Rustify PKCS7 unpadding

[nitneuqr]

Opening this as a smaller PR needed for #11555.

I'm new to rust, so please let me know if you see some issues in variable lifetime, or some unnecessary copying between Python & Rust.

cc @alex

[reaperhulk]

You can remove the pyfunction annotation from check_pkcs7_padding (which should also fix your coverage issue).

[nitneuqr]

You can remove the pyfunction annotation from check_pkcs7_padding (which should also fix your coverage issue).

Good catch! Actually, since we're making check_pkcs7_padding private, should we simplify the i/o of the function?

[alex]

Given the way check_pkcs7_padding is sensitive to being constant time, we should be conservative in making changes. That said, if you have an idea for how to improve it, happy to discuss!

…

On Fri, Sep 6, 2024 at 3:29 PM Quentin Retourne ***@***.***> wrote: You can remove the pyfunction annotation from check_pkcs7_padding (which should also fix your coverage issue). Good catch! Actually, since we're making check_pkcs7_padding private, should we simplify the i/o of the function? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you were mentioned.Message ID: ***@***.***>

-- All that is necessary for evil to succeed is for good people to do nothing.

[nitneuqr]

I'll check it out but saw the constant time part, and not planning on changing anything important on that side

[nitneuqr]

Should be better!

You can remove the pyfunction annotation from check_pkcs7_padding (which should also fix your coverage issue).

Good catch! Actually, since we're making check_pkcs7_padding private, should we simplify the i/o of the function?

Just realized this didn't make sense since the function input and output types are not pyo3 already

[alex]

Thanks!