linux-kernel - Re: [patch] firmware: qemu_fw_cfg.c: potential unintialized variable

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: <20160414191253.GH4247@mwanda>
Date:	Thu, 14 Apr 2016 22:12:53 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	"Gabriel L. Somlo" <somlo@....edu>
Cc:	"Michael S. Tsirkin" <mst@...hat.com>, qemu-devel@...gnu.org,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [patch] firmware: qemu_fw_cfg.c: potential unintialized variable

On Thu, Apr 14, 2016 at 02:40:06PM -0400, Gabriel L. Somlo wrote:
> On Thu, Apr 14, 2016 at 12:33:37PM +0300, Dan Carpenter wrote:
> > It acpi_acquire_global_lock() return AE_NOT_CONFIGURED then "glk" isn't
>   ^                               ^
>   If                            returns
> 
> > initialized, which, if you got very unlucky, could cause a bug.
> 
> 
> In principle I'm OK with being cautious and initializing local
> variables just in case, but I'm curious:
> 
> acpi_acquire_global_lock() (and its friend, acpi_release_global_lock())
> are both wrapped inside the same macro -- ACPI_HW_DEPENDENT_RETURN_STATUS
> -- which either makes them both do something useful, or makes them both
> no-ops returning a hardcoded AE_NOT_CONFIGURED.
> 
> So what else do you think could be a way to get very unlucky ?

If "glk" happened to to equal acpi_gbl_global_lock_handle by chance
then we would release it without acquiring it first.  Actually I could
initialize it to zero and that would be better, no?

regards,
dan carpenter