Playing around with security hardening compiler flags

[Alexander Leidinger]

Hi,

after reading

https://security.googleblog.com/2024/11/retrofitting-spatial-safety-to-hundreds.html

    https://libcxx.llvm.org/Hardening.html

https://best.openssf.org/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.html

I played around a bit with some of the flags there (in CFLAGS).

What doesn't work:


What works and results in a world+kernel which is able to boot:
 - -D_GLIBCXX_ASSERTIONS
 - -fstrict-flex-arrays=1
 - -fstack-clash-protection
 - -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_EXTENSIVE



Bye,
Alexander.

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- -fstrict-flex-arrays=3 (variable array issue in IIRC a tool for ath) - -fstrict-flex-arrays=2 (issue in another area, haven't checked further) Does someone has any reason / argument why some of those shouldn't be used when building FreeBSD? Should something like this be optional, and if yes, enabled by default, or disabled by default?

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