hostmem: Validate host-nodes before setting bitmap

host_memory_backend_set_host_nodes() was not validating
host-nodes before writing to backend->host_nodes, making QEMU
write beyond the end of the bitmap.

Fix the crash and add a simple regression test for the fix.

While at it, fix memory leak of the list returned by
visit_type_uint16List().

Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20181130122844.29103-1-ehabkost@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
[ehabkost: removed test case code]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 13 insertions, 4 deletions

diff --git a/backends/hostmem.c b/backends/hostmem.c
index 1a89342039..af800284e0 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -103,14 +103,23 @@ host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 {
 #ifdef CONFIG_NUMA
     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
-    uint16List *l = NULL;
+    uint16List *l, *host_nodes = NULL;
 
-    visit_type_uint16List(v, name, &l, errp);
+    visit_type_uint16List(v, name, &host_nodes, errp);
 
-    while (l) {
+    for (l = host_nodes; l; l = l->next) {
+        if (l->value >= MAX_NODES) {
+            error_setg(errp, "Invalid host-nodes value: %d", l->value);
+            goto out;
+        }
+    }
+
+    for (l = host_nodes; l; l = l->next) {
         bitmap_set(backend->host_nodes, l->value, 1);
-        l = l->next;
     }
+
+out:
+    qapi_free_uint16List(host_nodes);
 #else
     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 #endif