2002-10-23 18:56:04

by Ben Collins

Subject: [PATCH] potential NULL deref in serial/core.c

Not sure if it's supposed to be a BUG() for tty to be NULL, but it's
surely a bug to dereference it before checking for that.



--- drivers/serial/core.c~ 2002-10-23 14:59:17.000000000 -0400
+++ drivers/serial/core.c 2002-10-23 14:59:42.000000000 -0400
@@ -472,10 +472,12 @@

static void uart_put_char(struct tty_struct *tty, unsigned char ch)
{
- struct uart_info *info = tty->driver_data;
+ struct uart_info *info;

- if (tty)
+ if (tty) {
+ info = tty->driver_data;
__uart_put_char(info->port, &info->xmit, ch);
+ }
}

static void uart_flush_chars(struct tty_struct *tty)

--
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2002-10-23 19:04:47

by Ben Collins

Subject: Re: [PATCH] potential NULL deref in serial/core.c

On Wed, Oct 23, 2002 at 03:02:11PM -0400, Ben Collins wrote:
> Not sure if it's supposed to be a BUG() for tty to be NULL, but it's
> surely a bug to dereference it before checking for that.
>

Ug. Find one more after I sent this email.


--- drivers/serial/core.c~ 2002-10-23 14:59:17.000000000 -0400
+++ drivers/serial/core.c 2002-10-23 15:07:55.000000000 -0400
@@ -472,10 +472,12 @@

static void uart_put_char(struct tty_struct *tty, unsigned char ch)
{
- struct uart_info *info = tty->driver_data;
+ struct uart_info *info;

- if (tty)
+ if (tty) {
+ info = tty->driver_data;
__uart_put_char(info->port, &info->xmit, ch);
+ }
}

static void uart_flush_chars(struct tty_struct *tty)
@@ -487,10 +489,15 @@
uart_write(struct tty_struct *tty, int from_user, const unsigned char * buf,
int count)
{
- struct uart_info *info = tty->driver_data;
+ struct uart_info *info;
int ret;

- if (!tty || !info->xmit.buf)
+ if (!tty)
+ return 0;
+
+ info = tty->driver_data;
+
+ if (!info->xmit.buf)
return 0;

if (from_user)

--
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Linux 1394 - http://www.linux1394.org/
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