From: ebiederm@xmission.com (Eric W. Biederman)
To: Joe Perches <joe@perches.com>
Cc: Andrea Righi <andrea.righi@canonical.com>,
Dan Carpenter <dan.carpenter@oracle.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Sam Ravnborg <sam@ravnborg.org>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Peter Rosin <peda@axentia.se>, Gerd Hoffmann <kraxel@redhat.com>,
dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
security@kernel.org, Kees Cook <keescook@chromium.org>,
Julia Lawall <Julia.Lawall@lip6.fr>
Subject: Re: [PATCH] fbdev: potential information leak in do_fb_ioctl()
Date: Thu, 31 Oct 2019 17:12:10 -0500 [thread overview]
Message-ID: <87ftj8k1j9.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <734ef2833e4e4e7bded92e9d964bc2415aadf3c4.camel@perches.com> (Joe Perches's message of "Thu, 31 Oct 2019 11:16:39 -0700")
Joe Perches <joe@perches.com> writes:
> On Wed, 2019-10-30 at 21:12 +0100, Andrea Righi wrote:
>> Then memset() + memcpy() is probably the best option,
>> since copying all those fields one by one looks quite ugly to me...
>
> A memset of an automatic before a memcpy to the same
> automatic is unnecessary.
You still need to guarantee that all of the holes in the
structure you are copying are initialized before you copy it.
Otherwise you are just changing which unitialized memory that
is being copied to userspace.
Which is my concern with your very simple suggestion.
Eric
WARNING: multiple messages have this Message-ID (diff)
From: ebiederm@xmission.com (Eric W. Biederman)
To: Joe Perches <joe@perches.com>
Cc: linux-fbdev@vger.kernel.org, security@kernel.org,
Kees Cook <keescook@chromium.org>,
Julia Lawall <Julia.Lawall@lip6.fr>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
kernel-janitors@vger.kernel.org,
Daniel Vetter <daniel.vetter@ffwll.ch>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
Andrea Righi <andrea.righi@canonical.com>,
Gerd Hoffmann <kraxel@redhat.com>,
Sam Ravnborg <sam@ravnborg.org>, Peter Rosin <peda@axentia.se>,
Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [PATCH] fbdev: potential information leak in do_fb_ioctl()
Date: Thu, 31 Oct 2019 17:12:10 -0500 [thread overview]
Message-ID: <87ftj8k1j9.fsf@x220.int.ebiederm.org> (raw)
Message-ID: <20191031221210.laFf7D6ZoeSRgvAQnU3k6wjtCTGn5d5yGC84QYxI3co@z> (raw)
In-Reply-To: <734ef2833e4e4e7bded92e9d964bc2415aadf3c4.camel@perches.com> (Joe Perches's message of "Thu, 31 Oct 2019 11:16:39 -0700")
Joe Perches <joe@perches.com> writes:
> On Wed, 2019-10-30 at 21:12 +0100, Andrea Righi wrote:
>> Then memset() + memcpy() is probably the best option,
>> since copying all those fields one by one looks quite ugly to me...
>
> A memset of an automatic before a memcpy to the same
> automatic is unnecessary.
You still need to guarantee that all of the holes in the
structure you are copying are initialized before you copy it.
Otherwise you are just changing which unitialized memory that
is being copied to userspace.
Which is my concern with your very simple suggestion.
Eric
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next prev parent reply other threads:[~2019-10-31 22:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-29 18:23 [PATCH] fbdev: potential information leak in do_fb_ioctl() Dan Carpenter
2019-10-29 18:35 ` Joe Perches
2019-10-29 18:35 ` Joe Perches
2019-10-29 19:02 ` Eric W. Biederman
2019-10-29 19:02 ` Eric W. Biederman
2019-10-30 7:43 ` Andrea Righi
2019-10-30 7:43 ` Andrea Righi
2019-10-30 19:26 ` Eric W. Biederman
2019-10-30 19:26 ` Eric W. Biederman
2019-10-30 20:12 ` Andrea Righi
2019-10-30 20:12 ` Andrea Righi
2019-10-31 18:16 ` Joe Perches
2019-10-31 18:16 ` Joe Perches
2019-10-31 22:12 ` Eric W. Biederman [this message]
2019-10-31 22:12 ` Eric W. Biederman
2020-01-03 13:07 ` Bartlomiej Zolnierkiewicz
2020-01-13 11:08 ` [PATCH v2] " Dan Carpenter
2020-01-15 14:31 ` Bartlomiej Zolnierkiewicz
2020-01-13 12:49 ` [PATCH] " Arnd Bergmann
2020-01-15 13:09 ` Bartlomiej Zolnierkiewicz
2020-01-15 13:16 ` Arnd Bergmann
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