From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 3B2CD9000BD for ; Mon, 19 Sep 2011 13:31:44 -0400 (EDT) Received: by gxk2 with SMTP id 2so960288gxk.14 for ; Mon, 19 Sep 2011 10:31:42 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110919161837.GA2232@albatros> References: <20110910164001.GA2342@albatros> <20110910164134.GA2442@albatros> <20110914192744.GC4529@outflux.net> <20110918170512.GA2351@albatros> <20110919144657.GA5928@albatros> <20110919155718.GB16272@albatros> <20110919161837.GA2232@albatros> Date: Mon, 19 Sep 2011 20:31:42 +0300 Message-ID: Subject: Re: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo From: Pekka Enberg Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Vasiliy Kulikov Cc: Andrew Morton , kernel-hardening@lists.openwall.com, Kees Cook , Cyrill Gorcunov , Al Viro , Christoph Lameter , Matt Mackall , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dan Rosenberg , Theodore Tso , Alan Cox , Jesper Juhl , Linus Torvalds On Mon, Sep 19, 2011 at 7:18 PM, Vasiliy Kulikov wrote: >> However, if the encryptfs and infoleaks really are serious enough to >> hide /proc/slabinfo, I think you should consider switching over to >> kmalloc() instead of kmem_cache_alloc() to make sure nobody can >> gain access to the information. > > kmalloc() is still visible in slabinfo as kmalloc-128 or so. Yes, but there's no way for users to know where the allocations came from if you mix them up with other kmalloc-128 call-sites. That way the number of private files will stay private to the user, no? Doesn't that give you even better protection against the infoleak? Pekka -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org