From: Thomas Gleixner <tglx@linutronix.de>
To: Manjeet Pawar <manjeet.p@samsung.com>
Cc: Vaneet Narang <v.narang@samsung.com>,
alsa-devel@alsa-project.org, a.sahrawat@samsung.com,
tiwai@suse.de, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org, lalit.mohan@samsung.com,
pankaj.m@samsung.com
Subject: Re: [PATCH] ALSA: Adjust structure(snd_timer_tread) members to avoid 8 padding bytes
Date: Tue, 30 May 2017 08:26:01 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1705300824480.1950@nanos> (raw)
In-Reply-To: <1496125148-37895-1-git-send-email-manjeet.p@samsung.com>
On Tue, 30 May 2017, Manjeet Pawar wrote:
> This patch is made to fix below CVE issue where 8 padding bytes are sent to
> user without being initialized. Structure members are adjusted to avoid 8
> padding bytes.
>
> CVE-2016-4569/CVE-2016-4578:
> The stack object tread has a total size of 32 bytes. Its field
> event and val both contain 4 bytes padding. These 8 bytes
> padding bytes are sent to user without being initialized.
>
> Fix patch:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cec8f96e49d9be372fdb0c3836dcf31ec71e457e
> https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/commit/?h=for-next&id=9a47e9cff994f37f7f0dbd9ae23740d0f64f9fe6
>
> These patches does memset on structure object to initialize 8 padding bytes, which can be skipped by
> adjusting structure members.
And by rearranging the struct members you break existing user space, which
is a NONO. The struct has to stay as is.
Thanks,
tglx
prev parent reply other threads:[~2017-05-30 6:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20170530062242epcas5p1fb7f94e02c6550a60603ce28090cc70d@epcas5p1.samsung.com>
2017-05-30 6:19 ` [PATCH] ALSA: Adjust structure(snd_timer_tread) members to avoid 8 padding bytes Manjeet Pawar
2017-05-30 6:26 ` Thomas Gleixner [this message]
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