From: Dan Carpenter <error27@gmail.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Nelson Elhage <nelhage@ksplice.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Robert Olsson <robert.olsson@its.uu.se>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
netdev@vger.kernel.org
Subject: Re: [patch v3] fix stack overflow in pktgen_if_write()
Date: Mon, 1 Nov 2010 05:47:35 +0200 [thread overview]
Message-ID: <20101101034721.GA14069@bicker> (raw)
In-Reply-To: <87lj5hud36.fsf@basil.nowhere.org>
> > @@ -887,12 +887,17 @@ static ssize_t pktgen_if_write(struct file *file,
> > i += len;
> >
> > if (debug) {
> > - char tb[count + 1];
> > + char *tb;
> > +
> > + tb = kmalloc(count + 1, GFP_KERNEL);
>
>
> This is still trivially exploitable (for root) -- think what happens
> when count is near ULONG_MAX
>
In vfs_write() we call rw_verify_area() which caps count at INT_MAX or
LONG_MAX.
if (unlikely((ssize_t) count < 0))
return retval;
So I get lucky this time... ;)
regards,
dan carpenter
next prev parent reply other threads:[~2010-11-01 3:47 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-27 19:13 [PATCH] pktgen: Remove a dangerous debug print Nelson Elhage
2010-10-27 19:21 ` David Miller
2010-10-27 19:28 ` Nelson Elhage
2010-10-27 19:30 ` David Miller
2010-10-27 19:41 ` Eric Dumazet
2010-10-27 19:49 ` Nelson Elhage
2010-10-27 20:38 ` Ben Greear
2010-10-27 22:12 ` [patch] fix stack overflow in pktgen_if_write() Dan Carpenter
2010-10-27 22:40 ` Dan Carpenter
2010-10-27 22:43 ` [patch v2] " Dan Carpenter
2010-10-27 23:06 ` Nelson Elhage
2010-10-28 6:05 ` Dan Carpenter
2010-10-28 6:05 ` [patch v3] " Dan Carpenter
2010-10-28 15:22 ` Nelson Elhage
2010-10-28 16:28 ` Dan Carpenter
2010-10-28 16:30 ` Nelson Elhage
2010-10-28 23:11 ` Andi Kleen
2010-11-01 3:47 ` Dan Carpenter [this message]
2010-10-28 15:20 ` [PATCH] pktgen: Limit how much data we copy onto the stack Nelson Elhage
2010-10-28 18:32 ` David Miller
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