From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48561) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XqK19-0004cR-1S for qemu-devel@nongnu.org; Mon, 17 Nov 2014 05:58:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XqK14-0007Sj-8E for qemu-devel@nongnu.org; Mon, 17 Nov 2014 05:58:46 -0500 Message-ID: <5469D4C4.5090407@redhat.com> Date: Mon, 17 Nov 2014 11:58:12 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1416046008-7880-1-git-send-email-arei.gonglei@huawei.com> <1416046008-7880-10-git-send-email-arei.gonglei@huawei.com> In-Reply-To: <1416046008-7880-10-git-send-email-arei.gonglei@huawei.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 9/9] hcd-musb: fix dereference null return value List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: arei.gonglei@huawei.com, qemu-devel@nongnu.org Cc: weidong.huang@huawei.com, zhang.zhanghailiang@huawei.com, qemu-trivial@nongnu.org, mjt@tls.msk.ru, peter.huangpeng@huawei.com, Gerd Hoffmann On 15/11/2014 11:06, arei.gonglei@huawei.com wrote: > From: Gonglei > > Signed-off-by: Gonglei > --- > hw/usb/hcd-musb.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/hw/usb/hcd-musb.c b/hw/usb/hcd-musb.c > index 66bc61a..f2cb73c 100644 > --- a/hw/usb/hcd-musb.c > +++ b/hw/usb/hcd-musb.c > @@ -624,6 +624,10 @@ static void musb_packet(MUSBState *s, MUSBEndPoint *ep, > > /* A wild guess on the FADDR semantics... */ > dev = usb_find_device(&s->port, ep->faddr[idx]); > + if (!dev) { > + TRACE("Do not find an usb device"); > + return; > + } > uep = usb_ep_get(dev, pid, ep->type[idx] & 0xf); > usb_packet_setup(&ep->packey[dir].p, pid, uep, 0, > (dev->addr << 16) | (uep->nr << 8) | pid, false, true); > I think this patch is not the real fix. usb_ep_get and usb_handle_packet can deal with a NULL device, but we have to avoid dereferencing NULL pointers when building the id. Paolo diff --git a/hw/usb/hcd-musb.c b/hw/usb/hcd-musb.c index 66bc61a..40809f6 100644 --- a/hw/usb/hcd-musb.c +++ b/hw/usb/hcd-musb.c @@ -608,6 +608,7 @@ static void musb_packet(MUSBState *s, MUSBEndPoint *ep, USBDevice *dev; USBEndpoint *uep; int idx = epnum && dir; + int id; int ttype; /* ep->type[0,1] contains: @@ -625,8 +626,11 @@ static void musb_packet(MUSBState *s, MUSBEndPoint *ep, /* A wild guess on the FADDR semantics... */ dev = usb_find_device(&s->port, ep->faddr[idx]); uep = usb_ep_get(dev, pid, ep->type[idx] & 0xf); - usb_packet_setup(&ep->packey[dir].p, pid, uep, 0, - (dev->addr << 16) | (uep->nr << 8) | pid, false, true); + id = pid; + if (uep) { + id |= (dev->addr << 16) | (uep->nr << 8); + } + usb_packet_setup(&ep->packey[dir].p, pid, uep, 0, id, false, true); usb_packet_addbuf(&ep->packey[dir].p, ep->buf[idx], len); ep->packey[dir].ep = ep; ep->packey[dir].dir = dir;