openssl/providers/implementations/kem/ml_kem_kem.c

269 lines
8.1 KiB
C

/*
* Copyright 2024-2025 The OpenSSL Project Authors. 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/crypto.h>
#include <openssl/evp.h>
#include <openssl/core_dispatch.h>
#include <openssl/core_names.h>
#include <openssl/params.h>
#include <openssl/err.h>
#include <openssl/proverr.h>
#include "crypto/ml_kem.h"
#include "prov/provider_ctx.h"
#include "prov/implementations.h"
#include "prov/securitycheck.h"
#include "prov/providercommon.h"
static OSSL_FUNC_kem_newctx_fn ml_kem_newctx;
static OSSL_FUNC_kem_freectx_fn ml_kem_freectx;
static OSSL_FUNC_kem_encapsulate_init_fn ml_kem_encapsulate_init;
static OSSL_FUNC_kem_encapsulate_fn ml_kem_encapsulate;
static OSSL_FUNC_kem_decapsulate_init_fn ml_kem_decapsulate_init;
static OSSL_FUNC_kem_decapsulate_fn ml_kem_decapsulate;
static OSSL_FUNC_kem_set_ctx_params_fn ml_kem_set_ctx_params;
static OSSL_FUNC_kem_settable_ctx_params_fn ml_kem_settable_ctx_params;
typedef struct {
ML_KEM_KEY *key;
uint8_t entropy_buf[ML_KEM_RANDOM_BYTES];
uint8_t *entropy;
int op;
} PROV_ML_KEM_CTX;
static void *ml_kem_newctx(void *provctx)
{
PROV_ML_KEM_CTX *ctx;
if ((ctx = OPENSSL_malloc(sizeof(*ctx))) == NULL)
return NULL;
ctx->key = NULL;
ctx->entropy = NULL;
ctx->op = 0;
return ctx;
}
static void ml_kem_freectx(void *vctx)
{
PROV_ML_KEM_CTX *ctx = vctx;
if (ctx->entropy != NULL)
OPENSSL_cleanse(ctx->entropy, ML_KEM_RANDOM_BYTES);
OPENSSL_free(ctx);
}
static int ml_kem_init(void *vctx, int op, void *key,
const OSSL_PARAM params[])
{
PROV_ML_KEM_CTX *ctx = vctx;
if (!ossl_prov_is_running())
return 0;
ctx->key = key;
ctx->op = op;
return ml_kem_set_ctx_params(vctx, params);
}
static int ml_kem_encapsulate_init(void *vctx, void *vkey,
const OSSL_PARAM params[])
{
ML_KEM_KEY *key = vkey;
if (!ossl_ml_kem_have_pubkey(key)) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
return 0;
}
return ml_kem_init(vctx, EVP_PKEY_OP_ENCAPSULATE, key, params);
}
static int ml_kem_decapsulate_init(void *vctx, void *vkey,
const OSSL_PARAM params[])
{
ML_KEM_KEY *key = vkey;
if (!ossl_ml_kem_have_prvkey(key)) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
return 0;
}
return ml_kem_init(vctx, EVP_PKEY_OP_DECAPSULATE, key, params);
}
static int ml_kem_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
PROV_ML_KEM_CTX *ctx = vctx;
const OSSL_PARAM *p;
if (ctx == NULL)
return 0;
if (ctx->op == EVP_PKEY_OP_DECAPSULATE && ctx->entropy != NULL) {
/* Decapsulation is deterministic */
OPENSSL_cleanse(ctx->entropy, ML_KEM_RANDOM_BYTES);
ctx->entropy = NULL;
}
if (ossl_param_is_empty(params))
return 1;
/* Encapsulation ephemeral input key material "ikmE" */
if (ctx->op == EVP_PKEY_OP_ENCAPSULATE
&& (p = OSSL_PARAM_locate_const(params, OSSL_KEM_PARAM_IKME)) != NULL) {
size_t len = ML_KEM_RANDOM_BYTES;
ctx->entropy = ctx->entropy_buf;
if (OSSL_PARAM_get_octet_string(p, (void **)&ctx->entropy,
len, &len)
&& len == ML_KEM_RANDOM_BYTES)
return 1;
/* Possibly, but much less likely wrong type */
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_SEED_LENGTH);
ctx->entropy = NULL;
return 0;
}
return 1;
}
static const OSSL_PARAM *ml_kem_settable_ctx_params(ossl_unused void *vctx,
ossl_unused void *provctx)
{
static const OSSL_PARAM params[] = {
OSSL_PARAM_octet_string(OSSL_KEM_PARAM_IKME, NULL, 0),
OSSL_PARAM_END
};
return params;
}
static int ml_kem_encapsulate(void *vctx, unsigned char *ctext, size_t *clen,
unsigned char *shsec, size_t *slen)
{
PROV_ML_KEM_CTX *ctx = vctx;
ML_KEM_KEY *key = ctx->key;
const ML_KEM_VINFO *v;
size_t encap_clen;
size_t encap_slen;
int ret = 0;
if (!ossl_ml_kem_have_pubkey(key)) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
goto end;
}
v = ossl_ml_kem_key_vinfo(key);
encap_clen = v->ctext_bytes;
encap_slen = ML_KEM_SHARED_SECRET_BYTES;
if (ctext == NULL) {
if (clen == NULL && slen == NULL)
return 0;
if (clen != NULL)
*clen = encap_clen;
if (slen != NULL)
*slen = encap_slen;
return 1;
}
if (shsec == NULL) {
ERR_raise_data(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL,
"NULL shared-secret buffer");
goto end;
}
if (clen == NULL) {
ERR_raise_data(ERR_LIB_PROV, PROV_R_NULL_LENGTH_POINTER,
"null ciphertext input/output length pointer");
goto end;
} else if (*clen < encap_clen) {
ERR_raise_data(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL,
"ciphertext buffer too small");
goto end;
} else {
*clen = encap_clen;
}
if (slen == NULL) {
ERR_raise_data(ERR_LIB_PROV, PROV_R_NULL_LENGTH_POINTER,
"null shared secret input/output length pointer");
goto end;
} else if (*slen < encap_slen) {
ERR_raise_data(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL,
"shared-secret buffer too small");
goto end;
} else {
*slen = encap_slen;
}
if (ctx->entropy != NULL)
ret = ossl_ml_kem_encap_seed(ctext, encap_clen, shsec, encap_slen,
ctx->entropy, ML_KEM_RANDOM_BYTES, key);
else
ret = ossl_ml_kem_encap_rand(ctext, encap_clen, shsec, encap_slen, key);
end:
/*
* One shot entropy, each encapsulate call must either provide a new
* "ikmE", or else will use a random value. If a caller sets an explicit
* ikmE once for testing, and later performs multiple encapsulations
* without again calling encapsulate_init(), these should not share the
* original entropy.
*/
if (ctx->entropy != NULL) {
OPENSSL_cleanse(ctx->entropy, ML_KEM_RANDOM_BYTES);
ctx->entropy = NULL;
}
return ret;
}
static int ml_kem_decapsulate(void *vctx, uint8_t *shsec, size_t *slen,
const uint8_t *ctext, size_t clen)
{
PROV_ML_KEM_CTX *ctx = vctx;
ML_KEM_KEY *key = ctx->key;
size_t decap_slen = ML_KEM_SHARED_SECRET_BYTES;
if (!ossl_ml_kem_have_prvkey(key)) {
ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
return 0;
}
if (shsec == NULL) {
if (slen == NULL)
return 0;
*slen = ML_KEM_SHARED_SECRET_BYTES;
return 1;
}
/* For now tolerate newly-deprecated NULL length pointers. */
if (slen == NULL) {
slen = &decap_slen;
} else if (*slen < decap_slen) {
ERR_raise_data(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL,
"shared-secret buffer too small");
return 0;
} else {
*slen = decap_slen;
}
/* ML-KEM decap handles incorrect ciphertext lengths internally */
return ossl_ml_kem_decap(shsec, decap_slen, ctext, clen, key);
}
const OSSL_DISPATCH ossl_ml_kem_asym_kem_functions[] = {
{ OSSL_FUNC_KEM_NEWCTX, (OSSL_FUNC) ml_kem_newctx },
{ OSSL_FUNC_KEM_ENCAPSULATE_INIT, (OSSL_FUNC) ml_kem_encapsulate_init },
{ OSSL_FUNC_KEM_ENCAPSULATE, (OSSL_FUNC) ml_kem_encapsulate },
{ OSSL_FUNC_KEM_DECAPSULATE_INIT, (OSSL_FUNC) ml_kem_decapsulate_init },
{ OSSL_FUNC_KEM_DECAPSULATE, (OSSL_FUNC) ml_kem_decapsulate },
{ OSSL_FUNC_KEM_FREECTX, (OSSL_FUNC) ml_kem_freectx },
{ OSSL_FUNC_KEM_SET_CTX_PARAMS, (OSSL_FUNC) ml_kem_set_ctx_params },
{ OSSL_FUNC_KEM_SETTABLE_CTX_PARAMS, (OSSL_FUNC) ml_kem_settable_ctx_params },
OSSL_DISPATCH_END
};