mirror of
https://github.com/ElementsProject/lightning.git
synced 2025-01-18 13:25:43 +01:00
71 lines
1.6 KiB
C
71 lines
1.6 KiB
C
#include "signature.h"
|
|
#include "shadouble.h"
|
|
#include "bitcoin_tx.h"
|
|
#include <openssl/bn.h>
|
|
#include <openssl/obj_mac.h>
|
|
#include <assert.h>
|
|
#include <ccan/cast/cast.h>
|
|
|
|
u8 *sign_hash(const tal_t *ctx, EC_KEY *private_key,
|
|
const struct sha256_double *h)
|
|
{
|
|
ECDSA_SIG *sig;
|
|
int len;
|
|
unsigned char *der, *ret;
|
|
|
|
sig = ECDSA_do_sign(h->sha.u.u8, sizeof(*h), private_key);
|
|
if (!sig)
|
|
return NULL;
|
|
|
|
/* See https://github.com/sipa/bitcoin/commit/a81cd9680.
|
|
* There can only be one signature with an even S, so make sure we
|
|
* get that one. */
|
|
if (BN_is_odd(sig->s)) {
|
|
const EC_GROUP *group;
|
|
BIGNUM order;
|
|
|
|
BN_init(&order);
|
|
group = EC_KEY_get0_group(private_key);
|
|
EC_GROUP_get_order(group, &order, NULL);
|
|
BN_sub(sig->s, &order, sig->s);
|
|
BN_free(&order);
|
|
|
|
assert(!BN_is_odd(sig->s));
|
|
}
|
|
|
|
/* This tells it to allocate for us. */
|
|
der = NULL;
|
|
len = i2d_ECDSA_SIG(sig, &der);
|
|
ECDSA_SIG_free(sig);
|
|
|
|
if (len <= 0)
|
|
return NULL;
|
|
|
|
ret = tal_dup_arr(ctx, u8, der, len, 0);
|
|
OPENSSL_free(der);
|
|
return ret;
|
|
}
|
|
|
|
u8 *sign_tx_input(const tal_t *ctx, struct bitcoin_tx *tx, unsigned int in,
|
|
const u8 *subscript, size_t subscript_len, EC_KEY *privkey)
|
|
{
|
|
struct sha256_double hash;
|
|
struct sha256_ctx shactx;
|
|
|
|
/* Transaction gets signed as if the output subscript is the
|
|
* only input script. */
|
|
tx->input[in].script_length = subscript_len;
|
|
tx->input[in].script = cast_const(u8 *, subscript);
|
|
|
|
sha256_init(&shactx);
|
|
sha256_tx(&shactx, tx);
|
|
sha256_le32(&shactx, SIGHASH_ALL);
|
|
sha256_double_done(&shactx, &hash);
|
|
|
|
/* Reset it for next time. */
|
|
tx->input[in].script_length = 0;
|
|
tx->input[in].script = NULL;
|
|
|
|
return sign_hash(ctx, privkey, &hash);
|
|
}
|