linux-kernel - Re: [PATCH] overflow.h: Rename __ab_c_size() to __calc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190405082447.GD23348@zn.tnic>
Date:   Fri, 5 Apr 2019 10:24:47 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Rasmus Villemoes <linux@...musvillemoes.dk>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Kees Cook <keescook@...omium.org>,
        Matthew Wilcox <willy@...radead.org>
Subject: Re: [PATCH] overflow.h: Rename __ab_c_size() to __calc_size()

On Fri, Apr 05, 2019 at 10:09:31AM +0200, Rasmus Villemoes wrote:
> On 05/04/2019 09.52, Borislav Petkov wrote:
> > On Fri, Apr 05, 2019 at 08:26:45AM +0200, Rasmus Villemoes wrote:
> 
> >> It computes a*b+c with overflow checking at each step. calc_size
> >> is way too generic and doesn't say anything at all about how the
> >> calc(ulation) is done.
> > 
> > Ok, whatever.
> > 
> > Then it would need at least a comment above it to state what it does. I
> > don't want to go and parse the macros each time.
> 
> It's an internal helper, and struct_size is fully kernel-doc'ed. But
> yeah, a comment wouldn't hurt, and let's rename the parameters so they
> match the abc naming.
> 
> diff --git a/include/linux/overflow.h b/include/linux/overflow.h
> index 40b48e2133cb..6534a727cadb 100644
> --- a/include/linux/overflow.h
> +++ b/include/linux/overflow.h
> @@ -278,11 +278,15 @@ static inline __must_check size_t
> array3_size(size_t a, size_t b, size_t c)
>         return bytes;
>  }
> 
> -static inline __must_check size_t __ab_c_size(size_t n, size_t size,
> size_t c)
> +/*
> + * Compute a*b+c, returning SIZE_MAX on overflow. Internal helper for
> + * struct_size() below.
> + */
> +static inline __must_check size_t __ab_c_size(size_t a, size_t b, size_t c)
>  {
>         size_t bytes;
> 
> -       if (check_mul_overflow(n, size, &bytes))
> +       if (check_mul_overflow(a, b, &bytes))
>                 return SIZE_MAX;
>         if (check_add_overflow(bytes, c, &bytes))
>                 return SIZE_MAX;
> 
>

Reported-by: Borislav Petkov <bp@...e.de>
Acked-by: Borislav Petkov <bp@...e.de>

Thx.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.