x942kdf.c
/*
* Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2019, 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 "e_os.h"
#include <openssl/core_names.h>
#include <openssl/core_dispatch.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/params.h>
#include "internal/packet.h"
#include "internal/der.h"
#include "prov/provider_ctx.h"
#include "prov/providercommon.h"
#include "prov/providercommonerr.h"
#include "prov/implementations.h"
#include "prov/provider_util.h"
#include "prov/der_wrap.h"
#define X942KDF_MAX_INLEN (1 << 30)
static OSSL_FUNC_kdf_newctx_fn x942kdf_new;
static OSSL_FUNC_kdf_freectx_fn x942kdf_free;
static OSSL_FUNC_kdf_reset_fn x942kdf_reset;
static OSSL_FUNC_kdf_derive_fn x942kdf_derive;
static OSSL_FUNC_kdf_settable_ctx_params_fn x942kdf_settable_ctx_params;
static OSSL_FUNC_kdf_set_ctx_params_fn x942kdf_set_ctx_params;
static OSSL_FUNC_kdf_gettable_ctx_params_fn x942kdf_gettable_ctx_params;
static OSSL_FUNC_kdf_get_ctx_params_fn x942kdf_get_ctx_params;
typedef struct {
void *provctx;
PROV_DIGEST digest;
unsigned char *secret;
size_t secret_len;
unsigned char *ukm;
size_t ukm_len;
size_t dkm_len;
const unsigned char *cek_oid;
size_t cek_oid_len;
} KDF_X942;
/*
* A table of allowed wrapping algorithms, oids and the associated output
* lengths.
* NOTE: RC2wrap and camellia128_wrap have been removed as there are no
* corresponding ciphers for these operations.
*/
static const struct {
const char *name;
const unsigned char *oid;
size_t oid_len;
size_t keklen; /* size in bytes */
} kek_algs[] = {
{ "AES-128-WRAP", ossl_der_oid_id_aes128_wrap, DER_OID_SZ_id_aes128_wrap,
16 },
{ "AES-192-WRAP", ossl_der_oid_id_aes192_wrap, DER_OID_SZ_id_aes192_wrap,
24 },
{ "AES-256-WRAP", ossl_der_oid_id_aes256_wrap, DER_OID_SZ_id_aes256_wrap,
32 },
#ifndef FIPS_MODULE
{ "DES3-WRAP", ossl_der_oid_id_alg_CMS3DESwrap,
DER_OID_SZ_id_alg_CMS3DESwrap, 24 },
#endif
};
static int find_alg_id(OSSL_LIB_CTX *libctx, const char *algname,
const char *propq, size_t *id)
{
int ret = 1;
size_t i;
EVP_CIPHER *cipher;
cipher = EVP_CIPHER_fetch(libctx, algname, propq);
if (cipher != NULL) {
for (i = 0; i < OSSL_NELEM(kek_algs); i++) {
if (EVP_CIPHER_is_a(cipher, kek_algs[i].name)) {
*id = i;
goto end;
}
}
}
ret = 0;
ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_CEK_ALG);
end:
EVP_CIPHER_free(cipher);
return ret;
}
static int DER_w_keyinfo(WPACKET *pkt,
const unsigned char *der_oid, size_t der_oidlen,
unsigned char **pcounter)
{
return ossl_DER_w_begin_sequence(pkt, -1)
/* Store the initial value of 1 into the counter */
&& ossl_DER_w_octet_string_uint32(pkt, -1, 1)
/* Remember where we stored the counter in the buffer */
&& (pcounter == NULL
|| (*pcounter = WPACKET_get_curr(pkt)) != NULL)
&& ossl_DER_w_precompiled(pkt, -1, der_oid, der_oidlen)
&& ossl_DER_w_end_sequence(pkt, -1);
}
static int der_encode_sharedinfo(WPACKET *pkt, unsigned char *buf, size_t buflen,
const unsigned char *der_oid, size_t der_oidlen,
const unsigned char *ukm, size_t ukmlen,
uint32_t keylen_bits, unsigned char **pcounter)
{
return (buf != NULL ? WPACKET_init_der(pkt, buf, buflen) :
WPACKET_init_null_der(pkt))
&& ossl_DER_w_begin_sequence(pkt, -1)
&& ossl_DER_w_octet_string_uint32(pkt, 2, keylen_bits)
&& (ukm == NULL || ossl_DER_w_octet_string(pkt, 0, ukm, ukmlen))
&& DER_w_keyinfo(pkt, der_oid, der_oidlen, pcounter)
&& ossl_DER_w_end_sequence(pkt, -1)
&& WPACKET_finish(pkt);
}
/*
* Encode the other info structure.
*
* RFC2631 Section 2.1.2 Contains the following definition for otherinfo
*
* OtherInfo ::= SEQUENCE {
* keyInfo KeySpecificInfo,
* partyAInfo [0] OCTET STRING OPTIONAL,
* suppPubInfo [2] OCTET STRING
* }
* Note suppPubInfo is the key length (in bits) (stored into 4 bytes)
*
*
* KeySpecificInfo ::= SEQUENCE {
* algorithm OBJECT IDENTIFIER,
* counter OCTET STRING SIZE (4..4)
* }
*
* |keylen| is the length (in bytes) of the generated KEK. It is stored into
* suppPubInfo (in bits).
* |cek_oid| The oid of the key wrapping algorithm.
* |cek_oidlen| The length (in bytes) of the key wrapping algorithm oid,
* |ukm| is the optional user keying material that is stored into partyAInfo. It
* can be NULL.
* |ukmlen| is the user keying material length (in bytes).
* |der| is the returned encoded data. It must be freed by the caller.
* |der_len| is the returned size of the encoded data.
* |out_ctr| returns a pointer to the counter data which is embedded inside the
* encoded data. This allows the counter bytes to be updated without re-encoding.
*
* Returns: 1 if successfully encoded, or 0 otherwise.
* Assumptions: |der|, |der_len| & |out_ctr| are not NULL.
*/
static int x942_encode_otherinfo(size_t keylen,
const unsigned char *cek_oid, size_t cek_oidlen,
const unsigned char *ukm, size_t ukmlen,
unsigned char **der, size_t *der_len,
unsigned char **out_ctr)
{
int ret = 0;
unsigned char *pcounter = NULL, *der_buf = NULL;
size_t der_buflen = 0;
WPACKET pkt;
uint32_t keylen_bits;
/* keylenbits must fit into 4 bytes */
if (keylen > 0xFFFFFF)
return 0;
keylen_bits = 8 * keylen;
/* Calculate the size of the buffer */
if (!der_encode_sharedinfo(&pkt, NULL, 0, cek_oid, cek_oidlen, ukm, ukmlen,
keylen_bits, NULL)
|| !WPACKET_get_total_written(&pkt, &der_buflen))
goto err;
WPACKET_cleanup(&pkt);
/* Alloc the buffer */
der_buf = OPENSSL_zalloc(der_buflen);
if (der_buf == NULL)
goto err;
/* Encode into the buffer */
if (!der_encode_sharedinfo(&pkt, der_buf, der_buflen, cek_oid, cek_oidlen,
ukm, ukmlen, keylen_bits, &pcounter))
goto err;
/*
* Since we allocated the exact size required, the buffer should point to the
* start of the alllocated buffer at this point.
*/
if (WPACKET_get_curr(&pkt) != der_buf)
goto err;
/*
* The data for the DER encoded octet string of a 32 bit counter = 1
* should be 04 04 00 00 00 01
* So just check the header is correct and skip over it.
* This counter will be incremented in the kdf update loop.
*/
if (pcounter == NULL
|| pcounter[0] != 0x04
|| pcounter[1] != 0x04)
goto err;
*out_ctr = (pcounter + 2);
*der = der_buf;
*der_len = der_buflen;
ret = 1;
err:
WPACKET_cleanup(&pkt);
return ret;
}
static int x942kdf_hash_kdm(const EVP_MD *kdf_md,
const unsigned char *z, size_t z_len,
const unsigned char *other, size_t other_len,
unsigned char *ctr,
unsigned char *derived_key, size_t derived_key_len)
{
int ret = 0, hlen;
size_t counter, out_len, len = derived_key_len;
unsigned char mac[EVP_MAX_MD_SIZE];
unsigned char *out = derived_key;
EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
if (z_len > X942KDF_MAX_INLEN || other_len > X942KDF_MAX_INLEN
|| derived_key_len > X942KDF_MAX_INLEN
|| derived_key_len == 0) {
ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);
return 0;
}
hlen = EVP_MD_size(kdf_md);
if (hlen <= 0)
return 0;
out_len = (size_t)hlen;
ctx = EVP_MD_CTX_create();
ctx_init = EVP_MD_CTX_create();
if (ctx == NULL || ctx_init == NULL)
goto end;
if (!EVP_DigestInit(ctx_init, kdf_md))
goto end;
for (counter = 1;; counter++) {
/* updating the ctr modifies 4 bytes in the 'other' buffer */
ctr[0] = (unsigned char)((counter >> 24) & 0xff);
ctr[1] = (unsigned char)((counter >> 16) & 0xff);
ctr[2] = (unsigned char)((counter >> 8) & 0xff);
ctr[3] = (unsigned char)(counter & 0xff);
if (!EVP_MD_CTX_copy_ex(ctx, ctx_init)
|| !EVP_DigestUpdate(ctx, z, z_len)
|| !EVP_DigestUpdate(ctx, other, other_len))
goto end;
if (len >= out_len) {
if (!EVP_DigestFinal_ex(ctx, out, NULL))
goto end;
out += out_len;
len -= out_len;
if (len == 0)
break;
} else {
if (!EVP_DigestFinal_ex(ctx, mac, NULL))
goto end;
memcpy(out, mac, len);
break;
}
}
ret = 1;
end:
EVP_MD_CTX_free(ctx);
EVP_MD_CTX_free(ctx_init);
OPENSSL_cleanse(mac, sizeof(mac));
return ret;
}
static void *x942kdf_new(void *provctx)
{
KDF_X942 *ctx;
if (!ossl_prov_is_running())
return 0;
if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
ctx->provctx = provctx;
return ctx;
}
static void x942kdf_reset(void *vctx)
{
KDF_X942 *ctx = (KDF_X942 *)vctx;
void *provctx = ctx->provctx;
ossl_prov_digest_reset(&ctx->digest);
OPENSSL_clear_free(ctx->secret, ctx->secret_len);
OPENSSL_clear_free(ctx->ukm, ctx->ukm_len);
memset(ctx, 0, sizeof(*ctx));
ctx->provctx = provctx;
}
static void x942kdf_free(void *vctx)
{
KDF_X942 *ctx = (KDF_X942 *)vctx;
if (ctx != NULL) {
x942kdf_reset(ctx);
OPENSSL_free(ctx);
}
}
static int x942kdf_set_buffer(unsigned char **out, size_t *out_len,
const OSSL_PARAM *p)
{
if (p->data_size == 0 || p->data == NULL)
return 1;
OPENSSL_free(*out);
*out = NULL;
return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
}
static size_t x942kdf_size(KDF_X942 *ctx)
{
int len;
const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
if (md == NULL) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
return 0;
}
len = EVP_MD_size(md);
return (len <= 0) ? 0 : (size_t)len;
}
static int x942kdf_derive(void *vctx, unsigned char *key, size_t keylen)
{
KDF_X942 *ctx = (KDF_X942 *)vctx;
const EVP_MD *md;
int ret = 0;
unsigned char *ctr;
unsigned char *der = NULL;
size_t der_len = 0;
if (!ossl_prov_is_running())
return 0;
if (ctx->secret == NULL) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
return 0;
}
md = ossl_prov_digest_md(&ctx->digest);
if (md == NULL) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
return 0;
}
if (ctx->cek_oid == NULL || ctx->cek_oid_len == 0) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CEK_ALG);
return 0;
}
if (ctx->ukm != NULL && ctx->ukm_len >= X942KDF_MAX_INLEN) {
/*
* Note the ukm length MUST be 512 bits.
* For backwards compatibility the old check is being done.
*/
ERR_raise(ERR_LIB_PROV, PROV_R_INAVLID_UKM_LENGTH);
return 0;
}
/* generate the otherinfo der */
if (!x942_encode_otherinfo(ctx->dkm_len,
ctx->cek_oid, ctx->cek_oid_len,
ctx->ukm, ctx->ukm_len,
&der, &der_len, &ctr)) {
ERR_raise(ERR_LIB_PROV, PROV_R_BAD_ENCODING);
return 0;
}
ret = x942kdf_hash_kdm(md, ctx->secret, ctx->secret_len,
der, der_len, ctr, key, keylen);
OPENSSL_free(der);
return ret;
}
static int x942kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
const OSSL_PARAM *p, *pq;
KDF_X942 *ctx = vctx;
OSSL_LIB_CTX *provctx = PROV_LIBCTX_OF(ctx->provctx);
const char *propq = NULL;
size_t id;
if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
return 0;
if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL
|| (p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
if (!x942kdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
return 0;
if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_UKM)) != NULL)
if (!x942kdf_set_buffer(&ctx->ukm, &ctx->ukm_len, p))
return 0;
if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG)) != NULL) {
if (p->data_type != OSSL_PARAM_UTF8_STRING)
return 0;
pq = OSSL_PARAM_locate_const(params, OSSL_ALG_PARAM_PROPERTIES);
/*
* We already grab the properties during ossl_prov_digest_load_from_params()
* so there is no need to check the validity again..
*/
if (pq != NULL)
propq = p->data;
if (find_alg_id(provctx, p->data, propq, &id) == 0)
return 0;
ctx->cek_oid = kek_algs[id].oid;
ctx->cek_oid_len = kek_algs[id].oid_len;
ctx->dkm_len = kek_algs[id].keklen;
}
return 1;
}
static const OSSL_PARAM *x942kdf_settable_ctx_params(ossl_unused void *provctx)
{
static const OSSL_PARAM known_settable_ctx_params[] = {
OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
OSSL_PARAM_octet_string(OSSL_KDF_PARAM_UKM, NULL, 0),
OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),
OSSL_PARAM_END
};
return known_settable_ctx_params;
}
static int x942kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
KDF_X942 *ctx = (KDF_X942 *)vctx;
OSSL_PARAM *p;
if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
return OSSL_PARAM_set_size_t(p, x942kdf_size(ctx));
return -2;
}
static const OSSL_PARAM *x942kdf_gettable_ctx_params(ossl_unused void *provctx)
{
static const OSSL_PARAM known_gettable_ctx_params[] = {
OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
OSSL_PARAM_END
};
return known_gettable_ctx_params;
}
const OSSL_DISPATCH ossl_kdf_x942_kdf_functions[] = {
{ OSSL_FUNC_KDF_NEWCTX, (void(*)(void))x942kdf_new },
{ OSSL_FUNC_KDF_FREECTX, (void(*)(void))x942kdf_free },
{ OSSL_FUNC_KDF_RESET, (void(*)(void))x942kdf_reset },
{ OSSL_FUNC_KDF_DERIVE, (void(*)(void))x942kdf_derive },
{ OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
(void(*)(void))x942kdf_settable_ctx_params },
{ OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))x942kdf_set_ctx_params },
{ OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
(void(*)(void))x942kdf_gettable_ctx_params },
{ OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))x942kdf_get_ctx_params },
{ 0, NULL }
};
