[PATCH 1/1] NET: irda, fix potential null dereference

[PATCH 1/1] NET: irda, fix potential null dereference

[Jiri Slaby]

Stanse found a potential null dereference in ircomm_tty_close
and ircomm_tty_hangup. There is a check for tty being NULL,
but it is dereferenced earlier. Move the dereference after
the check.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: netdev@vger.kernel.org
---
 net/irda/ircomm/ircomm_tty.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index 811984d..42a7d75 100644
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -491,7 +491,7 @@ static int ircomm_tty_open(struct tty_struct *tty, struct file *filp)
  */
 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", __func__ );
@@ -499,6 +499,8 @@ static void ircomm_tty_close(struct tty_struct *tty, struct file *filp)
 	if (!tty)
 		return;
 
+	self = tty->driver_data;
+
 	IRDA_ASSERT(self != NULL, return;);
 	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);
 
@@ -999,17 +1001,19 @@ static void ircomm_tty_shutdown(struct ircomm_tty_cb *self)
  */
 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", __func__ );
 
-	IRDA_ASSERT(self != NULL, return;);
-	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);
-
 	if (!tty)
 		return;
 
+	self = 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);
 
-- 
1.6.5.7

[PATCH 1/1] NET: irda, remove unnecessary checks

[Jiri Slaby]

Stanse found a potential null dereference in ircomm_tty_close
and ircomm_tty_hangup. There is a check for tty being NULL,
but it is dereferenced earlier. But it is bogus, the tty cannot
be NULL, so remove the !tty checks.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: netdev@vger.kernel.org
---
 net/irda/ircomm/ircomm_tty.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index 811984d..8b85d77 100644
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -496,9 +496,6 @@ static void ircomm_tty_close(struct tty_struct *tty, struct file *filp)
 
 	IRDA_DEBUG(0, "%s()\n", __func__ );
 
-	if (!tty)
-		return;
-
 	IRDA_ASSERT(self != NULL, return;);
 	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);
 
@@ -1007,9 +1004,6 @@ static void ircomm_tty_hangup(struct tty_struct *tty)
 	IRDA_ASSERT(self != NULL, return;);
 	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);
 
-	if (!tty)
-		return;
-
 	/* ircomm_tty_flush_buffer(tty); */
 	ircomm_tty_shutdown(self);
 
-- 
1.6.5.7

Re: [PATCH 1/1] NET: irda, remove unnecessary checks

[David Miller]

From: Jiri Slaby <jslaby@suse.cz>
Date: Sun, 10 Jan 2010 12:17:34 +0100

> Stanse found a potential null dereference in ircomm_tty_close
> and ircomm_tty_hangup. There is a check for tty being NULL,
> but it is dereferenced earlier. But it is bogus, the tty cannot
> be NULL, so remove the !tty checks.
> 
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>

Applied.