From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominique Martinet Subject: Re: [PATCH] 9p: fix NULL pointer dereferences Date: Fri, 27 Jul 2018 00:15:27 +0200 Message-ID: <20180726221527.GA9426@nautica> References: <20180726081049.10527-1-tomasbortoli@gmail.com> <20180726081727.GA6699@nautica> <20180726094849.GA18334@nautica> <20180726142109.GA4235@nautica> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Dmitry Vyukov , David Miller , v9fs-developer@lists.sourceforge.net, netdev , LKML , syzkaller To: Tomas Bortoli Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Tomas Bortoli wrote on Thu, Jul 26, 2018: > > If we want to preserve the current behaviour for trans=fd (and I don't > > see why not) we just have to patch all the transports that use the > > device, that is all .create functions but p9_fd_create() > > > > Basically exactly what you did, just for a few more functions - I > > apparently was a little bit too optimistic thinking we could share > > this check. > > Does v9fs_mount() knows the transport ahead? Because in that case it'd > be possible to check if addr!=NULL && trans!=fd then return error > > Otherwise, patching all the .create, ok. 9p option parsing is all over the place, split in fs/9p/v9fs, net/9p/client and net/9p/trans_*... Which is actually somewhat of a problem because that means we can't warn on unused option as each parser does not know the full subset of options used, so if someone makes a typo they're on their own to figure it out :/ If you want to factor it in, v9fs_mount does not know which transport is used, but p9_client_create does know - although the functions/structs are all static so you need to check clnt->trans_mod->name with strcmp and I'm honestly not sure that's better than checking in each function.. But, as usual I'm happy as long as it works, so pick your poison :) -- Dominique Martinet