2 * Copyright 2016-2019 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 "internal/evp_int.h"
58 #include "internal/provider_ctx.h"
59 #include "internal/providercommonerr.h"
60 #include "internal/provider_algs.h"
63 static OSSL_OP_kdf_newctx_fn kdf_tls1_prf_new;
64 static OSSL_OP_kdf_freectx_fn kdf_tls1_prf_free;
65 static OSSL_OP_kdf_reset_fn kdf_tls1_prf_reset;
66 static OSSL_OP_kdf_derive_fn kdf_tls1_prf_derive;
67 static OSSL_OP_kdf_settable_ctx_params_fn kdf_tls1_prf_settable_ctx_params;
68 static OSSL_OP_kdf_set_ctx_params_fn kdf_tls1_prf_set_ctx_params;
70 static int tls1_prf_alg(const EVP_MD *md, const EVP_MD *sha1,
71 const unsigned char *sec, size_t slen,
72 const unsigned char *seed, size_t seed_len,
73 unsigned char *out, size_t olen);
75 #define TLS1_PRF_MAXBUF 1024
77 /* TLS KDF kdf context structure */
80 /* Digest to use for PRF */
82 /* Second digest for the MD5/SHA-1 combined PRF */
84 /* Secret value to use for PRF */
87 /* Buffer of concatenated seed data */
88 unsigned char seed[TLS1_PRF_MAXBUF];
92 static void *kdf_tls1_prf_new(void *provctx)
96 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
97 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
98 ctx->provctx = provctx;
102 static void kdf_tls1_prf_free(void *vctx)
104 TLS1_PRF *ctx = (TLS1_PRF *)vctx;
106 kdf_tls1_prf_reset(ctx);
107 EVP_MD_meth_free(ctx->sha1);
108 EVP_MD_meth_free(ctx->md);
112 static void kdf_tls1_prf_reset(void *vctx)
114 TLS1_PRF *ctx = (TLS1_PRF *)vctx;
116 OPENSSL_clear_free(ctx->sec, ctx->seclen);
117 OPENSSL_cleanse(ctx->seed, ctx->seedlen);
118 memset(ctx, 0, sizeof(*ctx));
121 static int kdf_tls1_prf_derive(void *vctx, unsigned char *key,
124 TLS1_PRF *ctx = (TLS1_PRF *)vctx;
126 if (ctx->md == NULL) {
127 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
130 if (ctx->sec == NULL) {
131 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
134 if (ctx->seedlen == 0) {
135 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SEED);
138 return tls1_prf_alg(ctx->md, ctx->sha1, ctx->sec, ctx->seclen,
139 ctx->seed, ctx->seedlen,
143 static int kdf_tls1_prf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
146 TLS1_PRF *ctx = vctx;
147 EVP_MD *md, *sha = NULL;
148 const char *properties = NULL, *name;
150 /* Grab search properties, this should be before the digest lookup */
151 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PROPERTIES))
153 if (p->data_type != OSSL_PARAM_UTF8_STRING)
155 properties = p->data;
157 /* Handle aliasing of digest parameter names */
158 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_DIGEST)) != NULL) {
159 if (p->data_type != OSSL_PARAM_UTF8_STRING)
162 if (strcasecmp(name, SN_md5_sha1) == 0) {
163 sha = EVP_MD_fetch(PROV_LIBRARY_CONTEXT_OF(ctx->provctx), SN_sha1,
166 ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOAD_SHA1);
171 md = EVP_MD_fetch(PROV_LIBRARY_CONTEXT_OF(ctx->provctx), name,
174 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST);
175 EVP_MD_meth_free(sha);
178 EVP_MD_meth_free(ctx->sha1);
179 EVP_MD_meth_free(ctx->md);
184 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL) {
185 OPENSSL_clear_free(ctx->sec, ctx->seclen);
187 if (!OSSL_PARAM_get_octet_string(p, (void **)&ctx->sec, 0, &ctx->seclen))
190 /* The seed fields concatenate, so process them all */
191 if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SEED)) != NULL) {
192 OPENSSL_cleanse(ctx->seed, ctx->seedlen);
195 for (; p != NULL; p = OSSL_PARAM_locate_const(p + 1,
196 OSSL_KDF_PARAM_SEED)) {
197 const void *q = ctx->seed + ctx->seedlen;
200 if (p->data_size != 0
202 && !OSSL_PARAM_get_octet_string(p, (void **)&q,
203 TLS1_PRF_MAXBUF - ctx->seedlen,
212 static const OSSL_PARAM *kdf_tls1_prf_settable_ctx_params(void)
214 static const OSSL_PARAM known_settable_ctx_params[] = {
215 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
216 OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
217 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
218 OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SEED, NULL, 0),
221 return known_settable_ctx_params;
224 static int kdf_tls1_prf_get_ctx_params(void *vctx, OSSL_PARAM params[])
228 if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
229 return OSSL_PARAM_set_size_t(p, SIZE_MAX);
233 static const OSSL_PARAM *kdf_tls1_prf_gettable_ctx_params(void)
235 static const OSSL_PARAM known_gettable_ctx_params[] = {
236 OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
239 return known_gettable_ctx_params;
242 const OSSL_DISPATCH kdf_tls1_prf_functions[] = {
243 { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_tls1_prf_new },
244 { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_tls1_prf_free },
245 { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_tls1_prf_reset },
246 { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_tls1_prf_derive },
247 { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
248 (void(*)(void))kdf_tls1_prf_settable_ctx_params },
249 { OSSL_FUNC_KDF_SET_CTX_PARAMS,
250 (void(*)(void))kdf_tls1_prf_set_ctx_params },
251 { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
252 (void(*)(void))kdf_tls1_prf_gettable_ctx_params },
253 { OSSL_FUNC_KDF_GET_CTX_PARAMS,
254 (void(*)(void))kdf_tls1_prf_get_ctx_params },
259 * Refer to "The TLS Protocol Version 1.0" Section 5
260 * (https://tools.ietf.org/html/rfc2246#section-5) and
261 * "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5
262 * (https://tools.ietf.org/html/rfc5246#section-5).
264 * P_<hash> is an expansion function that uses a single hash function to expand
265 * a secret and seed into an arbitrary quantity of output:
267 * P_<hash>(secret, seed) = HMAC_<hash>(secret, A(1) + seed) +
268 * HMAC_<hash>(secret, A(2) + seed) +
269 * HMAC_<hash>(secret, A(3) + seed) + ...
271 * where + indicates concatenation. P_<hash> can be iterated as many times as
272 * is necessary to produce the required quantity of data.
274 * A(i) is defined as:
276 * A(i) = HMAC_<hash>(secret, A(i-1))
278 static int tls1_prf_P_hash(const EVP_MD *md,
279 const unsigned char *sec, size_t sec_len,
280 const unsigned char *seed, size_t seed_len,
281 unsigned char *out, size_t olen)
285 EVP_MAC_CTX *ctx = NULL, *ctx_Ai = NULL, *ctx_init = NULL;
286 unsigned char Ai[EVP_MAX_MD_SIZE];
289 OSSL_PARAM params[4];
291 const char *mdname = EVP_MD_name(md);
293 mac = EVP_MAC_fetch(NULL, OSSL_MAC_NAME_HMAC, NULL); /* Implicit fetch */
294 ctx_init = EVP_MAC_CTX_new(mac);
295 if (ctx_init == NULL)
298 /* TODO(3.0) rethink "flags", also see hmac.c in providers */
299 mac_flags = EVP_MD_CTX_FLAG_NON_FIPS_ALLOW;
300 params[0] = OSSL_PARAM_construct_int(OSSL_MAC_PARAM_FLAGS, &mac_flags);
301 params[1] = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST,
303 params[2] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
304 (void *)sec, sec_len);
305 params[3] = OSSL_PARAM_construct_end();
306 if (!EVP_MAC_CTX_set_params(ctx_init, params))
308 if (!EVP_MAC_init(ctx_init))
310 chunk = EVP_MAC_size(ctx_init);
314 ctx_Ai = EVP_MAC_CTX_dup(ctx_init);
317 if (seed != NULL && !EVP_MAC_update(ctx_Ai, seed, seed_len))
321 /* calc: A(i) = HMAC_<hash>(secret, A(i-1)) */
322 if (!EVP_MAC_final(ctx_Ai, Ai, &Ai_len, sizeof(Ai)))
324 EVP_MAC_CTX_free(ctx_Ai);
327 /* calc next chunk: HMAC_<hash>(secret, A(i) + seed) */
328 ctx = EVP_MAC_CTX_dup(ctx_init);
331 if (!EVP_MAC_update(ctx, Ai, Ai_len))
333 /* save state for calculating next A(i) value */
335 ctx_Ai = EVP_MAC_CTX_dup(ctx);
339 if (seed != NULL && !EVP_MAC_update(ctx, seed, seed_len))
342 /* last chunk - use Ai as temp bounce buffer */
343 if (!EVP_MAC_final(ctx, Ai, &Ai_len, sizeof(Ai)))
345 memcpy(out, Ai, olen);
348 if (!EVP_MAC_final(ctx, out, NULL, olen))
350 EVP_MAC_CTX_free(ctx);
357 EVP_MAC_CTX_free(ctx);
358 EVP_MAC_CTX_free(ctx_Ai);
359 EVP_MAC_CTX_free(ctx_init);
361 OPENSSL_cleanse(Ai, sizeof(Ai));
366 * Refer to "The TLS Protocol Version 1.0" Section 5
367 * (https://tools.ietf.org/html/rfc2246#section-5) and
368 * "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5
369 * (https://tools.ietf.org/html/rfc5246#section-5).
371 * For TLS v1.0 and TLS v1.1:
373 * PRF(secret, label, seed) = P_MD5(S1, label + seed) XOR
374 * P_SHA-1(S2, label + seed)
376 * S1 is taken from the first half of the secret, S2 from the second half.
378 * L_S = length in bytes of secret;
379 * L_S1 = L_S2 = ceil(L_S / 2);
383 * PRF(secret, label, seed) = P_<hash>(secret, label + seed)
385 static int tls1_prf_alg(const EVP_MD *md, const EVP_MD *sha1,
386 const unsigned char *sec, size_t slen,
387 const unsigned char *seed, size_t seed_len,
388 unsigned char *out, size_t olen)
391 /* TLS v1.0 and TLS v1.1 */
394 /* calc: L_S1 = L_S2 = ceil(L_S / 2) */
395 size_t L_S1 = (slen + 1) / 2;
398 if (!tls1_prf_P_hash(md, sec, L_S1,
399 seed, seed_len, out, olen))
402 if ((tmp = OPENSSL_malloc(olen)) == NULL) {
403 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
406 if (!tls1_prf_P_hash(sha1, sec + slen - L_S2, L_S2,
407 seed, seed_len, tmp, olen)) {
408 OPENSSL_clear_free(tmp, olen);
411 for (i = 0; i < olen; i++)
413 OPENSSL_clear_free(tmp, olen);
418 if (!tls1_prf_P_hash(md, sec, slen, seed, seed_len, out, olen))