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 
48 int
49 cap_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 
90 static int
91 random_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 
117 CREATE_SERVICE("system.random", NULL, random_command, 0);
118