460 lines
15 KiB
C
460 lines
15 KiB
C
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/*
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* Copyright 2016-2023 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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/*
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* Refer to "The TLS Protocol Version 1.0" Section 5
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* (https://tools.ietf.org/html/rfc2246#section-5) and
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* "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5
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* (https://tools.ietf.org/html/rfc5246#section-5).
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*
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* For TLS v1.0 and TLS v1.1 the TLS PRF algorithm is given by:
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*
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* PRF(secret, label, seed) = P_MD5(S1, label + seed) XOR
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* P_SHA-1(S2, label + seed)
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*
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* where P_MD5 and P_SHA-1 are defined by P_<hash>, below, and S1 and S2 are
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* two halves of the secret (with the possibility of one shared byte, in the
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* case where the length of the original secret is odd). S1 is taken from the
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* first half of the secret, S2 from the second half.
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*
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* For TLS v1.2 the TLS PRF algorithm is given by:
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*
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* PRF(secret, label, seed) = P_<hash>(secret, label + seed)
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*
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* where hash is SHA-256 for all cipher suites defined in RFC 5246 as well as
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* those published prior to TLS v1.2 while the TLS v1.2 protocol is in effect,
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* unless defined otherwise by the cipher suite.
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*
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* P_<hash> is an expansion function that uses a single hash function to expand
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* a secret and seed into an arbitrary quantity of output:
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*
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* P_<hash>(secret, seed) = HMAC_<hash>(secret, A(1) + seed) +
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* HMAC_<hash>(secret, A(2) + seed) +
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* HMAC_<hash>(secret, A(3) + seed) + ...
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*
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* where + indicates concatenation. P_<hash> can be iterated as many times as
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* is necessary to produce the required quantity of data.
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*
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* A(i) is defined as:
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* A(0) = seed
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* A(i) = HMAC_<hash>(secret, A(i-1))
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*/
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/*
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* Low level APIs (such as DH) are deprecated for public use, but still ok for
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* internal use.
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*/
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#include "internal/deprecated.h"
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#include <stdio.h>
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#include <stdarg.h>
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#include <string.h>
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#include <openssl/evp.h>
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#include <openssl/kdf.h>
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#include <openssl/core_names.h>
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#include <openssl/params.h>
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#include <openssl/proverr.h>
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#include "internal/cryptlib.h"
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#include "internal/numbers.h"
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#include "crypto/evp.h"
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#include "prov/provider_ctx.h"
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#include "prov/providercommon.h"
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#include "prov/implementations.h"
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#include "prov/provider_util.h"
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#include "prov/securitycheck.h"
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#include "internal/e_os.h"
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static OSSL_FUNC_kdf_newctx_fn kdf_tls1_prf_new;
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static OSSL_FUNC_kdf_dupctx_fn kdf_tls1_prf_dup;
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static OSSL_FUNC_kdf_freectx_fn kdf_tls1_prf_free;
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static OSSL_FUNC_kdf_reset_fn kdf_tls1_prf_reset;
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static OSSL_FUNC_kdf_derive_fn kdf_tls1_prf_derive;
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static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_tls1_prf_settable_ctx_params;
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static OSSL_FUNC_kdf_set_ctx_params_fn kdf_tls1_prf_set_ctx_params;
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static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_tls1_prf_gettable_ctx_params;
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static OSSL_FUNC_kdf_get_ctx_params_fn kdf_tls1_prf_get_ctx_params;
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static int tls1_prf_alg(EVP_MAC_CTX *mdctx, EVP_MAC_CTX *sha1ctx,
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const unsigned char *sec, size_t slen,
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const unsigned char *seed, size_t seed_len,
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unsigned char *out, size_t olen);
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#define TLS1_PRF_MAXBUF 1024
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#define TLS_MD_MASTER_SECRET_CONST "\x6d\x61\x73\x74\x65\x72\x20\x73\x65\x63\x72\x65\x74"
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#define TLS_MD_MASTER_SECRET_CONST_SIZE 13
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/* TLS KDF kdf context structure */
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typedef struct {
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void *provctx;
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/* MAC context for the main digest */
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EVP_MAC_CTX *P_hash;
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/* MAC context for SHA1 for the MD5/SHA-1 combined PRF */
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EVP_MAC_CTX *P_sha1;
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/* Secret value to use for PRF */
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unsigned char *sec;
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size_t seclen;
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/* Buffer of concatenated seed data */
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unsigned char seed[TLS1_PRF_MAXBUF];
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size_t seedlen;
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} TLS1_PRF;
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static void *kdf_tls1_prf_new(void *provctx)
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{
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TLS1_PRF *ctx;
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if (!ossl_prov_is_running())
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return NULL;
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if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) != NULL)
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ctx->provctx = provctx;
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return ctx;
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}
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static void kdf_tls1_prf_free(void *vctx)
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{
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TLS1_PRF *ctx = (TLS1_PRF *)vctx;
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if (ctx != NULL) {
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kdf_tls1_prf_reset(ctx);
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OPENSSL_free(ctx);
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}
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}
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static void kdf_tls1_prf_reset(void *vctx)
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{
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TLS1_PRF *ctx = (TLS1_PRF *)vctx;
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void *provctx = ctx->provctx;
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EVP_MAC_CTX_free(ctx->P_hash);
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EVP_MAC_CTX_free(ctx->P_sha1);
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OPENSSL_clear_free(ctx->sec, ctx->seclen);
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OPENSSL_cleanse(ctx->seed, ctx->seedlen);
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memset(ctx, 0, sizeof(*ctx));
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ctx->provctx = provctx;
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}
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static void *kdf_tls1_prf_dup(void *vctx)
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{
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const TLS1_PRF *src = (const TLS1_PRF *)vctx;
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TLS1_PRF *dest;
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dest = kdf_tls1_prf_new(src->provctx);
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if (dest != NULL) {
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if (src->P_hash != NULL
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&& (dest->P_hash = EVP_MAC_CTX_dup(src->P_hash)) == NULL)
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goto err;
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if (src->P_sha1 != NULL
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&& (dest->P_sha1 = EVP_MAC_CTX_dup(src->P_sha1)) == NULL)
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goto err;
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if (!ossl_prov_memdup(src->sec, src->seclen, &dest->sec, &dest->seclen))
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goto err;
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memcpy(dest->seed, src->seed, src->seedlen);
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dest->seedlen = src->seedlen;
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}
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return dest;
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err:
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kdf_tls1_prf_free(dest);
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return NULL;
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}
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static int kdf_tls1_prf_derive(void *vctx, unsigned char *key, size_t keylen,
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const OSSL_PARAM params[])
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{
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TLS1_PRF *ctx = (TLS1_PRF *)vctx;
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OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
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if (!ossl_prov_is_running() || !kdf_tls1_prf_set_ctx_params(ctx, params))
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return 0;
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if (ctx->P_hash == NULL) {
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ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
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return 0;
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}
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if (ctx->sec == NULL) {
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ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
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return 0;
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}
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if (ctx->seedlen == 0) {
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ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SEED);
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return 0;
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}
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if (keylen == 0) {
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ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
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return 0;
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}
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/*
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* The seed buffer is prepended with a label.
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* If EMS mode is enforced then the label "master secret" is not allowed,
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* We do the check this way since the PRF is used for other purposes, as well
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* as "extended master secret".
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*/
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if (ossl_tls1_prf_ems_check_enabled(libctx)) {
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if (ctx->seedlen >= TLS_MD_MASTER_SECRET_CONST_SIZE
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&& memcmp(ctx->seed, TLS_MD_MASTER_SECRET_CONST,
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TLS_MD_MASTER_SECRET_CONST_SIZE) == 0) {
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ERR_raise(ERR_LIB_PROV, PROV_R_EMS_NOT_ENABLED);
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return 0;
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}
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}
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return tls1_prf_alg(ctx->P_hash, ctx->P_sha1,
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ctx->sec, ctx->seclen,
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ctx->seed, ctx->seedlen,
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key, keylen);
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}
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static int kdf_tls1_prf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
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{
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const OSSL_PARAM *p;
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TLS1_PRF *ctx = vctx;
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OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
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if (params == NULL)
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return 1;
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if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_DIGEST)) != NULL) {
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if (OPENSSL_strcasecmp(p->data, SN_md5_sha1) == 0) {
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if (!ossl_prov_macctx_load_from_params(&ctx->P_hash, params,
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OSSL_MAC_NAME_HMAC,
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NULL, SN_md5, libctx)
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|| !ossl_prov_macctx_load_from_params(&ctx->P_sha1, params,
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OSSL_MAC_NAME_HMAC,
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NULL, SN_sha1, libctx))
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return 0;
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} else {
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EVP_MAC_CTX_free(ctx->P_sha1);
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if (!ossl_prov_macctx_load_from_params(&ctx->P_hash, params,
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OSSL_MAC_NAME_HMAC,
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NULL, NULL, libctx))
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return 0;
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}
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}
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if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL) {
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OPENSSL_clear_free(ctx->sec, ctx->seclen);
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ctx->sec = NULL;
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if (!OSSL_PARAM_get_octet_string(p, (void **)&ctx->sec, 0, &ctx->seclen))
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return 0;
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}
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/* The seed fields concatenate, so process them all */
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if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SEED)) != NULL) {
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for (; p != NULL; p = OSSL_PARAM_locate_const(p + 1,
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OSSL_KDF_PARAM_SEED)) {
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const void *q = ctx->seed + ctx->seedlen;
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size_t sz = 0;
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if (p->data_size != 0
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&& p->data != NULL
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&& !OSSL_PARAM_get_octet_string(p, (void **)&q,
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TLS1_PRF_MAXBUF - ctx->seedlen,
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&sz))
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return 0;
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ctx->seedlen += sz;
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}
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}
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return 1;
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}
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static const OSSL_PARAM *kdf_tls1_prf_settable_ctx_params(
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ossl_unused void *ctx, ossl_unused void *provctx)
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{
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static const OSSL_PARAM known_settable_ctx_params[] = {
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OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
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OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
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OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
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OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SEED, NULL, 0),
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OSSL_PARAM_END
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};
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return known_settable_ctx_params;
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}
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static int kdf_tls1_prf_get_ctx_params(void *vctx, OSSL_PARAM params[])
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{
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OSSL_PARAM *p;
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if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
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return OSSL_PARAM_set_size_t(p, SIZE_MAX);
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return -2;
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}
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static const OSSL_PARAM *kdf_tls1_prf_gettable_ctx_params(
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ossl_unused void *ctx, ossl_unused void *provctx)
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{
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static const OSSL_PARAM known_gettable_ctx_params[] = {
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OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
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OSSL_PARAM_END
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};
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return known_gettable_ctx_params;
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}
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const OSSL_DISPATCH ossl_kdf_tls1_prf_functions[] = {
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{ OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_tls1_prf_new },
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{ OSSL_FUNC_KDF_DUPCTX, (void(*)(void))kdf_tls1_prf_dup },
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{ OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_tls1_prf_free },
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{ OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_tls1_prf_reset },
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{ OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_tls1_prf_derive },
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{ OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
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(void(*)(void))kdf_tls1_prf_settable_ctx_params },
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{ OSSL_FUNC_KDF_SET_CTX_PARAMS,
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(void(*)(void))kdf_tls1_prf_set_ctx_params },
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{ OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
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(void(*)(void))kdf_tls1_prf_gettable_ctx_params },
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{ OSSL_FUNC_KDF_GET_CTX_PARAMS,
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(void(*)(void))kdf_tls1_prf_get_ctx_params },
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OSSL_DISPATCH_END
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};
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/*
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* Refer to "The TLS Protocol Version 1.0" Section 5
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* (https://tools.ietf.org/html/rfc2246#section-5) and
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* "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5
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* (https://tools.ietf.org/html/rfc5246#section-5).
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*
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* P_<hash> is an expansion function that uses a single hash function to expand
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* a secret and seed into an arbitrary quantity of output:
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*
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* P_<hash>(secret, seed) = HMAC_<hash>(secret, A(1) + seed) +
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* HMAC_<hash>(secret, A(2) + seed) +
|
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|
|
* HMAC_<hash>(secret, A(3) + seed) + ...
|
||
|
|
*
|
||
|
|
* where + indicates concatenation. P_<hash> can be iterated as many times as
|
||
|
|
* is necessary to produce the required quantity of data.
|
||
|
|
*
|
||
|
|
* A(i) is defined as:
|
||
|
|
* A(0) = seed
|
||
|
|
* A(i) = HMAC_<hash>(secret, A(i-1))
|
||
|
|
*/
|
||
|
|
static int tls1_prf_P_hash(EVP_MAC_CTX *ctx_init,
|
||
|
|
const unsigned char *sec, size_t sec_len,
|
||
|
|
const unsigned char *seed, size_t seed_len,
|
||
|
|
unsigned char *out, size_t olen)
|
||
|
|
{
|
||
|
|
size_t chunk;
|
||
|
|
EVP_MAC_CTX *ctx = NULL, *ctx_Ai = NULL;
|
||
|
|
unsigned char Ai[EVP_MAX_MD_SIZE];
|
||
|
|
size_t Ai_len;
|
||
|
|
int ret = 0;
|
||
|
|
|
||
|
|
if (!EVP_MAC_init(ctx_init, sec, sec_len, NULL))
|
||
|
|
goto err;
|
||
|
|
chunk = EVP_MAC_CTX_get_mac_size(ctx_init);
|
||
|
|
if (chunk == 0)
|
||
|
|
goto err;
|
||
|
|
/* A(0) = seed */
|
||
|
|
ctx_Ai = EVP_MAC_CTX_dup(ctx_init);
|
||
|
|
if (ctx_Ai == NULL)
|
||
|
|
goto err;
|
||
|
|
if (seed != NULL && !EVP_MAC_update(ctx_Ai, seed, seed_len))
|
||
|
|
goto err;
|
||
|
|
|
||
|
|
for (;;) {
|
||
|
|
/* calc: A(i) = HMAC_<hash>(secret, A(i-1)) */
|
||
|
|
if (!EVP_MAC_final(ctx_Ai, Ai, &Ai_len, sizeof(Ai)))
|
||
|
|
goto err;
|
||
|
|
EVP_MAC_CTX_free(ctx_Ai);
|
||
|
|
ctx_Ai = NULL;
|
||
|
|
|
||
|
|
/* calc next chunk: HMAC_<hash>(secret, A(i) + seed) */
|
||
|
|
ctx = EVP_MAC_CTX_dup(ctx_init);
|
||
|
|
if (ctx == NULL)
|
||
|
|
goto err;
|
||
|
|
if (!EVP_MAC_update(ctx, Ai, Ai_len))
|
||
|
|
goto err;
|
||
|
|
/* save state for calculating next A(i) value */
|
||
|
|
if (olen > chunk) {
|
||
|
|
ctx_Ai = EVP_MAC_CTX_dup(ctx);
|
||
|
|
if (ctx_Ai == NULL)
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
if (seed != NULL && !EVP_MAC_update(ctx, seed, seed_len))
|
||
|
|
goto err;
|
||
|
|
if (olen <= chunk) {
|
||
|
|
/* last chunk - use Ai as temp bounce buffer */
|
||
|
|
if (!EVP_MAC_final(ctx, Ai, &Ai_len, sizeof(Ai)))
|
||
|
|
goto err;
|
||
|
|
memcpy(out, Ai, olen);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
if (!EVP_MAC_final(ctx, out, NULL, olen))
|
||
|
|
goto err;
|
||
|
|
EVP_MAC_CTX_free(ctx);
|
||
|
|
ctx = NULL;
|
||
|
|
out += chunk;
|
||
|
|
olen -= chunk;
|
||
|
|
}
|
||
|
|
ret = 1;
|
||
|
|
err:
|
||
|
|
EVP_MAC_CTX_free(ctx);
|
||
|
|
EVP_MAC_CTX_free(ctx_Ai);
|
||
|
|
OPENSSL_cleanse(Ai, sizeof(Ai));
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Refer to "The TLS Protocol Version 1.0" Section 5
|
||
|
|
* (https://tools.ietf.org/html/rfc2246#section-5) and
|
||
|
|
* "The Transport Layer Security (TLS) Protocol Version 1.2" Section 5
|
||
|
|
* (https://tools.ietf.org/html/rfc5246#section-5).
|
||
|
|
*
|
||
|
|
* For TLS v1.0 and TLS v1.1:
|
||
|
|
*
|
||
|
|
* PRF(secret, label, seed) = P_MD5(S1, label + seed) XOR
|
||
|
|
* P_SHA-1(S2, label + seed)
|
||
|
|
*
|
||
|
|
* S1 is taken from the first half of the secret, S2 from the second half.
|
||
|
|
*
|
||
|
|
* L_S = length in bytes of secret;
|
||
|
|
* L_S1 = L_S2 = ceil(L_S / 2);
|
||
|
|
*
|
||
|
|
* For TLS v1.2:
|
||
|
|
*
|
||
|
|
* PRF(secret, label, seed) = P_<hash>(secret, label + seed)
|
||
|
|
*/
|
||
|
|
static int tls1_prf_alg(EVP_MAC_CTX *mdctx, EVP_MAC_CTX *sha1ctx,
|
||
|
|
const unsigned char *sec, size_t slen,
|
||
|
|
const unsigned char *seed, size_t seed_len,
|
||
|
|
unsigned char *out, size_t olen)
|
||
|
|
{
|
||
|
|
if (sha1ctx != NULL) {
|
||
|
|
/* TLS v1.0 and TLS v1.1 */
|
||
|
|
size_t i;
|
||
|
|
unsigned char *tmp;
|
||
|
|
/* calc: L_S1 = L_S2 = ceil(L_S / 2) */
|
||
|
|
size_t L_S1 = (slen + 1) / 2;
|
||
|
|
size_t L_S2 = L_S1;
|
||
|
|
|
||
|
|
if (!tls1_prf_P_hash(mdctx, sec, L_S1,
|
||
|
|
seed, seed_len, out, olen))
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
if ((tmp = OPENSSL_malloc(olen)) == NULL)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
if (!tls1_prf_P_hash(sha1ctx, sec + slen - L_S2, L_S2,
|
||
|
|
seed, seed_len, tmp, olen)) {
|
||
|
|
OPENSSL_clear_free(tmp, olen);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
for (i = 0; i < olen; i++)
|
||
|
|
out[i] ^= tmp[i];
|
||
|
|
OPENSSL_clear_free(tmp, olen);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* TLS v1.2 */
|
||
|
|
if (!tls1_prf_P_hash(mdctx, sec, slen, seed, seed_len, out, olen))
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
return 1;
|
||
|
|
}
|