* https://www.openssl.org/source/license.html
*/
+/*
+ * 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 the TLS PRF algorithm is given by:
+ *
+ * PRF(secret, label, seed) = P_MD5(S1, label + seed) XOR
+ * P_SHA-1(S2, label + seed)
+ *
+ * where P_MD5 and P_SHA-1 are defined by P_<hash>, below, and S1 and S2 are
+ * two halves of the secret (with the possibility of one shared byte, in the
+ * case where the length of the original secret is odd). S1 is taken from the
+ * first half of the secret, S2 from the second half.
+ *
+ * For TLS v1.2 the TLS PRF algorithm is given by:
+ *
+ * PRF(secret, label, seed) = P_<hash>(secret, label + seed)
+ *
+ * where hash is SHA-256 for all cipher suites defined in RFC 5246 as well as
+ * those published prior to TLS v1.2 while the TLS v1.2 protocol is in effect,
+ * unless defined otherwise by the cipher suite.
+ *
+ * P_<hash> is an expansion function that uses a single hash function to expand
+ * a secret and seed into an arbitrary quantity of output:
+ *
+ * P_<hash>(secret, seed) = HMAC_<hash>(secret, A(1) + seed) +
+ * HMAC_<hash>(secret, A(2) + seed) +
+ * 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))
+ */
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include "internal/cryptlib.h"
#include <openssl/evp.h>
#include <openssl/kdf.h>
+#include <openssl/core_names.h>
+#include <openssl/params.h>
#include "internal/evp_int.h"
#include "kdf_local.h"
if (impl->sec == NULL)
return 0;
- impl->seclen = len;
+ impl->seclen = len;
return 1;
case EVP_KDF_CTRL_RESET_TLS_SEED:
key, keylen);
}
-const EVP_KDF_METHOD tls1_prf_kdf_meth = {
+const EVP_KDF tls1_prf_kdf_meth = {
EVP_KDF_TLS1_PRF,
kdf_tls1_prf_new,
kdf_tls1_prf_free,
kdf_tls1_prf_derive
};
+/*
+ * 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).
+ *
+ * P_<hash> is an expansion function that uses a single hash function to expand
+ * a secret and seed into an arbitrary quantity of output:
+ *
+ * P_<hash>(secret, seed) = HMAC_<hash>(secret, A(1) + seed) +
+ * HMAC_<hash>(secret, A(2) + seed) +
+ * 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(const EVP_MD *md,
const unsigned char *sec, size_t sec_len,
const unsigned char *seed, size_t seed_len,
unsigned char *out, size_t olen)
{
- int chunk;
- EVP_MAC_CTX *ctx = NULL, *ctx_tmp = NULL, *ctx_init = NULL;
- unsigned char A1[EVP_MAX_MD_SIZE];
- size_t A1_len;
+ size_t chunk;
+ EVP_MAC *mac = NULL;
+ EVP_MAC_CTX *ctx = NULL, *ctx_Ai = NULL, *ctx_init = NULL;
+ unsigned char Ai[EVP_MAX_MD_SIZE];
+ size_t Ai_len;
int ret = 0;
+ OSSL_PARAM params[4];
+ int mac_flags;
+ const char *mdname = EVP_MD_name(md);
- chunk = EVP_MD_size(md);
- if (!ossl_assert(chunk > 0))
+ mac = EVP_MAC_fetch(NULL, OSSL_MAC_NAME_HMAC, NULL); /* Implicit fetch */
+ ctx_init = EVP_MAC_CTX_new(mac);
+ if (ctx_init == NULL)
goto err;
- ctx = EVP_MAC_CTX_new_id(EVP_MAC_HMAC);
- ctx_tmp = EVP_MAC_CTX_new_id(EVP_MAC_HMAC);
- ctx_init = EVP_MAC_CTX_new_id(EVP_MAC_HMAC);
- if (ctx == NULL || ctx_tmp == NULL || ctx_init == NULL)
- goto err;
- if (EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_FLAGS, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW) != 1)
- goto err;
- if (EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_MD, md) != 1)
- goto err;
- if (EVP_MAC_ctrl(ctx_init, EVP_MAC_CTRL_SET_KEY, sec, sec_len) != 1)
+ /* TODO(3.0) rethink "flags", also see hmac.c in providers */
+ mac_flags = EVP_MD_CTX_FLAG_NON_FIPS_ALLOW;
+ params[0] = OSSL_PARAM_construct_int(OSSL_MAC_PARAM_FLAGS, &mac_flags);
+ params[1] = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST,
+ (char *)mdname,
+ strlen(mdname) + 1);
+ params[2] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
+ (void *)sec, sec_len);
+ params[3] = OSSL_PARAM_construct_end();
+ if (!EVP_MAC_CTX_set_params(ctx_init, params))
goto err;
if (!EVP_MAC_init(ctx_init))
goto err;
- if (!EVP_MAC_CTX_copy(ctx, ctx_init))
+ chunk = EVP_MAC_size(ctx_init);
+ if (chunk == 0)
goto err;
- if (seed != NULL && !EVP_MAC_update(ctx, seed, seed_len))
+ /* A(0) = seed */
+ ctx_Ai = EVP_MAC_CTX_dup(ctx_init);
+ if (ctx_Ai == NULL)
goto err;
- if (!EVP_MAC_final(ctx, A1, &A1_len))
+ if (seed != NULL && !EVP_MAC_update(ctx_Ai, seed, seed_len))
goto err;
for (;;) {
- /* Reinit mac contexts */
- if (!EVP_MAC_CTX_copy(ctx, ctx_init))
+ /* calc: A(i) = HMAC_<hash>(secret, A(i-1)) */
+ if (!EVP_MAC_final(ctx_Ai, Ai, &Ai_len, sizeof(Ai)))
goto err;
- if (!EVP_MAC_update(ctx, A1, A1_len))
+ 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 (olen > (size_t)chunk && !EVP_MAC_CTX_copy(ctx_tmp, ctx))
+ 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 > (size_t)chunk) {
- size_t mac_len;
- if (!EVP_MAC_final(ctx, out, &mac_len))
+ if (olen <= chunk) {
+ /* last chunk - use Ai as temp bounce buffer */
+ if (!EVP_MAC_final(ctx, Ai, &Ai_len, sizeof(Ai)))
goto err;
- out += mac_len;
- olen -= mac_len;
- /* calc the next A1 value */
- if (!EVP_MAC_final(ctx_tmp, A1, &A1_len))
- goto err;
- } else { /* last one */
-
- if (!EVP_MAC_final(ctx, A1, &A1_len))
- goto err;
- memcpy(out, A1, olen);
+ 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_tmp);
+ EVP_MAC_CTX_free(ctx_Ai);
EVP_MAC_CTX_free(ctx_init);
- OPENSSL_cleanse(A1, sizeof(A1));
+ EVP_MAC_free(mac);
+ 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(const EVP_MD *md,
const unsigned char *sec, size_t slen,
const unsigned char *seed, size_t seed_len,
unsigned char *out, size_t olen)
{
if (EVP_MD_type(md) == NID_md5_sha1) {
+ /* TLS v1.0 and TLS v1.1 */
size_t i;
unsigned char *tmp;
- if (!tls1_prf_P_hash(EVP_md5(), sec, slen/2 + (slen & 1),
+ /* 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(EVP_md5(), sec, L_S1,
seed, seed_len, out, olen))
return 0;
KDFerr(KDF_F_TLS1_PRF_ALG, ERR_R_MALLOC_FAILURE);
return 0;
}
- if (!tls1_prf_P_hash(EVP_sha1(), sec + slen/2, slen/2 + (slen & 1),
+ if (!tls1_prf_P_hash(EVP_sha1(), sec + slen - L_S2, L_S2,
seed, seed_len, tmp, olen)) {
OPENSSL_clear_free(tmp, olen);
return 0;
OPENSSL_clear_free(tmp, olen);
return 1;
}
+
+ /* TLS v1.2 */
if (!tls1_prf_P_hash(md, sec, slen, seed, seed_len, out, olen))
return 0;
projects / openssl.git / blobdiff