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a119822b DSH |
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 | |
ae5c8664 | 13 | * notice, this list of conditions and the following disclaimer. |
a119822b DSH |
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 | ||
a119822b | 60 | /* Key derivation function from X9.62/SECG */ |
72550c52 | 61 | /* Way more than we will ever need */ |
ae5c8664 | 62 | #define ECDH_KDF_MAX (1 << 30) |
a119822b | 63 | |
ae5c8664 MC |
64 | int ECDH_KDF_X9_62(unsigned char *out, size_t outlen, |
65 | const unsigned char *Z, size_t Zlen, | |
66 | const unsigned char *sinfo, size_t sinfolen, | |
67 | const EVP_MD *md) | |
68 | { | |
69 | EVP_MD_CTX mctx; | |
70 | int rv = 0; | |
71 | unsigned int i; | |
72 | size_t mdlen; | |
73 | unsigned char ctr[4]; | |
74 | if (sinfolen > ECDH_KDF_MAX || outlen > ECDH_KDF_MAX | |
75 | || Zlen > ECDH_KDF_MAX) | |
76 | return 0; | |
77 | mdlen = EVP_MD_size(md); | |
78 | EVP_MD_CTX_init(&mctx); | |
79 | for (i = 1;; i++) { | |
80 | unsigned char mtmp[EVP_MAX_MD_SIZE]; | |
81 | EVP_DigestInit_ex(&mctx, md, NULL); | |
82 | ctr[3] = i & 0xFF; | |
83 | ctr[2] = (i >> 8) & 0xFF; | |
84 | ctr[1] = (i >> 16) & 0xFF; | |
85 | ctr[0] = (i >> 24) & 0xFF; | |
86 | if (!EVP_DigestUpdate(&mctx, Z, Zlen)) | |
87 | goto err; | |
88 | if (!EVP_DigestUpdate(&mctx, ctr, sizeof(ctr))) | |
89 | goto err; | |
90 | if (!EVP_DigestUpdate(&mctx, sinfo, sinfolen)) | |
91 | goto err; | |
92 | if (outlen >= mdlen) { | |
93 | if (!EVP_DigestFinal(&mctx, out, NULL)) | |
94 | goto err; | |
95 | outlen -= mdlen; | |
96 | if (outlen == 0) | |
97 | break; | |
98 | out += mdlen; | |
99 | } else { | |
100 | if (!EVP_DigestFinal(&mctx, mtmp, NULL)) | |
101 | goto err; | |
102 | memcpy(out, mtmp, outlen); | |
103 | OPENSSL_cleanse(mtmp, mdlen); | |
104 | break; | |
105 | } | |
106 | } | |
107 | rv = 1; | |
108 | err: | |
109 | EVP_MD_CTX_cleanup(&mctx); | |
110 | return rv; | |
111 | } |