From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ray Wells Subject: Re: Ubuntu 8.04 / 8.10 Date: Sat, 14 Feb 2009 09:32:02 +1100 Message-ID: <4995F4E2.3060604@exemail.com.au> References: <4995564A.3050308@xnet.co.nz> <4995DEA5.7000203@exemail.com.au> <4995E895.10701@radagast.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4995E895.10701@radagast.org> Sender: linux-hams-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Dave Platt Cc: linux-hams Dave Platt wrote: > Ray Wells wrote: >> Peter, >> >> This problem arose with fbb around kernel 2.6.20 (can't remember just >> which one now) >> >> The fix I apply is to compile fbb with -fno-stack-protection added >> to its Makefile. I don't have a fix if you install fbb from a deb >> package. >> >> It seems that stack protection was included in kernels as a security >> plug for stack overflow. >> >> I sent quite a bit about this to the xfbb list around 18 months ago. > > The real question (to me at least) is whether the stack-smash abort > is a false alarm, or whether it indicates a real problem in the > FBB software. > > If there really is a way in which the FBB software is managing to > smash its own stack (via e.g. a buffer that's too small, indexing > out of bounds, etc.), then simply disabling the stack protection > feature via recompilation is a bit like replacing a blown fuse > with a larger one. You may get away with it, or it may burn your > house down :-( > > It'd probably be necessary to compile xfbb with -g and run it > under GDB or a similar debugger, and investigate the state of the > stack at the time of the abort, to figure out what's being > over-written. > -- > To unsubscribe from this list: send the line "unsubscribe linux-hams" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > The logic I applied at the time was that since fbb had always been broken (but not previously detected) I wasn't going to break it any more by disabling stack protection. I've certainly not detected any problems with fbb since I started doing this. If somebody with c programming skills wants to fix the real problem, we will welcome you with open arms, but I don't have those skills and I do need to keep the bbs functioning. I have achieved that target. Ray vk2tv