2 * Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
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
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).
16 * For TLS v1.0 and TLS v1.1 the TLS PRF algorithm is given by:
18 * PRF(secret, label, seed) = P_MD5(S1, label + seed) XOR
19 * P_SHA-1(S2, label + seed)
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.
26 * For TLS v1.2 the TLS PRF algorithm is given by:
28 * PRF(secret, label, seed) = P_<hash>(secret, label + seed)
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.
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:
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) + ...
41 * where + indicates concatenation. P_<hash> can be iterated as many times as
42 * is necessary to produce the required quantity of data.
46 * A(i) = HMAC_<hash>(secret, A(i-1))
51 #include <openssl/evp.h>
52 #include <openssl/kdf.h>
53 #include <openssl/core_names.h>
54 #include <openssl/params.h>
55 #include "internal/cryptlib.h"
56 #include "internal/numbers.h"
57 #include "crypto/evp.h"
58 #include "prov/provider_ctx.h"
59 #include "prov/providercommonerr.h"
60 #include "prov/implementations.h"
61 #include "prov/provider_util.h"
64 static OSSL_FUNC_kdf_newctx_fn kdf_tls1_prf_new;
65 static OSSL_FUNC_kdf_freectx_fn kdf_tls1_prf_free;
66 static OSSL_FUNC_kdf_reset_fn kdf_tls1_prf_reset;
67 static OSSL_FUNC_kdf_derive_fn kdf_tls1_prf_derive;
68 static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_tls1_prf_settable_ctx_params;
69 static OSSL_FUNC_kdf_set_ctx_params_fn kdf_tls1_prf_set_ctx_params;
70 static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_tls1_prf_gettable_ctx_params;
71 static OSSL_FUNC_kdf_get_ctx_params_fn kdf_tls1_prf_get_ctx_params;
73 static int tls1_prf_alg(EVP_MAC_CTX *mdctx, EVP_MAC_CTX *sha1ctx,
74 const unsigned char *sec, size_t slen,
75 const unsigned char *seed, size_t seed_len,
76 unsigned char *out, size_t olen);
78 #define TLS1_PRF_MAXBUF 1024
80 /* TLS KDF kdf context structure */
84 /* MAC context for the main digest */
86 /* MAC context for SHA1 for the MD5/SHA-1 combined PRF */
89 /* Secret value to use for PRF */
92 /* Buffer of concatenated seed data */
93 unsigned char seed[TLS1_PRF_MAXBUF];
97 static void *kdf_tls1_prf_new(void *provctx)
101 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
102 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
103 ctx->provctx = provctx;
107 static void kdf_tls1_prf_free(void *vctx)
109 TLS1_PRF *ctx = (TLS1_PRF *)vctx;
112 kdf_tls1_prf_reset(ctx);
117 static void kdf_tls1_prf_reset(void *vctx)
119 TLS1_PRF *ctx = (TLS1_PRF *)vctx;
120 void *provctx = ctx->provctx;
122 EVP_MAC_CTX_free(ctx->P_hash);
123 EVP_MAC_CTX_free(ctx->P_sha1);
124 OPENSSL_clear_free(ctx->sec, ctx->seclen);
125 OPENSSL_cleanse(ctx->seed, ctx->seedlen);
126 memset(ctx, 0, sizeof(*ctx));
127 ctx->provctx = provctx;
130 static int kdf_tls1_prf_derive(void *vctx, unsigned char *key,
133 TLS1_PRF *ctx = (TLS1_PRF *)vctx;
135 if (ctx->P_hash == NULL) {
136 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
139 if (ctx->sec == NULL) {
140 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
143 if (ctx->seedlen == 0) {
144 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SEED);
148 return tls1_prf_alg(ctx->P_hash, ctx->P_sha1,
149 ctx->sec, ctx->seclen,
150 ctx->seed, ctx->seedlen,
154 static int kdf_tls1_prf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
157 TLS1_PRF *ctx = vctx;
158 OPENSSL_CTX *libctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
160 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_DIGEST)) != NULL) {
161 if (strcasecmp(p->data, SN_md5_sha1) == 0) {
162 if (!ossl_prov_macctx_load_from_params(&ctx->P_hash, params,
164 NULL, SN_md5, libctx)
165 || !ossl_prov_macctx_load_from_params(&ctx->P_sha1, params,
167 NULL, SN_sha1, libctx))
170 EVP_MAC_CTX_free(ctx->P_sha1);
171 if (!ossl_prov_macctx_load_from_params(&ctx->P_hash, params,
178 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL) {
179 OPENSSL_clear_free(ctx->sec, ctx->seclen);
181 if (!OSSL_PARAM_get_octet_string(p, (void **)&ctx->sec, 0, &ctx->seclen))
184 /* The seed fields concatenate, so process them all */
185 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SEED)) != NULL) {
186 for (; p != NULL; p = OSSL_PARAM_locate_const(p + 1,
187 OSSL_KDF_PARAM_SEED)) {
188 const void *q = ctx->seed + ctx->seedlen;
191 if (p->data_size != 0
193 && !OSSL_PARAM_get_octet_string(p, (void **)&q,
194 TLS1_PRF_MAXBUF - ctx->seedlen,
203 static const OSSL_PARAM *kdf_tls1_prf_settable_ctx_params(void *provctx)
205 static const OSSL_PARAM known_settable_ctx_params[] = {
206 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
207 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
208 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
209 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SEED, NULL, 0),
212 return known_settable_ctx_params;
215 static int kdf_tls1_prf_get_ctx_params(void *vctx, OSSL_PARAM params[])
219 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
220 return OSSL_PARAM_set_size_t(p, SIZE_MAX);
224 static const OSSL_PARAM *kdf_tls1_prf_gettable_ctx_params(void *provctx)
226 static const OSSL_PARAM known_gettable_ctx_params[] = {
227 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
230 return known_gettable_ctx_params;
233 const OSSL_DISPATCH kdf_tls1_prf_functions[] = {
234 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_tls1_prf_new },
235 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_tls1_prf_free },
236 { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_tls1_prf_reset },
237 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_tls1_prf_derive },
238 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
239 (void(*)(void))kdf_tls1_prf_settable_ctx_params },
240 { OSSL_FUNC_KDF_SET_CTX_PARAMS,
241 (void(*)(void))kdf_tls1_prf_set_ctx_params },
242 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
243 (void(*)(void))kdf_tls1_prf_gettable_ctx_params },
244 { OSSL_FUNC_KDF_GET_CTX_PARAMS,
245 (void(*)(void))kdf_tls1_prf_get_ctx_params },
250 * Refer to "The TLS Protocol Version 1.0" Section 5
251 * (https://tools.ietf.org/html/rfc2246#section-5) and
252 * "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5
253 * (https://tools.ietf.org/html/rfc5246#section-5).
255 * P_<hash> is an expansion function that uses a single hash function to expand
256 * a secret and seed into an arbitrary quantity of output:
258 * P_<hash>(secret, seed) = HMAC_<hash>(secret, A(1) + seed) +
259 * HMAC_<hash>(secret, A(2) + seed) +
260 * HMAC_<hash>(secret, A(3) + seed) + ...
262 * where + indicates concatenation. P_<hash> can be iterated as many times as
263 * is necessary to produce the required quantity of data.
265 * A(i) is defined as:
267 * A(i) = HMAC_<hash>(secret, A(i-1))
269 static int tls1_prf_P_hash(EVP_MAC_CTX *ctx_init,
270 const unsigned char *sec, size_t sec_len,
271 const unsigned char *seed, size_t seed_len,
272 unsigned char *out, size_t olen)
275 EVP_MAC_CTX *ctx = NULL, *ctx_Ai = NULL;
276 unsigned char Ai[EVP_MAX_MD_SIZE];
279 OSSL_PARAM params[2], *p = params;
281 *p++ = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
282 (void *)sec, sec_len);
283 *p = OSSL_PARAM_construct_end();
284 if (!EVP_MAC_CTX_set_params(ctx_init, params))
286 if (!EVP_MAC_init(ctx_init))
288 chunk = EVP_MAC_size(ctx_init);
292 ctx_Ai = EVP_MAC_CTX_dup(ctx_init);
295 if (seed != NULL && !EVP_MAC_update(ctx_Ai, seed, seed_len))
299 /* calc: A(i) = HMAC_<hash>(secret, A(i-1)) */
300 if (!EVP_MAC_final(ctx_Ai, Ai, &Ai_len, sizeof(Ai)))
302 EVP_MAC_CTX_free(ctx_Ai);
305 /* calc next chunk: HMAC_<hash>(secret, A(i) + seed) */
306 ctx = EVP_MAC_CTX_dup(ctx_init);
309 if (!EVP_MAC_update(ctx, Ai, Ai_len))
311 /* save state for calculating next A(i) value */
313 ctx_Ai = EVP_MAC_CTX_dup(ctx);
317 if (seed != NULL && !EVP_MAC_update(ctx, seed, seed_len))
320 /* last chunk - use Ai as temp bounce buffer */
321 if (!EVP_MAC_final(ctx, Ai, &Ai_len, sizeof(Ai)))
323 memcpy(out, Ai, olen);
326 if (!EVP_MAC_final(ctx, out, NULL, olen))
328 EVP_MAC_CTX_free(ctx);
335 EVP_MAC_CTX_free(ctx);
336 EVP_MAC_CTX_free(ctx_Ai);
337 OPENSSL_cleanse(Ai, sizeof(Ai));
342 * Refer to "The TLS Protocol Version 1.0" Section 5
343 * (https://tools.ietf.org/html/rfc2246#section-5) and
344 * "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5
345 * (https://tools.ietf.org/html/rfc5246#section-5).
347 * For TLS v1.0 and TLS v1.1:
349 * PRF(secret, label, seed) = P_MD5(S1, label + seed) XOR
350 * P_SHA-1(S2, label + seed)
352 * S1 is taken from the first half of the secret, S2 from the second half.
354 * L_S = length in bytes of secret;
355 * L_S1 = L_S2 = ceil(L_S / 2);
359 * PRF(secret, label, seed) = P_<hash>(secret, label + seed)
361 static int tls1_prf_alg(EVP_MAC_CTX *mdctx, EVP_MAC_CTX *sha1ctx,
362 const unsigned char *sec, size_t slen,
363 const unsigned char *seed, size_t seed_len,
364 unsigned char *out, size_t olen)
366 if (sha1ctx != NULL) {
367 /* TLS v1.0 and TLS v1.1 */
370 /* calc: L_S1 = L_S2 = ceil(L_S / 2) */
371 size_t L_S1 = (slen + 1) / 2;
374 if (!tls1_prf_P_hash(mdctx, sec, L_S1,
375 seed, seed_len, out, olen))
378 if ((tmp = OPENSSL_malloc(olen)) == NULL) {
379 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
383 if (!tls1_prf_P_hash(sha1ctx, sec + slen - L_S2, L_S2,
384 seed, seed_len, tmp, olen)) {
385 OPENSSL_clear_free(tmp, olen);
388 for (i = 0; i < olen; i++)
390 OPENSSL_clear_free(tmp, olen);
395 if (!tls1_prf_P_hash(mdctx, sec, slen, seed, seed_len, out, olen))