make compile
[heimdal.git] / kadmin / random_password.c
blob0433b25bc7de066e9ba071ca3cb7399dd6f15c53
1 /*
2 * Copyright (c) 1998, 1999 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * 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.
17 * 3. Neither the name of the Institute nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
34 #include "kadmin_locl.h"
36 RCSID("$Id$");
38 /* This file defines some a function that generates a random password,
39 that can be used when creating a large amount of principals (such
40 as for a batch of students). Since this is a political matter, you
41 should think about how secure generated passwords has to be.
43 Both methods defined here will give you at least 55 bits of
44 entropy.
47 /* If you want OTP-style passwords, define OTP_STYLE */
49 #ifdef OTP_STYLE
50 #include <otp.h>
51 #else
52 static void generate_password(char **pw, int num_classes, ...);
53 #endif
55 void
56 random_password(char *pw, size_t len)
58 #ifdef OTP_STYLE
60 OtpKey newkey;
62 krb5_generate_random_block(&newkey, sizeof(newkey));
63 otp_print_stddict (newkey, pw, len);
64 strlwr(pw);
66 #else
67 char *pass;
68 generate_password(&pass, 3,
69 "abcdefghijklmnopqrstuvwxyz", 7,
70 "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 2,
71 "@$%&*()-+=:,/<>1234567890", 1);
72 strlcpy(pw, pass, len);
73 memset(pass, 0, strlen(pass));
74 free(pass);
75 #endif
78 /* some helper functions */
80 #ifndef OTP_STYLE
81 /* return a random value in range 0-127 */
82 static int
83 RND(unsigned char *key, int keylen, int *left)
85 if(*left == 0){
86 krb5_generate_random_block(key, keylen);
87 *left = keylen;
89 (*left)--;
90 return ((unsigned char*)key)[*left];
93 /* This a helper function that generates a random password with a
94 number of characters from a set of character classes.
96 If there are n classes, and the size of each class is Pi, and the
97 number of characters from each class is Ni, the number of possible
98 passwords are (given that the character classes are disjoint):
101 ----- / ---- \
102 | | Ni | \ |
103 | | Pi | \ Ni| !
104 | | ---- * | / |
105 | | Ni! | /___ |
106 i=1 \ i=1 /
108 Since it uses the RND function above, neither the size of each
109 class, nor the total length of the generated password should be
110 larger than 127 (without fixing RND).
113 static void
114 generate_password(char **pw, int num_classes, ...)
116 struct {
117 const char *str;
118 int len;
119 int freq;
120 } *classes;
121 va_list ap;
122 int len, i;
123 unsigned char rbuf[8]; /* random buffer */
124 int rleft = 0;
126 *pw = NULL;
128 classes = malloc(num_classes * sizeof(*classes));
129 if(classes == NULL)
130 return;
131 va_start(ap, num_classes);
132 len = 0;
133 for(i = 0; i < num_classes; i++){
134 classes[i].str = va_arg(ap, const char*);
135 classes[i].len = strlen(classes[i].str);
136 classes[i].freq = va_arg(ap, int);
137 len += classes[i].freq;
139 va_end(ap);
140 *pw = malloc(len + 1);
141 if(*pw == NULL) {
142 free(classes);
143 return;
145 for(i = 0; i < len; i++) {
146 int j;
147 int x = RND(rbuf, sizeof(rbuf), &rleft) % (len - i);
148 int t = 0;
149 for(j = 0; j < num_classes; j++) {
150 if(x < t + classes[j].freq) {
151 (*pw)[i] = classes[j].str[RND(rbuf, sizeof(rbuf), &rleft)
152 % classes[j].len];
153 classes[j].freq--;
154 break;
156 t += classes[j].freq;
159 (*pw)[len] = '\0';
160 memset(rbuf, 0, sizeof(rbuf));
161 free(classes);
163 #endif