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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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8
MdePkg/Include/Base.h
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@@ -396,6 +396,14 @@ struct _LIST_ENTRY {
#define MAX_INT64 ((INT64)0x7FFFFFFFFFFFFFFFULL)
#define MAX_UINT64 ((UINT64)0xFFFFFFFFFFFFFFFFULL)
///
/// Minimum values for the signed UEFI Data Types
///
#define MIN_INT8 (((INT8) -127) - 1)
#define MIN_INT16 (((INT16) -32767) - 1)
#define MIN_INT32 (((INT32) -2147483647) - 1)
#define MIN_INT64 (((INT64) -9223372036854775807LL) - 1)
#define BIT0 0x00000001
#define BIT1 0x00000002
#define BIT2 0x00000004