Re: [PATCH v2] ext4: replace strcpy() with '.' assignment

Theodore Ts'o
2025-05-23T14:25:10Z

On Fri, May 23, 2025 at 01:31:00PM +0100, David Laight wrote:
>
> The compiler (or headers files) can also allow strcpy() of constant
> length strings into arrays (known size). Erroring requests that are too long.
> The strcpy() is then converted to a memcpy() which can then be optimised
> into writes of constants.
>
> So using strcpy() under those conditions 'isn't all bad' and can generate
> better (and less bug prone) code than trying to hand-optimise it.
>
> So even through strcpy() is usually a bad idea, there is not need to
> remove the calls that the compiler can validate as safe.

I assume that what the hardening folks want to do is to assert that
strcpy is always evil(tm) so they can detect potential security bugs
by doing "git grep strcpy".

- Ted