linux-kernel - Re: [PATCH] gcc-plugins: Add structleak for more stack initialization

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Date:   Tue, 17 Jan 2017 19:54:38 +0100
From:   "PaX Team" <pageexec@...email.hu>
To:     Mark Rutland <mark.rutland@....com>
CC:     kernel-hardening@...ts.openwall.com,
        Kees Cook <keescook@...omium.org>,
        Emese Revfy <re.emese@...il.com>,
        "AKASHI, Takahiro" <takahiro.akashi@...aro.org>,
        park jinbum <jinb.park7@...il.com>,
        Daniel Micay <danielmicay@...il.com>,
        linux-kernel@...r.kernel.org, spender@...ecurity.net
Subject: Re: [PATCH] gcc-plugins: Add structleak for more stack initialization

On 17 Jan 2017 at 17:48, Mark Rutland wrote:

> That being the case, (and given the relevant bug has now been fixed),
> it's not clear to me what the value of this is today. i.e. given the
> general case, is this preventing many leaks?

no idea, i stopped looking at the instrumentation log long ago, but everyone
can enable the debug output (has a very specific comment on it ;) and look at
the results. i keep this plugin around because it costs nothing to maintain
it and the alternative (better) solution doesn't exist yet.

> > i never went into that direction because i think the security goal can
> > be achieved without the performance impact of forced initialization.
> 
> Was there a particular technique you had in mind?

sure, i mentioned it in my SSTIC'12 keynote (page 36):
https://pax.grsecurity.net/docs/PaXTeam-SSTIC12-keynote-20-years-of-PaX.pdf