[Qemu-devel] [PATCH v3 6/7] memory-device: avoid overflows on very huge devices

From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Michael S . Tsirkin" <mst@redhat.com>,
	Igor Mammedov <imammedo@redhat.com>,
	Markus Armbruster <armbru@redhat.com>,
	Michael Roth <mdroth@linux.vnet.ibm.com>,
	David Gibson <david@gibson.dropbear.id.au>,
	Eduardo Habkost <ehabkost@redhat.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	David Hildenbrand <david@redhat.com>
Subject: [Qemu-devel] [PATCH v3 6/7] memory-device: avoid overflows on very huge devices
Date: Tue, 23 Oct 2018 17:23:05 +0200	[thread overview]
Message-ID: <20181023152306.3123-7-david@redhat.com> (raw)
In-Reply-To: <20181023152306.3123-1-david@redhat.com>

Should not be a problem right now, but it could theoretically happen
in the future.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/mem/memory-device.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c
index 996ad1490f..8be63c8032 100644
--- a/hw/mem/memory-device.c
+++ b/hw/mem/memory-device.c
@@ -85,7 +85,8 @@ static void memory_device_check_addable(MachineState *ms, uint64_t size,
 
     /* will we exceed the total amount of memory specified */
     memory_device_used_region_size(OBJECT(ms), &used_region_size);
-    if (used_region_size + size > ms->maxram_size - ms->ram_size) {
+    if (used_region_size + size < used_region_size ||
+        used_region_size + size > ms->maxram_size - ms->ram_size) {
         error_setg(errp, "not enough space, currently 0x%" PRIx64
                    " in use of total space for memory devices 0x" RAM_ADDR_FMT,
                    used_region_size, ms->maxram_size - ms->ram_size);
-- 
2.17.1
