linux-kernel - Re: [PATCH] livepatch: add (un)patch hooks

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] [day] [month] [year] [list]

Date:   Fri, 28 Jul 2017 13:29:00 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Joe Lawrence <joe.lawrence@...hat.com>
Cc:     Petr Mladek <pmladek@...e.com>, live-patching@...r.kernel.org,
        linux-kernel@...r.kernel.org, Jessica Yu <jeyu@...nel.org>,
        Jiri Kosina <jikos@...nel.org>,
        Miroslav Benes <mbenes@...e.cz>,
        Chris J Arges <chris.j.arges@...onical.com>
Subject: Re: [PATCH] livepatch: add (un)patch hooks

On Fri, Jul 28, 2017 at 02:08:33PM -0400, Joe Lawrence wrote:
> On 07/27/2017 05:36 PM, Josh Poimboeuf wrote:
> > On Thu, Jul 27, 2017 at 04:43:58PM -0400, Joe Lawrence wrote:
> >> On 07/20/2017 12:17 AM, Josh Poimboeuf wrote:
> >>> - The post-patch and post-unpatch hooks will need to be run from either
> >>>   klp_complete_transition() or klp_module_coming/going(), depending on
> >>>   whether the to-be-patched module is already loaded or is being
> >>>   loaded/unloaded.
> >>
> >> You're suggesting that post-(un)patch-hooks:
> >>
> >>   1 - Notify klp_objects when a KLP_(UN)PATCHED transition completes
> > 
> > Right. (From klp_complete_transition())
> 
> We should be careful to only call hooks for those klp_objects that were
> actually (un)patched.  I don't think there is such state that makes it
> all the way out to klp_complete_transition(), but since both the
> completion and module_coming/going code both operate under the
> klp_mutex, perhaps klp_is_object_loaded() is a sufficient check?

Yeah, the mutex makes it safe to just check klp_is_object_loaded().

-- 
Josh