bitcoin/tx.c: don't free witness implicitly.

This causes a crash in mkfunding, which didn't expect it:

    $ devtools/mkfunding 16835ac8c154b616baac524163f41fb0c4f82c7b972ad35d4d6f18d854f6856b 1 0.01btc 253 76edf0c303b9e692da9cb491abedef46ca5b81d32f102eb4648461b239cb0f99 0000000000000000000000000000000000000000000000000000000000000010 0000000000000000000000000000000000000000000000000000000000000020
    # funding sig: 798d96d5a057b5b7797988a855217f41af05ece3ba8278366e2f69763c72e78565d5dd7eeddc0766ddf65557c92b9c52c301f23f94d2cf681860d32153e6ae1e
    # funding witnesses: [
    Aborted (core dumped)

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

bitcoin/tx.c

@@ -117,7 +117,8 @@ void bitcoin_tx_input_set_witness(struct bitcoin_tx *tx, int innum,
 	wally_tx_set_input_witness(tx->wtx, innum, stack);
 	if (stack)
 		wally_tx_witness_stack_free(stack);
-	tal_free(witness);
+	if (taken(witness))
+	    tal_free(witness);
 }
 
 void bitcoin_tx_input_set_script(struct bitcoin_tx *tx, int innum, u8 *script)

bitcoin/tx.h

@@ -116,7 +116,7 @@ struct amount_sat bitcoin_tx_output_get_amount(const struct bitcoin_tx *tx,
  * itself, we need a way to attach a witness to an existing input.
  */
 void bitcoin_tx_input_set_witness(struct bitcoin_tx *tx, int innum,
-				  u8 **witness);
+				  u8 **witness TAKES);
 
 /**
  * Set the input script on the given input.

channeld/test/run-commit_tx.c

@@ -350,7 +350,7 @@ static void report(struct bitcoin_tx *tx,
 	witness =
 	    bitcoin_witness_2of2(tx, &localsig, &remotesig,
 				 local_funding_pubkey, remote_funding_pubkey);
-	bitcoin_tx_input_set_witness(tx, 0, witness);
+	bitcoin_tx_input_set_witness(tx, 0, take(witness));
 	txhex = tal_hex(tmpctx, linearize_tx(tx, tx));
 	printf("output commit_tx: %s\n", txhex);
 
@@ -993,6 +993,7 @@ int main(void)
 
 	/* No memory leaks please */
 	secp256k1_context_destroy(secp256k1_ctx);
+	take_cleanup();
 	tal_free(tmpctx);
 
 	/* FIXME: Do BOLT comparison! */

common/htlc_tx.c

@@ -109,7 +109,7 @@ void htlc_success_tx_add_witness(struct bitcoin_tx *htlc_success,
 	witness = bitcoin_witness_htlc_success_tx(htlc_success,
 						  localhtlcsig, remotehtlcsig,
 						  payment_preimage, wscript);
-	bitcoin_tx_input_set_witness(htlc_success, 0, witness);
+	bitcoin_tx_input_set_witness(htlc_success, 0, take(witness));
 	tal_free(wscript);
 }
 
@@ -149,7 +149,7 @@ void htlc_timeout_tx_add_witness(struct bitcoin_tx *htlc_timeout,
 
 	witness = bitcoin_witness_htlc_timeout_tx(htlc_timeout, localhtlcsig,
 						  remotehtlcsig, wscript);
-	bitcoin_tx_input_set_witness(htlc_timeout, 0, witness);
+	bitcoin_tx_input_set_witness(htlc_timeout, 0, take(witness));
 	tal_free(wscript);
 }
 

devtools/mkcommit.c

@@ -396,7 +396,7 @@ int main(int argc, char *argv[])
 	witness =
 		bitcoin_witness_2of2(NULL, &local_sig, &remote_sig,
 				     &funding_localkey, &funding_remotekey);
-	bitcoin_tx_input_set_witness(local_txs[0], 0, witness);
+	bitcoin_tx_input_set_witness(local_txs[0], 0, take(witness));
 
 	printf("# signed local commitment: %s\n",
 	       tal_hex(NULL, linearize_tx(NULL, local_txs[0])));

hsmd/hsmd.c

@@ -1457,7 +1457,7 @@ static void sign_all_inputs(struct bitcoin_tx *tx, struct utxo **utxos)
 
 		/* The witness is [sig] [key] */
 		bitcoin_tx_input_set_witness(
-		    tx, i, bitcoin_witness_p2wpkh(tx, &sig, &inkey));
+			tx, i, take(bitcoin_witness_p2wpkh(tx, &sig, &inkey)));
 	}
 }
 

lightningd/peer_control.c

@@ -224,7 +224,7 @@ static void sign_last_tx(struct channel *channel)
 				 &sig, &channel->channel_info.remote_fundingkey,
 				 &channel->local_funding_pubkey);
 
-	bitcoin_tx_input_set_witness(channel->last_tx, 0, witness);
+	bitcoin_tx_input_set_witness(channel->last_tx, 0, take(witness));
 }
 
 static void remove_sig(struct bitcoin_tx *signed_tx)

onchaind/onchaind.c

@@ -368,7 +368,7 @@ static struct bitcoin_tx *tx_to_us(const tal_t *ctx,
 
 	witness = bitcoin_witness_sig_and_element(tx, &sig, elem,
 						  elemsize, wscript);
-	bitcoin_tx_input_set_witness(tx, 0, witness);
+	bitcoin_tx_input_set_witness(tx, 0, take(witness));
 	return tx;
 }
 
@@ -1277,7 +1277,7 @@ static void handle_preimage(const struct chainparams *chainparams,
 			witness = bitcoin_witness_htlc_success_tx(
 			    tx, &sig, outs[i]->remote_htlc_sig, preimage,
 			    outs[i]->wscript);
-			bitcoin_tx_input_set_witness(tx, 0, witness);
+			bitcoin_tx_input_set_witness(tx, 0, take(witness));
 			propose_resolution(outs[i], tx, 0, OUR_HTLC_SUCCESS_TX);
 		} else {
 			enum tx_type tx_type = THEIR_HTLC_FULFILL_TO_US;
@@ -1530,7 +1530,7 @@ static size_t resolve_our_htlc_ourcommit(const struct chainparams *chainparams,
 						  out->remote_htlc_sig,
 						  htlc_scripts[matches[i]]);
 
-	bitcoin_tx_input_set_witness(tx, 0, witness);
+	bitcoin_tx_input_set_witness(tx, 0, take(witness));
 
 	/* Steals tx onto out */
 	propose_resolution_at_block(out, tx, htlcs[matches[i]].cltv_expiry,