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push_tx: Don't create BIP 144 invalid transactions

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If no witnesses are present on any inputs, then extended serialisation
should not be used.

[ Amended to make adding new flags clearer in future -- RR ]
Signed-off-by: Jon Griffiths <jon_p_griffiths@yahoo.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Jon Griffiths 2018-02-02 10:18:46 +13:00 • committed by Rusty Russell
parent ff1a466ef3
commit 505a249966
1 changed files with 9 additions and 14 deletions
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23
bitcoin/tx.c
View file

@ -80,29 +80,24 @@ static void push_witnesses(const struct bitcoin_tx *tx,
static void push_tx(const struct bitcoin_tx *tx, static void push_tx(const struct bitcoin_tx *tx,
void (*push)(const void *, size_t, void *), void *pushp, void (*push)(const void *, size_t, void *), void *pushp,
bool extended) bool bip144)
{ {
varint_t i; varint_t i;
u8 flag = 0; u8 flag = 0;
push_le32(tx->version, push, pushp); push_le32(tx->version, push, pushp);
if (extended) { if (bip144 && uses_witness(tx))
u8 marker; flag |= SEGREGATED_WITNESS_FLAG;
/* BIP 141: The flag MUST be a 1-byte non-zero value. */
/* ie. if no flags set, we fallback to pre-BIP144-style */
if (flag) {
u8 marker = 0;
/* BIP 144 */ /* BIP 144 */
/* marker char Must be zero */ /* marker char Must be zero */
/* flag char Must be nonzero */ /* flag char Must be nonzero */
marker = 0;
push(&marker, 1, pushp); push(&marker, 1, pushp);
/* BIP 141: The flag MUST be a 1-byte non-zero
* value. Currently, 0x01 MUST be used.
*
* BUT: Current segwit4 branch breaks fundrawtransaction;
* it sees 0 inputs and thinks it's extended format.
* Make it really an extended format, but without
* witness. */
if (uses_witness(tx))
flag = SEGREGATED_WITNESS_FLAG;
push(&flag, 1, pushp); push(&flag, 1, pushp);
} }
@ -256,7 +251,7 @@ static void push_linearize(const void *data, size_t len, void *pptr_)
u8 *linearize_tx(const tal_t *ctx, const struct bitcoin_tx *tx) u8 *linearize_tx(const tal_t *ctx, const struct bitcoin_tx *tx)
{ {
u8 *arr = tal_arr(ctx, u8, 0); u8 *arr = tal_arr(ctx, u8, 0);
push_tx(tx, push_linearize, &arr, uses_witness(tx)); push_tx(tx, push_linearize, &arr, true);
return arr; return arr;
} }