MdePkg/BaseSafeIntLib: Add SafeIntLib class and instance
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
https://github.com/Microsoft/MS_UEFI/commit/21ef3a321c907b40fa93797619c9f6c686dd92e0
https://github.com/Microsoft/MS_UEFI/commit/ca516b1a61315c2d823f453e12d2135098f53d61
https://github.com/Microsoft/MS_UEFI/commit/33bab4031a417d7d5a7d356c15a14c2e60302b2d
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>
2017-04-25 01:37:20 +02:00
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## @file
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# Safe Integer Library
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#
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# This library provides helper functions to prevent integer overflow during
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# type conversion, addition, subtraction, and multiplication.
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#
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# Copyright (c) 2017, Microsoft Corporation
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#
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# All rights reserved.
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are met:
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# 1. Redistributions of source code must retain the above copyright notice,
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# this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright notice,
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# this list of conditions and the following disclaimer in the documentation
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# and/or other materials provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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# IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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# INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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##
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[Defines]
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INF_VERSION = 0x00010005
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BASE_NAME = BaseSafeIntLib
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FILE_GUID = 4EA91BFA-3482-4930-B136-70679C6CE489
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MODULE_TYPE = BASE
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VERSION_STRING = 1.0
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LIBRARY_CLASS = SafeIntLib
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#
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# The following information is for reference only and not required by the build tools.
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#
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# VALID_ARCHITECTURES = IA32 X64
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#
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[Sources]
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SafeIntLib.c
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[Sources.Ia32, Sources.ARM]
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SafeIntLib32.c
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[Sources.X64, Sources.IPF, Sources.AARCH64]
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SafeIntLib64.c
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[Sources.EBC]
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SafeIntLibEbc.c
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[Packages]
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MdePkg/MdePkg.dec
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2018-02-26 04:55:15 +01:00
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[LibraryClasses]
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BaseLib
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