This a refactor of the btcwallet main package to create a new wallet
package.
The main feature of this package is the integration of all the other
wallet components (waddrmgr, txstore, and chain) and the Wallet type is
'runnable', so it will be continuously updating itself against changes
notified by the remote btcd instance.
It also includes several methods which provide access to information
necessary to run a wallet RPC server.
Otherwise, if the websocket connection to btcd is lost and
reestablished, there is no sync to the current best block, and btcd
will not notify wallet of new relevant transactions.
This was previously using the most recently notified (by the chain
package) block, but transaction processing from this block may not be
finished yet. Using this block's height to calculate the number of
confirmations is therefore incorrect, and can result in every RPC
handler missing transactions or returning transactions from the wrong
block.
Wallet should handle these so that wallet clients don't end up
creating requests to btcd about the latest processed block, which is
not the same as wallet's most recently processed block.
By providing wallet clients with this info, we avoid a race where the
client thinks wallet has processed N blocks, but in fact is still
synced to N-1 (and perhaps currently processing transactions from
block N). This can cause unexpected results for many of the
bitcoind-compatible RPC APIs due to their reliance on number of
confirmations, rather than using absolute block heights.
This commit converts the wallet to use the new secure hierarchical
deterministic wallet address manager package as well as the walletdb
package.
The following is an overview of modified functionality:
- The wallet must now be created before starting the executable
- A new flag --create has been added to create the new wallet using wizard
style question and answer prompts
- Starting the process without an existing wallet will instruct now
display a message to run it with --create
- Providing the --create flag with an existing wallet will simply show an
error and return
In addition the snacl package has been modified to return the memory after
performing scrypt operations to the OS.
Previously a runtime.GC was being invoked which forced it to release the
memory as far as the garbage collector is concerned, but the memory was
not released back to the OS immediatley. This modification allows the
memory to be released immedately since it won't be needed again until the
next wallet unlock.
By using txscript.StandardVerifyFlags when creating and validating
transactions, we can ensure the transactions successfully created
won't be rejected due to script policy.
This commit introduces a new flag, --noservertls, which can be used to disable
TLS for the RPC server. However, the flag can only be used when the RPC
server is bound to localhost interfaces. This is intended to prevent the
situation where someone decides they want to expose the RPC server to the
web for remote management/access, but forgot they have TLS disabled.
This prevents a downgrade attack to the vulnerable SSLv3. While here,
go ahead and require at least TLS 1.2 since TLS 1.0 and 1.1 have their
own set of issues and it's only a matter of time before those would
need to be completely avoided as well.
Previously, the createencryptedwallet and stop requests did not check
that the client had successfully authenticated to the server. This
change moves the check outside of the select statement for these
special cased handlers (previously run from the default case) so an
auth check will occur even if a request method does not match either
of these two.
The stack trace did not make it evidant which request had caused this
issue, so add extra logging for the request that caused it. Sanitize
this request if it may contain any secrets.
Additionally, in this situation, begin shutting down the wallet rather
than simply dropping the response. This will help to catch the issue
since it's easier to notice all requests failing, rather than just one
that was dropped. If shutdown takes an unreasonably long time, panic.
Previously, registerations for wallet notifications (new txs, changed
account balances) were only passed up to websocket clients if the
wallet was loaded off disk (SetWallet was called with a non-nil
wallet), and not for the case when the RPC server would create the
wallet (if it wasn't created yet, and the user manually created it
with createencryptedwallet). This change fixes that by registering
for these notifications when this code path is taken.
The notified chain server connection state was being passed through
the wallet and then notified to the RPC server, which prevented this
notification from ever firing if a wallet didn't exist yet. Instead,
make the RPC server register for these notifications directly from the
chain server RPC client.
I'm not happy with this notification and how it's handled in the code,
but to not break existing clients this change is being made. Fixing
the notifiation mess and modifying existing clients to use a new
notification API will need to be done sometime later.
This prevents a hang when attempting to set the wallet (and register
for wallet notifications) when the process is interrupted and the rpc
server begins shutting down.
