From b18831e53e64414ebd35419fb8dffd51e8ec46f7 Mon Sep 17 00:00:00 2001
From: Sergio Lopez Pascual <slp@redhat.com>
Date: Mon, 15 Apr 2019 09:09:30 +0200
Subject: [PATCH] device_tree: Fix integer overflowing in load_device_tree()
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RH-Author: Sergio Lopez Pascual <slp@redhat.com>
Message-id: <20190415090930.27086-2-slp@redhat.com>
Patchwork-id: 85657
O-Subject: [RHEL-7.6.z qemu-kvm-ma PATCH 1/1] device_tree: Fix integer overflowing in load_device_tree()
Bugzilla: 1693112
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>

From: Markus Armbruster <armbru@redhat.com>

If the value of get_image_size() exceeds INT_MAX / 2 - 10000, the
computation of @dt_size overflows to a negative number, which then
gets converted to a very large size_t for g_malloc0() and
load_image_size().  In the (fortunately improbable) case g_malloc0()
succeeds and load_image_size() survives, we'd assign the negative
number to *sizep.  What that would do to the callers I can't say, but
it's unlikely to be good.

Fix by rejecting images whose size would overflow.

Reported-by: Kurtis Miller <kurtis.miller@nccgroup.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20190409174018.25798-1-armbru@redhat.com>
(cherry picked from commit 065e6298a75164b4347682b63381dbe752c2b156)
Signed-off-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 device_tree.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/device_tree.c b/device_tree.c
index 19458b3..2457f58 100644
--- a/device_tree.c
+++ b/device_tree.c
@@ -84,6 +84,10 @@ void *load_device_tree(const char *filename_path, int *sizep)
                      filename_path);
         goto fail;
     }
+    if (dt_size > INT_MAX / 2 - 10000) {
+        error_report("Device tree file '%s' is too large", filename_path);
+        goto fail;
+    }
 
     /* Expand to 2x size to give enough room for manipulation.  */
     dt_size += 10000;
-- 
1.8.3.1