[ros-diffs] [sir_richard] 48651: [NTOS]: Add an extra layer of protection for freed nonpaged pool: write a 4-byte signature on freed blocks, and assert its valid on checked builds. Use a slightly less egocentr...

Author: sir_richard
Date: Sun Aug 29 19:32:25 2010
New Revision: 48651

URL: http://svn.reactos.org/svn/reactos?rev=48651&view=rev
Log:
[NTOS]: Add an extra layer of protection for freed nonpaged pool: write a 4-byte signature on freed blocks, and assert its valid on checked builds. Use a slightly less egocentric ASCII value than on Windows (name of the developer who wrote the first memory manager).

Modified:
    trunk/reactos/ntoskrnl/mm/ARM3/pool.c

Modified: trunk/reactos/ntoskrnl/mm/ARM3/pool.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/pool.c?rev...
==============================================================================
--- trunk/reactos/ntoskrnl/mm/ARM3/pool.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/ARM3/pool.c [iso-8859-1] Sun Aug 29 19:32:25 2010
@@ -298,6 +298,7 @@
     FreeEntry = MmNonPagedPoolStart;
     FirstEntry = FreeEntry;
     FreeEntry->Size = PoolPages;
+    FreeEntry->Signature = MM_FREE_POOL_SIGNATURE;
     FreeEntry->Owner = FirstEntry;

//
@@ -316,6 +317,7 @@
         //
         FreeEntry = (PMMFREE_POOL_ENTRY)((ULONG_PTR)FreeEntry + PAGE_SIZE);
         FreeEntry->Owner = FirstEntry;
+        FreeEntry->Signature = MM_FREE_POOL_SIGNATURE;
     }

//
@@ -626,6 +628,7 @@
             // Grab the entry and see if it can handle our allocation
             //
             FreeEntry = CONTAINING_RECORD(NextEntry, MMFREE_POOL_ENTRY, List);
+            ASSERT(FreeEntry->Signature == MM_FREE_POOL_SIGNATURE);
             if (FreeEntry->Size >= SizeInPages)
             {
                 //
@@ -964,6 +967,7 @@
         //
         FreeEntry = (PMMFREE_POOL_ENTRY)((ULONG_PTR)StartingVa +
                                          (NumberOfPages << PAGE_SHIFT));
+        ASSERT(FreeEntry->Signature == MM_FREE_POOL_SIGNATURE);
         ASSERT(FreeEntry->Owner == FreeEntry);

/* Consume this entry's pages */
@@ -1032,6 +1036,7 @@
         // Get the free entry descriptor for that given page range
         //
         FreeEntry = (PMMFREE_POOL_ENTRY)((ULONG_PTR)StartingVa - PAGE_SIZE);
+        ASSERT(FreeEntry->Signature == MM_FREE_POOL_SIGNATURE);
         FreeEntry = FreeEntry->Owner;

/* Check if protected pool is enabled */
@@ -1118,6 +1123,7 @@
         // Link back to the parent free entry, and keep going
         //
         NextEntry->Owner = FreeEntry;
+        NextEntry->Signature = MM_FREE_POOL_SIGNATURE;
         NextEntry = (PMMFREE_POOL_ENTRY)((ULONG_PTR)NextEntry + PAGE_SIZE);
     } while (NextEntry != LastEntry);