Fix CVE-2017-5898 (integer overflow in emulated_apdu_from_guest):

http://seclists.org/oss-sec/2017/q1/328
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5898

Patch copied from upstream source repository:

http://git.qemu-project.org/?p=qemu.git;a=commitdiff;h=c7dfbf322595ded4e70b626bf83158a9f3807c6a

From c7dfbf322595ded4e70b626bf83158a9f3807c6a Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Fri, 3 Feb 2017 00:52:28 +0530
Subject: [PATCH] usb: ccid: check ccid apdu length

CCID device emulator uses Application Protocol Data Units(APDU)
to exchange command and responses to and from the host.
The length in these units couldn't be greater than 65536. Add
check to ensure the same. It'd also avoid potential integer
overflow in emulated_apdu_from_guest.

Reported-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-id: 20170202192228.10847-1-ppandit@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb/dev-smartcard-reader.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/usb/dev-smartcard-reader.c b/hw/usb/dev-smartcard-reader.c
index 89e11b68c4..1325ea1659 100644
--- a/hw/usb/dev-smartcard-reader.c
+++ b/hw/usb/dev-smartcard-reader.c
@@ -967,7 +967,7 @@ static void ccid_on_apdu_from_guest(USBCCIDState *s, CCID_XferBlock *recv)
     DPRINTF(s, 1, "%s: seq %d, len %d\n", __func__,
                 recv->hdr.bSeq, len);
     ccid_add_pending_answer(s, (CCID_Header *)recv);
-    if (s->card) {
+    if (s->card && len <= BULK_OUT_DATA_SIZE) {
         ccid_card_apdu_from_guest(s->card, recv->abData, len);
     } else {
         DPRINTF(s, D_WARN, "warning: discarded apdu\n");
-- 
2.11.1

