Subject: Re: [patch] isdn: make sure strings are null terminated

From: walter harms <[email-masked]>
Date: Wed, 23 Nov 2011 09:25:56 +0100

Am 23.11.2011 07:42, schrieb Dan Carpenter:
> These strings come from the user.  We strcpy() them inside
> cf_command() so we should check that they are NULL terminated and
> return an error if not.
> 
> Signed-off-by: Dan Carpenter <[email-masked]>
> 
> diff --git a/drivers/isdn/divert/divert_procfs.c b/drivers/isdn/divert/divert_procfs.c
> index 33ec9e4..0c16687 100644
> --- a/drivers/isdn/divert/divert_procfs.c
> +++ b/drivers/isdn/divert/divert_procfs.c
> @@ -242,6 +242,10 @@ static int isdn_divert_ioctl_unlocked(struct file *file, uint cmd, ulong arg)
>  		case IIOCDOCFINT:
>  			if (!divert_if.drv_to_name(dioctl.cf_ctrl.drvid))
>  				return (-EINVAL);	/* invalid driver */
> +			if (strlen(dioctl.cf_ctrl.msn) >= sizeof(dioctl.cf_ctrl.msn))
> +				return -EINVAL;
> +			if (strlen(dioctl.cf_ctrl.fwd_nr) >= sizeof(dioctl.cf_ctrl.fwd_nr))
> +				return -EINVAL;

forcing the last field to be zero seems more easy.
dioctl.cf_ctrl.fwd_nr[sizeof(dioctl.cf_ctrl.fwd_nr))-1]=0;

re,
 wh

>  			if ((i = cf_command(dioctl.cf_ctrl.drvid,
>  					    (cmd == IIOCDOCFACT) ? 1 : (cmd == IIOCDOCFDIS) ? 0 : 2,
>  					    dioctl.cf_ctrl.cfproc,
> --
> To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
> the body of a message to [email-masked]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
>