1 /*
2 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
3 * Use is subject to license terms.
4 */
5
6
7 /*
8 * lib/crypto/aes/aes_s2k.c
9 *
10 * Copyright 2003 by the Massachusetts Institute of Technology.
11 * All Rights Reserved.
12 *
13 * Export of this software from the United States of America may
14 * require a specific license from the United States Government.
15 * It is the responsibility of any person or organization contemplating
16 * export to obtain such a license before exporting.
17 *
18 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
19 * distribute this software and its documentation for any purpose and
20 * without fee is hereby granted, provided that the above copyright
21 * notice appear in all copies and that both that copyright notice and
22 * this permission notice appear in supporting documentation, and that
23 * the name of M.I.T. not be used in advertising or publicity pertaining
24 * to distribution of the software without specific, written prior
25 * permission. Furthermore if you modify this software you must label
26 * your software as modified software and not distribute it in such a
27 * fashion that it might be confused with the original M.I.T. software.
28 * M.I.T. makes no representations about the suitability of
29 * this software for any purpose. It is provided "as is" without express
30 * or implied warranty.
31 *
32 *
33 * krb5int_aes_string_to_key
34 */
35
36 #include "k5-int.h"
37 #include "dk.h"
38 #include "aes_s2k.h"
39
40 #define DEFAULT_ITERATION_COUNT 4096 /* was 0xb000L in earlier drafts */
41 #define MAX_ITERATION_COUNT 0x1000000L
42
43 krb5_error_code
krb5int_aes_string_to_key(krb5_context context,const struct krb5_enc_provider * enc,const krb5_data * string,const krb5_data * salt,const krb5_data * params,krb5_keyblock * key)44 krb5int_aes_string_to_key(krb5_context context,
45 const struct krb5_enc_provider *enc,
46 const krb5_data *string,
47 const krb5_data *salt,
48 const krb5_data *params,
49 krb5_keyblock *key)
50 {
51 unsigned long iter_count;
52 krb5_data out;
53 static const krb5_data usage = { KV5M_DATA, 8, "kerberos" };
54 krb5_error_code err;
55 /* Solaris Kerberos */
56 krb5_keyblock *inkey = NULL;
57
58 if (params) {
59 unsigned char *p = (unsigned char *) params->data;
60 if (params->length != 4)
61 return KRB5_ERR_BAD_S2K_PARAMS;
62 /* The first two need casts in case 'int' is 16 bits. */
63 iter_count = (((unsigned long)p[0] << 24)
64 | ((unsigned long)p[1] << 16)
65 | (p[2] << 8)
66 | (p[3]));
67 if (iter_count == 0) {
68 /*
69 iter_count = (1L << 16) << 16;
70 if (((iter_count >> 16) >> 16) != 1)
71 return KRB5_ERR_BAD_S2K_PARAMS;
72 */
73 iter_count = DEFAULT_ITERATION_COUNT;
74 }
75 } else
76 iter_count = DEFAULT_ITERATION_COUNT;
77
78 /* This is not a protocol specification constraint; this is an
79 implementation limit, which should eventually be controlled by
80 a config file. */
81 if (iter_count >= MAX_ITERATION_COUNT)
82 return KRB5_ERR_BAD_S2K_PARAMS;
83
84 /*
85 * Dense key space, no parity bits or anything, so take a shortcut
86 * and use the key contents buffer for the generated bytes.
87 */
88 /* Solaris Kerberos */
89 if (key->length != 16 && key->length != 32)
90 return KRB5_CRYPTO_INTERNAL;
91 out.data = (char *) key->contents;
92 out.length = key->length;
93 /* Solaris Kerberos */
94 err = krb5int_pbkdf2_hmac_sha1 (context, &out, iter_count, key->enctype,
95 string, salt);
96 if (err) {
97 memset(out.data, 0, out.length);
98 return err;
99 }
100
101 /*
102 * Solaris Kerberos:
103 * The derive key operation below will not work correctly
104 * if the input and output key pointers are to the same
105 * data. This is because the key object handle (PKCS#11)
106 * gets out-of-sync with the original key when the contents
107 * are modified. We copy the original key here for use
108 * below in the derive_key step, then we free this key
109 * before exiting.
110 */
111 err = krb5_copy_keyblock(context, key, &inkey);
112 if (err) {
113 memset(out.data, 0, out.length);
114 return err;
115 }
116
117 err = krb5_derive_key (context, enc, inkey, key, &usage);
118 if (err) {
119 memset(out.data, 0, out.length);
120 }
121 krb5_free_keyblock(context, inkey);
122
123 return (err);
124 }
125