MdePkg/Library/BaseStackCheckLib/BaseStackCheckGcc.c

   1 /** @file
   2  Base Stack Check library for GCC/clang.
   3
   4  Use -fstack-protector-all compiler flag to make the compiler insert the
   5  __stack_chk_guard "canary" value into the stack and check the value prior
   6  to exiting the function. If the "canary" is overwritten __stack_chk_fail()
   7  is called. This is GCC specific code.
   8
   9  Copyright (c) 2012, Apple Inc. All rights reserved.<BR>
  10  SPDX-License-Identifier: BSD-2-Clause-Patent
  11
  12 **/
  13
  14 #include <Base.h>
  15 #include <Library/BaseLib.h>
  16 #include <Library/DebugLib.h>
  17 #include <Library/PcdLib.h>
  18
  19 /// "canary" value that is inserted by the compiler into the stack frame.
  20 VOID *__stack_chk_guard = (VOID*)0x0AFF;
  21
  22 // If ASLR was enabled we could use
  23 //void (*__stack_chk_guard)(void) = __stack_chk_fail;
  24
  25 /**
  26  Error path for compiler generated stack "canary" value check code. If the
  27  stack canary has been overwritten this function gets called on exit of the
  28  function.
  29 **/
  30 VOID
  31 __stack_chk_fail (
  32  VOID
  33  )
  34 {
  35   UINT8 DebugPropertyMask;
  36
  37   DEBUG ((DEBUG_ERROR, "STACK FAULT: Buffer Overflow in function %a.\n", __builtin_return_address(0)));
  38
  39   //
  40   // Generate a Breakpoint, DeadLoop, or NOP based on PCD settings even if
  41   // BaseDebugLibNull is in use.
  42   //
  43   DebugPropertyMask = PcdGet8 (PcdDebugPropertyMask);
  44   if ((DebugPropertyMask & DEBUG_PROPERTY_ASSERT_BREAKPOINT_ENABLED) != 0) {
  45     CpuBreakpoint ();
  46   } else if ((DebugPropertyMask & DEBUG_PROPERTY_ASSERT_DEADLOOP_ENABLED) != 0) {
  47    CpuDeadLoop ();
  48   }
  49 }