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* [PATCH][4/4] let's kill verify_area - convert kernel/printk.c to access_ok()
@ 2005-01-07  1:18 Jesper Juhl
  2005-01-07 12:51 ` Vincent Hanquez
  0 siblings, 1 reply; 3+ messages in thread
From: Jesper Juhl @ 2005-01-07  1:18 UTC (permalink / raw)
  To: linux-kernel; +Cc: Andrew Morton


Here's a patch to convert verify_area to access_ok in kernel/printk.c


Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>

diff -up linux-2.6.10-bk9-orig/kernel/printk.c linux-2.6.10-bk9/kernel/printk.c
--- linux-2.6.10-bk9-orig/kernel/printk.c	2004-12-24 22:35:40.000000000 +0100
+++ linux-2.6.10-bk9/kernel/printk.c	2005-01-07 02:11:16.000000000 +0100
@@ -269,8 +269,8 @@ int do_syslog(int type, char __user * bu
 		error = 0;
 		if (!len)
 			goto out;
-		error = verify_area(VERIFY_WRITE,buf,len);
-		if (error)
+		error = access_ok(VERIFY_WRITE,buf,len);
+		if (!error)
 			goto out;
 		error = wait_event_interruptible(log_wait, (log_start - log_end));
 		if (error)
@@ -300,8 +300,8 @@ int do_syslog(int type, char __user * bu
 		error = 0;
 		if (!len)
 			goto out;
-		error = verify_area(VERIFY_WRITE,buf,len);
-		if (error)
+		error = access_ok(VERIFY_WRITE,buf,len);
+		if (!error)
 			goto out;
 		count = len;
 		if (count > log_buf_len)




^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH][4/4] let's kill verify_area - convert kernel/printk.c to access_ok()
  2005-01-07  1:18 [PATCH][4/4] let's kill verify_area - convert kernel/printk.c to access_ok() Jesper Juhl
@ 2005-01-07 12:51 ` Vincent Hanquez
  0 siblings, 0 replies; 3+ messages in thread
From: Vincent Hanquez @ 2005-01-07 12:51 UTC (permalink / raw)
  To: Jesper Juhl; +Cc: linux-kernel, Andrew Morton

On Fri, Jan 07, 2005 at 02:18:55AM +0100, Jesper Juhl wrote:
> @@ -300,8 +300,8 @@ int do_syslog(int type, char __user * bu
>  		error = 0;
>  		if (!len)
>  			goto out;
> -		error = verify_area(VERIFY_WRITE,buf,len);
> -		if (error)
> +		error = access_ok(VERIFY_WRITE,buf,len);
> +		if (!error)

I would rather put the ! on access_ok
"if (!error)" is read as "if no error"

-- 
Vincent Hanquez

^ permalink raw reply	[flat|nested] 3+ messages in thread

* RE: [PATCH][4/4] let's kill verify_area - convert kernel/printk.c to access_ok()
@ 2005-01-07 15:38 Peter Kjellerstedt
  0 siblings, 0 replies; 3+ messages in thread
From: Peter Kjellerstedt @ 2005-01-07 15:38 UTC (permalink / raw)
  To: Jesper Juhl, Vincent Hanquez; +Cc: linux-kernel, Andrew Morton

> -----Original Message-----
> From: linux-kernel-owner@vger.kernel.org 
> [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of 
> Vincent Hanquez
> Sent: Friday, January 07, 2005 13:52
> To: Jesper Juhl
> Cc: linux-kernel; Andrew Morton
> Subject: Re: [PATCH][4/4] let's kill verify_area - convert 
> kernel/printk.c to access_ok()
> 
> On Fri, Jan 07, 2005 at 02:18:55AM +0100, Jesper Juhl wrote:
> > @@ -300,8 +300,8 @@ int do_syslog(int type, char __user * bu
> >  		error = 0;
> >  		if (!len)
> >  			goto out;
> > -		error = verify_area(VERIFY_WRITE,buf,len);
> > -		if (error)
> > +		error = access_ok(VERIFY_WRITE,buf,len);
> > +		if (!error)
> 
> I would rather put the ! on access_ok
> "if (!error)" is read as "if no error"

Actually, this should be:

	error = access_ok(VERIFY_WRITE, buf, len) ? 0 : -EFAULT;
	if (error)
		goto out;

Alternatively:

	if (!access_ok(VERIFY_WRITE, buf, len)) {
		error = -EFAULT;
		goto out;
	}

Otherwise the returned value from do_syslog() is incorrect 
in case access_ok() fails (i.e., 0 instead of -EFAULT)...

//Peter

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2005-01-07 15:41 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2005-01-07  1:18 [PATCH][4/4] let's kill verify_area - convert kernel/printk.c to access_ok() Jesper Juhl
2005-01-07 12:51 ` Vincent Hanquez
2005-01-07 15:38 Peter Kjellerstedt

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