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

Alexey Dobriyan
2006-03-22T23:22:51Z

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);