core-lightning/common/psbt_internal.c
niftynei fe56f572ed df: finalize redeemscript at the same time as witness stack
libwally has a quirk where the finalize method will fail to 'completely'
finalize an input's parts if either the final_scriptsig or
final_redeemscript fields are set

since we manually set the final_witness stack here, we also need to
fully finalize the redeemscript -> final_scriptsig here as well.
2020-10-26 13:04:42 +10:30

108 lines
3.1 KiB
C

#include "common/psbt_internal.h"
#include <bitcoin/script.h>
#include <ccan/ccan/tal/tal.h>
#include <common/psbt_open.h>
#include <wally_psbt.h>
#include <wire/peer_wire.h>
#if EXPERIMENTAL_FEATURES
static void
psbt_input_set_final_witness_stack(const tal_t *ctx,
struct wally_psbt_input *in,
const struct witness_element **elements)
{
tal_wally_start();
wally_tx_witness_stack_init_alloc(tal_count(elements),
&in->final_witness);
for (size_t i = 0; i < tal_count(elements); i++)
wally_tx_witness_stack_add(in->final_witness,
elements[i]->witness,
tal_bytelen(elements[i]->witness));
tal_wally_end(ctx);
}
void psbt_finalize_input(const tal_t *ctx,
struct wally_psbt_input *in,
const struct witness_element **elements)
{
psbt_input_set_final_witness_stack(ctx, in, elements);
/* There's this horrible edgecase where we set the final_witnesses
* directly onto the PSBT, but the input is a P2SH-wrapped input
* (which has redeemscripts that belong in the scriptsig). Because
* of how the internal libwally stuff works calling 'finalize'
* on these just .. ignores it!? Murder. Anyway, here we do a final
* scriptsig check -- if there's a redeemscript field still around we
* just go ahead and mush it into the final_scriptsig field. */
if (in->redeem_script) {
u8 *redeemscript = tal_dup_arr(NULL, u8,
in->redeem_script,
in->redeem_script_len, 0);
in->final_scriptsig =
bitcoin_scriptsig_redeem(NULL,
take(redeemscript));
in->final_scriptsig_len =
tal_bytelen(in->final_scriptsig);
in->redeem_script = tal_free(in->redeem_script);
in->redeem_script_len = 0;
}
}
const struct witness_stack **
psbt_to_witness_stacks(const tal_t *ctx,
const struct wally_psbt *psbt,
enum tx_role side_to_stack)
{
size_t stack_index;
u16 serial_id;
const struct witness_stack **stacks
= tal_arr(ctx, const struct witness_stack *, psbt->num_inputs);
stack_index = 0;
for (size_t i = 0; i < psbt->num_inputs; i++) {
if (!psbt_get_serial_id(&psbt->inputs[i].unknowns,
&serial_id))
/* FIXME: throw an error ? */
return NULL;
/* BOLT-78de9a79b491ae9fb84b1fdb4546bacf642dce87 #2:
* - if is the `initiator`:
* - MUST send even `serial_id`s
*/
if (serial_id % 2 == side_to_stack) {
struct wally_tx_witness_stack *wtx_s =
psbt->inputs[i].final_witness;
struct witness_stack *stack =
tal(stacks, struct witness_stack);
/* Convert the wally_tx_witness_stack to
* a witness_stack entry */
stack->witness_element =
tal_arr(stack, struct witness_element *,
wtx_s->num_items);
for (size_t j = 0; j < tal_count(stack->witness_element); j++) {
stack->witness_element[j] = tal(stack,
struct witness_element);
stack->witness_element[j]->witness =
tal_dup_arr(stack, u8,
wtx_s->items[j].witness,
wtx_s->items[j].witness_len,
0);
}
stacks[stack_index++] = stack;
}
}
if (stack_index == 0)
return tal_free(stacks);
tal_resize(&stacks, stack_index);
return stacks;
}
#endif /* EXPERIMENTAL_FEATURES */