linux-kernel - Re: [PATCH] libkmod-module: Remove directory existence check for KMOD_MODULE

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: <87vbiysv1v.fsf@rustcorp.com.au>
Date:	Thu, 19 Feb 2015 09:10:12 +1030
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Lucas De Marchi <lucas.de.marchi@...il.com>
Cc:	Harish Jenny K N <harish_kandiga@...tor.com>,
	linux-modules <linux-modules@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	"greg KH" <gregkh@...uxfoundation.org>
Subject: Re: [PATCH] libkmod-module: Remove directory existence check for KMOD_MODULE_BUILTIN

Lucas De Marchi <lucas.de.marchi@...il.com> writes:
> On Wed, Feb 18, 2015 at 2:07 AM, Rusty Russell <rusty@...tcorp.com.au> wrote:
> Yeah, I just thought (an wanted that) the attributes were being
> created first and then hooked up in the sysfs tree under
> /sys/module/<modulename>. I.e. if the directory exists and there's no
> initstate this is because it's a builtin module. I don't want to
> wait/sleep on the file to appear because users of
> kmod_module_get_initstate() may not tolerate this behavior.
>
> Looking up at the old module-init-tools, it used an ugly loop with
> usleep() before trying to read the file again :-/
>
> Can we change kernel side guaranteeing the initstate file appears
> together with the directory?

Greg?  The core problem is that kmod looks for
/sys/module/<name>/initstate; if it's not there, it assumes a builtin
module.

However, this is racy when a module is being inserted.  Is there a way
to create this sysfs file and dir atomically?

Thanks,
Rusty.
--
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/