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/*
* Copyright (c) 2016 DeNA Co., Ltd., Kazuho Oku
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WINDOWS
#include "wincompat.h"
#else
#include <unistd.h>
#endif
#include "sha2.h"
#include "uECC.h"
#include "uECC_vli.h"
#include "picotls.h"
#include "picotls/minicrypto.h"
#define TYPE_UNCOMPRESSED_PUBLIC_KEY 4
struct st_secp256r1_key_exhchange_t {
ptls_key_exchange_context_t super;
uint8_t priv[SECP256R1_PRIVATE_KEY_SIZE];
uint8_t pub[SECP256R1_PUBLIC_KEY_SIZE];
};
static int secp256r1_on_exchange(ptls_key_exchange_context_t **_ctx, ptls_iovec_t *secret, ptls_iovec_t peerkey)
{
struct st_secp256r1_key_exhchange_t *ctx = (struct st_secp256r1_key_exhchange_t *)*_ctx;
uint8_t *secbytes = NULL;
int ret;
*_ctx = NULL;
if (secret == NULL) {
ret = 0;
goto Exit;
}
if (peerkey.len != SECP256R1_PUBLIC_KEY_SIZE || peerkey.base[0] != TYPE_UNCOMPRESSED_PUBLIC_KEY) {
ret = PTLS_ALERT_DECRYPT_ERROR;
goto Exit;
}
if ((secbytes = (uint8_t *)malloc(SECP256R1_SHARED_SECRET_SIZE)) == NULL) {
ret = PTLS_ERROR_NO_MEMORY;
goto Exit;
}
if (!uECC_shared_secret(peerkey.base + 1, ctx->priv, secbytes, uECC_secp256r1())) {
ret = PTLS_ALERT_DECRYPT_ERROR;
goto Exit;
}
*secret = ptls_iovec_init(secbytes, SECP256R1_SHARED_SECRET_SIZE);
ret = 0;
Exit:
if (ret != 0)
free(secbytes);
ptls_clear_memory(ctx->priv, sizeof(ctx->priv));
free(ctx);
return ret;
}
static int secp256r1_create_key_exchange(ptls_key_exchange_context_t **_ctx, ptls_iovec_t *pubkey)
{
struct st_secp256r1_key_exhchange_t *ctx;
if ((ctx = (struct st_secp256r1_key_exhchange_t *)malloc(sizeof(*ctx))) == NULL)
return PTLS_ERROR_NO_MEMORY;
ctx->super = (ptls_key_exchange_context_t){secp256r1_on_exchange};
ctx->pub[0] = TYPE_UNCOMPRESSED_PUBLIC_KEY;
uECC_make_key(ctx->pub + 1, ctx->priv, uECC_secp256r1());
*_ctx = &ctx->super;
*pubkey = ptls_iovec_init(ctx->pub, sizeof(ctx->pub));
return 0;
}
static int secp256r1_key_exchange(ptls_iovec_t *pubkey, ptls_iovec_t *secret, ptls_iovec_t peerkey)
{
uint8_t priv[SECP256R1_PRIVATE_KEY_SIZE], *pub = NULL, *secbytes = NULL;
int ret;
if (peerkey.len != SECP256R1_PUBLIC_KEY_SIZE || peerkey.base[0] != TYPE_UNCOMPRESSED_PUBLIC_KEY) {
ret = PTLS_ALERT_DECRYPT_ERROR;
goto Exit;
}
if ((pub = malloc(SECP256R1_PUBLIC_KEY_SIZE)) == NULL) {
ret = PTLS_ERROR_NO_MEMORY;
goto Exit;
}
if ((secbytes = malloc(SECP256R1_SHARED_SECRET_SIZE)) == NULL) {
ret = PTLS_ERROR_NO_MEMORY;
goto Exit;
}
pub[0] = TYPE_UNCOMPRESSED_PUBLIC_KEY;
uECC_make_key(pub + 1, priv, uECC_secp256r1());
if (!uECC_shared_secret(peerkey.base + 1, priv, secbytes, uECC_secp256r1())) {
ret = PTLS_ALERT_DECRYPT_ERROR;
goto Exit;
}
*pubkey = ptls_iovec_init(pub, SECP256R1_PUBLIC_KEY_SIZE);
*secret = ptls_iovec_init(secbytes, SECP256R1_SHARED_SECRET_SIZE);
ret = 0;
Exit:
ptls_clear_memory(priv, sizeof(priv));
if (ret != 0) {
free(secbytes);
free(pub);
}
return ret;
}
static int secp256r1sha256_sign(ptls_sign_certificate_t *_self, ptls_t *tls, uint16_t *selected_algorithm, ptls_buffer_t *outbuf,
ptls_iovec_t input, const uint16_t *algorithms, size_t num_algorithms)
{
ptls_minicrypto_secp256r1sha256_sign_certificate_t *self = (ptls_minicrypto_secp256r1sha256_sign_certificate_t *)_self;
uint8_t hash[32], sig[64];
size_t i;
int ret;
/* check algorithm */
for (i = 0; i != num_algorithms; ++i)
if (algorithms[i] == PTLS_SIGNATURE_ECDSA_SECP256R1_SHA256)
break;
if (i == num_algorithms)
return PTLS_ALERT_HANDSHAKE_FAILURE;
{ /* calc hash */
cf_sha256_context ctx;
cf_sha256_init(&ctx);
cf_sha256_update(&ctx, input.base, input.len);
cf_sha256_digest_final(&ctx, hash);
ptls_clear_memory(&ctx, sizeof(ctx));
}
/* sign */
uECC_sign(self->key, hash, sizeof(hash), sig, uECC_secp256r1());
/* encode using DER */
ptls_buffer_push_asn1_sequence(outbuf, {
if ((ret = ptls_buffer_push_asn1_ubigint(outbuf, sig, 32)) != 0)
goto Exit;
if ((ret = ptls_buffer_push_asn1_ubigint(outbuf, sig + 32, 32)) != 0)
goto Exit;
});
*selected_algorithm = PTLS_SIGNATURE_ECDSA_SECP256R1_SHA256;
ret = 0;
Exit:
ptls_clear_memory(hash, sizeof(hash));
ptls_clear_memory(sig, sizeof(sig));
return ret;
}
int ptls_minicrypto_init_secp256r1sha256_sign_certificate(ptls_minicrypto_secp256r1sha256_sign_certificate_t *self,
ptls_iovec_t key)
{
if (key.len != sizeof(self->key))
return PTLS_ERROR_INCOMPATIBLE_KEY;
self->super.cb = secp256r1sha256_sign;
memcpy(self->key, key.base, sizeof(self->key));
return 0;
}
ptls_key_exchange_algorithm_t ptls_minicrypto_secp256r1 = {PTLS_GROUP_SECP256R1, secp256r1_create_key_exchange,
secp256r1_key_exchange};
ptls_key_exchange_algorithm_t *ptls_minicrypto_key_exchanges[] = {&ptls_minicrypto_secp256r1, NULL};
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