From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: [PATCH v1 03/10] xen/pt: Check if reg->init function sets the 'data' past the reg->size Date: Thu, 2 Jul 2015 15:51:14 -0400 Message-ID: <1435866681-18468-4-git-send-email-konrad.wilk@oracle.com> References: <1435866681-18468-1-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 1ZAkWA-0007oD-7W for xen-devel@lists.xenproject.org; Thu, 02 Jul 2015 19:51:30 +0000 In-Reply-To: <1435866681-18468-1-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: stefano.stabellini@eu.citrix.com, xen-devel@lists.xenproject.org, qemu-devel@nongnu.org, JBeulich@suse.com Cc: Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org It should never happen, but in case it does (an developer adds a new register and the 'init_val' expands past the register size) we want to report. The code will only write up to reg->size so there is no runtime danger of the register spilling across other ones - however to catch this sort of thing we still return an error. Signed-off-by: Konrad Rzeszutek Wilk --- hw/xen/xen_pt_config_init.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c index 3938afd..09309ba 100644 --- a/hw/xen/xen_pt_config_init.c +++ b/hw/xen/xen_pt_config_init.c @@ -1904,9 +1904,15 @@ 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%04x expands past register size(%d)!\n", + offset, val, reg->size); + g_free(reg_entry); + return -ENXIO; + } /* 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