From: Linus Torvalds <torvalds@osdl.org>
To: Andi Kleen <ak@muc.de>
Cc: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>,
viro@www.linux.org.uk, linux-fsdevel@vger.kernel.org
Subject: Re: negative seek offsets in VFS
Date: Thu, 26 May 2005 12:39:19 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.58.0505261238090.2307@ppc970.osdl.org> (raw)
In-Reply-To: <20050526192526.GX86087@muc.de>
On Thu, 26 May 2005, Andi Kleen wrote:
>
> > I don't think there is a "positive loff_t", so I guess the code would have
> > to be something like
> >
> > /* Wraparound? */
> > if ((u64)(pos + count) < count)
> > goto Einval;
>
> Sometimes I think we should have a nice inline asm macro for that
> that checks carry.
Well, we'd need one in every size, and it's not common enough for us to
care about performance, so..
> > if ((loff_t) (pos + count) < 0)
> > if (!(file->f_mode & FMODE_ANY_OFFSET))
> > goto Einval;
>
> Looks good. But how to handle the broken devices viro worries about?
> I would prefer not to open any new security holes, but it is a bit too
> much code to audit all. Flag would be possible, but ugly.
I would _only_ ever set that FMODE_ANY_OFFSET for /dev/mem or other
devices that are known to be ok. IOW, this is not something that ever gets
set by default, and the user cannot set it.
Linus
next prev parent reply other threads:[~2005-05-26 19:37 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-25 16:39 negative seek offsets in VFS Andi Kleen
2005-05-25 16:56 ` Trond Myklebust
2005-05-25 18:48 ` Andi Kleen
2005-05-26 0:56 ` Bryan Henderson
2005-05-26 19:20 ` Andi Kleen
2005-05-26 15:15 ` Al Viro
2005-05-26 15:29 ` Linus Torvalds
2005-05-26 19:25 ` Andi Kleen
2005-05-26 19:39 ` Linus Torvalds [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-05-26 14:29 Paul Taysom
[not found] <s29588e0.089@sinclair.provo.novell.com>
2005-05-26 17:49 ` Bryan Henderson
2005-05-26 19:23 ` Andi Kleen
2005-05-26 21:17 ` Bryan Henderson
2005-05-27 10:43 ` Andi Kleen
2005-05-27 18:39 ` Bryan Henderson
2005-05-28 12:41 ` Jamie Lokier
2005-05-31 18:08 ` Bryan Henderson
2005-05-30 9:36 ` Andi Kleen
2005-05-31 18:33 ` Bryan Henderson
2005-05-28 12:37 ` Jamie Lokier
2005-05-30 9:32 ` Andi Kleen
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