On Fri, Aug 03, 2012 at 01:30:31PM +0200, richard -rw- weinberger wrote: > On Fri, Aug 3, 2012 at 1:27 PM, Cyrill Gorcunov <gorcunov@xxxxxxxxxx> wrote: > > On Fri, Aug 03, 2012 at 01:19:24PM +0200, richard -rw- weinberger wrote: > >> >> > >> >> CRIU folks, how do you deal with futex robust lists? > >> > > >> > Well, I believe we were over-optimistic in claiming that we don't need this > >> > syscall (to be fair I think we simply yet not faced the problem Eric points). > >> > So we need some way to fetch this address and set it back. If get_robust_list > >> > get deprecated maybe we could print it out in /proc/pid/stat or something? > >> > >> Kees, you said get_robust_list() can be used to bypass ASLR. > >> How? What makes it worse than /proc/pid/maps? > >> > >> If the robust list address itself is bad, removing get_robust_list() > >> and putting the information into /proc is useless. > > > > Look, the /proc entry might check for some CAP and do not allow > > a regular user to fetch this address. > > We could also add another check to get_robust_list(). > It does already ptrace_may_access(). Yes, and I'm definitely not against that ;) The problem is that this syscall was marked as deprecated and if people want to drop it we need to find a way to provide this address back in a sake of c/r. If c/r is the only _one_ who needs this facility than providing the address via /proc might be worth thing to do (since I can wrap it with CONFIG_CHECKPOINT_RESTORE and a regular kernel won't see this snippet at all). Cyrill -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
