Hao Wu ea0b15067c MdePkg/PrintLib: Fix possible negative value left shift
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=702

Within function InternalPrintLibSPrintMarker(), possible left shift of a
negative value is found in:
"(*(ArgumentString + 1) << 8)"

which involves undefined behavior.

Since '*(ArgumentString + 1)' is of type CONST CHAR8 (signed), it will be
promoted to type int (signed) during the left shift operation. If
'*(ArgumentString + 1)' is a negative value, the behavior will be
undefined.

According to the C11 spec, Section 6.5.7:
> 4 The result of E1 << E2 is E1 left-shifted E2 bit positions; vacated
>   bits are filled with zeros. If E1 has an unsigned type, the value
>   of the result is E1 * 2^E2 , reduced modulo one more than the
>   maximum value representable in the result type. If E1 has a signed
>   type and nonnegative value, and E1 * 2^E2 is representable in the
>   result type, then that is the resulting value; otherwise, the
>   behavior is undefined.

This commit explicitly cast '*(ArgumentString + 1)' with UINT8 to resolve
this issue.

Cc: Steven Shi <steven.shi@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
2017-09-29 16:14:17 +08:00
2014-10-14 16:08:15 +00:00

EDK II Project

A modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications from www.uefi.org.

Contributions to the EDK II open source project are covered by the TianoCore Contribution Agreement 1.1

The majority of the content in the EDK II open source project uses a BSD 2-Clause License. The EDK II open source project contains the following components that are covered by additional licenses:

The EDK II Project is composed of packages. The maintainers for each package are listed in Maintainers.txt.

Resources

Description
Acidanthera UEFI Development Kit based on EDK II edk2-stable202405
Readme 319 MiB
Languages
C 76.4%
Assembly 10.5%
Python 9.3%
Rich Text Format 1.5%
C++ 0.8%
Other 1.1%