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#include "locktime.h"
#include "pubkey.h"
#include "script.h"
#include "signature.h"
#include "tx.h"
#include <assert.h>
#include <ccan/crypto/ripemd160/ripemd160.h>
#include <ccan/crypto/sha256/sha256.h>
#include <ccan/endian/endian.h>
#include <ccan/mem/mem.h>
/* Some standard ops */
#define OP_0 0x00
#define OP_PUSHBYTES(val) (val)
#define OP_PUSHDATA1 0x4C
#define OP_PUSHDATA2 0x4D
#define OP_PUSHDATA4 0x4E
#define OP_NOP 0x61
#define OP_IF 0x63
#define OP_NOTIF 0x64
#define OP_ELSE 0x67
#define OP_ENDIF 0x68
#define OP_2DROP 0x6d
#define OP_DEPTH 0x74
#define OP_DROP 0x75
#define OP_DUP 0x76
#define OP_SWAP 0x7c
#define OP_EQUAL 0x87
#define OP_EQUALVERIFY 0x88
#define OP_SIZE 0x82
#define OP_1SUB 0x8C
#define OP_ADD 0x93
#define OP_CHECKSIG 0xAC
#define OP_CHECKMULTISIG 0xAE
#define OP_HASH160 0xA9
#define OP_CHECKSEQUENCEVERIFY 0xB2
#define OP_CHECKLOCKTIMEVERIFY 0xB1
/* Bitcoin's OP_HASH160 is RIPEMD(SHA256()) */
static void hash160(struct ripemd160 *redeemhash, const void *mem, size_t len)
{
struct sha256 h;
sha256(&h, mem, len);
ripemd160(redeemhash, h.u.u8, sizeof(h));
}
static void add(u8 **scriptp, const void *mem, size_t len)
{
size_t oldlen = tal_count(*scriptp);
tal_resize(scriptp, oldlen + len);
memcpy(*scriptp + oldlen, mem, len);
}
static void add_op(u8 **scriptp, u8 op)
{
add(scriptp, &op, 1);
}
static void add_push_bytes(u8 **scriptp, const void *mem, size_t len)
{
if (len < 76)
add_op(scriptp, OP_PUSHBYTES(len));
else if (len < 256) {
char c = len;
add_op(scriptp, OP_PUSHDATA1);
add(scriptp, &c, 1);
} else if (len < 65536) {
le16 v = cpu_to_le16(len);
add_op(scriptp, OP_PUSHDATA2);
add(scriptp, &v, 2);
} else {
le32 v = cpu_to_le32(len);
add_op(scriptp, OP_PUSHDATA4);
add(scriptp, &v, 4);
}
add(scriptp, memcheck(mem, len), len);
}
static void add_number(u8 **script, u32 num)
{
if (num == 0)
add_op(script, 0);
else if (num <= 16)
add_op(script, 0x50 + num);
else {
le32 n = cpu_to_le32(num);
if (num <= 0x000000FF)
add_push_bytes(script, &n, 1);
else if (num <= 0x0000FFFF)
add_push_bytes(script, &n, 2);
else if (num <= 0x00FFFFFF)
add_push_bytes(script, &n, 3);
else
add_push_bytes(script, &n, 4);
}
}
static void add_push_key(u8 **scriptp, const struct pubkey *key)
{
u8 der[PUBKEY_DER_LEN];
pubkey_to_der(der, key);
add_push_bytes(scriptp, der, sizeof(der));
}
static u8 *stack_key(const tal_t *ctx, const struct pubkey *key)
{
u8 der[PUBKEY_DER_LEN];
pubkey_to_der(der, key);
return tal_dup_arr(ctx, u8, der, sizeof(der), 0);
}
/* Bitcoin wants DER encoding. */
static u8 *stack_sig(const tal_t *ctx, const struct bitcoin_signature *sig)
{
u8 der[73];
size_t len = signature_to_der(der, &sig->sig);
/* Append sighash type */
der[len++] = sig->stype;
return tal_dup_arr(ctx, u8, der, len, 0);
}
/* Bitcoin script stack values are a special, special snowflake.
*
* They're little endian values, but 0 is an empty value. We only
* handle single byte values here. */
static u8 *stack_number(const tal_t *ctx, unsigned int num)
{
u8 val;
if (num == 0)
return tal_arr(ctx, u8, 0);
val = num;
assert(val == num);
/* We use tal_dup_arr since we want tal_count() to work */
return tal_dup_arr(ctx, u8, &val, 1, 0);
}
/* Is a < b? (If equal we don't care) */
static bool key_less(const struct pubkey *a, const struct pubkey *b)
{
u8 a_der[PUBKEY_DER_LEN], b_der[PUBKEY_DER_LEN];
pubkey_to_der(a_der, a);
pubkey_to_der(b_der, b);
return memcmp(a_der, b_der, sizeof(a_der)) < 0;
}
/* tal_count() gives the length of the script. */
u8 *bitcoin_redeem_2of2(const tal_t *ctx,
const struct pubkey *key1,
const struct pubkey *key2)
{
u8 *script = tal_arr(ctx, u8, 0);
add_number(&script, 2);
if (key_less(key1, key2)) {
add_push_key(&script, key1);
add_push_key(&script, key2);
} else {
add_push_key(&script, key2);
add_push_key(&script, key1);
}
add_number(&script, 2);
add_op(&script, OP_CHECKMULTISIG);
return script;
}
/* tal_count() gives the length of the script. */
u8 *bitcoin_redeem_single(const tal_t *ctx, const struct pubkey *key)
{
u8 *script = tal_arr(ctx, u8, 0);
add_push_key(&script, key);
add_op(&script, OP_CHECKSIG);
return script;
}
/* Create p2sh for this redeem script. */
u8 *scriptpubkey_p2sh(const tal_t *ctx, const u8 *redeemscript)
{
struct ripemd160 redeemhash;
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_HASH160);
hash160(&redeemhash, redeemscript, tal_count(redeemscript));
add_push_bytes(&script, redeemhash.u.u8, sizeof(redeemhash.u.u8));
add_op(&script, OP_EQUAL);
return script;
}
/* Create the redeemscript for a P2SH + P2WPKH (for signing tx) */
u8 *bitcoin_redeem_p2wpkh(const tal_t *ctx, const struct pubkey *key)
{
struct ripemd160 keyhash;
u8 der[PUBKEY_DER_LEN];
u8 *script = tal_arr(ctx, u8, 0);
/* BIP141: BIP16 redeemScript pushed in the scriptSig is exactly a
* push of a version byte plus a push of a witness program. */
add_number(&script, 0);
pubkey_to_der(der, key);
hash160(&keyhash, der, sizeof(der));
add_push_bytes(&script, &keyhash, sizeof(keyhash));
return script;
}
/* Create an input which spends the p2sh-p2wpkh. */
void bitcoin_witness_p2sh_p2wpkh(const tal_t *ctx,
struct bitcoin_tx_input *input,
const struct bitcoin_signature *sig,
const struct pubkey *key)
{
u8 *redeemscript = bitcoin_redeem_p2wpkh(ctx, key);
/* BIP141: The scriptSig must be exactly a push of the BIP16 redeemScript
* or validation fails. */
input->script = tal_arr(ctx, u8, 0);
add_push_bytes(&input->script, redeemscript, tal_count(redeemscript));
input->script_length = tal_count(input->script);
tal_free(redeemscript);
/* BIP141: The witness must consist of exactly 2 items (≤ 520
* bytes each). The first one a signature, and the second one
* a public key. */
input->witness = tal_arr(ctx, u8 *, 2);
input->witness[0] = stack_sig(input->witness, sig);
input->witness[1] = stack_key(input->witness, key);
}
/* Create an output script for a 32-byte witness. */
u8 *scriptpubkey_p2wsh(const tal_t *ctx, const u8 *witnessscript)
{
struct sha256 h;
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_0);
sha256(&h, witnessscript, tal_count(witnessscript));
add_push_bytes(&script, h.u.u8, sizeof(h.u.u8));
return script;
}
/* Create an output script for a 20-byte witness. */
u8 *scriptpubkey_p2wpkh(const tal_t *ctx, const struct pubkey *key)
{
struct ripemd160 h;
u8 der[PUBKEY_DER_LEN];
u8 *script = tal_arr(ctx, u8, 0);
add_op(&script, OP_0);
pubkey_to_der(der, key);
hash160(&h, der, sizeof(der));
add_push_bytes(&script, &h, sizeof(h));
return script;
}
/* Create a witness which spends the 2of2. */
u8 **bitcoin_witness_2of2(const tal_t *ctx,
const struct bitcoin_signature *sig1,
const struct bitcoin_signature *sig2,
const struct pubkey *key1,
const struct pubkey *key2)
{
u8 **witness = tal_arr(ctx, u8 *, 4);
/* OP_CHECKMULTISIG has an out-by-one bug, which MBZ */
witness[0] = stack_number(witness, 0);
/* sig order should match key order. */
if (key_less(key1, key2)) {
witness[1] = stack_sig(witness, sig1);
witness[2] = stack_sig(witness, sig2);
} else {
witness[1] = stack_sig(witness, sig2);
witness[2] = stack_sig(witness, sig1);
}
witness[3] = bitcoin_redeem_2of2(witness, key1, key2);
return witness;
}
/* Create a script for our HTLC output: sending. */
u8 *bitcoin_redeem_htlc_send(const tal_t *ctx,
const struct pubkey *ourkey,
const struct pubkey *theirkey,
const struct abs_locktime *htlc_abstimeout,
const struct rel_locktime *locktime,
const struct sha256 *commit_revoke,
const struct sha256 *rhash)
{
/* R value presented: -> them.
* Commit revocation value presented: -> them.
* HTLC times out -> us. */
u8 *script = tal_arr(ctx, u8, 0);
struct ripemd160 ripemd;
/* Must be 32 bytes long. */
add_op(&script, OP_SIZE);
add_number(&script, 32);
add_op(&script, OP_EQUALVERIFY);
add_op(&script, OP_HASH160);
add_op(&script, OP_DUP);
/* Did they supply HTLC R value? */
ripemd160(&ripemd, rhash->u.u8, sizeof(rhash->u));
add_push_bytes(&script, &ripemd, sizeof(ripemd));
add_op(&script, OP_EQUAL);
add_op(&script, OP_SWAP);
/* How about commit revocation value? */
ripemd160(&ripemd, commit_revoke->u.u8, sizeof(commit_revoke->u));
add_push_bytes(&script, &ripemd, sizeof(ripemd));
add_op(&script, OP_EQUAL);
add_op(&script, OP_ADD);
/* If either matched... */
add_op(&script, OP_IF);
add_push_key(&script, theirkey);
add_op(&script, OP_ELSE);
/* If HTLC times out, they can collect after a delay. */
add_number(&script, htlc_abstimeout->locktime);
add_op(&script, OP_CHECKLOCKTIMEVERIFY);
add_number(&script, locktime->locktime);
add_op(&script, OP_CHECKSEQUENCEVERIFY);
add_op(&script, OP_2DROP);
add_push_key(&script, ourkey);
add_op(&script, OP_ENDIF);
add_op(&script, OP_CHECKSIG);
return script;
}
/* Create a script for our HTLC output: receiving. */
u8 *bitcoin_redeem_htlc_recv(const tal_t *ctx,
const struct pubkey *ourkey,
const struct pubkey *theirkey,
const struct abs_locktime *htlc_abstimeout,
const struct rel_locktime *locktime,
const struct sha256 *commit_revoke,
const struct sha256 *rhash)
{
/* R value presented: -> us.
* Commit revocation value presented: -> them.
* HTLC times out -> them. */
u8 *script = tal_arr(ctx, u8, 0);
struct ripemd160 ripemd;
add_op(&script, OP_SIZE);
add_number(&script, 32);
add_op(&script, OP_EQUALVERIFY);
add_op(&script, OP_HASH160);
add_op(&script, OP_DUP);
/* Did we supply HTLC R value? */
ripemd160(&ripemd, rhash->u.u8, sizeof(rhash->u));
add_push_bytes(&script, &ripemd, sizeof(ripemd));
add_op(&script, OP_EQUAL);
add_op(&script, OP_IF);
add_number(&script, locktime->locktime);
add_op(&script, OP_CHECKSEQUENCEVERIFY);
/* Drop extra hash as well as locktime. */
add_op(&script, OP_2DROP);
add_push_key(&script, ourkey);
add_op(&script, OP_ELSE);
/* If they provided commit revocation, available immediately. */
ripemd160(&ripemd, commit_revoke->u.u8, sizeof(commit_revoke->u));
add_push_bytes(&script, &ripemd, sizeof(ripemd));
add_op(&script, OP_EQUAL);
add_op(&script, OP_NOTIF);
/* Otherwise, they must wait for HTLC timeout. */
add_number(&script, htlc_abstimeout->locktime);
add_op(&script, OP_CHECKLOCKTIMEVERIFY);
add_op(&script, OP_DROP);
add_op(&script, OP_ENDIF);
add_push_key(&script, theirkey);
add_op(&script, OP_ENDIF);
add_op(&script, OP_CHECKSIG);
return script;
}
/* Create scriptcode (fake witness, basically) for P2WPKH */
u8 *p2wpkh_scriptcode(const tal_t *ctx, const struct pubkey *key)
{
struct sha256 h;
struct ripemd160 pkhash;
u8 der[PUBKEY_DER_LEN];
u8 *script = tal_arr(ctx, u8, 0);
pubkey_to_der(der, key);
sha256(&h, der, sizeof(der));
ripemd160(&pkhash, h.u.u8, sizeof(h));
/* BIP143:
*
* For P2WPKH witness program, the scriptCode is
* 0x1976a914{20-byte-pubkey-hash}88ac.
*/
/* PUSH(25): OP_DUP OP_HASH160 PUSH(20) 20-byte-pubkey-hash
* OP_EQUALVERIFY OP_CHECKSIG */
add_op(&script, OP_DUP);
add_op(&script, OP_HASH160);
add_push_bytes(&script, &pkhash, sizeof(pkhash));
add_op(&script, OP_EQUALVERIFY);
add_op(&script, OP_CHECKSIG);
return script;
}
bool is_p2pkh(const u8 *script, size_t script_len)
{
if (script_len != 25)
return false;
if (script[0] != OP_DUP)
return false;
if (script[1] != OP_HASH160)
return false;
if (script[2] != OP_PUSHBYTES(20))
return false;
if (script[23] != OP_EQUALVERIFY)
return false;
if (script[24] != OP_CHECKSIG)
return false;
return true;
}
bool is_p2sh(const u8 *script, size_t script_len)
{
if (script_len != 23)
return false;
if (script[0] != OP_HASH160)
return false;
if (script[1] != OP_PUSHBYTES(20))
return false;
if (script[22] != OP_EQUAL)
return false;
return true;
}
bool is_p2wsh(const u8 *script, size_t script_len)
{
if (script_len != 1 + 1 + sizeof(struct sha256))
return false;
if (script[0] != OP_0)
return false;
if (script[1] != OP_PUSHBYTES(sizeof(struct sha256)))
return false;
return true;
}
bool is_p2wpkh(const u8 *script, size_t script_len)
{
if (script_len != 1 + 1 + sizeof(struct ripemd160))
return false;
if (script[0] != OP_0)
return false;
if (script[1] != OP_PUSHBYTES(sizeof(struct ripemd160)))
return false;
return true;
}
/* A common script pattern: A can have it with secret, or B can have
* it after delay. */
u8 *bitcoin_redeem_secret_or_delay(const tal_t *ctx,
const struct pubkey *delayed_key,
const struct rel_locktime *locktime,
const struct pubkey *key_if_secret_known,
const struct sha256 *hash_of_secret)
{
struct ripemd160 ripemd;
u8 *script = tal_arr(ctx, u8, 0);
ripemd160(&ripemd, hash_of_secret->u.u8, sizeof(hash_of_secret->u));
/* If the secret is supplied.... */
add_op(&script, OP_HASH160);
add_push_bytes(&script, ripemd.u.u8, sizeof(ripemd.u.u8));
add_op(&script, OP_EQUAL);
add_op(&script, OP_IF);
/* They can collect the funds. */
add_push_key(&script, key_if_secret_known);
add_op(&script, OP_ELSE);
/* Other can collect after a delay. */
add_number(&script, locktime->locktime);
add_op(&script, OP_CHECKSEQUENCEVERIFY);
add_op(&script, OP_DROP);
add_push_key(&script, delayed_key);
add_op(&script, OP_ENDIF);
add_op(&script, OP_CHECKSIG);
return script;
}
u8 **bitcoin_witness_secret(const tal_t *ctx,
const void *secret, size_t secret_len,
const struct bitcoin_signature *sig,
const u8 *witnessscript)
{
u8 **witness = tal_arr(ctx, u8 *, 3);
witness[0] = stack_sig(witness, sig);
witness[1] = tal_dup_arr(witness, u8, secret, secret_len, 0);
witness[2] = tal_dup_arr(witness, u8,
witnessscript, tal_count(witnessscript), 0);
return witness;
}
u8 **bitcoin_witness_htlc(const tal_t *ctx,
const void *htlc_or_revocation_preimage,
const struct bitcoin_signature *sig,
const u8 *witnessscript)
{
static const struct sha256 no_preimage;
/* Use 32 zeroes if no preimage. */
if (!htlc_or_revocation_preimage)
htlc_or_revocation_preimage = &no_preimage;
return bitcoin_witness_secret(ctx,
htlc_or_revocation_preimage,
32, sig, witnessscript);
}
bool scripteq(const u8 *s1, size_t s1len, const u8 *s2, size_t s2len)
{
memcheck(s1, s1len);
memcheck(s2, s2len);
if (s1len != s2len)
return false;
return memcmp(s1, s2, s1len) == 0;
}