
+                     PIMAGE_SECTION_HEADER PESectionHeaders)
+{
+  BOOL NeedsWriteAccess;
+  unsigned Idx;
+  ULONG Characteristics;
+  ULONG Length;
+  PVOID BaseAddress;
+
+  NeedsWriteAccess = FALSE;
+  /* Set the protections for the various parts of the driver */
+  for (Idx = 0; Idx < PEFileHeader->NumberOfSections && ! NeedsWriteAccess; Idx++)
+    {
+      Characteristics = PESectionHeaders[Idx].Characteristics;
+      if (!(Characteristics & IMAGE_SECTION_CHAR_CODE) ||
+         (Characteristics & IMAGE_SECTION_CHAR_WRITABLE ||
+          Characteristics & IMAGE_SECTION_CHAR_DATA ||
+          Characteristics & IMAGE_SECTION_CHAR_BSS))
+       {
+         Length = 
+             max(PESectionHeaders[Idx].Misc.VirtualSize,
+                 PESectionHeaders[Idx].SizeOfRawData);
+         BaseAddress = PESectionHeaders[Idx].VirtualAddress + DriverBase;
+         NeedsWriteAccess = BaseAddress < PageStart + PAGE_SIZE &&
+                            PageStart < (PVOID)((PCHAR) BaseAddress + Length);
+       }
+    }
+
+  return(NeedsWriteAccess);
+}
+
 static NTSTATUS
 LdrPEProcessModule(PVOID ModuleLoadBase,
                   PUNICODE_STRING FileName,
@@ -1122,20 +1156,32 @@ LdrPEProcessModule(PVOID ModuleLoadBase,
       ULONG Characteristics = PESectionHeaders[Idx].Characteristics;
       ULONG Length;
       PVOID BaseAddress;
-      ULONG i;
-      Length = 
-       max(PESectionHeaders[Idx].Misc.VirtualSize,
-           PESectionHeaders[Idx].SizeOfRawData);
-      BaseAddress = PESectionHeaders[Idx].VirtualAddress + DriverBase;
+      PVOID PageAddress;
       if (Characteristics & IMAGE_SECTION_CHAR_CODE &&
          !(Characteristics & IMAGE_SECTION_CHAR_WRITABLE ||
            Characteristics & IMAGE_SECTION_CHAR_DATA ||
            Characteristics & IMAGE_SECTION_CHAR_BSS))
        {
-         for (i = 0; i < PAGE_ROUND_UP(Length) / PAGE_SIZE; i++)
+         Length = 
+             max(PESectionHeaders[Idx].Misc.VirtualSize,
+                 PESectionHeaders[Idx].SizeOfRawData);
+         BaseAddress = PESectionHeaders[Idx].VirtualAddress + DriverBase;
+         PageAddress = (PVOID)PAGE_ROUND_DOWN(BaseAddress);
+         if (! PageNeedsWriteAccess(PageAddress, DriverBase, PEFileHeader, PESectionHeaders))
+           {
+             MmSetPageProtect(NULL, PageAddress, PAGE_READONLY);
+           }
+         PageAddress = (PVOID)((PCHAR) PageAddress + PAGE_SIZE);
+         while ((PVOID)((PCHAR) PageAddress + PAGE_SIZE) <
+                (PVOID)((PCHAR) BaseAddress + Length))
+           {
+             MmSetPageProtect(NULL, PageAddress, PAGE_READONLY);
+             PageAddress = (PVOID)((PCHAR) PageAddress + PAGE_SIZE);
+           }
+         if (PageAddress < (PVOID)((PCHAR) BaseAddress + Length) &&
+             ! PageNeedsWriteAccess(PageAddress, DriverBase, PEFileHeader, PESectionHeaders))
            {
-             MmSetPageProtect(NULL, BaseAddress + (i * PAGE_SIZE), 
-                              PAGE_READONLY);
+             MmSetPageProtect(NULL, PageAddress, PAGE_READONLY);
            }
        }
     }