From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51594) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ai3ds-0001p3-LL for qemu-devel@nongnu.org; Mon, 21 Mar 2016 13:29:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ai3dp-0000zc-Ax for qemu-devel@nongnu.org; Mon, 21 Mar 2016 13:29:24 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:49757) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ai3dp-0000yH-4M for qemu-devel@nongnu.org; Mon, 21 Mar 2016 13:29:21 -0400 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 21 Mar 2016 11:29:20 -0600 From: Michael Roth Date: Mon, 21 Mar 2016 12:27:59 -0500 Message-Id: <1458581313-19045-2-git-send-email-mdroth@linux.vnet.ibm.com> In-Reply-To: <1458581313-19045-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1458581313-19045-1-git-send-email-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 01/35] ehci: make idt processing more robust List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Michael Roth , qemu-stable@nongnu.org, Gerd Hoffmann From: Gerd Hoffmann Make ehci_process_itd return an error in case we didn't do any actual iso transfer because we've found no active transaction. That'll avoid ehci happily run in circles forever if the guest builds a loop out of idts. This is CVE-2015-8558. Cc: qemu-stable@nongnu.org Reported-by: Qinghao Tang Tested-by: P J P Signed-off-by: Gerd Hoffmann (cherry picked from commit 156a2e4dbffa85997636a7a39ef12da6f1b40254) Signed-off-by: Michael Roth --- hw/usb/hcd-ehci.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c index 4e2161b..d07f228 100644 --- a/hw/usb/hcd-ehci.c +++ b/hw/usb/hcd-ehci.c @@ -1389,7 +1389,7 @@ static int ehci_process_itd(EHCIState *ehci, { USBDevice *dev; USBEndpoint *ep; - uint32_t i, len, pid, dir, devaddr, endp; + uint32_t i, len, pid, dir, devaddr, endp, xfers = 0; uint32_t pg, off, ptr1, ptr2, max, mult; ehci->periodic_sched_active = PERIODIC_ACTIVE; @@ -1479,9 +1479,10 @@ static int ehci_process_itd(EHCIState *ehci, ehci_raise_irq(ehci, USBSTS_INT); } itd->transact[i] &= ~ITD_XACT_ACTIVE; + xfers++; } } - return 0; + return xfers ? 0 : -1; } -- 1.9.1