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/*
* Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/kdf.h>
#include <openssl/evp.h>
#include "internal/evp_int.h"
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);
#define TLS1_PRF_MAXBUF 1024
/* TLS KDF pkey context structure */
typedef struct {
/* Digest to use for PRF */
const EVP_MD *md;
/* Secret value to use for PRF */
unsigned char *sec;
size_t seclen;
/* Buffer of concatenated seed data */
unsigned char seed[TLS1_PRF_MAXBUF];
size_t seedlen;
} TLS1_PRF_PKEY_CTX;
static int pkey_tls1_prf_init(EVP_PKEY_CTX *ctx)
{
TLS1_PRF_PKEY_CTX *kctx;
kctx = OPENSSL_zalloc(sizeof(*kctx));
if (kctx == NULL)
return 0;
ctx->data = kctx;
return 1;
}
static void pkey_tls1_prf_cleanup(EVP_PKEY_CTX *ctx)
{
TLS1_PRF_PKEY_CTX *kctx = ctx->data;
OPENSSL_clear_free(kctx->sec, kctx->seclen);
OPENSSL_cleanse(kctx->seed, kctx->seedlen);
OPENSSL_free(kctx);
}
static int pkey_tls1_prf_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
{
TLS1_PRF_PKEY_CTX *kctx = ctx->data;
switch (type) {
case EVP_PKEY_CTRL_TLS_MD:
kctx->md = p2;
return 1;
case EVP_PKEY_CTRL_TLS_SECRET:
if (p1 < 0)
return 0;
if (kctx->sec != NULL)
OPENSSL_clear_free(kctx->sec, kctx->seclen);
OPENSSL_cleanse(kctx->seed, kctx->seedlen);
kctx->seedlen = 0;
kctx->sec = OPENSSL_memdup(p2, p1);
if (kctx->sec == NULL)
return 0;
kctx->seclen = p1;
return 1;
case EVP_PKEY_CTRL_TLS_SEED:
if (p1 == 0 || p2 == NULL)
return 1;
if (p1 < 0 || p1 > (int)(TLS1_PRF_MAXBUF - kctx->seedlen))
return 0;
memcpy(kctx->seed + kctx->seedlen, p2, p1);
kctx->seedlen += p1;
return 1;
default:
return -2;
}
}
static int pkey_tls1_prf_ctrl_str(EVP_PKEY_CTX *ctx,
const char *type, const char *value)
{
if (value == NULL) {
KDFerr(KDF_F_PKEY_TLS1_PRF_CTRL_STR, KDF_R_VALUE_MISSING);
return 0;
}
if (strcmp(type, "md") == 0) {
TLS1_PRF_PKEY_CTX *kctx = ctx->data;
const EVP_MD *md = EVP_get_digestbyname(value);
if (md == NULL) {
KDFerr(KDF_F_PKEY_TLS1_PRF_CTRL_STR, KDF_R_INVALID_DIGEST);
return 0;
}
kctx->md = md;
return 1;
}
if (strcmp(type, "secret") == 0)
return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_TLS_SECRET, value);
if (strcmp(type, "hexsecret") == 0)
return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_TLS_SECRET, value);
if (strcmp(type, "seed") == 0)
return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_TLS_SEED, value);
if (strcmp(type, "hexseed") == 0)
return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_TLS_SEED, value);
return -2;
}
static int pkey_tls1_prf_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
size_t *keylen)
{
TLS1_PRF_PKEY_CTX *kctx = ctx->data;
if (kctx->md == NULL || kctx->sec == NULL || kctx->seedlen == 0) {
KDFerr(KDF_F_PKEY_TLS1_PRF_DERIVE, KDF_R_MISSING_PARAMETER);
return 0;
}
return tls1_prf_alg(kctx->md, kctx->sec, kctx->seclen,
kctx->seed, kctx->seedlen,
key, *keylen);
}
const EVP_PKEY_METHOD tls1_prf_pkey_meth = {
EVP_PKEY_TLS1_PRF,
0,
pkey_tls1_prf_init,
0,
pkey_tls1_prf_cleanup,
0, 0,
0, 0,
0,
0,
0,
0,
0, 0,
0, 0, 0, 0,
0, 0,
0, 0,
0,
pkey_tls1_prf_derive,
pkey_tls1_prf_ctrl,
pkey_tls1_prf_ctrl_str
};
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_MD_CTX *ctx = NULL, *ctx_tmp = NULL, *ctx_init = NULL;
EVP_PKEY *mac_key = NULL;
unsigned char A1[EVP_MAX_MD_SIZE];
size_t A1_len;
int ret = 0;
chunk = EVP_MD_size(md);
OPENSSL_assert(chunk >= 0);
ctx = EVP_MD_CTX_new();
ctx_tmp = EVP_MD_CTX_new();
ctx_init = EVP_MD_CTX_new();
if (ctx == NULL || ctx_tmp == NULL || ctx_init == NULL)
goto err;
EVP_MD_CTX_set_flags(ctx_init, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
mac_key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, sec, sec_len);
if (mac_key == NULL)
goto err;
if (!EVP_DigestSignInit(ctx_init, NULL, md, NULL, mac_key))
goto err;
if (!EVP_MD_CTX_copy_ex(ctx, ctx_init))
goto err;
if (seed != NULL && !EVP_DigestSignUpdate(ctx, seed, seed_len))
goto err;
if (!EVP_DigestSignFinal(ctx, A1, &A1_len))
goto err;
for (;;) {
/* Reinit mac contexts */
if (!EVP_MD_CTX_copy_ex(ctx, ctx_init))
goto err;
if (!EVP_DigestSignUpdate(ctx, A1, A1_len))
goto err;
if (olen > (size_t)chunk && !EVP_MD_CTX_copy_ex(ctx_tmp, ctx))
goto err;
if (seed && !EVP_DigestSignUpdate(ctx, seed, seed_len))
goto err;
if (olen > (size_t)chunk) {
size_t mac_len;
if (!EVP_DigestSignFinal(ctx, out, &mac_len))
goto err;
out += mac_len;
olen -= mac_len;
/* calc the next A1 value */
if (!EVP_DigestSignFinal(ctx_tmp, A1, &A1_len))
goto err;
} else { /* last one */
if (!EVP_DigestSignFinal(ctx, A1, &A1_len))
goto err;
memcpy(out, A1, olen);
break;
}
}
ret = 1;
err:
EVP_PKEY_free(mac_key);
EVP_MD_CTX_free(ctx);
EVP_MD_CTX_free(ctx_tmp);
EVP_MD_CTX_free(ctx_init);
OPENSSL_cleanse(A1, sizeof(A1));
return ret;
}
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) {
size_t i;
unsigned char *tmp;
if (!tls1_prf_P_hash(EVP_md5(), sec, slen/2 + (slen & 1),
seed, seed_len, out, olen))
return 0;
tmp = OPENSSL_malloc(olen);
if (tmp == NULL)
return 0;
if (!tls1_prf_P_hash(EVP_sha1(), sec + slen/2, slen/2 + (slen & 1),
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;
}
if (!tls1_prf_P_hash(md, sec, slen, seed, seed_len, out, olen))
return 0;
return 1;
}
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