316c316
< if (tgt_fd > MAX_FD)
---
> if (tgt_fd < 0 || tgt_fd > MAX_FD)
325,326c325,326
< if (tgt_fd > MAX_FD)
< panic("sim_fd_obj called in fd out of range.");
---
> if (tgt_fd < 0 || tgt_fd > MAX_FD)
> return NULL;