Messages in this thread | | | Date | Wed, 23 Jun 2010 07:54:37 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v2] security: Yama LSM |
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Hi Andi,
On Wed, Jun 23, 2010 at 01:43:41PM +0200, Andi Kleen wrote: > Kees Cook <kees.cook@canonical.com> writes: > > + > > +config SECURITY_YAMA_SYMLINKS > > + bool "Yama: protect symlink following in sticky world-writable > > dirs" > > IMHO it's bad style to have CONFIGs that just set defaults, > if that can be done at runtime too. Especially as in your case if it's > a lot of settings. Is it that bad to have a init script and drop these > CONFIGs?
Oh, er, I actually added these configs because Eric Paris recommended them as handy for distributions. I'm fine with dropping them, but will I be asked to add them back later? And what about the case of CONFIG_SYSCTL being unset?
> However the help texts are useful, these should be in the sysctl > documentatin in Documentation instead.
I documented the sysctls in Documentation/Yama.txt (where SELinux.txt and Smack.txt live) should I create an additional file in Documentation/sysctl/ with that information (moved from Yama.txt) or move Yama.txt there?
> > + if (rc) { > > + printk_ratelimited(KERN_INFO "ptrace of non-child" > > + " pid %d was attempted by: %s (pid %d)\n", > > + child->pid, get_task_comm(name, current), > > + current->pid); > > It's probably obscure and other kernel code has this too, but at some point > there were attacks to use terminal ESC sequences to attack root's > terminal when they dmesg. Couldn't that be done through "comm" here?
I actually think this is a flaw in get_task_comm. (Though actually it's the fault of terminals if they process dangerous escape sequences. Worst case tends to just be confusing output, but that's not important -- nothing should spew non-printables regardless.) Would a patch to get_task_comm be accepted to replace non-printables with "?" or something when filling the buffer?
Thanks,
-Kees
-- Kees Cook Ubuntu Security Team
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