/src/openssl/providers/implementations/kdfs/tls1_prf.c
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1 | | /* |
2 | | * Copyright 2016-2024 The OpenSSL Project Authors. All Rights Reserved. |
3 | | * |
4 | | * Licensed under the Apache License 2.0 (the "License"). You may not use |
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 |
8 | | */ |
9 | | |
10 | | /* |
11 | | * Refer to "The TLS Protocol Version 1.0" Section 5 |
12 | | * (https://tools.ietf.org/html/rfc2246#section-5) and |
13 | | * "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5 |
14 | | * (https://tools.ietf.org/html/rfc5246#section-5). |
15 | | * |
16 | | * For TLS v1.0 and TLS v1.1 the TLS PRF algorithm is given by: |
17 | | * |
18 | | * PRF(secret, label, seed) = P_MD5(S1, label + seed) XOR |
19 | | * P_SHA-1(S2, label + seed) |
20 | | * |
21 | | * where P_MD5 and P_SHA-1 are defined by P_<hash>, below, and S1 and S2 are |
22 | | * two halves of the secret (with the possibility of one shared byte, in the |
23 | | * case where the length of the original secret is odd). S1 is taken from the |
24 | | * first half of the secret, S2 from the second half. |
25 | | * |
26 | | * For TLS v1.2 the TLS PRF algorithm is given by: |
27 | | * |
28 | | * PRF(secret, label, seed) = P_<hash>(secret, label + seed) |
29 | | * |
30 | | * where hash is SHA-256 for all cipher suites defined in RFC 5246 as well as |
31 | | * those published prior to TLS v1.2 while the TLS v1.2 protocol is in effect, |
32 | | * unless defined otherwise by the cipher suite. |
33 | | * |
34 | | * P_<hash> is an expansion function that uses a single hash function to expand |
35 | | * a secret and seed into an arbitrary quantity of output: |
36 | | * |
37 | | * P_<hash>(secret, seed) = HMAC_<hash>(secret, A(1) + seed) + |
38 | | * HMAC_<hash>(secret, A(2) + seed) + |
39 | | * HMAC_<hash>(secret, A(3) + seed) + ... |
40 | | * |
41 | | * where + indicates concatenation. P_<hash> can be iterated as many times as |
42 | | * is necessary to produce the required quantity of data. |
43 | | * |
44 | | * A(i) is defined as: |
45 | | * A(0) = seed |
46 | | * A(i) = HMAC_<hash>(secret, A(i-1)) |
47 | | */ |
48 | | |
49 | | /* |
50 | | * Low level APIs (such as DH) are deprecated for public use, but still ok for |
51 | | * internal use. |
52 | | */ |
53 | | #include "internal/deprecated.h" |
54 | | |
55 | | #include <stdio.h> |
56 | | #include <stdarg.h> |
57 | | #include <string.h> |
58 | | #include <openssl/evp.h> |
59 | | #include <openssl/kdf.h> |
60 | | #include <openssl/core_names.h> |
61 | | #include <openssl/params.h> |
62 | | #include <openssl/proverr.h> |
63 | | #include "internal/cryptlib.h" |
64 | | #include "internal/numbers.h" |
65 | | #include "crypto/evp.h" |
66 | | #include "prov/provider_ctx.h" |
67 | | #include "prov/providercommon.h" |
68 | | #include "prov/implementations.h" |
69 | | #include "prov/provider_util.h" |
70 | | #include "prov/securitycheck.h" |
71 | | #include "prov/fipscommon.h" |
72 | | #include "prov/fipsindicator.h" |
73 | | #include "internal/e_os.h" |
74 | | #include "internal/safe_math.h" |
75 | | |
76 | | OSSL_SAFE_MATH_UNSIGNED(size_t, size_t) |
77 | | |
78 | | static OSSL_FUNC_kdf_newctx_fn kdf_tls1_prf_new; |
79 | | static OSSL_FUNC_kdf_dupctx_fn kdf_tls1_prf_dup; |
80 | | static OSSL_FUNC_kdf_freectx_fn kdf_tls1_prf_free; |
81 | | static OSSL_FUNC_kdf_reset_fn kdf_tls1_prf_reset; |
82 | | static OSSL_FUNC_kdf_derive_fn kdf_tls1_prf_derive; |
83 | | static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_tls1_prf_settable_ctx_params; |
84 | | static OSSL_FUNC_kdf_set_ctx_params_fn kdf_tls1_prf_set_ctx_params; |
85 | | static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_tls1_prf_gettable_ctx_params; |
86 | | static OSSL_FUNC_kdf_get_ctx_params_fn kdf_tls1_prf_get_ctx_params; |
87 | | |
88 | | static int tls1_prf_alg(EVP_MAC_CTX *mdctx, EVP_MAC_CTX *sha1ctx, |
89 | | const unsigned char *sec, size_t slen, |
90 | | const unsigned char *seed, size_t seed_len, |
91 | | unsigned char *out, size_t olen); |
92 | | |
93 | | #define TLS_MD_MASTER_SECRET_CONST "\x6d\x61\x73\x74\x65\x72\x20\x73\x65\x63\x72\x65\x74" |
94 | | #define TLS_MD_MASTER_SECRET_CONST_SIZE 13 |
95 | | |
96 | | /* TLS KDF kdf context structure */ |
97 | | typedef struct { |
98 | | void *provctx; |
99 | | |
100 | | /* MAC context for the main digest */ |
101 | | EVP_MAC_CTX *P_hash; |
102 | | /* MAC context for SHA1 for the MD5/SHA-1 combined PRF */ |
103 | | EVP_MAC_CTX *P_sha1; |
104 | | |
105 | | /* Secret value to use for PRF */ |
106 | | unsigned char *sec; |
107 | | size_t seclen; |
108 | | /* Concatenated seed data */ |
109 | | unsigned char *seed; |
110 | | size_t seedlen; |
111 | | |
112 | | OSSL_FIPS_IND_DECLARE |
113 | | } TLS1_PRF; |
114 | | |
115 | | static void *kdf_tls1_prf_new(void *provctx) |
116 | 0 | { |
117 | 0 | TLS1_PRF *ctx; |
118 | |
|
119 | 0 | if (!ossl_prov_is_running()) |
120 | 0 | return NULL; |
121 | | |
122 | 0 | if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) != NULL) { |
123 | 0 | ctx->provctx = provctx; |
124 | 0 | OSSL_FIPS_IND_INIT(ctx) |
125 | 0 | } |
126 | 0 | return ctx; |
127 | 0 | } |
128 | | |
129 | | static void kdf_tls1_prf_free(void *vctx) |
130 | 0 | { |
131 | 0 | TLS1_PRF *ctx = (TLS1_PRF *)vctx; |
132 | |
|
133 | 0 | if (ctx != NULL) { |
134 | 0 | kdf_tls1_prf_reset(ctx); |
135 | 0 | OPENSSL_free(ctx); |
136 | 0 | } |
137 | 0 | } |
138 | | |
139 | | static void kdf_tls1_prf_reset(void *vctx) |
140 | 0 | { |
141 | 0 | TLS1_PRF *ctx = (TLS1_PRF *)vctx; |
142 | 0 | void *provctx = ctx->provctx; |
143 | |
|
144 | 0 | EVP_MAC_CTX_free(ctx->P_hash); |
145 | 0 | EVP_MAC_CTX_free(ctx->P_sha1); |
146 | 0 | OPENSSL_clear_free(ctx->sec, ctx->seclen); |
147 | 0 | OPENSSL_clear_free(ctx->seed, ctx->seedlen); |
148 | 0 | memset(ctx, 0, sizeof(*ctx)); |
149 | 0 | ctx->provctx = provctx; |
150 | 0 | } |
151 | | |
152 | | static void *kdf_tls1_prf_dup(void *vctx) |
153 | 0 | { |
154 | 0 | const TLS1_PRF *src = (const TLS1_PRF *)vctx; |
155 | 0 | TLS1_PRF *dest; |
156 | |
|
157 | 0 | dest = kdf_tls1_prf_new(src->provctx); |
158 | 0 | if (dest != NULL) { |
159 | 0 | if (src->P_hash != NULL |
160 | 0 | && (dest->P_hash = EVP_MAC_CTX_dup(src->P_hash)) == NULL) |
161 | 0 | goto err; |
162 | 0 | if (src->P_sha1 != NULL |
163 | 0 | && (dest->P_sha1 = EVP_MAC_CTX_dup(src->P_sha1)) == NULL) |
164 | 0 | goto err; |
165 | 0 | if (!ossl_prov_memdup(src->sec, src->seclen, &dest->sec, &dest->seclen)) |
166 | 0 | goto err; |
167 | 0 | if (!ossl_prov_memdup(src->seed, src->seedlen, &dest->seed, |
168 | 0 | &dest->seedlen)) |
169 | 0 | goto err; |
170 | 0 | OSSL_FIPS_IND_COPY(dest, src) |
171 | 0 | } |
172 | 0 | return dest; |
173 | | |
174 | 0 | err: |
175 | 0 | kdf_tls1_prf_free(dest); |
176 | 0 | return NULL; |
177 | 0 | } |
178 | | |
179 | | #ifdef FIPS_MODULE |
180 | | |
181 | | static int fips_ems_check_passed(TLS1_PRF *ctx) |
182 | | { |
183 | | OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx); |
184 | | /* |
185 | | * Check that TLS is using EMS. |
186 | | * |
187 | | * The seed buffer is prepended with a label. |
188 | | * If EMS mode is enforced then the label "master secret" is not allowed, |
189 | | * We do the check this way since the PRF is used for other purposes, as well |
190 | | * as "extended master secret". |
191 | | */ |
192 | | int ems_approved = (ctx->seedlen < TLS_MD_MASTER_SECRET_CONST_SIZE |
193 | | || memcmp(ctx->seed, TLS_MD_MASTER_SECRET_CONST, |
194 | | TLS_MD_MASTER_SECRET_CONST_SIZE) != 0); |
195 | | |
196 | | if (!ems_approved) { |
197 | | if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE0, |
198 | | libctx, "TLS_PRF", "EMS", |
199 | | FIPS_tls_prf_ems_check)) { |
200 | | ERR_raise(ERR_LIB_PROV, PROV_R_EMS_NOT_ENABLED); |
201 | | return 0; |
202 | | } |
203 | | } |
204 | | return 1; |
205 | | } |
206 | | |
207 | | static int fips_digest_check_passed(TLS1_PRF *ctx, const EVP_MD *md) |
208 | | { |
209 | | OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx); |
210 | | /* |
211 | | * Perform digest check |
212 | | * |
213 | | * According to NIST SP 800-135r1 section 5.2, the valid hash functions are |
214 | | * specified in FIPS 180-3. ACVP also only lists the same set of hash |
215 | | * functions. |
216 | | */ |
217 | | int digest_unapproved = !EVP_MD_is_a(md, SN_sha256) |
218 | | && !EVP_MD_is_a(md, SN_sha384) |
219 | | && !EVP_MD_is_a(md, SN_sha512); |
220 | | |
221 | | if (digest_unapproved) { |
222 | | if (!OSSL_FIPS_IND_ON_UNAPPROVED(ctx, OSSL_FIPS_IND_SETTABLE1, |
223 | | libctx, "TLS_PRF", "Digest", |
224 | | FIPS_tls1_prf_digest_check)) { |
225 | | ERR_raise(ERR_LIB_PROV, PROV_R_DIGEST_NOT_ALLOWED); |
226 | | return 0; |
227 | | } |
228 | | } |
229 | | return 1; |
230 | | } |
231 | | #endif |
232 | | |
233 | | static int kdf_tls1_prf_derive(void *vctx, unsigned char *key, size_t keylen, |
234 | | const OSSL_PARAM params[]) |
235 | 0 | { |
236 | 0 | TLS1_PRF *ctx = (TLS1_PRF *)vctx; |
237 | |
|
238 | 0 | if (!ossl_prov_is_running() || !kdf_tls1_prf_set_ctx_params(ctx, params)) |
239 | 0 | return 0; |
240 | | |
241 | 0 | if (ctx->P_hash == NULL) { |
242 | 0 | ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST); |
243 | 0 | return 0; |
244 | 0 | } |
245 | 0 | if (ctx->sec == NULL) { |
246 | 0 | ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET); |
247 | 0 | return 0; |
248 | 0 | } |
249 | 0 | if (ctx->seedlen == 0) { |
250 | 0 | ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SEED); |
251 | 0 | return 0; |
252 | 0 | } |
253 | 0 | if (keylen == 0) { |
254 | 0 | ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH); |
255 | 0 | return 0; |
256 | 0 | } |
257 | | |
258 | | #ifdef FIPS_MODULE |
259 | | if (!fips_ems_check_passed(ctx)) |
260 | | return 0; |
261 | | #endif |
262 | | |
263 | 0 | return tls1_prf_alg(ctx->P_hash, ctx->P_sha1, |
264 | 0 | ctx->sec, ctx->seclen, |
265 | 0 | ctx->seed, ctx->seedlen, |
266 | 0 | key, keylen); |
267 | 0 | } |
268 | | |
269 | | static int kdf_tls1_prf_set_ctx_params(void *vctx, const OSSL_PARAM params[]) |
270 | 0 | { |
271 | 0 | const OSSL_PARAM *p; |
272 | 0 | TLS1_PRF *ctx = vctx; |
273 | 0 | OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx); |
274 | |
|
275 | 0 | if (params == NULL) |
276 | 0 | return 1; |
277 | | |
278 | 0 | if (!OSSL_FIPS_IND_SET_CTX_PARAM(ctx, OSSL_FIPS_IND_SETTABLE0, params, |
279 | 0 | OSSL_KDF_PARAM_FIPS_EMS_CHECK)) |
280 | 0 | return 0; |
281 | 0 | if (!OSSL_FIPS_IND_SET_CTX_PARAM(ctx, OSSL_FIPS_IND_SETTABLE1, params, |
282 | 0 | OSSL_KDF_PARAM_FIPS_DIGEST_CHECK)) |
283 | 0 | return 0; |
284 | | |
285 | 0 | if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_DIGEST)) != NULL) { |
286 | 0 | PROV_DIGEST digest; |
287 | 0 | const EVP_MD *md = NULL; |
288 | |
|
289 | 0 | if (OPENSSL_strcasecmp(p->data, SN_md5_sha1) == 0) { |
290 | 0 | if (!ossl_prov_macctx_load_from_params(&ctx->P_hash, params, |
291 | 0 | OSSL_MAC_NAME_HMAC, |
292 | 0 | NULL, SN_md5, libctx) |
293 | 0 | || !ossl_prov_macctx_load_from_params(&ctx->P_sha1, params, |
294 | 0 | OSSL_MAC_NAME_HMAC, |
295 | 0 | NULL, SN_sha1, libctx)) |
296 | 0 | return 0; |
297 | 0 | } else { |
298 | 0 | EVP_MAC_CTX_free(ctx->P_sha1); |
299 | 0 | if (!ossl_prov_macctx_load_from_params(&ctx->P_hash, params, |
300 | 0 | OSSL_MAC_NAME_HMAC, |
301 | 0 | NULL, NULL, libctx)) |
302 | 0 | return 0; |
303 | 0 | } |
304 | | |
305 | 0 | memset(&digest, 0, sizeof(digest)); |
306 | 0 | if (!ossl_prov_digest_load_from_params(&digest, params, libctx)) |
307 | 0 | return 0; |
308 | | |
309 | 0 | md = ossl_prov_digest_md(&digest); |
310 | 0 | if ((EVP_MD_get_flags(md) & EVP_MD_FLAG_XOF) != 0) { |
311 | 0 | ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED); |
312 | 0 | ossl_prov_digest_reset(&digest); |
313 | 0 | return 0; |
314 | 0 | } |
315 | | |
316 | | #ifdef FIPS_MODULE |
317 | | if (!fips_digest_check_passed(ctx, md)) { |
318 | | ossl_prov_digest_reset(&digest); |
319 | | return 0; |
320 | | } |
321 | | #endif |
322 | | |
323 | 0 | ossl_prov_digest_reset(&digest); |
324 | 0 | } |
325 | | |
326 | 0 | if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL) { |
327 | 0 | OPENSSL_clear_free(ctx->sec, ctx->seclen); |
328 | 0 | ctx->sec = NULL; |
329 | 0 | if (!OSSL_PARAM_get_octet_string(p, (void **)&ctx->sec, 0, &ctx->seclen)) |
330 | 0 | return 0; |
331 | 0 | } |
332 | | /* The seed fields concatenate, so process them all */ |
333 | 0 | if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SEED)) != NULL) { |
334 | 0 | for (; p != NULL; p = OSSL_PARAM_locate_const(p + 1, |
335 | 0 | OSSL_KDF_PARAM_SEED)) { |
336 | 0 | if (p->data_size != 0 && p->data != NULL) { |
337 | 0 | const void *val = NULL; |
338 | 0 | size_t sz = 0; |
339 | 0 | unsigned char *seed; |
340 | 0 | size_t seedlen; |
341 | 0 | int err = 0; |
342 | |
|
343 | 0 | if (!OSSL_PARAM_get_octet_string_ptr(p, &val, &sz)) |
344 | 0 | return 0; |
345 | | |
346 | 0 | seedlen = safe_add_size_t(ctx->seedlen, sz, &err); |
347 | 0 | if (err) |
348 | 0 | return 0; |
349 | | |
350 | 0 | seed = OPENSSL_clear_realloc(ctx->seed, ctx->seedlen, seedlen); |
351 | 0 | if (!seed) |
352 | 0 | return 0; |
353 | | |
354 | 0 | ctx->seed = seed; |
355 | 0 | if (ossl_assert(sz != 0)) |
356 | 0 | memcpy(ctx->seed + ctx->seedlen, val, sz); |
357 | 0 | ctx->seedlen = seedlen; |
358 | 0 | } |
359 | 0 | } |
360 | 0 | } |
361 | 0 | return 1; |
362 | 0 | } |
363 | | |
364 | | static const OSSL_PARAM *kdf_tls1_prf_settable_ctx_params( |
365 | | ossl_unused void *ctx, ossl_unused void *provctx) |
366 | 0 | { |
367 | 0 | static const OSSL_PARAM known_settable_ctx_params[] = { |
368 | 0 | OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0), |
369 | 0 | OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0), |
370 | 0 | OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0), |
371 | 0 | OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SEED, NULL, 0), |
372 | 0 | OSSL_FIPS_IND_SETTABLE_CTX_PARAM(OSSL_KDF_PARAM_FIPS_EMS_CHECK) |
373 | 0 | OSSL_FIPS_IND_SETTABLE_CTX_PARAM(OSSL_KDF_PARAM_FIPS_DIGEST_CHECK) |
374 | 0 | OSSL_PARAM_END |
375 | 0 | }; |
376 | 0 | return known_settable_ctx_params; |
377 | 0 | } |
378 | | |
379 | | static int kdf_tls1_prf_get_ctx_params(void *vctx, OSSL_PARAM params[]) |
380 | 0 | { |
381 | 0 | OSSL_PARAM *p; |
382 | |
|
383 | 0 | if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL) { |
384 | 0 | if (!OSSL_PARAM_set_size_t(p, SIZE_MAX)) |
385 | 0 | return 0; |
386 | 0 | } |
387 | 0 | if (!OSSL_FIPS_IND_GET_CTX_PARAM(((TLS1_PRF *)vctx), params)) |
388 | 0 | return 0; |
389 | 0 | return 1; |
390 | 0 | } |
391 | | |
392 | | static const OSSL_PARAM *kdf_tls1_prf_gettable_ctx_params( |
393 | | ossl_unused void *ctx, ossl_unused void *provctx) |
394 | 0 | { |
395 | 0 | static const OSSL_PARAM known_gettable_ctx_params[] = { |
396 | 0 | OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), |
397 | 0 | OSSL_FIPS_IND_GETTABLE_CTX_PARAM() |
398 | 0 | OSSL_PARAM_END |
399 | 0 | }; |
400 | 0 | return known_gettable_ctx_params; |
401 | 0 | } |
402 | | |
403 | | const OSSL_DISPATCH ossl_kdf_tls1_prf_functions[] = { |
404 | | { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_tls1_prf_new }, |
405 | | { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kdf_tls1_prf_dup }, |
406 | | { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_tls1_prf_free }, |
407 | | { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_tls1_prf_reset }, |
408 | | { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_tls1_prf_derive }, |
409 | | { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS, |
410 | | (void(*)(void))kdf_tls1_prf_settable_ctx_params }, |
411 | | { OSSL_FUNC_KDF_SET_CTX_PARAMS, |
412 | | (void(*)(void))kdf_tls1_prf_set_ctx_params }, |
413 | | { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS, |
414 | | (void(*)(void))kdf_tls1_prf_gettable_ctx_params }, |
415 | | { OSSL_FUNC_KDF_GET_CTX_PARAMS, |
416 | | (void(*)(void))kdf_tls1_prf_get_ctx_params }, |
417 | | OSSL_DISPATCH_END |
418 | | }; |
419 | | |
420 | | /* |
421 | | * Refer to "The TLS Protocol Version 1.0" Section 5 |
422 | | * (https://tools.ietf.org/html/rfc2246#section-5) and |
423 | | * "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5 |
424 | | * (https://tools.ietf.org/html/rfc5246#section-5). |
425 | | * |
426 | | * P_<hash> is an expansion function that uses a single hash function to expand |
427 | | * a secret and seed into an arbitrary quantity of output: |
428 | | * |
429 | | * P_<hash>(secret, seed) = HMAC_<hash>(secret, A(1) + seed) + |
430 | | * HMAC_<hash>(secret, A(2) + seed) + |
431 | | * HMAC_<hash>(secret, A(3) + seed) + ... |
432 | | * |
433 | | * where + indicates concatenation. P_<hash> can be iterated as many times as |
434 | | * is necessary to produce the required quantity of data. |
435 | | * |
436 | | * A(i) is defined as: |
437 | | * A(0) = seed |
438 | | * A(i) = HMAC_<hash>(secret, A(i-1)) |
439 | | */ |
440 | | static int tls1_prf_P_hash(EVP_MAC_CTX *ctx_init, |
441 | | const unsigned char *sec, size_t sec_len, |
442 | | const unsigned char *seed, size_t seed_len, |
443 | | unsigned char *out, size_t olen) |
444 | 0 | { |
445 | 0 | size_t chunk; |
446 | 0 | EVP_MAC_CTX *ctx = NULL, *ctx_Ai = NULL; |
447 | 0 | unsigned char Ai[EVP_MAX_MD_SIZE]; |
448 | 0 | size_t Ai_len; |
449 | 0 | int ret = 0; |
450 | |
|
451 | 0 | if (!EVP_MAC_init(ctx_init, sec, sec_len, NULL)) |
452 | 0 | goto err; |
453 | 0 | chunk = EVP_MAC_CTX_get_mac_size(ctx_init); |
454 | 0 | if (chunk == 0) |
455 | 0 | goto err; |
456 | | /* A(0) = seed */ |
457 | 0 | ctx_Ai = EVP_MAC_CTX_dup(ctx_init); |
458 | 0 | if (ctx_Ai == NULL) |
459 | 0 | goto err; |
460 | 0 | if (seed != NULL && !EVP_MAC_update(ctx_Ai, seed, seed_len)) |
461 | 0 | goto err; |
462 | | |
463 | 0 | for (;;) { |
464 | | /* calc: A(i) = HMAC_<hash>(secret, A(i-1)) */ |
465 | 0 | if (!EVP_MAC_final(ctx_Ai, Ai, &Ai_len, sizeof(Ai))) |
466 | 0 | goto err; |
467 | 0 | EVP_MAC_CTX_free(ctx_Ai); |
468 | 0 | ctx_Ai = NULL; |
469 | | |
470 | | /* calc next chunk: HMAC_<hash>(secret, A(i) + seed) */ |
471 | 0 | ctx = EVP_MAC_CTX_dup(ctx_init); |
472 | 0 | if (ctx == NULL) |
473 | 0 | goto err; |
474 | 0 | if (!EVP_MAC_update(ctx, Ai, Ai_len)) |
475 | 0 | goto err; |
476 | | /* save state for calculating next A(i) value */ |
477 | 0 | if (olen > chunk) { |
478 | 0 | ctx_Ai = EVP_MAC_CTX_dup(ctx); |
479 | 0 | if (ctx_Ai == NULL) |
480 | 0 | goto err; |
481 | 0 | } |
482 | 0 | if (seed != NULL && !EVP_MAC_update(ctx, seed, seed_len)) |
483 | 0 | goto err; |
484 | 0 | if (olen <= chunk) { |
485 | | /* last chunk - use Ai as temp bounce buffer */ |
486 | 0 | if (!EVP_MAC_final(ctx, Ai, &Ai_len, sizeof(Ai))) |
487 | 0 | goto err; |
488 | 0 | memcpy(out, Ai, olen); |
489 | 0 | break; |
490 | 0 | } |
491 | 0 | if (!EVP_MAC_final(ctx, out, NULL, olen)) |
492 | 0 | goto err; |
493 | 0 | EVP_MAC_CTX_free(ctx); |
494 | 0 | ctx = NULL; |
495 | 0 | out += chunk; |
496 | 0 | olen -= chunk; |
497 | 0 | } |
498 | 0 | ret = 1; |
499 | 0 | err: |
500 | 0 | EVP_MAC_CTX_free(ctx); |
501 | 0 | EVP_MAC_CTX_free(ctx_Ai); |
502 | 0 | OPENSSL_cleanse(Ai, sizeof(Ai)); |
503 | 0 | return ret; |
504 | 0 | } |
505 | | |
506 | | /* |
507 | | * Refer to "The TLS Protocol Version 1.0" Section 5 |
508 | | * (https://tools.ietf.org/html/rfc2246#section-5) and |
509 | | * "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5 |
510 | | * (https://tools.ietf.org/html/rfc5246#section-5). |
511 | | * |
512 | | * For TLS v1.0 and TLS v1.1: |
513 | | * |
514 | | * PRF(secret, label, seed) = P_MD5(S1, label + seed) XOR |
515 | | * P_SHA-1(S2, label + seed) |
516 | | * |
517 | | * S1 is taken from the first half of the secret, S2 from the second half. |
518 | | * |
519 | | * L_S = length in bytes of secret; |
520 | | * L_S1 = L_S2 = ceil(L_S / 2); |
521 | | * |
522 | | * For TLS v1.2: |
523 | | * |
524 | | * PRF(secret, label, seed) = P_<hash>(secret, label + seed) |
525 | | */ |
526 | | static int tls1_prf_alg(EVP_MAC_CTX *mdctx, EVP_MAC_CTX *sha1ctx, |
527 | | const unsigned char *sec, size_t slen, |
528 | | const unsigned char *seed, size_t seed_len, |
529 | | unsigned char *out, size_t olen) |
530 | 0 | { |
531 | 0 | if (sha1ctx != NULL) { |
532 | | /* TLS v1.0 and TLS v1.1 */ |
533 | 0 | size_t i; |
534 | 0 | unsigned char *tmp; |
535 | | /* calc: L_S1 = L_S2 = ceil(L_S / 2) */ |
536 | 0 | size_t L_S1 = (slen + 1) / 2; |
537 | 0 | size_t L_S2 = L_S1; |
538 | |
|
539 | 0 | if (!tls1_prf_P_hash(mdctx, sec, L_S1, |
540 | 0 | seed, seed_len, out, olen)) |
541 | 0 | return 0; |
542 | | |
543 | 0 | if ((tmp = OPENSSL_malloc(olen)) == NULL) |
544 | 0 | return 0; |
545 | | |
546 | 0 | if (!tls1_prf_P_hash(sha1ctx, sec + slen - L_S2, L_S2, |
547 | 0 | seed, seed_len, tmp, olen)) { |
548 | 0 | OPENSSL_clear_free(tmp, olen); |
549 | 0 | return 0; |
550 | 0 | } |
551 | 0 | for (i = 0; i < olen; i++) |
552 | 0 | out[i] ^= tmp[i]; |
553 | 0 | OPENSSL_clear_free(tmp, olen); |
554 | 0 | return 1; |
555 | 0 | } |
556 | | |
557 | | /* TLS v1.2 */ |
558 | 0 | if (!tls1_prf_P_hash(mdctx, sec, slen, seed, seed_len, out, olen)) |
559 | 0 | return 0; |
560 | | |
561 | 0 | return 1; |
562 | 0 | } |