pkey_kdf.c
/*
* Copyright 2018-2020 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
*
* Licensed under the Apache License 2.0 (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 <string.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/buffer.h>
#include <openssl/kdf.h>
#include <openssl/core.h>
#include <openssl/core_names.h>
#include <openssl/params.h>
#include "internal/numbers.h"
#include "crypto/evp.h"
#define MAX_PARAM 20
typedef struct {
EVP_KDF_CTX *kctx;
/*
* EVP_PKEY implementations collect bits of certain data
*/
BUF_MEM *collected_seed;
BUF_MEM *collected_info;
} EVP_PKEY_KDF_CTX;
static void pkey_kdf_free_collected(EVP_PKEY_KDF_CTX *pkctx)
{
BUF_MEM_free(pkctx->collected_seed);
pkctx->collected_seed = NULL;
BUF_MEM_free(pkctx->collected_info);
pkctx->collected_info = NULL;
}
static int pkey_kdf_init(EVP_PKEY_CTX *ctx)
{
EVP_PKEY_KDF_CTX *pkctx;
EVP_KDF_CTX *kctx;
const char *kdf_name = OBJ_nid2sn(ctx->pmeth->pkey_id);
EVP_KDF *kdf;
pkctx = OPENSSL_zalloc(sizeof(*pkctx));
if (pkctx == NULL)
return 0;
kdf = EVP_KDF_fetch(NULL, kdf_name, NULL);
kctx = EVP_KDF_new_ctx(kdf);
EVP_KDF_free(kdf);
if (kctx == NULL) {
OPENSSL_free(pkctx);
return 0;
}
pkctx->kctx = kctx;
ctx->data = pkctx;
return 1;
}
static void pkey_kdf_cleanup(EVP_PKEY_CTX *ctx)
{
EVP_PKEY_KDF_CTX *pkctx = ctx->data;
EVP_KDF_free_ctx(pkctx->kctx);
pkey_kdf_free_collected(pkctx);
OPENSSL_free(pkctx);
}
static int collect(BUF_MEM **collector, void *data, size_t datalen)
{
size_t i;
if (*collector == NULL)
*collector = BUF_MEM_new();
if (*collector == NULL) {
ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
return 0;
}
if (data != NULL && datalen > 0) {
i = (*collector)->length; /* BUF_MEM_grow() changes it! */
if (!BUF_MEM_grow(*collector, i + datalen))
return 0;
memcpy((*collector)->data + i, data, datalen);
}
return 1;
}
static int pkey_kdf_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
{
EVP_PKEY_KDF_CTX *pkctx = ctx->data;
EVP_KDF_CTX *kctx = pkctx->kctx;
enum { T_OCTET_STRING, T_UINT64, T_DIGEST, T_INT } cmd;
const char *name, *mdname;
BUF_MEM **collector = NULL;
OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
switch (type) {
case EVP_PKEY_CTRL_PASS:
cmd = T_OCTET_STRING;
name = OSSL_KDF_PARAM_PASSWORD;
break;
case EVP_PKEY_CTRL_HKDF_SALT:
case EVP_PKEY_CTRL_SCRYPT_SALT:
cmd = T_OCTET_STRING;
name = OSSL_KDF_PARAM_SALT;
break;
case EVP_PKEY_CTRL_TLS_MD:
case EVP_PKEY_CTRL_HKDF_MD:
cmd = T_DIGEST;
name = OSSL_KDF_PARAM_DIGEST;
break;
case EVP_PKEY_CTRL_TLS_SECRET:
cmd = T_OCTET_STRING;
name = OSSL_KDF_PARAM_SECRET;
/*
* Perform the semantics described in
* EVP_PKEY_CTX_add1_tls1_prf_seed(3)
*/
if (ctx->pmeth->pkey_id == NID_tls1_prf) {
BUF_MEM_free(pkctx->collected_seed);
pkctx->collected_seed = NULL;
}
break;
case EVP_PKEY_CTRL_TLS_SEED:
cmd = T_OCTET_STRING;
name = OSSL_KDF_PARAM_SEED;
collector = &pkctx->collected_seed;
break;
case EVP_PKEY_CTRL_HKDF_KEY:
cmd = T_OCTET_STRING;
name = OSSL_KDF_PARAM_KEY;
break;
case EVP_PKEY_CTRL_HKDF_INFO:
cmd = T_OCTET_STRING;
name = OSSL_KDF_PARAM_INFO;
collector = &pkctx->collected_info;
break;
case EVP_PKEY_CTRL_HKDF_MODE:
cmd = T_INT;
name = OSSL_KDF_PARAM_MODE;
break;
case EVP_PKEY_CTRL_SCRYPT_N:
cmd = T_UINT64;
name = OSSL_KDF_PARAM_SCRYPT_N;
break;
case EVP_PKEY_CTRL_SCRYPT_R:
cmd = T_UINT64; /* Range checking occurs on the provider side */
name = OSSL_KDF_PARAM_SCRYPT_R;
break;
case EVP_PKEY_CTRL_SCRYPT_P:
cmd = T_UINT64; /* Range checking occurs on the provider side */
name = OSSL_KDF_PARAM_SCRYPT_P;
break;
case EVP_PKEY_CTRL_SCRYPT_MAXMEM_BYTES:
cmd = T_UINT64;
name = OSSL_KDF_PARAM_SCRYPT_MAXMEM;
break;
default:
return -2;
}
if (collector != NULL) {
switch (cmd) {
case T_OCTET_STRING:
return collect(collector, p2, p1);
default:
OPENSSL_assert("You shouldn't be here");
break;
}
return 1;
}
switch (cmd) {
case T_OCTET_STRING:
params[0] =
OSSL_PARAM_construct_octet_string(name, (unsigned char *)p2,
(size_t)p1);
break;
case T_DIGEST:
mdname = EVP_MD_name((const EVP_MD *)p2);
params[0] = OSSL_PARAM_construct_utf8_string(name, (char *)mdname, 0);
break;
/*
* These are special because the helper macros pass a pointer to the
* stack, so a local copy is required.
*/
case T_INT:
params[0] = OSSL_PARAM_construct_int(name, &p1);
break;
case T_UINT64:
params[0] = OSSL_PARAM_construct_uint64(name, (uint64_t *)p2);
break;
}
return EVP_KDF_set_ctx_params(kctx, params);
}
static int pkey_kdf_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
const char *value)
{
EVP_PKEY_KDF_CTX *pkctx = ctx->data;
EVP_KDF_CTX *kctx = pkctx->kctx;
const EVP_KDF *kdf = EVP_KDF_get_ctx_kdf(kctx);
BUF_MEM **collector = NULL;
const OSSL_PARAM *defs = EVP_KDF_settable_ctx_params(kdf);
OSSL_PARAM params[2] = { OSSL_PARAM_END, OSSL_PARAM_END };
int ok = 0;
/* Deal with ctrl name aliasing */
if (strcmp(type, "md") == 0)
type = OSSL_KDF_PARAM_DIGEST;
/* scrypt uses 'N', params uses 'n' */
if (strcmp(type, "N") == 0)
type = OSSL_KDF_PARAM_SCRYPT_N;
if (!OSSL_PARAM_allocate_from_text(¶ms[0], defs, type,
value, strlen(value), NULL))
return 0;
/*
* We do the same special casing of seed and info here as in
* pkey_kdf_ctrl()
*/
if (strcmp(params[0].key, OSSL_KDF_PARAM_SEED) == 0)
collector = &pkctx->collected_seed;
else if (strcmp(params[0].key, OSSL_KDF_PARAM_INFO) == 0)
collector = &pkctx->collected_info;
if (collector != NULL)
ok = collect(collector, params[0].data, params[0].data_size);
else
ok = EVP_KDF_set_ctx_params(kctx, params);
OPENSSL_free(params[0].data);
return ok;
}
static int pkey_kdf_derive_init(EVP_PKEY_CTX *ctx)
{
EVP_PKEY_KDF_CTX *pkctx = ctx->data;
pkey_kdf_free_collected(pkctx);
if (pkctx->kctx != NULL)
EVP_KDF_reset(pkctx->kctx);
return 1;
}
/*
* For fixed-output algorithms the keylen parameter is an "out" parameter
* otherwise it is an "in" parameter.
*/
static int pkey_kdf_derive(EVP_PKEY_CTX *ctx, unsigned char *key,
size_t *keylen)
{
EVP_PKEY_KDF_CTX *pkctx = ctx->data;
EVP_KDF_CTX *kctx = pkctx->kctx;
size_t outlen = EVP_KDF_size(kctx);
int r;
if (pkctx->collected_seed != NULL) {
OSSL_PARAM params[] = { OSSL_PARAM_END, OSSL_PARAM_END };
params[0] =
OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SEED,
pkctx->collected_seed->data,
pkctx->collected_seed->length);
r = EVP_KDF_set_ctx_params(kctx, params);
pkey_kdf_free_collected(pkctx);
if (!r)
return 0;
}
if (pkctx->collected_info != NULL) {
OSSL_PARAM params[] = { OSSL_PARAM_END, OSSL_PARAM_END };
params[0] =
OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
pkctx->collected_info->data,
pkctx->collected_info->length);
r = EVP_KDF_set_ctx_params(kctx, params);
pkey_kdf_free_collected(pkctx);
if (!r)
return 0;
}
if (outlen == 0 || outlen == SIZE_MAX) {
/* Variable-output algorithm */
if (key == NULL)
return 0;
} else {
/* Fixed-output algorithm */
*keylen = outlen;
if (key == NULL)
return 1;
}
return EVP_KDF_derive(kctx, key, *keylen);
}
#ifndef OPENSSL_NO_SCRYPT
static const EVP_PKEY_METHOD scrypt_pkey_meth = {
EVP_PKEY_SCRYPT,
0,
pkey_kdf_init,
0,
pkey_kdf_cleanup,
0, 0,
0, 0,
0,
0,
0,
0,
0, 0,
0, 0, 0, 0,
0, 0,
0, 0,
pkey_kdf_derive_init,
pkey_kdf_derive,
pkey_kdf_ctrl,
pkey_kdf_ctrl_str
};
const EVP_PKEY_METHOD *scrypt_pkey_method(void)
{
return &scrypt_pkey_meth;
}
#endif
static const EVP_PKEY_METHOD tls1_prf_pkey_meth = {
EVP_PKEY_TLS1_PRF,
0,
pkey_kdf_init,
0,
pkey_kdf_cleanup,
0, 0,
0, 0,
0,
0,
0,
0,
0, 0,
0, 0, 0, 0,
0, 0,
0, 0,
pkey_kdf_derive_init,
pkey_kdf_derive,
pkey_kdf_ctrl,
pkey_kdf_ctrl_str
};
const EVP_PKEY_METHOD *tls1_prf_pkey_method(void)
{
return &tls1_prf_pkey_meth;
}
static const EVP_PKEY_METHOD hkdf_pkey_meth = {
EVP_PKEY_HKDF,
0,
pkey_kdf_init,
0,
pkey_kdf_cleanup,
0, 0,
0, 0,
0,
0,
0,
0,
0, 0,
0, 0, 0, 0,
0, 0,
0, 0,
pkey_kdf_derive_init,
pkey_kdf_derive,
pkey_kdf_ctrl,
pkey_kdf_ctrl_str
};
const EVP_PKEY_METHOD *hkdf_pkey_method(void)
{
return &hkdf_pkey_meth;
}
