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MdePkg/BaseSafeIntLib: Add SafeIntLib class and instance

Browse Source 
https://bugzilla.tianocore.org/show_bug.cgi?id=798

SafeIntLib provides helper functions to prevent integer overflow
during type conversion, addition, subtraction, and multiplication.

Conversion Functions
====================
* Converting from a signed type to an unsigned type of the same
  size, or vice-versa.
* Converting to a smaller type that could possibly overflow.
* Converting from a signed type to a larger unsigned type.

Unsigned Addition, Subtraction, Multiplication
===============================================
* Unsigned integer math functions protect from overflow and
  underflow (in case of subtraction).

Signed Addition, Subtraction, Multiplication
============================================
* Strongly consider using unsigned numbers.
* Signed numbers are often used where unsigned numbers should
  be used. For example file sizes and array indices should always
  be unsigned. Subtracting a larger positive signed number from a
  smaller positive signed number with SafeInt32Sub() will succeed,
  producing a negative number, that then must not be used as an
  array index (but can occasionally be used as a pointer index.)
  Similarly for adding a larger magnitude negative number to a
  smaller magnitude positive number.
* SafeIntLib does not protect you from such errors. It tells you
  if your integer operations overflowed, not if you are doing the
  right thing with your non-overflowed integers.
* Likewise you can overflow a buffer with a non-overflowed
  unsigned index.

Based on content from the following branch/commits:
https://github.com/Microsoft/MS_UEFI/tree/share/MsCapsuleSupport
21ef3a321c
ca516b1a61
33bab4031a

Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Sean Brogan <sean.brogan@microsoft.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
This commit is contained in:
Sean Brogan
2017-04-24 16:37:20 -07:00
committed by Kinney, Michael D
parent 11cf02f6d0
commit d7a09cb86a
15 changed files with 8915 additions and 9 deletions
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7
MdePkg/Include/Ipf/ProcessorBind.h
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@@ -1,7 +1,7 @@
/** @file
Processor or Compiler specific defines and types for Intel Itanium(TM) processors.
Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
distribution. The full text of the license may be found at
@@ -242,6 +242,11 @@ typedef INT64 INTN;
#define MAX_INTN ((INTN)0x7FFFFFFFFFFFFFFFULL)
#define MAX_UINTN ((UINTN)0xFFFFFFFFFFFFFFFFULL)
///
/// Minimum legal Itanium-based INTN value.
///
#define MIN_INTN (((INTN)-9223372036854775807LL) - 1)
///
/// Per the Itanium Software Conventions and Runtime Architecture Guide,
/// section 3.3.4, IPF stack must always be 16-byte aligned.