1 /* ====================================================================
2 * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in
13 * the documentation and/or other materials provided with the
14 * distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 * software must display the following acknowledgment:
18 * "This product includes software developed by the OpenSSL Project
19 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 * endorse or promote products derived from this software without
23 * prior written permission. For written permission, please contact
24 * [email protected].
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 * nor may "OpenSSL" appear in their names without prior written
28 * permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 * acknowledgment:
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ====================================================================
48 *
49 * This product includes cryptographic software written by Eric Young
50 * ([email protected]). This product includes software written by Tim
51 * Hudson ([email protected]). */
52
53 #include <assert.h>
54
55 #include <openssl/bytestring.h>
56 #include <openssl/digest.h>
57 #include <openssl/hkdf.h>
58 #include <openssl/hmac.h>
59 #include <openssl/mem.h>
60
61 #include "internal.h"
62 #include "../../internal.h"
63 #include "../service_indicator/internal.h"
64
65
66 // tls1_P_hash computes the TLS P_<hash> function as described in RFC 5246,
67 // section 5. It XORs |out_len| bytes to |out|, using |md| as the hash and
68 // |secret| as the secret. |label|, |seed1|, and |seed2| are concatenated to
69 // form the seed parameter. It returns true on success and false on failure.
tls1_P_hash(uint8_t * out,size_t out_len,const EVP_MD * md,const uint8_t * secret,size_t secret_len,const char * label,size_t label_len,const uint8_t * seed1,size_t seed1_len,const uint8_t * seed2,size_t seed2_len)70 static int tls1_P_hash(uint8_t *out, size_t out_len,
71 const EVP_MD *md,
72 const uint8_t *secret, size_t secret_len,
73 const char *label, size_t label_len,
74 const uint8_t *seed1, size_t seed1_len,
75 const uint8_t *seed2, size_t seed2_len) {
76 HMAC_CTX ctx, ctx_tmp, ctx_init;
77 uint8_t A1[EVP_MAX_MD_SIZE];
78 unsigned A1_len;
79 int ret = 0;
80
81 const size_t chunk = EVP_MD_size(md);
82 HMAC_CTX_init(&ctx);
83 HMAC_CTX_init(&ctx_tmp);
84 HMAC_CTX_init(&ctx_init);
85
86 if (!HMAC_Init_ex(&ctx_init, secret, secret_len, md, NULL) ||
87 !HMAC_CTX_copy_ex(&ctx, &ctx_init) ||
88 !HMAC_Update(&ctx, (const uint8_t *) label, label_len) ||
89 !HMAC_Update(&ctx, seed1, seed1_len) ||
90 !HMAC_Update(&ctx, seed2, seed2_len) ||
91 !HMAC_Final(&ctx, A1, &A1_len)) {
92 goto err;
93 }
94
95 for (;;) {
96 unsigned len_u;
97 uint8_t hmac[EVP_MAX_MD_SIZE];
98 if (!HMAC_CTX_copy_ex(&ctx, &ctx_init) ||
99 !HMAC_Update(&ctx, A1, A1_len) ||
100 // Save a copy of |ctx| to compute the next A1 value below.
101 (out_len > chunk && !HMAC_CTX_copy_ex(&ctx_tmp, &ctx)) ||
102 !HMAC_Update(&ctx, (const uint8_t *) label, label_len) ||
103 !HMAC_Update(&ctx, seed1, seed1_len) ||
104 !HMAC_Update(&ctx, seed2, seed2_len) ||
105 !HMAC_Final(&ctx, hmac, &len_u)) {
106 goto err;
107 }
108 size_t len = len_u;
109 assert(len == chunk);
110
111 // XOR the result into |out|.
112 if (len > out_len) {
113 len = out_len;
114 }
115 for (size_t i = 0; i < len; i++) {
116 out[i] ^= hmac[i];
117 }
118 out += len;
119 out_len -= len;
120
121 if (out_len == 0) {
122 break;
123 }
124
125 // Calculate the next A1 value.
126 if (!HMAC_Final(&ctx_tmp, A1, &A1_len)) {
127 goto err;
128 }
129 }
130
131 ret = 1;
132
133 err:
134 OPENSSL_cleanse(A1, sizeof(A1));
135 HMAC_CTX_cleanup(&ctx);
136 HMAC_CTX_cleanup(&ctx_tmp);
137 HMAC_CTX_cleanup(&ctx_init);
138 return ret;
139 }
140
CRYPTO_tls1_prf(const EVP_MD * digest,uint8_t * out,size_t out_len,const uint8_t * secret,size_t secret_len,const char * label,size_t label_len,const uint8_t * seed1,size_t seed1_len,const uint8_t * seed2,size_t seed2_len)141 int CRYPTO_tls1_prf(const EVP_MD *digest,
142 uint8_t *out, size_t out_len,
143 const uint8_t *secret, size_t secret_len,
144 const char *label, size_t label_len,
145 const uint8_t *seed1, size_t seed1_len,
146 const uint8_t *seed2, size_t seed2_len) {
147 if (out_len == 0) {
148 return 1;
149 }
150
151 OPENSSL_memset(out, 0, out_len);
152
153 const EVP_MD *const original_digest = digest;
154 FIPS_service_indicator_lock_state();
155 int ret = 0;
156
157 if (digest == EVP_md5_sha1()) {
158 // If using the MD5/SHA1 PRF, |secret| is partitioned between MD5 and SHA-1.
159 size_t secret_half = secret_len - (secret_len / 2);
160 if (!tls1_P_hash(out, out_len, EVP_md5(), secret, secret_half, label,
161 label_len, seed1, seed1_len, seed2, seed2_len)) {
162 goto end;
163 }
164
165 // Note that, if |secret_len| is odd, the two halves share a byte.
166 secret += secret_len - secret_half;
167 secret_len = secret_half;
168 digest = EVP_sha1();
169 }
170
171 ret = tls1_P_hash(out, out_len, digest, secret, secret_len, label, label_len,
172 seed1, seed1_len, seed2, seed2_len);
173
174 end:
175 FIPS_service_indicator_unlock_state();
176 if (ret) {
177 TLSKDF_verify_service_indicator(original_digest);
178 }
179 return ret;
180 }
181
CRYPTO_tls13_hkdf_expand_label(uint8_t * out,size_t out_len,const EVP_MD * digest,const uint8_t * secret,size_t secret_len,const uint8_t * label,size_t label_len,const uint8_t * hash,size_t hash_len)182 int CRYPTO_tls13_hkdf_expand_label(uint8_t *out, size_t out_len,
183 const EVP_MD *digest, //
184 const uint8_t *secret, size_t secret_len,
185 const uint8_t *label, size_t label_len,
186 const uint8_t *hash, size_t hash_len) {
187 static const uint8_t kProtocolLabel[] = "tls13 ";
188 CBB cbb, child;
189 uint8_t *hkdf_label = NULL;
190 size_t hkdf_label_len;
191
192 FIPS_service_indicator_lock_state();
193 CBB_zero(&cbb);
194 if (!CBB_init(&cbb, 2 + 1 + sizeof(kProtocolLabel) - 1 + label_len + 1 +
195 hash_len) ||
196 !CBB_add_u16(&cbb, out_len) ||
197 !CBB_add_u8_length_prefixed(&cbb, &child) ||
198 !CBB_add_bytes(&child, kProtocolLabel, sizeof(kProtocolLabel) - 1) ||
199 !CBB_add_bytes(&child, label, label_len) ||
200 !CBB_add_u8_length_prefixed(&cbb, &child) ||
201 !CBB_add_bytes(&child, hash, hash_len) ||
202 !CBB_finish(&cbb, &hkdf_label, &hkdf_label_len)) {
203 CBB_cleanup(&cbb);
204 FIPS_service_indicator_unlock_state();
205 return 0;
206 }
207
208 const int ret = HKDF_expand(out, out_len, digest, secret, secret_len,
209 hkdf_label, hkdf_label_len);
210 OPENSSL_free(hkdf_label);
211
212 FIPS_service_indicator_unlock_state();
213 if (ret) {
214 TLSKDF_verify_service_indicator(digest);
215 }
216 return ret;
217 }
218
219