linux-kernel - RE: [PATCH] drm/i915: Use copy_from

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:   Mon, 11 Dec 2017 09:41:35 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Kees Cook' <keescook@...omium.org>
CC:     Jason Ekstrand <jason@...kstrand.net>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        "intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] drm/i915: Use copy_from_user() in fence copying

From: Kees Cook
> Sent: 08 December 2017 21:10
> >> There's no good reason to separate the access_ok() from the copy,
> >> especially since the access_ok() size is hard-coded instead of using
> >> sizeof(). Instead, just use copy_from_user() directly.
> >
> > Looks like an optimisation to save doing the access_ok() check
> > for every 'fence'.
> 
> If it really makes a difference, okay, but access_ok() checks are fast. :P

Not compared to get_user() :-)

	David