Legacy wallets should only import keys to the keypool if they came in a
single key descriptor. Instead of relying on assumptions about the
descriptor based on how many pubkeys show up after expanding the
descriptor, explicitly mark descriptors as being single key type and use
that for the check.
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.
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()`).
As we update the descriptor's db record every time that
the wallet is loaded (at `TopUp` time), if the spkm ID differs
from the one in db, the wallet will enter in an unrecoverable
corruption state, and no soft version will be able to open
it anymore.
Because we cannot change the past, to stay compatible between
releases, we need to always use the apostrophe version for the
spkm IDs.
If the computed descriptor's ID doesn't match the wallet's
DB spkm ID, return early from the loading process to prevent
DB data from being modified in any post-loading procedure
(e.g 'TopUp' updates the descriptor's data).
In order to get records beginning with a prefix, we will need a cursor
specifically for that prefix. So add a GetPrefixCursor function and
DatabaseCursor classes for dealing with those prefixes.
Tested on each supported db engine.
1) Write two different key->value elements to db.
2) Create a new prefix cursor and walk-through every returned element,
verifying that it gets parsed properly.
3) Try to move the cursor outside the filtered range: expect failure
and flag complete=true.
Co-Authored-By: Ryan Ofsky <ryan@ofsky.org>
Co-Authored-By: furszy <matiasfurszyfer@protonmail.com>
In the wallet ckey loading test, we modify various ckey records to test
corruption handling. As the database is now a mockable database, we can
modify the records that the database will be initialized with. This
avoids having to use the verbose database reading and writing functions.
Since we have a mockable wallet database, we don't really need to be
using BDB or SQLite's in-memory database capabilities. It doesn't really
help us to be using those as we aren't doing anything that requires one
type of db over the other, and will just prefer SQLite if it's
available.
MockableDatabase is suitable for these uses, so use
CreateMockableWalletDatabase to use that.
-BEGIN VERIFY SCRIPT-
sed -i "s/CreateMockWalletDatabase(options)/CreateMockableWalletDatabase()/" $(git grep -l "CreateMockWalletDatabase(options)" -- ":(exclude)src/wallet/walletdb.*")
sed -i "s/CreateMockWalletDatabase/CreateMockableWalletDatabase/" $(git grep -l "CreateMockWalletDatabase" -- ":(exclude)src/wallet/walletdb.*")
-END VERIFY SCRIPT-
Next()'s result is a tri-state - failed, more to go, complete. Replace
the way that this is returned with an enum with values FAIL, MORE, and
DONE rather than with two booleans.
Adds test coverage for the wallet's crypted key loading from db process.
The following scenarios are covered:
1) "All ckeys checksums valid" test:
Loads an encrypted wallet with all the crypted keys with a valid checksum and
verifies that 'CWallet::Unlock' doesn't force an entire crypted keys re-write.
(we force a complete ckeys re-write if we find any missing crypted key checksum
during the wallet loading process)
2) "Missing checksum in one ckey" test:
Verifies that loading up a wallet with, at least one, 'ckey' with no checksum
triggers a complete re-write of the crypted keys.
3) "Invalid ckey checksum error" test:
Verifies that loading up a ckey with an invalid checksum stops the wallet loading
process with a corruption error.
4) "Invalid ckey pubkey error" test:
Verifies that loading up a ckey with an invalid pubkey stops the wallet loading
process with a corruption error.
