1/*-
2 * Copyright (c) 2013 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by Pawel Jakub Dawidek under sponsorship from
6 * the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD$");
32
33#include <sys/nv.h>
34
35#include <assert.h>
36#include <errno.h>
37#include <stdio.h>
38#include <stdlib.h>
39#include <string.h>
40
41#include <libcasper.h>
42#include <libcasper_service.h>
43
44#include "cap_random.h"
45
46#define	MAXSIZE	(1024 * 1024)
47
48int
49cap_random_buf(cap_channel_t *chan, void *buf, size_t nbytes)
50{
51	nvlist_t *nvl;
52	const void *randbuf;
53	uint8_t *ptr;
54	size_t left, randbufsize;
55
56	left = nbytes;
57	ptr = buf;
58
59	while (left > 0) {
60		nvl = nvlist_create(0);
61		nvlist_add_string(nvl, "cmd", "generate");
62		nvlist_add_number(nvl, "size",
63		    (uint64_t)(left > MAXSIZE ? MAXSIZE : left));
64		nvl = cap_xfer_nvlist(chan, nvl, 0);
65		if (nvl == NULL)
66			return (-1);
67		if (nvlist_get_number(nvl, "error") != 0) {
68			errno = (int)nvlist_get_number(nvl, "error");
69			nvlist_destroy(nvl);
70			return (-1);
71		}
72
73		randbuf = nvlist_get_binary(nvl, "data", &randbufsize);
74		memcpy(ptr, randbuf, randbufsize);
75
76		nvlist_destroy(nvl);
77
78		ptr += randbufsize;
79		assert(left >= randbufsize);
80		left -= randbufsize;
81	}
82
83	return (0);
84}
85
86/*
87 * Service functions.
88 */
89
90static int
91random_command(const char *cmd, const nvlist_t *limits __unused,
92    nvlist_t *nvlin, nvlist_t *nvlout)
93{
94	void *data;
95	size_t size;
96
97	if (strcmp(cmd, "generate") != 0)
98		return (EINVAL);
99	if (!nvlist_exists_number(nvlin, "size"))
100		return (EINVAL);
101
102	size = (size_t)nvlist_get_number(nvlin, "size");
103	if (size == 0 || size > MAXSIZE)
104		return (EINVAL);
105
106	data = malloc(size);
107	if (data == NULL)
108		return (ENOMEM);
109
110	arc4random_buf(data, size);
111
112	nvlist_move_binary(nvlout, "data", data, size);
113
114	return (0);
115}
116
117CREATE_SERVICE("system.random", NULL, random_command, 0);
118