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/*
* Copyright 2020 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
*/
/*
* RSA low level APIs are deprecated for public use, but still ok for
* internal use.
*/
#include "internal/deprecated.h"
#include "e_os.h" /* strcasecmp */
#include <openssl/crypto.h>
#include <openssl/evp.h>
#include <openssl/core_dispatch.h>
#include <openssl/core_names.h>
#include <openssl/rsa.h>
#include <openssl/params.h>
#include <openssl/err.h>
#include <crypto/rsa.h>
#include "prov/providercommonerr.h"
#include "prov/provider_ctx.h"
#include "prov/implementations.h"
#include "prov/securitycheck.h"
static OSSL_FUNC_kem_newctx_fn rsakem_newctx;
static OSSL_FUNC_kem_encapsulate_init_fn rsakem_encapsulate_init;
static OSSL_FUNC_kem_encapsulate_fn rsakem_generate;
static OSSL_FUNC_kem_decapsulate_init_fn rsakem_decapsulate_init;
static OSSL_FUNC_kem_decapsulate_fn rsakem_recover;
static OSSL_FUNC_kem_freectx_fn rsakem_freectx;
static OSSL_FUNC_kem_dupctx_fn rsakem_dupctx;
static OSSL_FUNC_kem_get_ctx_params_fn rsakem_get_ctx_params;
static OSSL_FUNC_kem_gettable_ctx_params_fn rsakem_gettable_ctx_params;
static OSSL_FUNC_kem_set_ctx_params_fn rsakem_set_ctx_params;
static OSSL_FUNC_kem_settable_ctx_params_fn rsakem_settable_ctx_params;
/*
* Only the KEM for RSASVE as defined in SP800-56b r2 is implemented
* currently.
*/
#define KEM_OP_UNDEFINED -1
#define KEM_OP_RSASVE 0
/*
* What's passed as an actual key is defined by the KEYMGMT interface.
* We happen to know that our KEYMGMT simply passes RSA structures, so
* we use that here too.
*/
typedef struct {
OSSL_LIB_CTX *libctx;
RSA *rsa;
int op;
} PROV_RSA_CTX;
static const OSSL_ITEM rsakem_opname_id_map[] = {
{ KEM_OP_RSASVE, OSSL_KEM_PARAM_OPERATION_RSASVE },
};
static int name2id(const char *name, const OSSL_ITEM *map, size_t sz)
{
size_t i;
if (name == NULL)
return -1;
for (i = 0; i < sz; ++i) {
if (strcasecmp(map[i].ptr, name) == 0)
return map[i].id;
}
return -1;
}
static int rsakem_opname2id(const char *name)
{
return name2id(name, rsakem_opname_id_map, OSSL_NELEM(rsakem_opname_id_map));
}
static void *rsakem_newctx(void *provctx)
{
PROV_RSA_CTX *prsactx = OPENSSL_zalloc(sizeof(PROV_RSA_CTX));
if (prsactx == NULL)
return NULL;
prsactx->libctx = PROV_LIBCTX_OF(provctx);
prsactx->op = KEM_OP_UNDEFINED;
return prsactx;
}
static void rsakem_freectx(void *vprsactx)
{
PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;
RSA_free(prsactx->rsa);
OPENSSL_free(prsactx);
}
static void *rsakem_dupctx(void *vprsactx)
{
PROV_RSA_CTX *srcctx = (PROV_RSA_CTX *)vprsactx;
PROV_RSA_CTX *dstctx;
dstctx = OPENSSL_zalloc(sizeof(*srcctx));
if (dstctx == NULL)
return NULL;
*dstctx = *srcctx;
if (dstctx->rsa != NULL && !RSA_up_ref(dstctx->rsa)) {
OPENSSL_free(dstctx);
return NULL;
}
return dstctx;
}
static int rsakem_init(void *vprsactx, void *vrsa, int operation)
{
PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;
if (prsactx == NULL || vrsa == NULL || !RSA_up_ref(vrsa))
return 0;
RSA_free(prsactx->rsa);
prsactx->rsa = vrsa;
if (!ossl_rsa_check_key(vrsa, operation == EVP_PKEY_OP_ENCAPSULATE)) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
return 0;
}
return 1;
}
static int rsakem_encapsulate_init(void *vprsactx, void *vrsa)
{
return rsakem_init(vprsactx, vrsa, EVP_PKEY_OP_ENCAPSULATE);
}
static int rsakem_decapsulate_init(void *vprsactx, void *vrsa)
{
return rsakem_init(vprsactx, vrsa, EVP_PKEY_OP_DECAPSULATE);
}
static int rsakem_get_ctx_params(void *vprsactx, OSSL_PARAM *params)
{
PROV_RSA_CTX *ctx = (PROV_RSA_CTX *)vprsactx;
if (ctx == NULL || params == NULL)
return 0;
return 1;
}
static const OSSL_PARAM known_gettable_rsakem_ctx_params[] = {
OSSL_PARAM_END
};
static const OSSL_PARAM *rsakem_gettable_ctx_params(ossl_unused void *provctx)
{
return known_gettable_rsakem_ctx_params;
}
static int rsakem_set_ctx_params(void *vprsactx, const OSSL_PARAM params[])
{
PROV_RSA_CTX *prsactx = (PROV_RSA_CTX *)vprsactx;
const OSSL_PARAM *p;
int op;
if (prsactx == NULL || params == NULL)
return 0;
p = OSSL_PARAM_locate_const(params, OSSL_KEM_PARAM_OPERATION);
if (p != NULL) {
if (p->data_type != OSSL_PARAM_UTF8_STRING)
return 0;
op = rsakem_opname2id(p->data);
if (op < 0)
return 0;
prsactx->op = op;
}
return 1;
}
static const OSSL_PARAM known_settable_rsakem_ctx_params[] = {
OSSL_PARAM_utf8_string(OSSL_KEM_PARAM_OPERATION, NULL, 0),
OSSL_PARAM_END
};
static const OSSL_PARAM *rsakem_settable_ctx_params(ossl_unused void *provctx)
{
return known_settable_rsakem_ctx_params;
}
/*
* NIST.SP.800-56Br2
* 7.2.1.2 RSASVE Generate Operation (RSASVE.GENERATE).
*
* Generate a random in the range 1 < z < (n – 1)
*/
static int rsasve_gen_rand_bytes(RSA *rsa_pub,
unsigned char *out, int outlen)
{
int ret = 0;
BN_CTX *bnctx;
BIGNUM *z, *nminus3;
bnctx = BN_CTX_secure_new_ex(ossl_rsa_get0_libctx(rsa_pub));
if (bnctx == NULL)
return 0;
/*
* Generate a random in the range 1 < z < (n – 1).
* Since BN_priv_rand_range_ex() returns a value in range 0 <= r < max
* We can achieve this by adding 2.. but then we need to subtract 3 from
* the upper bound i.e: 2 + (0 <= r < (n - 3))
*/
BN_CTX_start(bnctx);
nminus3 = BN_CTX_get(bnctx);
z = BN_CTX_get(bnctx);
ret = (z != NULL
&& (BN_copy(nminus3, RSA_get0_n(rsa_pub)) != NULL)
&& BN_sub_word(nminus3, 3)
&& BN_priv_rand_range_ex(z, nminus3, bnctx)
&& BN_add_word(z, 2)
&& (BN_bn2binpad(z, out, outlen) == outlen));
BN_CTX_end(bnctx);
BN_CTX_free(bnctx);
return ret;
}
/*
* NIST.SP.800-56Br2
* 7.2.1.2 RSASVE Generate Operation (RSASVE.GENERATE).
*/
static int rsasve_generate(PROV_RSA_CTX *prsactx,
unsigned char *out, size_t *outlen,
unsigned char *secret, size_t *secretlen)
{
int ret;
size_t nlen;
/* Step (1): nlen = Ceil(len(n)/8) */
nlen = RSA_size(prsactx->rsa);
if (out == NULL) {
if (nlen == 0) {
ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY);
return 0;
}
if (outlen == NULL && secretlen == NULL)
return 0;
if (outlen != NULL)
*outlen = nlen;
if (secretlen != NULL)
*secretlen = nlen;
return 1;
}
/*
* Step (2): Generate a random byte string z of nlen bytes where
* 1 < z < n - 1
*/
if (!rsasve_gen_rand_bytes(prsactx->rsa, secret, nlen))
return 0;
/* Step(3): out = RSAEP((n,e), z) */
ret = RSA_public_encrypt(nlen, secret, out, prsactx->rsa, RSA_NO_PADDING);
if (ret) {
ret = 1;
if (outlen != NULL)
*outlen = nlen;
if (secretlen != NULL)
*secretlen = nlen;
} else {
OPENSSL_cleanse(secret, nlen
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