Branch data Line data Source code
1 : : /* crypto/ecdh/ec_kdf.c */
2 : : /*
3 : : * Written by Stephen Henson for the OpenSSL project.
4 : : */
5 : : /* ====================================================================
6 : : * Copyright (c) 2013 The OpenSSL Project. All rights reserved.
7 : : *
8 : : * Redistribution and use in source and binary forms, with or without
9 : : * modification, are permitted provided that the following conditions
10 : : * are met:
11 : : *
12 : : * 1. Redistributions of source code must retain the above copyright
13 : : * notice, this list of conditions and the following disclaimer.
14 : : *
15 : : * 2. Redistributions in binary form must reproduce the above copyright
16 : : * notice, this list of conditions and the following disclaimer in
17 : : * the documentation and/or other materials provided with the
18 : : * distribution.
19 : : *
20 : : * 3. All advertising materials mentioning features or use of this
21 : : * software must display the following acknowledgment:
22 : : * "This product includes software developed by the OpenSSL Project
23 : : * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
24 : : *
25 : : * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 : : * endorse or promote products derived from this software without
27 : : * prior written permission. For written permission, please contact
28 : : * openssl-core@openssl.org.
29 : : *
30 : : * 5. Products derived from this software may not be called "OpenSSL"
31 : : * nor may "OpenSSL" appear in their names without prior written
32 : : * permission of the OpenSSL Project.
33 : : *
34 : : * 6. Redistributions of any form whatsoever must retain the following
35 : : * acknowledgment:
36 : : * "This product includes software developed by the OpenSSL Project
37 : : * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
38 : : *
39 : : * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 : : * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 : : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 : : * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 : : * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 : : * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 : : * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 : : * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 : : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 : : * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 : : * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 : : * OF THE POSSIBILITY OF SUCH DAMAGE.
51 : : * ====================================================================
52 : : */
53 : :
54 : : #define OPENSSL_FIPSAPI
55 : :
56 : : #include <string.h>
57 : : #include <openssl/ecdh.h>
58 : : #include <openssl/evp.h>
59 : :
60 : :
61 : : /* Key derivation function from X9.62/SECG */
62 : : /* Way more than we will ever need */
63 : : #define ECDH_KDF_MAX (1 << 30)
64 : :
65 : 6 : int ECDH_KDF_X9_62(unsigned char *out, size_t outlen,
66 : : const unsigned char *Z, size_t Zlen,
67 : : const unsigned char *sinfo, size_t sinfolen,
68 : : const EVP_MD *md)
69 : : {
70 : : EVP_MD_CTX mctx;
71 : 6 : int rv = 0;
72 : : unsigned int i;
73 : : size_t mdlen;
74 : : unsigned char ctr[4];
75 [ + - ][ + - ]: 6 : if (sinfolen > ECDH_KDF_MAX || outlen > ECDH_KDF_MAX || Zlen > ECDH_KDF_MAX)
76 : : return 0;
77 : 6 : mdlen = EVP_MD_size(md);
78 : 6 : EVP_MD_CTX_init(&mctx);
79 : 6 : for (i = 1;;i++)
80 : : {
81 : : unsigned char mtmp[EVP_MAX_MD_SIZE];
82 : 8 : EVP_DigestInit_ex(&mctx, md, NULL);
83 : 8 : ctr[3] = i & 0xFF;
84 : 8 : ctr[2] = (i >> 8) & 0xFF;
85 : 8 : ctr[1] = (i >> 16) & 0xFF;
86 : 8 : ctr[0] = (i >> 24) & 0xFF;
87 [ + - ]: 8 : if (!EVP_DigestUpdate(&mctx, Z, Zlen))
88 : : goto err;
89 [ + - ]: 8 : if (!EVP_DigestUpdate(&mctx, ctr, sizeof(ctr)))
90 : : goto err;
91 [ + - ]: 8 : if (!EVP_DigestUpdate(&mctx, sinfo, sinfolen))
92 : : goto err;
93 [ + + ]: 8 : if (outlen >= mdlen)
94 : : {
95 [ + - ]: 2 : if (!EVP_DigestFinal(&mctx, out, NULL))
96 : : goto err;
97 : 2 : outlen -= mdlen;
98 [ + - ]: 2 : if (outlen == 0)
99 : : break;
100 : 2 : out += mdlen;
101 : : }
102 : : else
103 : : {
104 [ + - ]: 6 : if (!EVP_DigestFinal(&mctx, mtmp, NULL))
105 : : goto err;
106 : : memcpy(out, mtmp, outlen);
107 : 6 : OPENSSL_cleanse(mtmp, mdlen);
108 : 6 : break;
109 : : }
110 : 2 : }
111 : 6 : rv = 1;
112 : : err:
113 : 6 : EVP_MD_CTX_cleanup(&mctx);
114 : 6 : return rv;
115 : : }
116 : :
|
