Avoid potentially unaligned half-word read

diff --git a/src/charon/sa/tasks/child_create.c b/src/charon/sa/tasks/child_create.c
index def190d230cc32738d87b4c3ba6ee09726c4f921..6325b878c0964549a704b6e13f4d40dfb781a955 100644 (file)
--- a/src/charon/sa/tasks/child_create.c
+++ b/src/charon/sa/tasks/child_create.c
@@ -1011,15 +1011,18 @@ static status_t process_i(private_child_create_t *this, message_t *message)
                                case INVALID_KE_PAYLOAD:
                                {
                                        chunk_t data;
-                                       diffie_hellman_group_t bad_group;
+                                       u_int16_t group = MODP_NONE;
 
-                                       bad_group = this->dh_group;
                                        data = notify->get_notification_data(notify);
-                                       this->dh_group = ntohs(*((u_int16_t*)data.ptr));
+                                       if (data.len == sizeof(group))
+                                       {
+                                               memcpy(&group, data.ptr, data.len);
+                                               group = ntohs(group);
+                                       }
                                        DBG1(DBG_IKE, "peer didn't accept DH group %N, "
                                                 "it requested %N", diffie_hellman_group_names,
-                                                bad_group, diffie_hellman_group_names, this->dh_group);
-
+                                                this->dh_group, diffie_hellman_group_names, group);
+                                       this->dh_group = group;
                                        this->public.task.migrate(&this->public.task, this->ike_sa);
                                        enumerator->destroy(enumerator);
                                        return NEED_MORE;