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cmp_{kemrsa.c, local.h}: add rsa kem and kdf2 implementation
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@rajeev-0
rajeev-0 committed Sep 22, 2023
1 parent 1f7d6b4 commit 3c0d543
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196 changes: 196 additions & 0 deletions crypto/cmp/cmp_kemrsa.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,196 @@
/*
* Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
* Copyright Siemens AG 2023
*
* 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 "cmp_local.h"
#include <openssl/evp.h>
#include <openssl/kdf.h>
#include <openssl/params.h>
#include <openssl/core_names.h>
#include <openssl/cmp_util.h>

#define RSAKEM_KEYLENGTH 32

/* using X963KDF without info */
static int kdf2(OSSL_CMP_CTX *ctx,
unsigned char *secret, size_t secret_len,
unsigned char *out, int out_len)
{
EVP_KDF *kdf;
EVP_KDF_CTX *kctx;
OSSL_PARAM params[4], *p = params;

if (out == NULL)
return 0;

kdf = EVP_KDF_fetch(ctx->libctx, "X963KDF", ctx->propq);
kctx = EVP_KDF_CTX_new(kdf);
EVP_KDF_free(kdf);

*p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
SN_sha256, strlen(SN_sha256));
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SECRET,
secret, (size_t)secret_len);
*p = OSSL_PARAM_construct_end();
if (EVP_KDF_derive(kctx, out, out_len, params) <= 0) {
return 0;
}
EVP_KDF_CTX_free(kctx);
return 1;
}

X509_ALGOR *ossl_cmp_rsakem_algor(OSSL_CMP_CTX *ctx)
{
X509_ALGOR *kemrsa_algo = NULL;
OSSL_CMP_RSAKEMPARAMETERS *param = NULL;
ASN1_STRING *stmp = NULL;

if ((param = OSSL_CMP_RSAKEMPARAMETERS_new()) == NULL
|| (param->KeyDerivationFunction
= ossl_cmp_kem_kdf_algor(ctx, NID_id_kdf_kdf2)) == NULL
|| !ASN1_INTEGER_set(param->KeyLength, RSAKEM_KEYLENGTH))
goto err;

if (ASN1_item_pack(param, ASN1_ITEM_rptr(OSSL_CMP_RSAKEMPARAMETERS),
&stmp) == NULL)
goto err;
kemrsa_algo = ossl_X509_ALGOR_from_nid(NID_id_kem_rsa,
V_ASN1_SEQUENCE, stmp);
if (kemrsa_algo == NULL)
goto err;
stmp = NULL;
err:
OSSL_CMP_RSAKEMPARAMETERS_free(param);
ASN1_STRING_free(stmp);
return kemrsa_algo;
}

int ossl_cmp_kemrsa_decapsulation(OSSL_CMP_CTX *ctx, EVP_PKEY *pkey,
const unsigned char *ct, size_t ct_len,
unsigned char **secret, size_t *secret_len)
{
int ret = 0;
size_t sec_len;
unsigned char *sec;

if (ctx == NULL || pkey == NULL
|| ct == NULL
|| secret == NULL || secret_len == NULL)
return 0;

if (EVP_PKEY_get_base_id(pkey) != EVP_PKEY_RSA)
return 0;

EVP_PKEY_CTX *kem_decaps_ctx = EVP_PKEY_CTX_new_from_pkey(ctx->libctx,
pkey,
ctx->propq);

if (kem_decaps_ctx == NULL
|| EVP_PKEY_decapsulate_init(kem_decaps_ctx, NULL) <= 0
|| EVP_PKEY_CTX_set_kem_op(kem_decaps_ctx, "RSASVE") <= 0
|| EVP_PKEY_decapsulate(kem_decaps_ctx, NULL, &sec_len,
ct, ct_len) <= 0) {
goto err;
}

sec = OPENSSL_malloc(sec_len);
if (sec == NULL)
goto err;

if (EVP_PKEY_decapsulate(kem_decaps_ctx,
sec, &sec_len,
ct, ct_len) <= 0) {
OPENSSL_free(sec);
goto err;
}

*secret_len = RSAKEM_KEYLENGTH;
*secret = OPENSSL_malloc(*secret_len);
if (*secret == NULL) {
OPENSSL_clear_free(sec, sec_len);
goto err;
}

if (!kdf2(ctx, sec, sec_len, *secret, *secret_len)) {
OPENSSL_clear_free(sec, sec_len);
OPENSSL_clear_free(*secret, *secret_len);
goto err;
}
OPENSSL_clear_free(sec, sec_len);
ret = 1;
err:
EVP_PKEY_CTX_free(kem_decaps_ctx);
return ret;
}

int ossl_cmp_kemrsa_encapsulation(OSSL_CMP_CTX *ctx,
const EVP_PKEY *pubkey,
size_t *secret_len, unsigned char **secret,
size_t *ct_len, unsigned char **ct)
{
int ret = 0;
size_t sec_len;
unsigned char *sec;
EVP_PKEY_CTX *kem_encaps_ctx;

if (ctx == NULL || pubkey == NULL
|| ct == NULL
|| secret == NULL || secret_len == NULL)
return 0;

if (EVP_PKEY_get_base_id(pubkey) != EVP_PKEY_RSA)
return 0;

kem_encaps_ctx = EVP_PKEY_CTX_new_from_pkey(ctx->libctx,
(EVP_PKEY *)pubkey,
ctx->propq);

if (kem_encaps_ctx == NULL
|| EVP_PKEY_encapsulate_init(kem_encaps_ctx, NULL) <= 0
|| EVP_PKEY_CTX_set_kem_op(kem_encaps_ctx, "RSASVE") <= 0
|| EVP_PKEY_encapsulate(kem_encaps_ctx, NULL, ct_len,
NULL, &sec_len) <= 0) {
goto err;
}

*ct = OPENSSL_malloc(*ct_len);
if (*ct == NULL)
goto err;

sec = OPENSSL_malloc(sec_len);
if (sec == NULL) {
OPENSSL_free(*ct);
goto err;
}

if (EVP_PKEY_encapsulate(kem_encaps_ctx, *ct, ct_len,
sec, &sec_len) <= 0) {
OPENSSL_free(*ct);
OPENSSL_free(sec);
goto err;
}

*secret_len = RSAKEM_KEYLENGTH;
*secret = OPENSSL_malloc(*secret_len);
if (*secret == NULL) {
OPENSSL_clear_free(sec, sec_len);
goto err;
}

if (!kdf2(ctx, sec, sec_len, *secret, *secret_len)) {
OPENSSL_clear_free(sec, sec_len);
OPENSSL_clear_free(*secret, *secret_len);
OPENSSL_clear_free(*ct, *ct_len);
goto err;
}
OPENSSL_clear_free(sec, sec_len);
ret = 1;
err:
EVP_PKEY_CTX_free(kem_encaps_ctx);
return ret;
}
11 changes: 11 additions & 0 deletions crypto/cmp/cmp_local.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1063,6 +1063,7 @@ int ossl_cmp_exchange_error(OSSL_CMP_CTX *ctx, int status, int fail_info,

/* from cmp_kem.c */
X509_ALGOR *ossl_cmp_kem_BasedMac_algor(const OSSL_CMP_CTX *ctx);
X509_ALGOR *ossl_cmp_kem_kdf_algor(const OSSL_CMP_CTX *ctx, int nid_kdf);
int ossl_cmp_kem_BasedMac_required(OSSL_CMP_CTX *ctx);
int ossl_cmp_kem_derivessk(OSSL_CMP_CTX *ctx,
unsigned char *secret, int secret_len,
Expand All @@ -1076,6 +1077,16 @@ int ossl_cmp_kem_derive_ssk_using_srvcert(OSSL_CMP_CTX *ctx,
OSSL_CMP_ITAV *ossl_cmp_kem_get_KemCiphertext(OSSL_CMP_CTX *ctx,
const EVP_PKEY *pubkey);

/* from cmp_kemrsa.c */
X509_ALGOR *ossl_cmp_rsakem_algor(OSSL_CMP_CTX *ctx);
int ossl_cmp_kemrsa_decapsulation(OSSL_CMP_CTX *ctx, EVP_PKEY *pkey,
const unsigned char *ct, size_t ct_len,
unsigned char **secret, size_t *secret_len);
int ossl_cmp_kemrsa_encapsulation(OSSL_CMP_CTX *ctx,
const EVP_PKEY *pubkey,
size_t *secret_len, unsigned char **secret,
size_t *ct_len, unsigned char **ct);

/* from cmp_genm.c */
OSSL_CMP_ITAV *ossl_cmp_genm_get_itav(OSSL_CMP_CTX *ctx,
OSSL_CMP_ITAV *req, /* gets consumed */
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