From: TINNES Julien RD-MAPS-ISS <julien.tinnes@francetelecom.com>
Date: Thu, 23 Jun 2005 07:10:08 +0000 (-0700)
Subject: [PATCH] Potential null pointer dereference in amiga serial driver
X-Git-Tag: v2.6.13-rc1~68^2~407
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d9ad7ef1979d65a4200847ec91be5b9ad961eba8;p=linux-2.6

[PATCH] Potential null pointer dereference in amiga serial driver

A pointer is dereferenced before it is null-checked.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/drivers/char/amiserial.c b/drivers/char/amiserial.c
index 1dc4259213..777bc499bb 100644
--- a/drivers/char/amiserial.c
+++ b/drivers/char/amiserial.c
@@ -861,13 +861,18 @@ static void change_speed(struct async_struct *info,
 
 static void rs_put_char(struct tty_struct *tty, unsigned char ch)
 {
-	struct async_struct *info = (struct async_struct *)tty->driver_data;
+	struct async_struct *info;
 	unsigned long flags;
 
+	if (!tty)
+		return;
+
+	info = tty->driver_data;
+
 	if (serial_paranoia_check(info, tty->name, "rs_put_char"))
 		return;
 
-	if (!tty || !info->xmit.buf)
+	if (!info->xmit.buf)
 		return;
 
 	local_irq_save(flags);
@@ -910,13 +915,18 @@ static void rs_flush_chars(struct tty_struct *tty)
 static int rs_write(struct tty_struct * tty, const unsigned char *buf, int count)
 {
 	int	c, ret = 0;
-	struct async_struct *info = (struct async_struct *)tty->driver_data;
+	struct async_struct *info;
 	unsigned long flags;
 
+	if (!tty)
+		return 0;
+
+	info = tty->driver_data;
+
 	if (serial_paranoia_check(info, tty->name, "rs_write"))
 		return 0;
 
-	if (!tty || !info->xmit.buf || !tmp_buf)
+	if (!info->xmit.buf || !tmp_buf)
 		return 0;
 
 	local_save_flags(flags);