gcc-8.5.0-4.el8

The gcc packages provide compilers for C, C++, Java, Fortran, Objective C, and Ada 95 GNU, as well as related support libraries.

Security Fix(es):

* Developer environment: Unicode's bidirectional (BiDi) override characters can cause trojan source attacks (CVE-2021-42574)

The following changes were introduced in gcc in order to facilitate detection of BiDi Unicode characters:

This update implements a new warning option -Wbidirectional to warn about possibly dangerous bidirectional characters.

There are three levels of warning supported by gcc:
"-Wbidirectional=unpaired", which warns about improperly terminated BiDi contexts. (This is the default.)
"-Wbidirectional=none", which turns the warning off.
"-Wbidirectional=any", which warns about any use of bidirectional characters.

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

CVE-2021-42574
An issue was discovered in the Bidirectional Algorithm in the Unicode Specification through 14.0. It permits the visual reordering of characters via control sequences, which can be used to craft source code that renders different logic than the logical ordering of tokens ingested by compilers and interpreters. Adversaries can leverage this to encode source code for compilers accepting Unicode such that targeted vulnerabilities are introduced invisibly to human reviewers.