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Commit | Line | Data |
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dc1ce3bc | 1 | /* |
aa6bb135 | 2 | * Copyright 2013-2016 The OpenSSL Project Authors. All Rights Reserved. |
dc1ce3bc | 3 | * |
e38873f5 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
aa6bb135 RS |
5 | * this file except in compliance with the License. You can obtain a copy |
6 | * in the file LICENSE in the source distribution or at | |
7 | * https://www.openssl.org/source/license.html | |
dc1ce3bc DSH |
8 | */ |
9 | ||
bef7a815 | 10 | #include "e_os.h" |
e968561d DB |
11 | |
12 | #ifndef OPENSSL_NO_CMS | |
dc1ce3bc DSH |
13 | #include <string.h> |
14 | #include <openssl/dh.h> | |
15 | #include <openssl/evp.h> | |
16 | #include <openssl/asn1.h> | |
17 | #include <openssl/cms.h> | |
18 | ||
e968561d | 19 | |
dc1ce3bc | 20 | /* Key derivation from X9.42/RFC2631 */ |
e968561d | 21 | /* Uses CMS functions, hence the #ifdef wrapper. */ |
dc1ce3bc | 22 | |
0f113f3e | 23 | #define DH_KDF_MAX (1L << 30) |
dc1ce3bc DSH |
24 | |
25 | /* Skip past an ASN1 structure: for OBJECT skip content octets too */ | |
26 | ||
27 | static int skip_asn1(unsigned char **pp, long *plen, int exptag) | |
0f113f3e MC |
28 | { |
29 | const unsigned char *q = *pp; | |
30 | int i, tag, xclass; | |
31 | long tmplen; | |
32 | i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen); | |
33 | if (i & 0x80) | |
34 | return 0; | |
35 | if (tag != exptag || xclass != V_ASN1_UNIVERSAL) | |
36 | return 0; | |
37 | if (tag == V_ASN1_OBJECT) | |
38 | q += tmplen; | |
39 | *plen -= q - *pp; | |
40 | *pp = (unsigned char *)q; | |
41 | return 1; | |
42 | } | |
dc1ce3bc | 43 | |
0f113f3e MC |
44 | /* |
45 | * Encode the DH shared info structure, return an offset to the counter value | |
46 | * so we can update the structure without reencoding it. | |
dc1ce3bc DSH |
47 | */ |
48 | ||
dc1ce3bc | 49 | static int dh_sharedinfo_encode(unsigned char **pder, unsigned char **pctr, |
0f113f3e MC |
50 | ASN1_OBJECT *key_oid, size_t outlen, |
51 | const unsigned char *ukm, size_t ukmlen) | |
52 | { | |
53 | unsigned char *p; | |
54 | int derlen; | |
55 | long tlen; | |
56 | /* "magic" value to check offset is sane */ | |
57 | static unsigned char ctr[4] = { 0xF3, 0x17, 0x22, 0x53 }; | |
58 | X509_ALGOR atmp; | |
59 | ASN1_OCTET_STRING ctr_oct, ukm_oct, *pukm_oct; | |
60 | ASN1_TYPE ctr_atype; | |
61 | if (ukmlen > DH_KDF_MAX || outlen > DH_KDF_MAX) | |
62 | return 0; | |
63 | ctr_oct.data = ctr; | |
64 | ctr_oct.length = 4; | |
65 | ctr_oct.flags = 0; | |
66 | ctr_oct.type = V_ASN1_OCTET_STRING; | |
67 | ctr_atype.type = V_ASN1_OCTET_STRING; | |
68 | ctr_atype.value.octet_string = &ctr_oct; | |
69 | atmp.algorithm = key_oid; | |
70 | atmp.parameter = &ctr_atype; | |
71 | if (ukm) { | |
72 | ukm_oct.type = V_ASN1_OCTET_STRING; | |
73 | ukm_oct.flags = 0; | |
74 | ukm_oct.data = (unsigned char *)ukm; | |
75 | ukm_oct.length = ukmlen; | |
76 | pukm_oct = &ukm_oct; | |
77 | } else | |
78 | pukm_oct = NULL; | |
79 | derlen = CMS_SharedInfo_encode(pder, &atmp, pukm_oct, outlen); | |
80 | if (derlen <= 0) | |
81 | return 0; | |
82 | p = *pder; | |
83 | tlen = derlen; | |
84 | if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)) | |
85 | return 0; | |
86 | if (!skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)) | |
87 | return 0; | |
88 | if (!skip_asn1(&p, &tlen, V_ASN1_OBJECT)) | |
89 | return 0; | |
90 | if (!skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING)) | |
91 | return 0; | |
92 | if (CRYPTO_memcmp(p, ctr, 4)) | |
93 | return 0; | |
94 | *pctr = p; | |
95 | return derlen; | |
96 | } | |
dc1ce3bc | 97 | |
0f113f3e MC |
98 | int DH_KDF_X9_42(unsigned char *out, size_t outlen, |
99 | const unsigned char *Z, size_t Zlen, | |
100 | ASN1_OBJECT *key_oid, | |
101 | const unsigned char *ukm, size_t ukmlen, const EVP_MD *md) | |
102 | { | |
6e59a892 | 103 | EVP_MD_CTX *mctx = NULL; |
0f113f3e MC |
104 | int rv = 0; |
105 | unsigned int i; | |
106 | size_t mdlen; | |
107 | unsigned char *der = NULL, *ctr; | |
108 | int derlen; | |
109 | if (Zlen > DH_KDF_MAX) | |
110 | return 0; | |
bfb0641f | 111 | mctx = EVP_MD_CTX_new(); |
6e59a892 RL |
112 | if (mctx == NULL) |
113 | return 0; | |
0f113f3e | 114 | mdlen = EVP_MD_size(md); |
0f113f3e MC |
115 | derlen = dh_sharedinfo_encode(&der, &ctr, key_oid, outlen, ukm, ukmlen); |
116 | if (derlen == 0) | |
117 | goto err; | |
118 | for (i = 1;; i++) { | |
119 | unsigned char mtmp[EVP_MAX_MD_SIZE]; | |
d166ed8c DSH |
120 | if (!EVP_DigestInit_ex(mctx, md, NULL) |
121 | || !EVP_DigestUpdate(mctx, Z, Zlen)) | |
0f113f3e MC |
122 | goto err; |
123 | ctr[3] = i & 0xFF; | |
124 | ctr[2] = (i >> 8) & 0xFF; | |
125 | ctr[1] = (i >> 16) & 0xFF; | |
126 | ctr[0] = (i >> 24) & 0xFF; | |
6e59a892 | 127 | if (!EVP_DigestUpdate(mctx, der, derlen)) |
0f113f3e MC |
128 | goto err; |
129 | if (outlen >= mdlen) { | |
6e59a892 | 130 | if (!EVP_DigestFinal(mctx, out, NULL)) |
0f113f3e MC |
131 | goto err; |
132 | outlen -= mdlen; | |
133 | if (outlen == 0) | |
134 | break; | |
135 | out += mdlen; | |
136 | } else { | |
6e59a892 | 137 | if (!EVP_DigestFinal(mctx, mtmp, NULL)) |
0f113f3e MC |
138 | goto err; |
139 | memcpy(out, mtmp, outlen); | |
140 | OPENSSL_cleanse(mtmp, mdlen); | |
141 | break; | |
142 | } | |
143 | } | |
144 | rv = 1; | |
145 | err: | |
b548a1f1 | 146 | OPENSSL_free(der); |
bfb0641f | 147 | EVP_MD_CTX_free(mctx); |
0f113f3e MC |
148 | return rv; |
149 | } | |
e968561d | 150 | #endif |