linux-kernel - Re: suppress page allocation failure warnings from sys

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120329020820.GB22697@redhat.com>
Date:	Wed, 28 Mar 2012 22:08:20 -0400
From:	Dave Jones <davej@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Joe Perches <joe@...ches.com>, Dave Chinner <david@...morbit.com>,
	viro@...iv.linux.org.uk,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	David Rientjes <rientjes@...gle.com>
Subject: Re: suppress page allocation failure warnings from sys_listxattr

On Wed, Mar 28, 2012 at 07:02:11PM -0700, Andrew Morton wrote:

 > > Also, what happens if something allocates
 > > and sits on a bunch of vmalloc'd memory ? would we start seeing oom kills ?
 > 
 > vmalloc() would fail.

Ok, that's a pretty boring failure mode, so not a big deal probably.

 > > (thinking of the context of my fuzzing tool where a bunch of instances could
 > >  feasibly call these syscalls and not sit on huge amounts per thread, but
 > >  collectively...  I'm wondering if it could be provoked into killing
 > >  processes I don't own)
 > 
 > umm, if you wanted to deliberately trigger a vmalloc() failure then I
 > guess a good approach would be to locate a vmalloc() site which can
 > persist beyond the syscall (modprobe is a good one!) then exercise it
 > in a way so that there are no N-byte holes left in the arena, then
 > trigger an N-byte vmalloc().

Well modprobe is root-only, so that's not so bad. But it looks like
key_add (see other thread from this evening) and probably others can be
called as a user and gobble up vmalloc space. omnomnom.

	Dave

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/