msvc6/ntoskrnl/mm_i386_memsafe.c

   1 #include <ddk/ntddk.h>
   2
   3
   4 void MmSafeCopyToUserRestart();
   5 void MmSafeCopyToUserUnsafeStart();
   6 void MmSafeCopyFromUserUnsafeStart();
   7 void MmSafeCopyFromUserRestart();
   8
   9         /*
  10          * NTSTATUS MmSafeCopyFromUser(PVOID Dest, PVOID Src,
  11          *                             ULONG NumberOfBytes)
  12          */
  13 __declspec(naked)
  14 NTSTATUS MmSafeCopyFromUser(PVOID Dest, const VOID *Src, ULONG Count)
  15 {
  16         __asm
  17         {
  18                 push    ebp
  19                 mov     ebp,esp
  20
  21                 push    esi
  22                 push    edi
  23                 push    ecx
  24
  25                 mov     edi, 8[ebp]
  26                 mov     esi, 12[ebp]
  27                 mov     ecx, 16[ebp]
  28
  29                 /*
  30                  * Default return code
  31                  */
  32                 xor             eax,eax
  33
  34                 jmp             MmSafeCopyFromUserUnsafeStart
  35         }
  36 }
  37
  38
  39 __declspec(naked)
  40 void MmSafeCopyFromUserUnsafeStart()
  41 {
  42         __asm
  43         {
  44                 /*
  45                  * This is really a synthetic instruction since if we incur a
  46                  * pagefault then eax will be set to an appropiate STATUS code
  47                  */
  48                 cld
  49                 rep movsb
  50
  51                 jmp             MmSafeCopyFromUserRestart
  52         }
  53 }
  54
  55 __declspec(naked)
  56 void MmSafeCopyFromUserRestart()
  57 {
  58         __asm
  59         {
  60                 pop             ecx
  61                 pop             edi
  62                 pop             esi
  63
  64                 pop             ebp
  65                 ret
  66         }
  67 }
  68
  69 /*****************************************************************************/
  70
  71         /*
  72          * NTSTATUS MmSafeCopyToUser(PVOID Dest, PVOID Src,
  73          *                      ULONG NumberOfBytes)
  74          */
  75 NTSTATUS MmSafeCopyToUser(PVOID Dest, const VOID *Src, ULONG Count)
  76 {
  77         __asm
  78         {
  79                 push    ebp
  80                 mov     esp,ebp
  81
  82                 push    esi
  83                 push    edi
  84                 push    ecx
  85
  86                 mov     edi, 8[ebp]
  87                 mov     esi, 12[ebp]
  88                 mov     ecx, 16[ebp]
  89
  90                 /*
  91                  * Default return code
  92                  */
  93                 xor             eax,eax
  94
  95                 jmp             MmSafeCopyToUserUnsafeStart
  96         }
  97 }
  98
  99 __declspec(naked)
 100 void MmSafeCopyToUserUnsafeStart()
 101 {
 102         __asm
 103         {
 104         /*
 105          * This is really a synthetic instruction since if we incur a
 106          * pagefault then eax will be set to an appropiate STATUS code
 107          */
 108         cld
 109         rep movsb
 110         jmp MmSafeCopyToUserRestart
 111         }
 112 }
 113
 114 __declspec(naked)
 115 void MmSafeCopyToUserRestart()
 116 {
 117         __asm
 118         {
 119                 pop             ecx
 120                 pop             edi
 121                 pop             esi
 122
 123                 pop             ebp
 124                 ret
 125         }
 126 }