Re: [gentoo-user] memset_s

[Jorge Almeida <jjalmeida@gmail.com>]

On Fri, Nov 10, 2017 at 12:09 PM, Jorge Almeida <jjalmeida@gmail.com> wrote:

> http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buffer.html
>
>
>>> Of course, what would really solve the optimize-into-oblivion problem
>>> is a pragma that when invoked on a particular block of code (maybe
>>> only a function definition) would tell the compiler to do what the
>>> programmer says rather than viewing a function as a kind of black box.
>>>
>>

It seems a solution exists with gcc:

https://stackoverflow.com/questions/2219829/how-to-prevent-gcc-optimizing-some-statements-in-c

The last reply:

void __attribute__((optimize("O0"))) foo(unsigned char data) {
    // unmodifiable compiler code
}

Any comments, anyone? Yes, it's gcc, but IMO this should be in the
language itself. Am I right to assume this is a poorly known feature
of gcc?
It allows, for example,  to replace sensitive data by random bytes,
existing system callls like memset() or getrandom() can be used as
they are, no reimplementation needed.

Jorge Almeida