/** @file
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Base Stack Check library for GCC/clang.
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Use -fstack-protector-all compiler flag to make the compiler insert the
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__stack_chk_guard "canary" value into the stack and check the value prior
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to exiting the function. If the "canary" is overwritten __stack_chk_fail()
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is called. This is GCC specific code.
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Copyright (c) 2012, Apple Inc. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include <Base.h>
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#include <Library/BaseLib.h>
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#include <Library/DebugLib.h>
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#include <Library/PcdLib.h>
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/// "canary" value that is inserted by the compiler into the stack frame.
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VOID *__stack_chk_guard = (VOID*)0x0AFF;
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// If ASLR was enabled we could use
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//void (*__stack_chk_guard)(void) = __stack_chk_fail;
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/**
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Error path for compiler generated stack "canary" value check code. If the
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stack canary has been overwritten this function gets called on exit of the
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function.
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**/
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VOID
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__stack_chk_fail (
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VOID
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)
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{
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UINT8 DebugPropertyMask;
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DEBUG ((DEBUG_ERROR, "STACK FAULT: Buffer Overflow in function %a.\n", __builtin_return_address(0)));
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//
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// Generate a Breakpoint, DeadLoop, or NOP based on PCD settings even if
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// BaseDebugLibNull is in use.
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//
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DebugPropertyMask = PcdGet8 (PcdDebugPropertyMask);
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if ((DebugPropertyMask & DEBUG_PROPERTY_ASSERT_BREAKPOINT_ENABLED) != 0) {
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CpuBreakpoint ();
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} else if ((DebugPropertyMask & DEBUG_PROPERTY_ASSERT_DEADLOOP_ENABLED) != 0) {
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CpuDeadLoop ();
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}
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}
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