From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Date: Thu, 16 Sep 2010 16:07:45 +0000 Subject: Re: [PATCH] drivers/video/via/ioctl.c: prevent reading Message-Id: <20100916160745.GC14318@home.goodmis.org> List-Id: References: <1284587059.6275.101.camel@dan> In-Reply-To: <1284587059.6275.101.camel@dan> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dan Rosenberg 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 On Wed, Sep 15, 2010 at 05:44:19PM -0400, Dan Rosenberg wrote: > The VIAFB_GET_INFO device ioctl allows unprivileged users to read 1968 > 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 > > --- 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)); > + Again, this could probably be better off as: - struct viafb_ioctl_info viainfo; + struct viafb_ioctl_info viainfo = { + .viafb_id = VIAID, + .vendor_id = PCI_VIA_VENDOR_ID, + }; - viainfo.viafb_id = VIAID; - viainfo.vendor_id = PCI_VIA_VENDOR_ID; -- Steve > viainfo.viafb_id = VIAID; > viainfo.vendor_id = PCI_VIA_VENDOR_ID; > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755303Ab0IPQHv (ORCPT ); Thu, 16 Sep 2010 12:07:51 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:52606 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751780Ab0IPQHu (ORCPT ); Thu, 16 Sep 2010 12:07:50 -0400 X-Authority-Analysis: v=1.1 cv=8l6A00wGdfxWf8DimOOtudg6dZOi9rXZmlWhmOLJpog= c=1 sm=0 a=MyfHXT5GpaUA:10 a=kj9zAlcOel0A:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=pGLkceISAAAA:8 a=VwQbUJbxAAAA:8 a=W0vUJOdyAAAA:8 a=dRyNUfIVAE1akBsrmUIA:9 a=mxeHl28Mf2i2LuSbHSAA:7 a=GKCk2wTLM8w0grWQl4DupwQ4NdYA:4 a=CjuIK1q_8ugA:10 a=x8gzFH9gYPwA:10 a=MSl-tDqOz04A:10 wl=env:18 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Date: Thu, 16 Sep 2010 12:07:45 -0400 From: Steven Rostedt To: Dan Rosenberg 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] drivers/video/via/ioctl.c: prevent reading uninitialized stack memory Message-ID: <20100916160745.GC14318@home.goodmis.org> References: <1284587059.6275.101.camel@dan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1284587059.6275.101.camel@dan> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 15, 2010 at 05:44:19PM -0400, Dan Rosenberg wrote: > The VIAFB_GET_INFO device ioctl allows unprivileged users to read 1968 > 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 > > --- 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)); > + Again, this could probably be better off as: - struct viafb_ioctl_info viainfo; + struct viafb_ioctl_info viainfo = { + .viafb_id = VIAID, + .vendor_id = PCI_VIA_VENDOR_ID, + }; - viainfo.viafb_id = VIAID; - viainfo.vendor_id = PCI_VIA_VENDOR_ID; -- Steve > viainfo.viafb_id = VIAID; > viainfo.vendor_id = PCI_VIA_VENDOR_ID; > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/