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From: Arjan van de Ven <arjan@infradead.org>
To: selvakumar nagendran <kernelselva@yahoo.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Bug : Out of range ptr error in module indicates bug in slab.c
Date: Thu, 30 Dec 2004 12:18:40 +0100	[thread overview]
Message-ID: <1104405521.4170.10.camel@laptopd505.fenrus.org> (raw)
In-Reply-To: <20041230105452.26574.qmail@web60605.mail.yahoo.com>

On Thu, 2004-12-30 at 02:54 -0800, selvakumar nagendran wrote:
> 		else	{
> 			new -> pipe_read_end = fdes[0];
> 			new -> pipe_write_end = fdes[1];

this is a bug; fdes is a USERSPACE pointer, you cannot directly access
that from kernel space, you need to use copy_from_user() for that.

And note, what you are doing is unreliable, since the user is capable of
changing that information before you log it in your structure, so if you
want to use the data you log for anything security related or for
something that has to be accurate, it's broken...

> 	while(temp != NULL)
> 	{
> 		kfree(temp);
> 		temp = temp -> next;
> 	}

that is of course wrong; you free temp and THEN you access it!!



  reply	other threads:[~2004-12-30 11:18 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-30 10:54 selvakumar nagendran
2004-12-30 11:18 ` Arjan van de Ven [this message]
2004-12-30 12:13   ` Bug_reply " selvakumar nagendran
2004-12-30 12:18     ` Arjan van de Ven
2004-12-31  6:51       ` Interception for a resource based scheduler selvakumar nagendran
2004-12-31  7:48         ` Arjan van de Ven

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