linux-kernel - Re: [PATCH] vfs: rw_copy_check_uvector()

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Message-ID: <20140425162712.GH10187@tucsk.piliscsaba.szeredi.hu>
Date:	Fri, 25 Apr 2014 18:27:12 +0200
From:	Miklos Szeredi <miklos@...redi.hu>
To:	Eric Biggers <ebiggers3@...il.com>
Cc:	Dave Jones <davej@...hat.com>, Al Viro <viro@...iv.linux.org.uk>,
	Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux-Fsdevel <linux-fsdevel@...r.kernel.org>
Subject: Re: [PATCH] vfs: rw_copy_check_uvector() - free iov on error

On Wed, Apr 23, 2014 at 12:25:34AM -0500, Eric Biggers wrote:
> On Wed, Apr 23, 2014 at 12:06:39AM -0500, Eric Biggers wrote:
> > The proposed patch doesn't work because in compat_rw_copy_check_uvector(),
> > 'iov' is incremented in the loop before it is freed or returned.  This
> > probably should be changed to indexing with 'seg', like in the non-compat
> > version...
> 
> Also, there is still a memory leak in vmsplice() as it does not free the iov
> buffer if 0 is returned from rw_copy_check_uvector() (possible if all segments
> are of zero length).

There are more problems.  E.g. count is zero so nothing will be copied.  This
function needs some care and attention (and testing).

Thanks,
Miklos
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