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
))