From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: Re: [PATCH RFC 1 3/8] xen/pt: Check if reg->init is past the reg->size Date: Wed, 1 Jul 2015 14:54:02 +0100 Message-ID: References: <1435611725-15161-1-git-send-email-konrad.wilk@oracle.com> <1435611725-15161-4-git-send-email-konrad.wilk@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZAITX-0005el-Ni for xen-devel@lists.xenproject.org; Wed, 01 Jul 2015 13:54:55 +0000 In-Reply-To: <1435611725-15161-4-git-send-email-konrad.wilk@oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Konrad Rzeszutek Wilk Cc: xen-devel@lists.xenproject.org, qemu-devel@nongnu.org, stefano.stabellini@eu.citrix.com List-Id: xen-devel@lists.xenproject.org On Mon, 29 Jun 2015, Konrad Rzeszutek Wilk wrote: > It should never happen, but in case it does we want to > report. The code will only write up to reg->size so there > is no runtime danger. > > Signed-off-by: Konrad Rzeszutek Wilk > --- > hw/xen/xen_pt_config_init.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c > index 91c3a14..bc871c9 100644 > --- a/hw/xen/xen_pt_config_init.c > +++ b/hw/xen/xen_pt_config_init.c > @@ -1901,9 +1901,13 @@ static int xen_pt_config_reg_init(XenPCIPassthroughState *s, > } else > val = data; > > + if (val & size_mask) { > + XEN_PT_ERR(&s->dev,"Offset 0x%04x:0x%04u expands past register size(%d)!\n", > + offset, val, reg->size); should we return early? > + } > /* This could be just pci_set_long as we don't modify the bits > - * past reg->size, but in case this routine is run in parallel > - * we do not want to over-write other registers. */ > + * past reg->size, but in case this routine is run in parallel or the > + * init value is larger, we do not want to over-write registers. */ > switch (reg->size) { > case 1: pci_set_byte(s->dev.config + offset, (uint8_t)val); break; > case 2: pci_set_word(s->dev.config + offset, (uint16_t)val); break; > -- > 2.1.0 >