From owner-freebsd-bugs Fri Jun 29 10:10: 9 2001 Delivered-To: freebsd-bugs@hub.freebsd.org Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21]) by hub.freebsd.org (Postfix) with ESMTP id 8410D37B406 for ; Fri, 29 Jun 2001 10:10:05 -0700 (PDT) (envelope-from gnats@FreeBSD.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.11.3/8.11.3) id f5THA5V02424; Fri, 29 Jun 2001 10:10:05 -0700 (PDT) (envelope-from gnats) Date: Fri, 29 Jun 2001 10:10:05 -0700 (PDT) Message-Id: <200106291710.f5THA5V02424@freefall.freebsd.org> To: freebsd-bugs@FreeBSD.org Cc: From: Peter Pentchev Subject: Re: misc/28522: The ability to crash any freebsd box with 8 lines of shell script Reply-To: Peter Pentchev Sender: owner-freebsd-bugs@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org The following reply was made to PR misc/28522; it has been noted by GNATS. From: Peter Pentchev To: David Malone Cc: freebsd-gnats-submit@FreeBSD.org Subject: Re: misc/28522: The ability to crash any freebsd box with 8 lines of shell script Date: Fri, 29 Jun 2001 20:08:29 +0300 On Fri, Jun 29, 2001 at 10:00:19AM -0700, David Malone wrote: > The following reply was made to PR misc/28522; it has been noted by GNATS. > > From: David Malone > To: Ryan Malek > Cc: freebsd-gnats-submit@FreeBSD.org > Subject: Re: misc/28522: The ability to crash any freebsd box with 8 lines of shell script > Date: Fri, 29 Jun 2001 17:54:34 +0100 > > On Fri, Jun 29, 2001 at 09:11:32AM -0700, Ryan Malek wrote: > > I wrote a small paper documenting this problem. I _think_ its quite a serious problem considering the fact that I can drop any FreeBSD box with 7 or 8 lines of shell scripting. Here is the paper I wrote on it: > > > > http://exotica.mach3ww.com/~squirl/devzero-vuln.txt > > You seem to have rediscovered the fork bomb - if the admin has > suitable process limits set then this shouldn't be a problem. Try > saying "limit maxproc 10" and running the catbomb, you should find > it is less effective. > > (I'll close the PR unless there is more to the problem than this). But is it really ineffective? Just five instances of 'cat' would consume quite a lot of kernel resources (fake read, fake write, two syscalls, data copies to userspace and back...). G'luck, Peter -- I am the thought you are now thinking. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message