Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752586AbYKMBNs (ORCPT ); Wed, 12 Nov 2008 20:13:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751584AbYKMBNh (ORCPT ); Wed, 12 Nov 2008 20:13:37 -0500 Received: from exchtp08.via.com.tw ([61.66.243.7]:56548 "EHLO exchtp08.via.com.tw" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751544AbYKMBNh convert rfc822-to-8bit (ORCPT ); Wed, 12 Nov 2008 20:13:37 -0500 X-Greylist: delayed 911 seconds by postgrey-1.27 at vger.kernel.org; Wed, 12 Nov 2008 20:13:36 EST X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Subject: RE: [PATCH] Fix crash in viafb due to 4k stack overflow Date: Thu, 13 Nov 2008 08:58:22 +0800 Message-ID: In-Reply-To: <20081112150104.8f7a71f6.akpm@linux-foundation.org> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [PATCH] Fix crash in viafb due to 4k stack overflow Thread-Index: AclFGpiN1zqkXWX5T3+lCZxgh33mYQAEBNww From: To: , Cc: , , X-OriginalArrivalTime: 13 Nov 2008 00:58:23.0937 (UTC) FILETIME=[EDEBDB10:01C9452A] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3388 Lines: 80 I will try this new patch later. :) BRs, Joseph Chan -----Original Message----- From: Andrew Morton [mailto:akpm@linux-foundation.org] Sent: Thursday, November 13, 2008 7:01 AM To: Bruno Pr?mont Cc: arjan@infradead.org; Joseph Chan; linux-fbdev-devel@lists.sourceforge.net; linux-kernel@vger.kernel.org Subject: Re: [PATCH] Fix crash in viafb due to 4k stack overflow On Mon, 10 Nov 2008 22:00:46 +0100 Bruno Pr__mont wrote: > During conversion of viafb_ioctl() I noticed the following: > > Those two cases just copy_from_user and do nothing with copied data, > incomplete implementation?: > case VIAFB_SET_PANEL_POSITION: > if (copy_from_user(&u.panel_pos_size_para, argp, > sizeof(u.panel_pos_size_para))) > return -EFAULT; > break; > case VIAFB_SET_PANEL_SIZE: > if (copy_from_user(&u.panel_pos_size_para, argp, > sizeof(u.panel_pos_size_para))) > return -EFAULT; > break; > > Handling of GET/SET GAMMA looks buggy: > In each case 256*4 bytes are allocated but only 4 bytes (size of > pointer) are copied to/from userspace though > viafb_(get|set)_gamma_table() operates on the full 256 elements... > case VIAFB_SET_GAMMA_LUT: > viafb_gamma_table = kmalloc(256 * sizeof(u32), GFP_KERNEL); > if (!viafb_gamma_table) > return -ENOMEM; > if (copy_from_user(viafb_gamma_table, argp, > sizeof(viafb_gamma_table))) { > kfree(viafb_gamma_table); > return -EFAULT; > } > viafb_set_gamma_table(viafb_bpp, viafb_gamma_table); > kfree(viafb_gamma_table); > break; > > case VIAFB_GET_GAMMA_LUT: > viafb_gamma_table = kmalloc(256 * sizeof(u32), GFP_KERNEL); > if (!viafb_gamma_table) > return -ENOMEM; > viafb_get_gamma_table(viafb_gamma_table); > if (copy_to_user(argp, viafb_gamma_table, > sizeof(viafb_gamma_table))) { > kfree(viafb_gamma_table); > return -EFAULT; > } > kfree(viafb_gamma_table); > break; > > I don't know if there is a userspace app that uses these VIA IOCTLs... > so the ioctl part is just compile-tested. > After checking, fbset just uses some generic framebuffer IOCTLs > outside of viafb's scope, thus not passing through viafb_ioctl(). > > > > --- > --- linux-2.6.28-rc3/drivers/video/via/viafbdev.c.orig 2008-11-09 19:36:47.000000000 +0100 > +++ linux-2.6.28-rc3/drivers/video/via/viafbdev.c 2008-11-10 20:50:32.000000000 +0100 hm, OK, I dropped the old patch and merged this one. It'd be nice to have it runtime tested and reviewed by Joseph, but we haven't heard from him yet. viafb might be 8k-stacks-only in 2.6.27, which would be bad. -- 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/