The following scripted-diff commit will replace ParseHex("...") with "..."_hex_u8, but this replacement will not work in cases where vectors are needed instead of arrays, and is not ideal in cases where std::byte is accepted.
For example, it is currently necessary to use _hex_v_u8 when calling CScript operator<< because that operator does not currently support std::array or std::byte.
Conversely, it is incorrect to use _hex_v instead of _hex in net_processing.cpp for the MakeAndPushMessage argument, because if the argument is a std::vector it is considered variable-length and serialized with a size prefix, but if the argument is a std::array or Span is it considered fixed length and serialized without a prefix.
By the same logic, it is also safe to change the NUMS_H constant in pubkey.cpp from a std::vector to std::array because it is never serialized.
a0abcbd382 doc: Mention multipath specifier (Ava Chow)
0019f61fc5 tests: Test importing of multipath descriptors (Ava Chow)
f97d5c137d wallet, rpc: Allow importdescriptors to import multipath descriptors (Ava Chow)
32dcbca3fb rpc: Allow importmulti to import multipath descriptors correctly (Ava Chow)
64dfe3ce4b wallet: Move internal to be per key when importing (Ava Chow)
1692245525 tests: Multipath descriptors for scantxoutset and deriveaddresses (Ava Chow)
cddc0ba9a9 rpc: Have deriveaddresses derive receiving and change (Ava Chow)
360456cd22 tests: Multipath descriptors for getdescriptorinfo (Ava Chow)
a90eee444c tests: Add unit tests for multipath descriptors (Ava Chow)
1bbf46e2da descriptors: Change Parse to return vector of descriptors (Ava Chow)
0d640c6f02 descriptors: Have ParseKeypath handle multipath specifiers (Ava Chow)
a5f39b1034 descriptors: Change ParseScript to return vector of descriptors (Ava Chow)
0d55deae15 descriptors: Add DescriptorImpl::Clone (Ava Chow)
7e86541f72 descriptors: Add PubkeyProvider::Clone (Ava Chow)
Pull request description:
It is convenient to have a descriptor which specifies both receiving and change addresses in a single string. However, as discussed in https://github.com/bitcoin/bitcoin/issues/17190#issuecomment-895515768, it is not feasible to use a generic multipath specification like BIP 88 due to combinatorial blow up and that it would result in unexpected descriptors.
To resolve that problem, this PR proposes a targeted solution which allows only a single pair of 2 derivation indexes to be inserted in the place of a single derivation index. So instead of two descriptor `wpkh(xpub.../0/0/*)` and `wpkh(xpub.../0/1/*)` to represent receive and change addresses, this could be written as `wpkh(xpub.../0/<0;1>/*)`. The multipath specifier is of the form `<NUM;NUM>`. Each `NUM` can have its own hardened specifier, e.g. `<0;1h>` is valid. The multipath specifier can also only appear in one path index in the derivation path.
This results in the parser returning two descriptors. The first descriptor uses the first `NUM` in all pairs present, and the second uses the second `NUM`. In our implementation, if a multipath descriptor is not provided, a pair is still returned, but the second element is just `nullptr`.
The wallet will not output the multipath descriptors (yet). Furthermore, when a multipath descriptor is imported, it is expanded to the two descriptors and each imported on its own, with the second descriptor being implicitly for internal (change) addresses. There is no change to how the wallet stores or outputs descriptors (yet).
Note that the path specifier is different from what was proposed. It uses angle brackets and the semicolon because these are unused characters available in the character set and I wanted to avoid conflicts with characters already in use in descriptors.
Closes#17190
ACKs for top commit:
darosior:
re-ACK a0abcbd382
mjdietzx:
reACK a0abcbd382
pythcoiner:
reACK a0abcbd
furszy:
Code review ACK a0abcbd
glozow:
light code review ACK a0abcbd382
Tree-SHA512: 84ea40b3fd1b762194acd021cae018c2f09b98e595f5e87de5c832c265cfe8a6d0bc4dae25785392fa90db0f6301ddf9aea787980a29c74f81d04b711ac446c2
There are no changes to behavior. Changes in this commit are all additions, and
are easiest to review using "git diff -U0 --word-diff-regex=." options.
Motivation for this change is to keep util functions with really generic names
like "Split" and "Join" out of the global namespace so it is easier to see
where these functions are defined, and so they don't interfere with function
overloading, especially since the util library is a dependency of the kernel
library and intended to be used with external code.
This will help move the miniscript / descriptor parsing functions out of the
util library in an upcoming commit, so they are not exposed to libbitcoinkernel
applications. Moving the Split functions should also make them more
discoverable since they now close to related functions like Join.
The functions are moved verbatim without any changes.
We make the Satisfier a base in which to store the common methods
between the Tapscript and P2WSH satisfier, and from which they both
inherit.
A field is added to SignatureData to be able to satisfy pkh() under
Tapscript context (to get the pubkey hash preimage) without wallet data.
For instance in `finalizepsbt` RPC. See also the next commits for a
functional test that exercises this.
The descriptor documentation (doc/descriptors.md) and BIP380 explicitly
require that hex-encoded public keys start with 02 or 03 (compressed) or
04 (uncompressed). However, the current parsing/inference code permit 06
and 07 (hybrid) encoding as well. Fix this.
When estimating the maximum size of an input, we were assuming the
number of elements on the witness stack could be encode in a single
byte. This is a valid approximation for all the descriptors we support
(including P2WSH Miniscript ones), but may not hold anymore once we
support Miniscript within Taproot descriptors (since the max standard
witness stack size of 100 gets lifted).
It's a low-hanging fruit to account for it correctly, so just do it now.
Instead of using the dummysigner to compute a placeholder satisfaction,
infer a descriptor on the scriptPubKey of the coin being spent and use
the estimation of the satisfaction size given by the descriptor
directly.
Note this (almost, see next paragraph) exactly conserves the previous
behaviour. For instance CalculateMaximumSignedInputSize was previously
assuming the input to be spent in a transaction that spends at least one
Segwit coin, since it was always accounting for the serialization of the
number of witness elements.
In this commit we use a placeholder for the size of the serialization of
the witness stack size (1 byte). Since the logic in this commit is
already tricky enough to review, and that it is only a very tiny
approximation not observable through the existing tests, it is addressed
in the next commit.
In the wallet code, we are currently estimating the size of a signed
input by doing a dry run of the signing logic. This is unnecessary as
all outputs we are able to sign for can be represented by a descriptor,
and we can derive the size of a satisfaction ("signature") from the
descriptor itself directly.
In addition, this approach does not scale: getting the size of a
satisfaction through a dry run of the signing logic is only possible for
the most basic scripts.
This commit introduces the computation of the size of satisfaction per
descriptor. It's a bit intricate for 2 main reasons:
- We want to conserve the behaviour of the current dry-run logic used by
the wallet that sometimes assumes ECDSA signatures will be low-r,
sometimes not (when we don't create them).
- We need to account for the witness discount. A single descriptor may
sometimes benefit of it, sometimes not (for instance `pk()` if used as
top-level versus if used inside `wsh()`).
Had to change some hashes in descriptor_tests, presumably because of the
differences between when Elements and Bitcoin when it comes to Taproot.
Please review this carefully and investigate the FIXME
Tests vectors were calculated by running the same tests on
v25. Which was the last release prior to introducing the
diff in the descriptor's string representation ('h' format).
Co-authored-by: Sjors Provoost <sjors@sprovoost.nl>
This makes it easier to handle descriptor strings manually. E.g. an RPC call that takes an array of descriptors can now use '["desc": ".../0h/..."]'.
Both markers can still be parsed. The default for new descriptors is changed to h. In normalized form h is also used. For private keys the chosen marker is preserved in a round trip.
The hdkeypath field in getaddressinfo is also impacted by this change.
6c7a17a8e0 psbt: support externally provided preimages for Miniscript satisfaction (Antoine Poinsot)
840a396029 qa: add a "smart" Miniscript fuzz target (Antoine Poinsot)
17e3547241 qa: add a fuzz target generating random nodes from a binary encoding (Antoine Poinsot)
611e12502a qa: functional test Miniscript signing with key and timelocks (Antoine Poinsot)
d57b7f2021 refactor: make descriptors in Miniscript functional test more readable (Antoine Poinsot)
0a8fc9e200 wallet: check solvability using descriptor in AvailableCoins (Antoine Poinsot)
560e62b1e2 script/sign: signing support for Miniscripts with hash preimage challenges (Antoine Poinsot)
a2f81b6a8f script/sign: signing support for Miniscript with timelocks (Antoine Poinsot)
61c6d1a844 script/sign: basic signing support for Miniscript descriptors (Antoine Poinsot)
4242c1c521 Align 'e' property of or_d and andor with website spec (Pieter Wuille)
f5deb41780 Various additional explanations of the satisfaction logic from Pieter (Pieter Wuille)
22c5b00345 miniscript: satisfaction support (Antoine Poinsot)
Pull request description:
This makes the Miniscript descriptors solvable.
Note this introduces signing support for much more complex scripts than the wallet was previously able to solve, and the whole tooling isn't provided for a complete Miniscript integration in the wallet. Particularly, the PSBT<->Miniscript integration isn't entirely covered in this PR.
ACKs for top commit:
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sipa:
utACK 6c7a17a8e0 (to the extent that it's not my own code).
Tree-SHA512: a71ec002aaf66bd429012caa338fc58384067bcd2f453a46e21d381ed1bacc8e57afb9db57c0fb4bf40de43b30808815e9ebc0ae1fbd9e61df0e7b91a17771cc
Try to solve a script using the Miniscript satisfier if the legacy
solver fails under P2WSH context. Only solve public key and public key
hash challenges for now.
We don't entirely replace the raw solver and especially rule out trying to
solve CHECKMULTISIG-based multisigs with the Miniscript satisfier since
some features, such as the transaction input combiner, rely on the
specific behaviour of the former.
