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#include "bitcoin/privkey.h"
#include "bitcoin/shadouble.h"
#include "bitcoin/signature.h"
#include "lightningd.h"
#include "log.h"
#include "peer.h"
#include "peer_internal.h"
#include "secrets.h"
#include "utils.h"
#include <ccan/crypto/sha256/sha256.h>
#include <ccan/crypto/shachain/shachain.h>
#include <ccan/mem/mem.h>
#include <ccan/noerr/noerr.h>
#include <ccan/read_write_all/read_write_all.h>
#include <ccan/short_types/short_types.h>
#include <ccan/tal/str/str.h>
#include <errno.h>
#include <fcntl.h>
#include <secp256k1.h>
#include <sodium/randombytes.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
struct secret {
/* Secret ID of our node; public is dstate->id. */
struct privkey privkey;
};
void privkey_sign(struct lightningd_state *dstate, const void *src, size_t len,
secp256k1_ecdsa_signature *sig)
{
struct sha256_double h;
sha256_double(&h, memcheck(src, len), len);
sign_hash(&dstate->secret->privkey, &h, sig);
}
struct peer_secrets {
/* Two private keys, one for commit txs, one for final output. */
struct privkey commit, final;
/* Seed from which we generate revocation hashes. */
struct sha256 revocation_seed;
};
void peer_sign_theircommit(const struct peer *peer,
struct bitcoin_tx *commit,
secp256k1_ecdsa_signature *sig)
{
/* Commit tx only has one input: that of the anchor. */
sign_tx_input(commit, 0,
NULL,
peer->anchor.witnessscript,
&peer->secrets->commit,
&peer->local.commitkey,
sig);
}
void peer_sign_ourcommit(const struct peer *peer,
struct bitcoin_tx *commit,
secp256k1_ecdsa_signature *sig)
{
/* Commit tx only has one input: that of the anchor. */
sign_tx_input(commit, 0,
NULL,
peer->anchor.witnessscript,
&peer->secrets->commit,
&peer->local.commitkey,
sig);
}
void peer_sign_spend(const struct peer *peer,
struct bitcoin_tx *spend,
const u8 *commit_witnessscript,
secp256k1_ecdsa_signature *sig)
{
/* Spend tx only has one input: that of the commit tx. */
sign_tx_input(spend, 0,
NULL,
commit_witnessscript,
&peer->secrets->final,
&peer->local.finalkey,
sig);
}
void peer_sign_htlc_refund(const struct peer *peer,
struct bitcoin_tx *spend,
const u8 *htlc_witnessscript,
secp256k1_ecdsa_signature *sig)
{
/* Spend tx only has one input: that of the commit tx. */
sign_tx_input(spend, 0,
NULL,
htlc_witnessscript,
&peer->secrets->final,
&peer->local.finalkey,
sig);
}
void peer_sign_htlc_fulfill(const struct peer *peer,
struct bitcoin_tx *spend,
const u8 *htlc_witnessscript,
secp256k1_ecdsa_signature *sig)
{
/* Spend tx only has one input: that of the commit tx. */
sign_tx_input(spend, 0,
NULL,
htlc_witnessscript,
&peer->secrets->final,
&peer->local.finalkey,
sig);
}
void peer_sign_mutual_close(const struct peer *peer,
struct bitcoin_tx *close,
secp256k1_ecdsa_signature *sig)
{
sign_tx_input(close, 0,
NULL,
peer->anchor.witnessscript,
&peer->secrets->commit,
&peer->local.commitkey,
sig);
}
void peer_sign_steal_input(const struct peer *peer,
struct bitcoin_tx *spend,
size_t i,
const u8 *witnessscript,
secp256k1_ecdsa_signature *sig)
{
/* Spend tx only has one input: that of the commit tx. */
sign_tx_input(spend, i,
NULL,
witnessscript,
&peer->secrets->final,
&peer->local.finalkey,
sig);
}
static void new_keypair(struct lightningd_state *dstate,
struct privkey *privkey, struct pubkey *pubkey)
{
do {
randombytes_buf(privkey->secret, sizeof(privkey->secret));
} while (!pubkey_from_privkey(privkey, pubkey));
}
void peer_secrets_init(struct peer *peer)
{
peer->secrets = tal(peer, struct peer_secrets);
new_keypair(peer->dstate, &peer->secrets->commit, &peer->local.commitkey);
new_keypair(peer->dstate, &peer->secrets->final, &peer->local.finalkey);
randombytes_buf(peer->secrets->revocation_seed.u.u8, sizeof(peer->secrets->revocation_seed.u.u8));
}
void peer_get_revocation_preimage(const struct peer *peer, u64 index,
struct sha256 *preimage)
{
// generate hashes in reverse order, otherwise the first hash gives away everything
shachain_from_seed(&peer->secrets->revocation_seed, 0xFFFFFFFFFFFFFFFFL - index, preimage);
}
void peer_get_revocation_hash(const struct peer *peer, u64 index,
struct sha256 *rhash)
{
struct sha256 preimage;
peer_get_revocation_preimage(peer, index, &preimage);
sha256(rhash, preimage.u.u8, sizeof(preimage.u.u8));
}
const char *peer_secrets_for_db(const tal_t *ctx, struct peer *peer)
{
const struct peer_secrets *ps = peer->secrets;
return tal_fmt(ctx, "x'%s', x'%s', x'%s'",
tal_hexstr(ctx, &ps->commit, sizeof(ps->commit)),
tal_hexstr(ctx, &ps->final, sizeof(ps->final)),
tal_hexstr(ctx, &ps->revocation_seed,
sizeof(ps->revocation_seed)));
}
void peer_set_secrets_from_db(struct peer *peer,
const void *commit_privkey,
size_t commit_privkey_len,
const void *final_privkey,
size_t final_privkey_len,
const void *revocation_seed,
size_t revocation_seed_len)
{
struct peer_secrets *ps = tal(peer, struct peer_secrets);
assert(!peer->secrets);
peer->secrets = ps;
if (commit_privkey_len != sizeof(ps->commit)
|| final_privkey_len != sizeof(ps->final)
|| revocation_seed_len != sizeof(ps->revocation_seed))
fatal("peer_set_secrets_from_db: bad lengths %zu/%zu/%zu",
commit_privkey_len, final_privkey_len,
revocation_seed_len);
memcpy(&ps->commit, commit_privkey, commit_privkey_len);
memcpy(&ps->final, final_privkey, final_privkey_len);
memcpy(&ps->revocation_seed, revocation_seed, revocation_seed_len);
if (!pubkey_from_privkey(&ps->commit, &peer->local.commitkey))
fatal("peer_set_secrets_from_db:bad commit privkey");
if (!pubkey_from_privkey(&ps->final, &peer->local.finalkey))
fatal("peer_set_secrets_from_db:bad final privkey");
}
void secrets_init(struct lightningd_state *dstate)
{
int fd;
dstate->secret = tal(dstate, struct secret);
fd = open("privkey", O_RDONLY);
if (fd < 0) {
if (errno != ENOENT)
fatal("Failed to open privkey: %s", strerror(errno));
log_unusual(dstate->base_log, "Creating privkey file");
new_keypair(dstate, &dstate->secret->privkey, &dstate->id);
fd = open("privkey", O_CREAT|O_EXCL|O_WRONLY, 0400);
if (fd < 0)
fatal("Failed to create privkey file: %s",
strerror(errno));
if (!write_all(fd, dstate->secret->privkey.secret,
sizeof(dstate->secret->privkey.secret))) {
unlink_noerr("privkey");
fatal("Failed to write to privkey file: %s",
strerror(errno));
}
if (fsync(fd) != 0)
fatal("Failed to sync to privkey file: %s",
strerror(errno));
close(fd);
fd = open("privkey", O_RDONLY);
if (fd < 0)
fatal("Failed to reopen privkey: %s", strerror(errno));
}
if (!read_all(fd, dstate->secret->privkey.secret,
sizeof(dstate->secret->privkey.secret)))
fatal("Failed to read privkey: %s", strerror(errno));
close(fd);
if (!pubkey_from_privkey(&dstate->secret->privkey, &dstate->id))
fatal("Invalid privkey");
log_info_struct(dstate->base_log, "ID: %s", struct pubkey, &dstate->id);
}