9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi/*
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * This file and its contents are supplied under the terms of the
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * Common Development and Distribution License ("CDDL"), version 1.0.
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * You may only use this file in accordance with the terms of version
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * 1.0 of the CDDL.
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi *
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * A full copy of the text of the CDDL should have accompanied this
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * source. A copy of the CDDL is also available via the Internet at
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * http://www.illumos.org/license/CDDL.
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi */
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi/*
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * Copyright (c) 2015, Joyent, Inc.
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi */
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi/*
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * getrandom system call implementation
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi */
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#include <sys/types.h>
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#include <sys/errno.h>
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#include <sys/systm.h>
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#include <sys/random.h>
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#include <sys/ddi.h>
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#include <sys/sunddi.h>
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#include <sys/sysmacros.h>
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#include <sys/random.h>
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi/*
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * Impose a maximum upper bound on the number of bytes that we'll read in one
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * go, ala a read of /dev/random. For /dev/urandom, we clamp it based on our
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * return value, because the system call returns an int, we can't handle more
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi * than INT_MAX.
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi */
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#define MAXRANDBYTES 1024
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi#define MAXURANDBYTES INT_MAX
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchiint
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchigetrandom(void *bufp, size_t buflen, int flags)
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi{
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi int out = 0;
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi uint8_t rbytes[128];
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi uint8_t *buf = bufp;
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi if (flags & ~(GRND_NONBLOCK | GRND_RANDOM))
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi return (set_errno(EINVAL));
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi if ((flags & GRND_RANDOM) && buflen > MAXRANDBYTES) {
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi buflen = MAXRANDBYTES;
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi } else if (buflen > MAXURANDBYTES) {
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi buflen = MAXURANDBYTES;
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi }
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
a17dff0dc9d07cb9734943b1f593b856d17776b4Robert Mustacchi while (out < buflen) {
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi int err;
a17dff0dc9d07cb9734943b1f593b856d17776b4Robert Mustacchi size_t len = MIN(sizeof (rbytes), buflen - out);
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi if (flags & GRND_RANDOM) {
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi if (flags & GRND_NONBLOCK)
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi err = random_get_bytes(rbytes, len);
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi else
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi err = random_get_blocking_bytes(rbytes, len);
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi } else {
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi err = random_get_pseudo_bytes(rbytes, len);
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi }
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi if (err == 0) {
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi if (ddi_copyout(rbytes, buf + out, len, 0) != 0)
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi return (set_errno(EFAULT));
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi out += len;
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi } else if (err == EAGAIN && out > 0) {
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi break;
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi } else {
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi return (set_errno(err));
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi }
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi }
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi return (out);
9d12795f87b63c2e39e87bff369182edd34677d3Robert Mustacchi}