[aandrejevic] 59452: [NTVDM] Fix bugs in the VDM DOS executable loader.

Author: aandrejevic
Date: Tue Jul  9 17:28:16 2013
New Revision: 59452

URL: http://svn.reactos.org/svn/reactos?rev=59452&view=rev
Log:
[NTVDM]
Fix bugs in the VDM DOS executable loader.

Modified:
    branches/ntvdm/subsystems/ntvdm/dos.c

Modified: branches/ntvdm/subsystems/ntvdm/dos.c
URL: http://svn.reactos.org/svn/reactos/branches/ntvdm/subsystems/ntvdm/dos.c?rev...
==============================================================================
--- branches/ntvdm/subsystems/ntvdm/dos.c	[iso-8859-1] (original)
+++ branches/ntvdm/subsystems/ntvdm/dos.c	[iso-8859-1] Tue Jul  9 17:28:16 2013
@@ -637,6 +637,7 @@
     CHAR CommandLineCopy[128];
     INT ParamCount = 0;
     DWORD Segment = 0;
+    WORD MaxAllocSize;
     DWORD i, FileSize, ExeSize;
     PIMAGE_DOS_HEADER Header;
     PDWORD RelocationTable;
@@ -701,8 +702,6 @@
         /* Get the MZ header */
         Header = (PIMAGE_DOS_HEADER)Address;

-        // TODO: Verify checksum and executable!
-
         /* Get the base size of the file, in paragraphs (rounded up) */
         ExeSize = (((Header->e_cp - 1) * 512) + Header->e_cblp + 0x0F) >> 4;

@@ -740,7 +739,8 @@
         RtlCopyMemory((PVOID)((ULONG_PTR)BaseAddress
                       + TO_LINEAR(Segment, 0x100)),
                       Address + (Header->e_cparhdr << 4),
-                      FileSize - (Header->e_cparhdr << 4));
+                      min(FileSize - (Header->e_cparhdr << 4),
+                          (ExeSize << 4) - sizeof(DOS_PSP)));

/* Get the relocation table */
         RelocationTable = (PDWORD)(Address + Header->e_lfarlc);
@@ -777,9 +777,19 @@
     {
         /* COM file */

-        /* Allocate memory for the whole program and the PSP */
-        Segment = DosAllocateMemory((FileSize + sizeof(DOS_PSP)) >> 4, NULL);
+        /* Find the maximum amount of memory that can be allocated */
+        DosAllocateMemory(0xFFFF, &MaxAllocSize);
+
+        /* Make sure it's enough for the whole program and the PSP */
+        if ((MaxAllocSize << 4) < (FileSize + sizeof(DOS_PSP))) goto Cleanup;
+
+        /* Allocate all of it */
+        Segment = DosAllocateMemory(MaxAllocSize, NULL);
         if (Segment == 0) goto Cleanup;
+
+        /* The process owns its own memory */
+        DosChangeMemoryOwner(Segment, Segment);
+        DosChangeMemoryOwner(EnvBlock, Segment);

/* Copy the program to Segment:0100 */
         RtlCopyMemory((PVOID)((ULONG_PTR)BaseAddress