Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755498Ab3JaUn5 (ORCPT ); Thu, 31 Oct 2013 16:43:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33234 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751819Ab3JaUn4 (ORCPT ); Thu, 31 Oct 2013 16:43:56 -0400 Date: Thu, 31 Oct 2013 13:45:58 -0700 From: Greg KH To: Kees Cook Cc: Al Viro , Chen Gang , "Eric W. Biederman" , Serge Hallyn , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] fs/befs/linuxvfs.c: need signed cast for variable 'block' Message-ID: <20131031204558.GA30290@kroah.com> References: <5271C5E5.6080606@asianux.com> <20131031190608.GH13318@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1796 Lines: 41 On Thu, Oct 31, 2013 at 12:08:33PM -0700, Kees Cook wrote: > On Thu, Oct 31, 2013 at 12:06 PM, Al Viro wrote: > > On Thu, Oct 31, 2013 at 09:53:59AM -0700, Kees Cook wrote: > > > >> If block (type sector_t) is unsigned, we shouldn't cast it signed. > >> This entire code path should be removed. What is BEFS's expected > >> maximum block size? (Looks like even befs_blocknr_t is u64, so nothing > >> seems trivially in danger of wrapping.) I would also note that all the > >> format strings are wrong too (%ld instead of %lu). > > > > FWIW, this > > res = befs_fblock2brun(sb, ds, block, &run); > > if (res != BEFS_OK) { > > befs_error(sb, > > "<--- befs_get_block() for inode %lu, block " > > "%ld ERROR", inode->i_ino, block); > > return -EFBIG; > > } > > also looks wrong - ioctl(..., FIBMAP, ...) shouldn't be able to spew > > printks on a valid fs and hitting it with block number greater than > > file length will, AFAICS, trigger that. > > > > I agree that this code needs fixing, but just making gcc STFU about the > > comparison would only serve to hide the problem. Anybody familiar with > > befs or willing to learn it? > > Agreed. MAINTAINERS shows it as orphaned. Perhaps it should be moved > into staging? Only if we want to delete the thing. I'll be glad to take it there, and remove it in 2 releases and then if anyone complains, we can add it back easily. Just let me know. thanks, greg k-h -- 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/