Re: [Patch] Pointer dereference in net/irda/ircomm/ircomm_tty.c

[Alexey Dobriyan]

On Wed, Mar 22, 2006 at 11:46:05PM +0100, Eric Sesterhenn wrote:
> this fixes coverity bugs #855 and #854. In both cases tty
> is dereferenced before getting checked for NULL.

Before Al will flame you,

IMO, what should be done is removing asserts checking for "self",
because ->driver_data is filled in ircomm_tty_open() with valid pointer.

> --- linux-2.6.16/net/irda/ircomm/ircomm_tty.c.orig
> +++ linux-2.6.16/net/irda/ircomm/ircomm_tty.c
> @@ -493,7 +493,7 @@ static int ircomm_tty_open(struct tty_st
>   */
>  static void ircomm_tty_close(struct tty_struct *tty, struct file *filp)
>  {
> -	struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;
> +	struct ircomm_tty_cb *self;
>  	unsigned long flags;
>
>  	IRDA_DEBUG(0, "%s()\n", __FUNCTION__ );
> @@ -501,6 +501,8 @@ static void ircomm_tty_close(struct tty_
>  	if (!tty)
>  		return;
>
> +	self = (struct ircomm_tty_cb *) tty->driver_data;
> +
>  	IRDA_ASSERT(self != NULL, return;);
>  	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);
>
> @@ -1006,17 +1008,19 @@ static void ircomm_tty_shutdown(struct i
>   */
>  static void ircomm_tty_hangup(struct tty_struct *tty)
>  {
> -	struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;
> +	struct ircomm_tty_cb *self;
>  	unsigned long	flags;
>
>  	IRDA_DEBUG(0, "%s()\n", __FUNCTION__ );
>
> -	IRDA_ASSERT(self != NULL, return;);
> -	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);
> -
>  	if (!tty)
>  		return;
>
> +	self = (struct ircomm_tty_cb *) tty->driver_data;
> +
> +	IRDA_ASSERT(self != NULL, return;);
> +	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);
> +
>  	/* ircomm_tty_flush_buffer(tty); */
>  	ircomm_tty_shutdown(self);

-
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