From: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
To: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: JosephChan@via.com.tw, ScottFang@viatech.com.cn,
linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
security@kernel.org, stable@kernel.org
Subject: Re: [PATCH v2] drivers/video/via/ioctl.c: prevent reading uninitialized stack memory
Date: Thu, 16 Sep 2010 01:45:34 +0200 [thread overview]
Message-ID: <4C915A9E.408@gmx.de> (raw)
In-Reply-To: <1284592104.10727.12.camel@dan>
Dan Rosenberg schrieb:
> Disregard previous version, which had a typo and wouldn't compile.
> Also, math is fun: the ioctl allows reading of 1968 BITS = 246 bytes,
> not 1968 bytes as previously reported.
Thanks, I will take care of getting it in mainline as soon as possible,
Florian Tobias Schandinat
>
> The VIAFB_GET_INFO device ioctl allows unprivileged users to read 246
> bytes of uninitialized stack memory, because the "reserved" member of
> the viafb_ioctl_info struct declared on the stack is not altered or
> zeroed before being copied back to the user. This patch takes care of
> it.
>
> Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
>
> --- linux-2.6.35.4.orig/drivers/video/via/ioctl.c 2010-08-26 19:47:12.000000000 -0400
> +++ linux-2.6.35.4/drivers/video/via/ioctl.c 2010-09-15 11:53:29.997375748 -0400
> @@ -25,6 +25,8 @@ int viafb_ioctl_get_viafb_info(u_long ar
> {
> struct viafb_ioctl_info viainfo;
>
> + memset(&viainfo, 0, sizeof(struct viafb_ioctl_info));
> +
> viainfo.viafb_id = VIAID;
> viainfo.vendor_id = PCI_VIA_VENDOR_ID;
>
>
>
> --
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>
prev parent reply other threads:[~2010-09-15 23:45 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-15 23:08 [PATCH v2] drivers/video/via/ioctl.c: prevent reading uninitialized stack memory Dan Rosenberg
2010-09-15 23:45 ` Florian Tobias Schandinat [this message]
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