Subject: [PATCH 19/31] usb: sanity check setup_index+setup_len in post_load

From: Michael S. Tsirkin <[email-masked]>
Date: Wed, 14 May 2014 08:36:01 +0200

RH-Author: Michael S. Tsirkin <[email-masked]>
Message-id: <[email-masked]>
Patchwork-id: 58865
O-Subject: [PATCH qemu-kvm RHEL7.1 2/2] usb: sanity check setup_index+setup_len in post_load
Bugzilla: 1095747
RH-Acked-by: Marcel Apfelbaum <[email-masked]>
RH-Acked-by: Paolo Bonzini <[email-masked]>
RH-Acked-by: Gerd Hoffmann <[email-masked]>

CVE-2013-4541

s->setup_len and s->setup_index are fed into usb_packet_copy as
size/offset into s->data_buf, it's possible for invalid state to exploit
this to load arbitrary data.

setup_len and setup_index should be checked to make sure
they are not negative.

Cc: Gerd Hoffmann <[email-masked]>
Signed-off-by: Michael S. Tsirkin <[email-masked]>
Reviewed-by: Gerd Hoffmann <[email-masked]>
Signed-off-by: Juan Quintela <[email-masked]>
(cherry picked from commit 9f8e9895c504149d7048e9fc5eb5cbb34b16e49a)

Brew build: http://brewweb.devel.redhat.com/brew/taskinfo?taskID=7452039
Tested: lightly on developer's box
Bugzilla: 1095743

Note: the fix isn't complete upstream. there's a separate bugzilla to
fix more issues upstream and in rhel.
---
 hw/usb/bus.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Signed-off-by: Miroslav Rezanina <[email-masked]>
---
 hw/usb/bus.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index e0c3a77..9766b7f 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -49,7 +49,9 @@ static int usb_device_post_load(void *opaque, int version_id)
     } else {
         dev->attached = 1;
     }
-    if (dev->setup_index >= sizeof(dev->data_buf) ||
+    if (dev->setup_index < 0 ||
+        dev->setup_len < 0 ||
+        dev->setup_index >= sizeof(dev->data_buf) ||
         dev->setup_len >= sizeof(dev->data_buf)) {
         return -EINVAL;
     }
-- 
1.7.1