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1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.] */
56 
57 #include <openssl/cipher.h>
58 
59 #include <assert.h>
60 
61 #include <openssl/digest.h>
62 #include <openssl/mem.h>
63 
64 
65 #define PKCS5_SALT_LEN 8
66 
EVP_BytesToKey(const EVP_CIPHER * type,const EVP_MD * md,const uint8_t * salt,const uint8_t * data,size_t data_len,unsigned count,uint8_t * key,uint8_t * iv)67 int EVP_BytesToKey(const EVP_CIPHER *type, const EVP_MD *md,
68                    const uint8_t *salt, const uint8_t *data, size_t data_len,
69                    unsigned count, uint8_t *key, uint8_t *iv) {
70   EVP_MD_CTX c;
71   uint8_t md_buf[EVP_MAX_MD_SIZE];
72   unsigned niv, nkey, addmd = 0;
73   unsigned mds = 0, i;
74   int rv = 0;
75 
76   nkey = type->key_len;
77   niv = type->iv_len;
78 
79   assert(nkey <= EVP_MAX_KEY_LENGTH);
80   assert(niv <= EVP_MAX_IV_LENGTH);
81 
82   if (data == NULL) {
83     return nkey;
84   }
85 
86   EVP_MD_CTX_init(&c);
87   for (;;) {
88     if (!EVP_DigestInit_ex(&c, md, NULL)) {
89       return 0;
90     }
91     if (addmd++) {
92       if (!EVP_DigestUpdate(&c, md_buf, mds)) {
93         goto err;
94       }
95     }
96     if (!EVP_DigestUpdate(&c, data, data_len)) {
97       goto err;
98     }
99     if (salt != NULL) {
100       if (!EVP_DigestUpdate(&c, salt, PKCS5_SALT_LEN)) {
101         goto err;
102       }
103     }
104     if (!EVP_DigestFinal_ex(&c, md_buf, &mds)) {
105       goto err;
106     }
107 
108     for (i = 1; i < count; i++) {
109       if (!EVP_DigestInit_ex(&c, md, NULL) ||
110           !EVP_DigestUpdate(&c, md_buf, mds) ||
111           !EVP_DigestFinal_ex(&c, md_buf, &mds)) {
112         goto err;
113       }
114     }
115 
116     i = 0;
117     if (nkey) {
118       for (;;) {
119         if (nkey == 0 || i == mds) {
120           break;
121         }
122         if (key != NULL) {
123           *(key++) = md_buf[i];
124         }
125         nkey--;
126         i++;
127       }
128     }
129 
130     if (niv && i != mds) {
131       for (;;) {
132         if (niv == 0 || i == mds) {
133           break;
134         }
135         if (iv != NULL) {
136           *(iv++) = md_buf[i];
137         }
138         niv--;
139         i++;
140       }
141     }
142     if (nkey == 0 && niv == 0) {
143       break;
144     }
145   }
146   rv = type->key_len;
147 
148 err:
149   EVP_MD_CTX_cleanup(&c);
150   OPENSSL_cleanse(md_buf, EVP_MAX_MD_SIZE);
151   return rv;
152 }
153