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From: Greg KH <gregkh@linuxfoundation.org>
To: Tomas Winkler <tomas.winkler@intel.com>
Cc: arnd@arndb.de, linux-kernel@vger.kernel.org
Subject: Re: [char-misc-next 2/8] mei: hbm: validate client index is not exceeding allocated array size
Date: Tue, 29 Oct 2013 16:19:45 -0700	[thread overview]
Message-ID: <20131029231945.GB30410@kroah.com> (raw)
In-Reply-To: <1382382343-12066-3-git-send-email-tomas.winkler@intel.com>

On Mon, Oct 21, 2013 at 10:05:37PM +0300, Tomas Winkler wrote:
> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
> ---
>  drivers/misc/mei/hbm.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
> index 9b3a0fb..0f5e8ca 100644
> --- a/drivers/misc/mei/hbm.c
> +++ b/drivers/misc/mei/hbm.c
> @@ -228,8 +228,6 @@ static int mei_hbm_prop_req(struct mei_device *dev)
>  	unsigned long client_num;
>  
>  
> -	client_num = dev->me_client_presentation_num;
> -
>  	next_client_index = find_next_bit(dev->me_clients_map, MEI_CLIENTS_MAX,
>  					  dev->me_client_index);
>  
> @@ -241,6 +239,10 @@ static int mei_hbm_prop_req(struct mei_device *dev)
>  		return 0;
>  	}
>  
> +	client_num = dev->me_client_presentation_num;
> +	if (WARN_ON(dev->me_clients_num <= client_num))
> +		return -EIO;

How can this happen?  Why is spitting out a huge warning in the syslog
going to help anything?  If a user can do this, then great, now you can
DoS your syslog :(

If a user can't do this, then why tell them, it's your driver's bug that
you should just fix.

greg k-h

  reply	other threads:[~2013-10-29 23:19 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-21 19:05 [char-misc-next 0/8] mei security fixes and cleanups Tomas Winkler
2013-10-21 19:05 ` [char-misc-next 1/8] mei: debugfs: validate dev is not null Tomas Winkler
2013-10-29 23:18   ` Greg KH
2013-10-30  7:16     ` Winkler, Tomas
2013-10-30 13:26       ` Greg KH
2013-10-30 21:14         ` Winkler, Tomas
2013-10-21 19:05 ` [char-misc-next 2/8] mei: hbm: validate client index is not exceeding allocated array size Tomas Winkler
2013-10-29 23:19   ` Greg KH [this message]
2013-10-30  7:31     ` Winkler, Tomas
2013-10-30 13:27       ` Greg KH
2013-11-07 12:21         ` Winkler, Tomas
2013-10-21 19:05 ` [char-misc-next 3/8] mei: nfc: fix memory leak in error path Tomas Winkler
2013-10-21 19:05 ` [char-misc-next 4/8] mei: wd: host_init propagate error codes from called functions Tomas Winkler
2013-10-21 19:05 ` [char-misc-next 5/8] mei: bus: propagate error code returned by mei_me_cl_by_id Tomas Winkler
2013-10-21 19:05 ` [char-misc-next 6/8] mei: mei_cl_link remove duplicated check for open_handle_count Tomas Winkler
2013-10-21 19:05 ` [char-misc-next 7/8] mei: replace stray pr_debug with dev_dbg Tomas Winkler
2013-10-21 19:05 ` [char-misc-next 8/8] mei: print correct device state during unexpected reset Tomas Winkler

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