clean slc-lex.c
[heimdal.git] / kadmin / random_password.c
blob970e99d34adbc1bf17235493d277a47775df4c78
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 /* This file defines some a function that generates a random password,
37 that can be used when creating a large amount of principals (such
38 as for a batch of students). Since this is a political matter, you
39 should think about how secure generated passwords has to be.
41 Both methods defined here will give you at least 55 bits of
42 entropy.
45 /* If you want OTP-style passwords, define OTP_STYLE */
47 #ifdef OTP_STYLE
48 #include <otp.h>
49 #else
50 static void generate_password(char **pw, int num_classes, ...);
51 #endif
53 void
54 random_password(char *pw, size_t len)
56 #ifdef OTP_STYLE
58 OtpKey newkey;
60 krb5_generate_random_block(&newkey, sizeof(newkey));
61 otp_print_stddict (newkey, pw, len);
62 strlwr(pw);
64 #else
65 char *pass;
66 generate_password(&pass, 3,
67 "abcdefghijklmnopqrstuvwxyz", 7,
68 "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 2,
69 "@$%&*()-+=:,/<>1234567890", 1);
70 strlcpy(pw, pass, len);
71 memset(pass, 0, strlen(pass));
72 free(pass);
73 #endif
76 /* some helper functions */
78 #ifndef OTP_STYLE
79 /* return a random value in range 0-127 */
80 static int
81 RND(unsigned char *key, int keylen, int *left)
83 if(*left == 0){
84 krb5_generate_random_block(key, keylen);
85 *left = keylen;
87 (*left)--;
88 return ((unsigned char*)key)[*left];
91 /* This a helper function that generates a random password with a
92 number of characters from a set of character classes.
94 If there are n classes, and the size of each class is Pi, and the
95 number of characters from each class is Ni, the number of possible
96 passwords are (given that the character classes are disjoint):
98 n n
99 ----- / ---- \
100 | | Ni | \ |
101 | | Pi | \ Ni| !
102 | | ---- * | / |
103 | | Ni! | /___ |
104 i=1 \ i=1 /
106 Since it uses the RND function above, neither the size of each
107 class, nor the total length of the generated password should be
108 larger than 127 (without fixing RND).
111 static void
112 generate_password(char **pw, int num_classes, ...)
114 struct {
115 const char *str;
116 int len;
117 int freq;
118 } *classes;
119 va_list ap;
120 int len, i;
121 unsigned char rbuf[8]; /* random buffer */
122 int rleft = 0;
124 *pw = NULL;
126 classes = malloc(num_classes * sizeof(*classes));
127 if(classes == NULL)
128 return;
129 va_start(ap, num_classes);
130 len = 0;
131 for(i = 0; i < num_classes; i++){
132 classes[i].str = va_arg(ap, const char*);
133 classes[i].len = strlen(classes[i].str);
134 classes[i].freq = va_arg(ap, int);
135 len += classes[i].freq;
137 va_end(ap);
138 *pw = malloc(len + 1);
139 if(*pw == NULL) {
140 free(classes);
141 return;
143 for(i = 0; i < len; i++) {
144 int j;
145 int x = RND(rbuf, sizeof(rbuf), &rleft) % (len - i);
146 int t = 0;
147 for(j = 0; j < num_classes; j++) {
148 if(x < t + classes[j].freq) {
149 (*pw)[i] = classes[j].str[RND(rbuf, sizeof(rbuf), &rleft)
150 % classes[j].len];
151 classes[j].freq--;
152 break;
154 t += classes[j].freq;
157 (*pw)[len] = '\0';
158 memset(rbuf, 0, sizeof(rbuf));
159 free(classes);
161 #endif