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f78ea05fc5
When other side uses their escape tx, we extract the secret to we can use our fast-escape. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
103 lines
2.3 KiB
C
103 lines
2.3 KiB
C
#include <ccan/crypto/shachain/shachain.h>
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#include <ccan/read_write_all/read_write_all.h>
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#include <ccan/short_types/short_types.h>
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#include <ccan/tal/tal.h>
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#include <ccan/opt/opt.h>
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#include <ccan/str/hex/hex.h>
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#include <ccan/err/err.h>
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#include "bitcoin/tx.h"
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#include <unistd.h>
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#define OP_PUSHDATA1 0x4C
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#define OP_PUSHDATA2 0x4D
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#define OP_PUSHDATA4 0x4E
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static bool pull_value(const u8 **s, const u8 *end, void *dst, size_t max)
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{
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size_t len;
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if (*s >= end)
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return false;
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if (**s < 76) {
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len = **s;
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(*s)++;
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} else if (**s == OP_PUSHDATA1) {
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(*s)++;
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if (*s >= end)
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return false;
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len = **s;
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(*s)++;
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} else if (**s == OP_PUSHDATA2) {
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(*s)++;
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if (*s + 1 >= end)
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return false;
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len = (u32)(*s)[0] | ((u32)(*s)[1] << 8);
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(*s) += 2;
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} else if (**s == OP_PUSHDATA4) {
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(*s)++;
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if (*s + 3 >= end)
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return false;
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len = (u32)(*s)[0] | ((u32)(*s)[1] << 8) | ((u32)(*s)[2] << 16)
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| ((u32)(*s)[3] << 24);
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(*s) += 4;
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} else
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return false;
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if (len > max)
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return false;
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memcpy(dst, *s, len);
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(*s) += len;
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return true;
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}
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int main(int argc, char *argv[])
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{
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const tal_t *ctx = tal_arr(NULL, char, 0);
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struct bitcoin_tx *tx;
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const u8 *s, *end;
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struct sha256 secret;
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u8 sig[73];
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char hexstr[hex_str_size(sizeof(secret))];
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err_set_progname(argv[0]);
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/* FIXME: Take update.pbs to adjust channel */
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opt_register_noarg("--help|-h", opt_usage_and_exit,
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"<escape-txfile>\n"
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"Print the secret revealed by this escape tx",
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"Print this message.");
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opt_parse(&argc, argv, opt_log_stderr_exit);
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if (argc != 2)
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opt_usage_exit_fail("Expected 1 argument");
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tx = bitcoin_tx_from_file(ctx, argv[1]);
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if (tx->input_count != 1)
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errx(1, "Expected 1 input");
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s = tx->input[0].script;
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end = s + tx->input[0].script_length;
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if (!pull_value(&s, end, NULL, 0))
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errx(1, "Expected 0");
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if (!pull_value(&s, end, sig, sizeof(sig)))
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errx(1, "Expected sig1");
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if (!pull_value(&s, end, sig, sizeof(sig)))
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errx(1, "Expected sig2");
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if (!pull_value(&s, end, secret.u.u8, sizeof(secret.u.u8)))
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errx(1, "Expected secret");
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if (!hex_encode(&secret.u.u8, sizeof(secret.u.u8), hexstr, sizeof(hexstr)))
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abort();
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/* Print it out. */
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if (!write_all(STDOUT_FILENO, hexstr, strlen(hexstr)))
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err(1, "Writing out secret");
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tal_free(ctx);
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return 0;
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}
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