Introduce an ECDSA signature verification into btcd in order to
mitigate a certain DoS attack and as a performance optimization.
The benefits of SigCache are two fold. Firstly, usage of SigCache
mitigates a DoS attack wherein an attacker causes a victim's client to
hang due to worst-case behavior triggered while processing attacker
crafted invalid transactions. A detailed description of the mitigated
DoS attack can be found here: https://bitslog.wordpress.com/2013/01/23/fixed-bitcoin-vulnerability-explanation-why-the-signature-cache-is-a-dos-protection/
Secondly, usage of the SigCache introduces a signature verification
optimization which speeds up the validation of transactions within a
block, if they've already been seen and verified within the mempool.
The server itself manages the sigCache instance. The blockManager and
txMempool respectively now receive pointers to the created sigCache
instance. All read (sig triplet existence) operations on the sigCache
will not block unless a separate goroutine is adding an entry (writing)
to the sigCache. GetBlockTemplate generation now also utilizes the
sigCache in order to avoid unnecessarily double checking signatures
when generating a template after previously accepting a txn to the
mempool. Consequently, the CPU miner now also employs the same
optimization.
The maximum number of entries for the sigCache has been introduced as a
config parameter in order to allow users to configure the amount of
memory consumed by this new additional caching.
While current existing numeric opcodes are limited to 4 bytes, new
opcodes may need different limits.
This mimics Bitcoin Core commit 99088d60d8a7747c6d1a7fd5d8cd388be1b3e138
This commit optimizes the createVinList function which is used to
generate the JSON list of transaction inputs. It also makes it more
consistent with the createVinListPrevOut function.
In particular, it entails the following changes:
- Only do a single coinbase check and return right away instead of
checking multiple times inside the loop over the inputs
- Use a pointer for populating the details of each entry to avoid
multiple unnecessary array lookups and bounds checks
- Group all fields that populate the entry for better readability
SFNodeBloom is a new service flag that a node is required to use to
indicate that it supports bloom filtering. This includes a protocol
version bump to 70011 and a wire version bump to 0.3.0.
btcd:
The SFNodeBloom flag is set by default. A new configuration option
--nopeerbloomfilters has been added to to disable bloom filtering.
Any node advertising a version greater than or equal to 70011 that
attempts to use bloom filtering will be disconnected if bloom
filtering is disabled.
This mimics Bitcoin Core commit afb0ccaf9c9e4e8fac7db3564c4e19c9218c6b03
This commit modifies the DisasmString function to use a bytes buffer for
constructing the disassembled string instead of naive string
concatenation. This makes a huge difference when disassembling scripts
with large numbers of opcodes.
The Bitcoin wire protocol includes several fields with their lengths
encoded according to a variable length integer encoding scheme that does
not enforce a unique encoding for all numbers.
This can lead to a situation where deserializing and re-serializing the
same data can result in different bytes. There are no currently known
issues due to this, but it is safer to reject such subtle differences as
they could potentially lead to exploits.
Consequently, this commit modifies the varint decoding function to error
when the value is not canonically encoded which effectively means that
all messages with varints that are not canonically encoded will now be
rejected. This will not cause issues with old client versions in
regards to blocks and transactions since the data is deserialized into
memory and then reserialized before being relayed thereby effectively
erasing any non-canonical encodings.
Also, new tests have been added to ensure non-canonical encodings are
properly rejected and exercise the new code, and the default user agent
version for wire has been bumped to version 0.2.1 to differentiate the
new behavior.
The equivalent logic was implemented in Bitcoin Core by PR 2884.
This commit improves the most-recently used inventory map human readable
string to only show the inventory vectors. and adds tests for the entire
structure to bring its coverage to 100%.
In addition, removes the type assertion check in the Add function since
the internal inventory list is only managed by the type itself and the
tests would now catch any mistakes in the type of entries in the list.
This commit converts all block height references to int32 instead of
int64. The current target block production rate is 10 mins per block
which means it will take roughly 40,800 years to reach the maximum
height an int32 affords. Even if the target rate were lowered to one
block per minute, it would still take roughly another 4,080 years to
reach the maximum.
In the mean time, there is no reason to use a larger type which results
in higher memory and disk space usage. However, for now, in order to
avoid having to reserialize a bunch of database information, the heights
are still serialized to the database as 8-byte uint64s.
This is being mainly being done in preparation for further upcoming
infrastructure changes which will use the smaller and more efficient
4-byte serialization in the database as well.
IsUnspendable takes a public key script and returns whether it is
spendable.
Additionally, hook this into the mempool isDust function, since
unspendable outputs can't be spent.
This mimics Bitcoin Core commit 0aad1f13b2430165062bf9436036c1222a8724da
The comment says "only allow recent nodes (10mins) after we failed 30 times",
but the server actually did the opposite and allowed only recent nodes before
30 failed connection attempts. This corrects the server's behavior.
This commit modifies the createTxRawResult code path along with callers
to work with block headers as opposed to btcutil.Blocks. This in turn
allows the code in handleGetRawTransaction and
handleSearchRawTransactions to perform a much cheaper block header load
as opposed to a full block load.
While here, also very slightly optimize the createVinList function to
avoid creating a util.Tx wrapper and to take advantage of the
btcutil.Amount type added after the function was originally written
This commit updates the merkle block handling to for the latest changes
to the btcutil API and optimizes it along the way.
Previously, the code was inefficiently reloading the transactions for
the matched hashes from the database instead of simply pulling them from
the full block that was used to create the merkle block.
At the current time, there is no difference between the wire encoding
at protocol version 0 and the stable long-term storage format. These
methods are simply for consistency with the other types.
This commit updates the wire tests for transactions which force
serialization and deserialization errors to force an error in the the
transaction lock time path.
This brings the wire test coverage back up to 100%.
This commit correctly replaces persistent peers that are being retried in
the list of persistent peers so it will continue to be retried as
intended.
Also, limit the maximum retry interval for persistent peers to 5 minutes.
Fixes#463.
This change moves IsFinalizedTransaction to txscript and also changes
the first argument to take a wire.MsgTx instead of btcutil.Tx. This
is needed for an upcoming diff in which txscript will require
IsFinalizedTransaction and we do not want to import the btcd/blockchain.
This allows clients watching for both to know when all mined
transaction notifications for the block have been received.
Otherwise, clients would be aware that there is a new block, see the
exact same block hash/height in the next tx notifications, but never
know when all txs from the block have been received and processed.
This fixes a synchronization issue in btcwallet where the wallet would
mark itself synced to some block height before any of those blocks'
transactions were processed. If the RPC connection is lost between
sending the blockconnected notification and receiving the last
transaction notification, the wallet would not know of this and
continue with missing transactions.
The configured onion proxy was not being used due to checking if the
passed string had suffix '.onion', which never matched because the
port number is part of the string.
