On Thu, Nov 04, 2021 at 09:07:44AM +0800, Di Zhu wrote:
> +int sock_map_bpf_prog_query(const union bpf_attr *attr,
> + union bpf_attr __user *uattr)
> +{
> + __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
> + u32 prog_cnt = 0, flags = 0, ufd = attr->target_fd;
> + struct bpf_prog **pprog;
> + struct bpf_prog *prog;
> + struct bpf_map *map;
> + struct fd f;
> + u32 id = 0;
> + int ret;
> +
> + if (attr->query.query_flags)
> + return -EINVAL;
> +
> + f = fdget(ufd);
> + map = __bpf_map_get(f);
> + if (IS_ERR(map))
> + return PTR_ERR(map);
> +
> + rcu_read_lock();
> +
> + ret = sock_map_prog_lookup(map, &pprog, attr->query.attach_type);
> + if (ret)
> + goto end;
> +
> + prog = *pprog;
> + prog_cnt = (!prog) ? 0 : 1;
> +
> + if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
> + goto end;
This sanity check (except prog_cnt) can be moved before RCU read lock?
> +
> + id = prog->aux->id;
> + if (id == 0)
> + prog_cnt = 0;
The id seems generic, so why not handle it in bpf_prog_query() for all progs?
> +
> +end:
> + rcu_read_unlock();
> +
> + if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)) ||
'flags' is always 0 here, right? So this is not needed as uattr has been already
cleared in __sys_bpf().
Thanks.
