From: Andi Kleen <ak@suse.de>
To: Bryan Rittmeyer <bryan@ixiacom.com>
Cc: warchild@spoofed.org, linux-kernel@vger.kernel.org
Subject: Re: remote memory reading using arp?
Date: 28 Apr 2002 14:26:24 +0200 [thread overview]
Message-ID: <p73znzom2kv.fsf@oldwotan.suse.de> (raw)
In-Reply-To: <20020427202756.GC6240@spoofed.org.suse.lists.linux.kernel> <3CCB0EAB.9050602@ixiacom.com.suse.lists.linux.kernel>
Bryan Rittmeyer <bryan@ixiacom.com> writes:
> It's not the ARP layer that's causing the padding... Ethernet has a
> minimum transmit size of 64 bytes (everything below that is disgarded
> by hardware as a fragment), so the network device driver or
> the hardware itself will pad any Linux skb smaller than 60 bytes up to
> that size (so that it's 64 bytes after appending CRC32). Apparently, in
> some cases that's done by just transmitting whatever uninitialized
> memory follows skb->data, which, after the system has been running
> for a while, may be inside a page previously used by userspace.
The driver should be fixed in that case. I would consider it a driver
bug. The cost of clearing the tail should be minimal, it is at most
two cache lines.
Is it known which driver caused this?
>
> This is NOT a "remote memory reading" exploit, since there is no way to
It really is.
-Andi
next parent reply other threads:[~2002-04-28 12:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20020427202756.GC6240@spoofed.org.suse.lists.linux.kernel>
[not found] ` <3CCB0EAB.9050602@ixiacom.com.suse.lists.linux.kernel>
2002-04-28 12:26 ` Andi Kleen [this message]
2002-04-28 17:47 ` remote memory reading using arp? warchild
2002-04-29 15:24 ` Calin A. Culianu
2002-04-29 15:31 ` Andi Kleen
2002-04-30 3:04 ` warchild
2002-05-01 19:37 ` Dirty memory? (WAS Re: remote memory reading using arp?) Calin A. Culianu
2002-05-01 22:24 ` Calin A. Culianu
2002-04-27 20:27 remote memory reading using arp? Warchild
2002-04-27 20:48 ` Bryan Rittmeyer
2002-04-27 21:19 ` Warchild
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