Branch data Line data Source code
1 : : /* crypto/dh/dh_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 : : #include <string.h>
55 : : #include <openssl/dh.h>
56 : : #include <openssl/evp.h>
57 : : #include <openssl/asn1.h>
58 : : #include <openssl/cms.h>
59 : :
60 : :
61 : : /* Key derivation from X9.42/RFC2631 */
62 : :
63 : : #define DH_KDF_MAX (1L << 30)
64 : :
65 : : /* Skip past an ASN1 structure: for OBJECT skip content octets too */
66 : :
67 : 8 : static int skip_asn1(unsigned char **pp, long *plen, int exptag)
68 : : {
69 : 8 : const unsigned char *q = *pp;
70 : : int i, tag, xclass;
71 : : long tmplen;
72 : 8 : i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen);
73 [ + - ]: 8 : if (i & 0x80)
74 : : return 0;
75 [ + - ][ + - ]: 8 : if (tag != exptag || xclass != V_ASN1_UNIVERSAL)
76 : : return 0;
77 [ + + ]: 8 : if (tag == V_ASN1_OBJECT)
78 : 2 : q += tmplen;
79 : 8 : *plen -= q - *pp;
80 : 8 : *pp = (unsigned char *)q;
81 : 8 : return 1;
82 : : }
83 : :
84 : : /* Encode the DH shared info structure, return an offset to the counter
85 : : * value so we can update the structure without reencoding it.
86 : : */
87 : :
88 : :
89 : 2 : static int dh_sharedinfo_encode(unsigned char **pder, unsigned char **pctr,
90 : : ASN1_OBJECT *key_oid, size_t outlen,
91 : : const unsigned char *ukm, size_t ukmlen)
92 : : {
93 : : unsigned char *p;
94 : : int derlen;
95 : : long tlen;
96 : : /* "magic" value to check offset is sane */
97 : : static unsigned char ctr[4] = {0xF3, 0x17, 0x22, 0x53};
98 : : X509_ALGOR atmp;
99 : : ASN1_OCTET_STRING ctr_oct, ukm_oct, *pukm_oct;
100 : : ASN1_TYPE ctr_atype;
101 [ + - ]: 2 : if (ukmlen > DH_KDF_MAX || outlen > DH_KDF_MAX)
102 : : return 0;
103 : 2 : ctr_oct.data = ctr;
104 : 2 : ctr_oct.length = 4;
105 : 2 : ctr_oct.flags = 0;
106 : 2 : ctr_oct.type = V_ASN1_OCTET_STRING;
107 : 2 : ctr_atype.type = V_ASN1_OCTET_STRING;
108 : 2 : ctr_atype.value.octet_string = &ctr_oct;
109 : 2 : atmp.algorithm = key_oid;
110 : 2 : atmp.parameter = &ctr_atype;
111 [ - + ]: 2 : if (ukm)
112 : : {
113 : 0 : ukm_oct.type = V_ASN1_OCTET_STRING;
114 : 0 : ukm_oct.flags = 0;
115 : 0 : ukm_oct.data = (unsigned char *)ukm;
116 : 0 : ukm_oct.length = ukmlen;
117 : 0 : pukm_oct = &ukm_oct;
118 : : }
119 : : else
120 : : pukm_oct = NULL;
121 : 2 : derlen = CMS_SharedInfo_encode(pder, &atmp, pukm_oct, outlen);
122 [ + - ]: 2 : if (derlen <= 0)
123 : : return 0;
124 : 2 : p = *pder;
125 : 2 : tlen = derlen;
126 [ + - ]: 2 : if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE))
127 : : return 0;
128 [ + - ]: 2 : if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE))
129 : : return 0;
130 [ + - ]: 2 : if (!skip_asn1(&p, &tlen, V_ASN1_OBJECT))
131 : : return 0;
132 [ + - ]: 2 : if (!skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING))
133 : : return 0;
134 [ + - ]: 2 : if (memcmp(p, ctr, 4))
135 : : return 0;
136 : 2 : *pctr = p;
137 : 2 : return derlen;
138 : : }
139 : :
140 : 2 : int DH_KDF_X9_42(unsigned char *out, size_t outlen,
141 : : const unsigned char *Z, size_t Zlen,
142 : : ASN1_OBJECT *key_oid,
143 : : const unsigned char *ukm, size_t ukmlen,
144 : : const EVP_MD *md)
145 : : {
146 : : EVP_MD_CTX mctx;
147 : 2 : int rv = 0;
148 : : unsigned int i;
149 : : size_t mdlen;
150 : 2 : unsigned char *der = NULL, *ctr;
151 : : int derlen;
152 [ + - ]: 2 : if (Zlen > DH_KDF_MAX)
153 : : return 0;
154 : 2 : mdlen = EVP_MD_size(md);
155 : 2 : EVP_MD_CTX_init(&mctx);
156 : 2 : derlen = dh_sharedinfo_encode(&der, &ctr, key_oid, outlen,
157 : : ukm, ukmlen);
158 [ + - ]: 2 : if (derlen == 0)
159 : : goto err;
160 : 0 : for (i = 1;;i++)
161 : : {
162 : : unsigned char mtmp[EVP_MAX_MD_SIZE];
163 : 2 : EVP_DigestInit_ex(&mctx, md, NULL);
164 [ + - ]: 2 : if (!EVP_DigestUpdate(&mctx, Z, Zlen))
165 : : goto err;
166 : 2 : ctr[3] = i & 0xFF;
167 : 2 : ctr[2] = (i >> 8) & 0xFF;
168 : 2 : ctr[1] = (i >> 16) & 0xFF;
169 : 2 : ctr[0] = (i >> 24) & 0xFF;
170 [ + - ]: 2 : if (!EVP_DigestUpdate(&mctx, der, derlen))
171 : : goto err;
172 [ - + ]: 2 : if (outlen >= mdlen)
173 : : {
174 [ # # ]: 0 : if (!EVP_DigestFinal(&mctx, out, NULL))
175 : : goto err;
176 : 0 : outlen -= mdlen;
177 [ # # ]: 0 : if (outlen == 0)
178 : : break;
179 : 0 : out += mdlen;
180 : : }
181 : : else
182 : : {
183 [ + - ]: 2 : if (!EVP_DigestFinal(&mctx, mtmp, NULL))
184 : : goto err;
185 : : memcpy(out, mtmp, outlen);
186 : 2 : OPENSSL_cleanse(mtmp, mdlen);
187 : 2 : break;
188 : : }
189 : 0 : }
190 : 2 : rv = 1;
191 : : err:
192 [ + - ]: 2 : if (der)
193 : 2 : OPENSSL_free(der);
194 : 2 : EVP_MD_CTX_cleanup(&mctx);
195 : 2 : return rv;
196 : : }
197 : :
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