From: Nelson Elhage <nelhage@ksplice.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>,
robert.olsson@its.uu.se, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, eugene@redhat.com
Subject: Re: [PATCH] pktgen: Remove a dangerous debug print.
Date: Wed, 27 Oct 2010 15:49:05 -0400 [thread overview]
Message-ID: <20101027194905.GQ16803@ksplice.com> (raw)
In-Reply-To: <1288208499.2658.19.camel@edumazet-laptop>
I tested this and was able to oops both amd64 and i386 test machines with 8k
writes to the pktgen file. I haven't investigated whether that's because there's
no PAGE_SIZE limit, or because one page ends up being enough to cause a problem
on all my test machines.
- Nelson
On Wed, Oct 27, 2010 at 09:41:39PM +0200, Eric Dumazet wrote:
> Le mercredi 27 octobre 2010 à 15:28 -0400, Nelson Elhage a écrit :
> > How would you feel about limiting the debug print to at most, say, 512 or 1024
> > bytes? Even if it's only accessible to root by default, I don't a userspace
> > program should be able to accidentally corrupt the kernel stack by writing too
> > many bytes to a file in /proc.
>
> Arent /proc writes limited to PAGE_SIZE anyway ?
>
> On x86 at least, you cannot corrupt kernel stack, since its bigger than
> PAGE_SIZE.
>
> I agree pktgen code is a bit ugly and needs a cleanup, but who
> cares ? :)
>
>
>
>
next prev parent reply other threads:[~2010-10-27 19:49 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 [this message]
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
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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