From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753320AbaH2LVZ (ORCPT ); Fri, 29 Aug 2014 07:21:25 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:45577 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751006AbaH2LVY (ORCPT ); Fri, 29 Aug 2014 07:21:24 -0400 Date: Fri, 29 Aug 2014 14:21:04 +0300 From: Dan Carpenter To: walter harms Cc: linux-kernel@vger.kernel.org, George Zhang , Greg Kroah-Hartman , kernel-janitors@vger.kernel.org Subject: Re: [patch] VMCI: integer overflow in vmci_datagram_dispatch() Message-ID: <20140829112104.GF5071@mwanda> References: <20140829084256.GA14780@mwanda> <5400606B.8010905@bfs.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5400606B.8010905@bfs.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 29, 2014 at 01:13:47PM +0200, walter harms wrote: > > > Am 29.08.2014 10:42, schrieb Dan Carpenter: > > This is untrusted user data from vmci_host_do_send_datagram() so the > > VMCI_DG_SIZE() macro can have an integer overflow. > > > > Signed-off-by: Dan Carpenter > > > > diff --git a/drivers/misc/vmw_vmci/vmci_datagram.c b/drivers/misc/vmw_vmci/vmci_datagram.c > > index f3cdd90..8226652 100644 > > --- a/drivers/misc/vmw_vmci/vmci_datagram.c > > +++ b/drivers/misc/vmw_vmci/vmci_datagram.c > > @@ -328,7 +328,8 @@ int vmci_datagram_dispatch(u32 context_id, > > > > BUILD_BUG_ON(sizeof(struct vmci_datagram) != 24); > > > > - if (VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) { > > + if (dg->payload_size > VMCI_MAX_DG_SIZE || > > + VMCI_DG_SIZE(dg) > VMCI_MAX_DG_SIZE) { > > pr_devel("Payload (size=%llu bytes) too big to send\n", > > (unsigned long long)dg->payload_size); > > return VMCI_ERROR_INVALID_ARGS; > > Are your sure about that ">" ? maybe ">=" was intended ? Yes, I'm sure. As a rule of thumb, > is used for size comparisons and >= is used for index comparisons. regards, dan carpenter