1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /* lib/krb5/krb/random_str.c - Definition of krb5int_random_string() */
3 /*
4 * Copyright (C) 2013 by the Massachusetts Institute of Technology.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 *
14 * * Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
17 * distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
23 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
24 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
25 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
26 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
28 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
30 * OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #include "k5-int.h"
34
35 /* Utility routine: Creates a readable random string in a fixed size buffer. */
36 krb5_error_code
krb5int_random_string(krb5_context context,char * string,unsigned int length)37 krb5int_random_string(krb5_context context, char *string, unsigned int length)
38 {
39 static const unsigned char charlist[] =
40 "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
41 krb5_error_code err = 0;
42 unsigned char *bytes = NULL;
43 unsigned int bytecount = length - 1;
44
45 if (!err) {
46 bytes = malloc (bytecount);
47 if (bytes == NULL) { err = ENOMEM; }
48 }
49
50 if (!err) {
51 krb5_data data;
52 data.length = bytecount;
53 data.data = (char *) bytes;
54 err = krb5_c_random_make_octets (context, &data);
55 }
56
57 if (!err) {
58 unsigned int i;
59 for (i = 0; i < bytecount; i++) {
60 string [i] = charlist[bytes[i] % (sizeof (charlist) - 1)];
61 }
62 string[length - 1] = '\0';
63 }
64
65 if (bytes != NULL) { free (bytes); }
66
67 return err;
68 }
69