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d2e9e320 | 1 | /* |
28428130 | 2 | * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved. |
aacfb134 | 3 | * |
7bb803e8 | 4 | * Licensed under the Apache License 2.0 (the "License"). You may not use |
d2e9e320 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 | |
aacfb134 AG |
8 | */ |
9 | ||
10 | #include <stdlib.h> | |
5a285add | 11 | #include <stdarg.h> |
aacfb134 AG |
12 | #include <string.h> |
13 | #include <openssl/hmac.h> | |
aacfb134 | 14 | #include <openssl/evp.h> |
5a285add | 15 | #include <openssl/kdf.h> |
aacfb134 AG |
16 | #include "internal/cryptlib.h" |
17 | #include "internal/evp_int.h" | |
5a285add | 18 | #include "kdf_local.h" |
aacfb134 AG |
19 | |
20 | #define HKDF_MAXBUF 1024 | |
21 | ||
5a285add DM |
22 | static void kdf_hkdf_reset(EVP_KDF_IMPL *impl); |
23 | static int HKDF(const EVP_MD *evp_md, | |
24 | const unsigned char *salt, size_t salt_len, | |
25 | const unsigned char *key, size_t key_len, | |
26 | const unsigned char *info, size_t info_len, | |
27 | unsigned char *okm, size_t okm_len); | |
28 | static int HKDF_Extract(const EVP_MD *evp_md, | |
29 | const unsigned char *salt, size_t salt_len, | |
30 | const unsigned char *key, size_t key_len, | |
31 | unsigned char *prk, size_t prk_len); | |
32 | static int HKDF_Expand(const EVP_MD *evp_md, | |
33 | const unsigned char *prk, size_t prk_len, | |
34 | const unsigned char *info, size_t info_len, | |
35 | unsigned char *okm, size_t okm_len); | |
36 | ||
37 | struct evp_kdf_impl_st { | |
d2139cf8 | 38 | int mode; |
aacfb134 AG |
39 | const EVP_MD *md; |
40 | unsigned char *salt; | |
41 | size_t salt_len; | |
42 | unsigned char *key; | |
43 | size_t key_len; | |
44 | unsigned char info[HKDF_MAXBUF]; | |
45 | size_t info_len; | |
5a285add | 46 | }; |
aacfb134 | 47 | |
5a285add | 48 | static EVP_KDF_IMPL *kdf_hkdf_new(void) |
aacfb134 | 49 | { |
5a285add | 50 | EVP_KDF_IMPL *impl; |
aacfb134 | 51 | |
5a285add DM |
52 | if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL) |
53 | KDFerr(KDF_F_KDF_HKDF_NEW, ERR_R_MALLOC_FAILURE); | |
54 | return impl; | |
55 | } | |
aacfb134 | 56 | |
5a285add DM |
57 | static void kdf_hkdf_free(EVP_KDF_IMPL *impl) |
58 | { | |
59 | kdf_hkdf_reset(impl); | |
60 | OPENSSL_free(impl); | |
aacfb134 AG |
61 | } |
62 | ||
5a285add | 63 | static void kdf_hkdf_reset(EVP_KDF_IMPL *impl) |
aacfb134 | 64 | { |
5a285add DM |
65 | OPENSSL_free(impl->salt); |
66 | OPENSSL_clear_free(impl->key, impl->key_len); | |
67 | OPENSSL_cleanse(impl->info, impl->info_len); | |
68 | memset(impl, 0, sizeof(*impl)); | |
aacfb134 AG |
69 | } |
70 | ||
5a285add | 71 | static int kdf_hkdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args) |
aacfb134 | 72 | { |
5a285add DM |
73 | const unsigned char *p; |
74 | size_t len; | |
75 | const EVP_MD *md; | |
aacfb134 | 76 | |
5a285add DM |
77 | switch (cmd) { |
78 | case EVP_KDF_CTRL_SET_MD: | |
79 | md = va_arg(args, const EVP_MD *); | |
80 | if (md == NULL) | |
aacfb134 AG |
81 | return 0; |
82 | ||
5a285add | 83 | impl->md = md; |
aacfb134 AG |
84 | return 1; |
85 | ||
5a285add DM |
86 | case EVP_KDF_CTRL_SET_HKDF_MODE: |
87 | impl->mode = va_arg(args, int); | |
d2139cf8 MC |
88 | return 1; |
89 | ||
5a285add DM |
90 | case EVP_KDF_CTRL_SET_SALT: |
91 | p = va_arg(args, const unsigned char *); | |
92 | len = va_arg(args, size_t); | |
93 | if (len == 0 || p == NULL) | |
aacfb134 AG |
94 | return 1; |
95 | ||
5a285add DM |
96 | OPENSSL_free(impl->salt); |
97 | impl->salt = OPENSSL_memdup(p, len); | |
98 | if (impl->salt == NULL) | |
aacfb134 AG |
99 | return 0; |
100 | ||
5a285add | 101 | impl->salt_len = len; |
aacfb134 AG |
102 | return 1; |
103 | ||
5a285add DM |
104 | case EVP_KDF_CTRL_SET_KEY: |
105 | p = va_arg(args, const unsigned char *); | |
106 | len = va_arg(args, size_t); | |
107 | OPENSSL_clear_free(impl->key, impl->key_len); | |
108 | impl->key = OPENSSL_memdup(p, len); | |
109 | if (impl->key == NULL) | |
aacfb134 AG |
110 | return 0; |
111 | ||
5a285add DM |
112 | impl->key_len = len; |
113 | return 1; | |
aacfb134 | 114 | |
5a285add DM |
115 | case EVP_KDF_CTRL_RESET_HKDF_INFO: |
116 | OPENSSL_cleanse(impl->info, impl->info_len); | |
117 | impl->info_len = 0; | |
aacfb134 AG |
118 | return 1; |
119 | ||
5a285add DM |
120 | case EVP_KDF_CTRL_ADD_HKDF_INFO: |
121 | p = va_arg(args, const unsigned char *); | |
122 | len = va_arg(args, size_t); | |
123 | if (len == 0 || p == NULL) | |
aacfb134 AG |
124 | return 1; |
125 | ||
5a285add | 126 | if (len > (HKDF_MAXBUF - impl->info_len)) |
aacfb134 AG |
127 | return 0; |
128 | ||
5a285add DM |
129 | memcpy(impl->info + impl->info_len, p, len); |
130 | impl->info_len += len; | |
aacfb134 AG |
131 | return 1; |
132 | ||
133 | default: | |
134 | return -2; | |
aacfb134 AG |
135 | } |
136 | } | |
137 | ||
5a285add DM |
138 | static int kdf_hkdf_ctrl_str(EVP_KDF_IMPL *impl, const char *type, |
139 | const char *value) | |
aacfb134 | 140 | { |
ddd2c389 MC |
141 | if (strcmp(type, "mode") == 0) { |
142 | int mode; | |
143 | ||
144 | if (strcmp(value, "EXTRACT_AND_EXPAND") == 0) | |
5a285add | 145 | mode = EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND; |
ddd2c389 | 146 | else if (strcmp(value, "EXTRACT_ONLY") == 0) |
5a285add | 147 | mode = EVP_KDF_HKDF_MODE_EXTRACT_ONLY; |
ddd2c389 | 148 | else if (strcmp(value, "EXPAND_ONLY") == 0) |
5a285add | 149 | mode = EVP_KDF_HKDF_MODE_EXPAND_ONLY; |
ddd2c389 MC |
150 | else |
151 | return 0; | |
152 | ||
5a285add | 153 | return call_ctrl(kdf_hkdf_ctrl, impl, EVP_KDF_CTRL_SET_HKDF_MODE, mode); |
ddd2c389 MC |
154 | } |
155 | ||
5a285add DM |
156 | if (strcmp(type, "digest") == 0) |
157 | return kdf_md2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_MD, value); | |
aacfb134 AG |
158 | |
159 | if (strcmp(type, "salt") == 0) | |
5a285add | 160 | return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_SALT, value); |
aacfb134 AG |
161 | |
162 | if (strcmp(type, "hexsalt") == 0) | |
5a285add | 163 | return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_SALT, value); |
aacfb134 AG |
164 | |
165 | if (strcmp(type, "key") == 0) | |
5a285add | 166 | return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_KEY, value); |
aacfb134 AG |
167 | |
168 | if (strcmp(type, "hexkey") == 0) | |
5a285add | 169 | return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_SET_KEY, value); |
aacfb134 AG |
170 | |
171 | if (strcmp(type, "info") == 0) | |
5a285add DM |
172 | return kdf_str2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_ADD_HKDF_INFO, |
173 | value); | |
aacfb134 AG |
174 | |
175 | if (strcmp(type, "hexinfo") == 0) | |
5a285add DM |
176 | return kdf_hex2ctrl(impl, kdf_hkdf_ctrl, EVP_KDF_CTRL_ADD_HKDF_INFO, |
177 | value); | |
aacfb134 AG |
178 | |
179 | return -2; | |
180 | } | |
181 | ||
5a285add | 182 | static size_t kdf_hkdf_size(EVP_KDF_IMPL *impl) |
ca55d70b | 183 | { |
5a285add DM |
184 | if (impl->mode != EVP_KDF_HKDF_MODE_EXTRACT_ONLY) |
185 | return SIZE_MAX; | |
ca55d70b | 186 | |
5a285add DM |
187 | if (impl->md == NULL) { |
188 | KDFerr(KDF_F_KDF_HKDF_SIZE, KDF_R_MISSING_MESSAGE_DIGEST); | |
189 | return 0; | |
190 | } | |
191 | return EVP_MD_size(impl->md); | |
ca55d70b MC |
192 | } |
193 | ||
5a285add DM |
194 | static int kdf_hkdf_derive(EVP_KDF_IMPL *impl, unsigned char *key, |
195 | size_t keylen) | |
aacfb134 | 196 | { |
5a285add DM |
197 | if (impl->md == NULL) { |
198 | KDFerr(KDF_F_KDF_HKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST); | |
f55129c7 JB |
199 | return 0; |
200 | } | |
5a285add DM |
201 | if (impl->key == NULL) { |
202 | KDFerr(KDF_F_KDF_HKDF_DERIVE, KDF_R_MISSING_KEY); | |
aacfb134 | 203 | return 0; |
e65f6509 | 204 | } |
aacfb134 | 205 | |
5a285add DM |
206 | switch (impl->mode) { |
207 | case EVP_KDF_HKDF_MODE_EXTRACT_AND_EXPAND: | |
208 | return HKDF(impl->md, impl->salt, impl->salt_len, impl->key, | |
209 | impl->key_len, impl->info, impl->info_len, key, | |
210 | keylen); | |
d2139cf8 | 211 | |
5a285add DM |
212 | case EVP_KDF_HKDF_MODE_EXTRACT_ONLY: |
213 | return HKDF_Extract(impl->md, impl->salt, impl->salt_len, impl->key, | |
214 | impl->key_len, key, keylen); | |
d2139cf8 | 215 | |
5a285add DM |
216 | case EVP_KDF_HKDF_MODE_EXPAND_ONLY: |
217 | return HKDF_Expand(impl->md, impl->key, impl->key_len, impl->info, | |
218 | impl->info_len, key, keylen); | |
d2139cf8 MC |
219 | |
220 | default: | |
aacfb134 AG |
221 | return 0; |
222 | } | |
aacfb134 AG |
223 | } |
224 | ||
5a285add DM |
225 | const EVP_KDF_METHOD hkdf_kdf_meth = { |
226 | EVP_KDF_HKDF, | |
227 | kdf_hkdf_new, | |
228 | kdf_hkdf_free, | |
229 | kdf_hkdf_reset, | |
230 | kdf_hkdf_ctrl, | |
231 | kdf_hkdf_ctrl_str, | |
232 | kdf_hkdf_size, | |
233 | kdf_hkdf_derive | |
aacfb134 AG |
234 | }; |
235 | ||
5a285add DM |
236 | static int HKDF(const EVP_MD *evp_md, |
237 | const unsigned char *salt, size_t salt_len, | |
238 | const unsigned char *key, size_t key_len, | |
239 | const unsigned char *info, size_t info_len, | |
240 | unsigned char *okm, size_t okm_len) | |
aacfb134 AG |
241 | { |
242 | unsigned char prk[EVP_MAX_MD_SIZE]; | |
5a285add DM |
243 | int ret; |
244 | size_t prk_len = EVP_MD_size(evp_md); | |
aacfb134 | 245 | |
5a285add DM |
246 | if (!HKDF_Extract(evp_md, salt, salt_len, key, key_len, prk, prk_len)) |
247 | return 0; | |
aacfb134 | 248 | |
d2139cf8 MC |
249 | ret = HKDF_Expand(evp_md, prk, prk_len, info, info_len, okm, okm_len); |
250 | OPENSSL_cleanse(prk, sizeof(prk)); | |
251 | ||
252 | return ret; | |
aacfb134 AG |
253 | } |
254 | ||
5a285add DM |
255 | static int HKDF_Extract(const EVP_MD *evp_md, |
256 | const unsigned char *salt, size_t salt_len, | |
257 | const unsigned char *key, size_t key_len, | |
258 | unsigned char *prk, size_t prk_len) | |
aacfb134 | 259 | { |
5a285add DM |
260 | if (prk_len != (size_t)EVP_MD_size(evp_md)) { |
261 | KDFerr(KDF_F_HKDF_EXTRACT, KDF_R_WRONG_OUTPUT_BUFFER_SIZE); | |
262 | return 0; | |
263 | } | |
264 | return HMAC(evp_md, salt, salt_len, key, key_len, prk, NULL) != NULL; | |
aacfb134 AG |
265 | } |
266 | ||
5a285add DM |
267 | static int HKDF_Expand(const EVP_MD *evp_md, |
268 | const unsigned char *prk, size_t prk_len, | |
269 | const unsigned char *info, size_t info_len, | |
270 | unsigned char *okm, size_t okm_len) | |
aacfb134 AG |
271 | { |
272 | HMAC_CTX *hmac; | |
5a285add | 273 | int ret = 0; |
aacfb134 | 274 | unsigned int i; |
aacfb134 | 275 | unsigned char prev[EVP_MAX_MD_SIZE]; |
aacfb134 | 276 | size_t done_len = 0, dig_len = EVP_MD_size(evp_md); |
aacfb134 | 277 | size_t n = okm_len / dig_len; |
5a285add | 278 | |
aacfb134 AG |
279 | if (okm_len % dig_len) |
280 | n++; | |
281 | ||
d2139cf8 | 282 | if (n > 255 || okm == NULL) |
5a285add | 283 | return 0; |
aacfb134 AG |
284 | |
285 | if ((hmac = HMAC_CTX_new()) == NULL) | |
5a285add | 286 | return 0; |
aacfb134 AG |
287 | |
288 | if (!HMAC_Init_ex(hmac, prk, prk_len, evp_md, NULL)) | |
289 | goto err; | |
290 | ||
291 | for (i = 1; i <= n; i++) { | |
292 | size_t copy_len; | |
293 | const unsigned char ctr = i; | |
294 | ||
295 | if (i > 1) { | |
296 | if (!HMAC_Init_ex(hmac, NULL, 0, NULL, NULL)) | |
297 | goto err; | |
298 | ||
299 | if (!HMAC_Update(hmac, prev, dig_len)) | |
300 | goto err; | |
301 | } | |
302 | ||
303 | if (!HMAC_Update(hmac, info, info_len)) | |
304 | goto err; | |
305 | ||
306 | if (!HMAC_Update(hmac, &ctr, 1)) | |
307 | goto err; | |
308 | ||
309 | if (!HMAC_Final(hmac, prev, NULL)) | |
310 | goto err; | |
311 | ||
312 | copy_len = (done_len + dig_len > okm_len) ? | |
313 | okm_len - done_len : | |
314 | dig_len; | |
315 | ||
316 | memcpy(okm + done_len, prev, copy_len); | |
317 | ||
318 | done_len += copy_len; | |
319 | } | |
5a285add | 320 | ret = 1; |
aacfb134 AG |
321 | |
322 | err: | |
64ed55ab | 323 | OPENSSL_cleanse(prev, sizeof(prev)); |
aacfb134 | 324 | HMAC_CTX_free(hmac); |
64ed55ab | 325 | return ret; |
aacfb134 | 326 | } |