linux-kernel - Re: [PATCH] kdb: prefer strlcpy to strncpy

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Message-ID: <CAMuHMdXE980MDNO4mxOkwO=5AWV=Nzwwu1Sjt653AK8bMHbWsA@mail.gmail.com>
Date:   Wed, 30 May 2018 22:47:13 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Daniel Thompson <daniel.thompson@...aro.org>
Cc:     Nick Desaulniers <nick.desaulniers@...il.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jason Wessel <jason.wessel@...driver.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Baolin Wang <baolin.wang@...aro.org>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        kgdb-bugreport@...ts.sourceforge.net,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        ebiggers@...gle.com
Subject: Re: [PATCH] kdb: prefer strlcpy to strncpy

H Daniel,

On Wed, May 30, 2018 at 4:34 PM, Daniel Thompson
<daniel.thompson@...aro.org> wrote:
> On Tue, May 29, 2018 at 07:01:35PM -0700, Nick Desaulniers wrote:
>> On Tue, May 29, 2018 at 12:57 AM, Arnd Bergmann <arnd@...db.de> wrote:
>> > On Tue, May 29, 2018 at 7:57 AM, Nick Desaulniers
>> > <nick.desaulniers@...il.com> wrote:
>> >> Fixes stringop-truncation and stringop-overflow warnings from gcc-8.

>> Eric points out that this will leak kernel memory if size is less than
>> sizeof src.
>
> Don't quite understand what this means (there's no allocation here, how
> can there be a leak?) but the symbol completion certainly won't work if
> we truncate the copy here.

Not leak an is memory leak, but leak as in information leak of uninitialized
data to userspace (if the buffer is ever copied to userspace).

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds