This udpates the txscript module to use v2 of the dcrutil module and v2
of the chaincfg module since dcrutil/v2 requires it.
While here, it also modifies the signing functions to accept the new
dcrutil.AddressParams instead of a pointer to a chaincfg.Params struct
in order to remove the tight coupling between txscript and chaincfg at
the API boundary.
It also updates the tests accordingly.
This converts the tests for calculating signature hashes to use the
exported function which handles the raw script versus the now deprecated
variant requiring parsed opcodes.
This removes the MINIMALDATA script verify flag from the various
reference test data since it is now a noop due to the corresponding flag
being removed from the script engine.
This removes the ScriptVerifyMinimalData flag from the txscript package,
changes the default semantics to always enforce its behavior, and
updates all callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so
there is no need to require a flag to conditionally toggle it.
It should be noted that the tests removed from script_tests.json
specifically dealt with ensuring equivalency of different ways to encode
the same numbers when the ScriptVerifyMinimalData flag is not set.
Therefore, they are no longer necessary.
A few tests which dealt with equivalency that did not already have
expected failing counterparts were converted to expected failure.
Also, several of the tests which dealt with ensuring the specific
encoding of numeric opcodes is being used have been converted to use
hashes since the minimal data requirements specifically prevent
alternate ways of pushing the same encoding which is necessary for
directly checking equality of the raw bytes.
Finally, the MINIMALDATA indicator to enable the flag in the test data
has been retained for now in order to isolate the logic changes as much
as possible.
This removes the DERSIG script verify flag from the various reference
test data since it is now a noop due to the corresponding flag being
removed from the script engine.
This removes the ScriptVerifyDERSignatures flag from the txscript
package, changes the default semantics to always enforce its behavior
and updates all callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so
there is no need to require a flag to conditionally toggle it.
It should be noted that the tests removed from script_tests.json
specifically dealt with ensuring non-DER-compliant signatures were
handled properly when the ScriptVerifyDERSignatures flag was not set.
Therefore, they are no longer necessary.
Finally, the DERSIG indicator to enable the flag in the test data has
been retained for now in order to keep the logic changes separate.
This removes the P2SH script verify flag from the various reference test
data since it is now a noop due to the corresponding flag being removed
from the script engine.
This removes the ScriptBip16 flag from the txscript package, changes the
default semantics to always enforce its behavior, and updates all
callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so there is
no need to require a flag to conditionally toggle it.
Also, since it is no longer possible to invoke the script engine without
the flag with the clean stack flag, it removes the now unused
ErrInvalidFlags error and associated tests.
It should be noted that the test removed from script_tests.json
specifically dealt with ensuring a signature script that contained
non-data-pushing opcodes was successful when neither the ScriptBip16 or
ScriptVerifySigPushOnly flags were set. Therefore, it is no longer
necessary.
Finally, the P2SH indicator to enable the flag in the test data has been
retained for now in order to keep the logic changes separate.
This updates the data driven transaction script tests to combine the
previously separate valid and invalid test data files into a single file
and adds a field for the expected result. This is a nice improvement
since it means tests can now ensure script failures are due to a
specific expected reason as opposed to only generically detecting
failure as the previous format required.
Since it is possible that the script engine might return more fine
grained errors than that test data expects, the test adapter handles
this by allowing expected errors in the test data to be mapped to
multiple txscript errors.
While performing the conversion, it also adds several tests for the
following areas:
- The test harness itself to ensure the parsing logic, particularly for
the recently added repetition syntax, is working as intended
- All of the opcodes which were converted to NOPs in Decred
to ensure they are also discouraged from use
- All of the reserved opcodes in Decred
This converts the majority of script errors from generic errors created
via errors.New and fmt.Errorf to use a concrete type that implements the
error interface with an error code and description.
This allows callers to programmatically detect the type of error via
type assertions and an error code while still allowing the errors to
provide more context.
For example, instead of just having an error the reads "disabled opcode"
as would happen prior to these changes when a disabled opcode is
encountered, the error will now read "attempt to execute disabled opcode
OP_FOO".
While it was previously possible to programmatically detect many errors
due to them being exported, they provided no additional context and
there were also various instances that were just returning errors
created on the spot which callers could not reliably detect without
resorting to looking at the actual error message, which is nearly always
bad practice.
Also, while here, export the MaxStackSize and MaxScriptSize constants
since they can be useful for consumers of the package and perform some
minor cleanup of some of the tests.
This removes the STRICTENC script verify flag from the various test data
since it is now a noop due to the corresponding flag being removed from
the script engine.
This removes the ScriptVerifyStrictEncoding flag from the txscript
package, changes the default semantics to always enforce its behavior
and updates all callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so
there is no need to require a flag to conditionally toggle it.
It should be noted that the tests removed from script_valid.json
specifically dealt with ensuring signatures not compliant with DER
encoding did not cause execution to halt early on invalid signatures
when neither of the ScriptVerifyStrictEncoding or
ScriptVerifyDERSignatures flags were set. Therefore, they are no longer
necessary.
For nearly the same reason, the tx test related to the empty pubkey
tx_valid.json was moved to tx_invalid.json. In particular, an empty
pubkey without ScriptVerifyStrictEncoding simply failed the signature
check and continued execution, while the same condition with the flag
halts execution. Thus, without the flag the final NOT in the script
would allow the script to succeed, while it does not under the strict
encoding rules.
Finally, the STRICTENC indicator to enable the flag in the test data has
been retained for now in order to keep the logic changes separate.
This removes the ScriptVerifyLowS flag from the txscript package,
changes the default semantics to always enforce its behavior and updates
all callers in the repository accordingly.
This change is being made to simplify the script engine code since the
flag has always been active and required by consensus in Decred, so
there is no need to require a flag to conditionally toggle it.
This expands upon the recently added ability to specify repeated
raw and quoted data in the test data short script form syntax to also
add syntax to allow repeated sequences of opcodes and updates several
tests to make use of it.
While here, it also corrects a few tests to actually test what they were
originally intended to test but were not updated correctly for Decred
limit changes. In particular, the following tests were corrected:
- The negative test that ensures exceeding the max opcode limit via
CHECKMULTISIG and CHECKMULTISIGVERIFY results in failure
- The positive test that ensures hitting the max opcode limit via
CHECKMULTISIG and CHECKMULTISIGVERIFY with and without keys succeeds
This improves the test data short script form syntax to allow repeated
raw and quoted data and updates several tests to make use of it.
While here, it also corrects a few tests to actually test what they were
originally intended to test but were not updated correctly for Decred
limit changes. In particular, the following tests were corrected:
- The negative test that ensures to exceeding the maximum allowed script
size results in failure
- The positive test that ensures a fully maxed out script (max script
size, max element size push, max opcodes, and max stack items)
succeeds
- The positive test that ensures OP_RESERVED does not count towards the
opcode limit
This adds a significant number of JSON-based tests with various
transactions, scripts, and hash types, to ensure the signature hash
calculated generates the expected hash in each case.
It specifically tests some specialized transactions such as coinbase,
ticket purchase, vote, and revocation. It also includes carefully
created tests for all combinations of defined hash types along with
triggering an error due to improper use of SigHashSingle.
Finally, it also includes fuzz testing by providing a selection of 100
regular transactions with various numbers of inputs and outputs along
with randomly generated (including undefined) signature hash types and
input indexes. Due to the way that masking of the signature hash type
works, a couple of the fuzzer tests also hit the improper use of
SigHashSingle.
The test data was generated as JSON in order to make it easier for
developers of software in other languages and platforms that need to
deal with generating signature hashes to consume and prove correctness
of their implementation as well.
Putting the test code in the same package makes it easier for forks
since they don't have to change the import paths as much and it also
gets rid of the need for internal_test.go to bridge.
Also, do some light cleanup on a few tests while here.
This merge commit adds the following code from the
github.com/decred/dcrutil package into a new
github.com/decred/dcrd/dcrutil package:
* Address handling
* Amount type
* AppDataDir func
* bitflags functions
* Block wrapper type
* Hash160 func
* Tx wrapper type
* WIF type
as well as all tests for this code.
The old github.com/decred/dcrutil/hdkeychain package has also been
merged and moved to github.com/decred/dcrd/dcrutil/hdkeychain.
dcrd packages have been updated to use the new packages and the dep
files have been updated for this change.
This modifies the script engine to replace OP_NOP3 with
OP_CHECKSEQUENCEVERIFY and adds a flag to selectively enable its
enforcement.
The new opcode examines the top item on the stack and compares it
against the sequence number of the associated transaction input in order
to allow scripts to conditionally enforce the inclusion of relative time
locks to the transaction.
The following is an overview of the changes:
- Introduce a new flag named ScriptVerifyCheckSequenceVerify to
provide conditional enforcement of the new opcode
- Introduce a constant named OP_CHECKSEQUENCEVERIFY which has the same
value as OP_NOP3 since it is replacing it
- Update opcode to name mappings accordingly
- Abstract the logic that deals with time lock verification since it is
the same for both the new opcode and OP_CHECKLOCKTIMEVERIFY
- Implement the required opcode semantics
- Add tests to ensure the opcode works as expected including when used
both correctly and incorrectly
This reverts the changes related to the CheckSequenceVerify opcode that
were merged from upstream since additional changes are needed and it's
much cleaner to implement all of code related to the sequence locks in
the same PR which will be referenced by the DCP as opposed to being
split up in multiple.
This modifies the script engine to replace OP_UNKNOWN192 with OP_SHA256
along with a flag named ScriptVerifySHA256 to selectively enable its
enforcement.
The new opcode consumes the top item from the data stack, computes its
SHA-256, and pushes the resulting digest back to the data stack.
Since it requires an item on the data stack, execution will terminate
with an error when the stack is empty. This behavior differs from
OP_UNKNOWN192 which does not consume any elements from the data stack
and therefore makes this is hard-forking change when interpreted with
the new semantics due to the ScriptVerifySHA256 flag being set. Code to
selectively enable the opcode based on the result of an agenda vote will
be added in a separate commit.
This also includes tests to ensure the opcode works as expected
including when used both correctly and incorrectly.
Upstream commit a6bf1d9850.
The merge commit modifies all of the encoded transactions in the test
data to use Decred native format and contains some other minor
modifications necessary to integrate with Decred.
This cleans up the reference test file to remove references to bitcoin
since it no longer applies to decred and remove a TODO that was recently
completed.
Contains the following commits:
- 711f33450c
- b6b1e55d1e
- Reverted because Travis is already at a more recent version
- bd4e64d1d4
Also, the merge commit contains the necessary decred-specific
alterations, converts all other references to sha to hash to keep with
the spirit of the merged commits, and various other cleanup intended to
bring the code bases more in line with one another.
This commit is the first stage of several that are planned to convert
the blockchain package into a concurrent safe package that will
ultimately allow support for multi-peer download and concurrent chain
processing. The goal is to update btcd proper after each step so it can
take advantage of the enhancements as they are developed.
In addition to the aforementioned benefit, this staged approach has been
chosen since it is absolutely critical to maintain consensus.
Separating the changes into several stages makes it easier for reviewers
to logically follow what is happening and therefore helps prevent
consensus bugs. Naturally there are significant automated tests to help
prevent consensus issues as well.
The main focus of this stage is to convert the blockchain package to use
the new database interface and implement the chain-related functionality
which it no longer handles. It also aims to improve efficiency in
various areas by making use of the new database and chain capabilities.
The following is an overview of the chain changes:
- Update to use the new database interface
- Add chain-related functionality that the old database used to handle
- Main chain structure and state
- Transaction spend tracking
- Implement a new pruned unspent transaction output (utxo) set
- Provides efficient direct access to the unspent transaction outputs
- Uses a domain specific compression algorithm that understands the
standard transaction scripts in order to significantly compress them
- Removes reliance on the transaction index and paves the way toward
eventually enabling block pruning
- Modify the New function to accept a Config struct instead of
inidividual parameters
- Replace the old TxStore type with a new UtxoViewpoint type that makes
use of the new pruned utxo set
- Convert code to treat the new UtxoViewpoint as a rolling view that is
used between connects and disconnects to improve efficiency
- Make best chain state always set when the chain instance is created
- Remove now unnecessary logic for dealing with unset best state
- Make all exported functions concurrent safe
- Currently using a single chain state lock as it provides a straight
forward and easy to review path forward however this can be improved
with more fine grained locking
- Optimize various cases where full blocks were being loaded when only
the header is needed to help reduce the I/O load
- Add the ability for callers to get a snapshot of the current best
chain stats in a concurrent safe fashion
- Does not block callers while new blocks are being processed
- Make error messages that reference transaction outputs consistently
use <transaction hash>:<output index>
- Introduce a new AssertError type an convert internal consistency
checks to use it
- Update tests and examples to reflect the changes
- Add a full suite of tests to ensure correct functionality of the new
code
The following is an overview of the btcd changes:
- Update to use the new database and chain interfaces
- Temporarily remove all code related to the transaction index
- Temporarily remove all code related to the address index
- Convert all code that uses transaction stores to use the new utxo
view
- Rework several calls that required the block manager for safe
concurrency to use the chain package directly now that it is
concurrent safe
- Change all calls to obtain the best hash to use the new best state
snapshot capability from the chain package
- Remove workaround for limits on fetching height ranges since the new
database interface no longer imposes them
- Correct the gettxout RPC handler to return the best chain hash as
opposed the hash the txout was found in
- Optimize various RPC handlers:
- Change several of the RPC handlers to use the new chain snapshot
capability to avoid needlessly loading data
- Update several handlers to use new functionality to avoid accessing
the block manager so they are able to return the data without
blocking when the server is busy processing blocks
- Update non-verbose getblock to avoid deserialization and
serialization overhead
- Update getblockheader to request the block height directly from
chain and only load the header
- Update getdifficulty to use the new cached data from chain
- Update getmininginfo to use the new cached data from chain
- Update non-verbose getrawtransaction to avoid deserialization and
serialization overhead
- Update gettxout to use the new utxo store versus loading
full transactions using the transaction index
The following is an overview of the utility changes:
- Update addblock to use the new database and chain interfaces
- Update findcheckpoint to use the new database and chain interfaces
- Remove the dropafter utility which is no longer supported
NOTE: The transaction index and address index will be reimplemented in
another commit.
This is mostly a backport of some of the same modifications made in
Decred along with a few additional things cleaned up. In particular,
this updates the code to make use of the new chainhash package.
Also, since this required API changes anyways and the hash algorithm is
no longer tied specifically to SHA, all other functions throughout the
code base which had "Sha" in their name have been changed to Hash so
they are not incorrectly implying the hash algorithm.
The following is an overview of the changes:
- Remove the wire.ShaHash type
- Update all references to wire.ShaHash to the new chainhash.Hash type
- Rename the following functions and update all references:
- wire.BlockHeader.BlockSha -> BlockHash
- wire.MsgBlock.BlockSha -> BlockHash
- wire.MsgBlock.TxShas -> TxHashes
- wire.MsgTx.TxSha -> TxHash
- blockchain.ShaHashToBig -> HashToBig
- peer.ShaFunc -> peer.HashFunc
- Rename all variables that included sha in their name to include hash
instead
- Update for function name changes in other dependent packages such as
btcutil
- Update copyright dates on all modified files
- Update glide.lock file to use the required version of btcutil
Profiles discovered that lookups into the signature cache included an
expensive comparison to the stored `sigInfo` struct. This lookup had the
potential to be more expensive than directly verifying the signature
itself!
In addition, evictions were rather expensive because they involved
reading from /dev/urandom, or equivalent, for each eviction once the
signature cache was full as well as potentially iterating over every
item in the cache in the worst-case.
To remedy this poor performance several changes have been made:
* Change the lookup key to the fixed sized 32-byte signature hash
* Perform a full equality check only if there is a cache hit which
results in a significant speed up for both insertions and existence
checks
* Override entries in the case of a colliding hash on insert Add an
* .IsEqual() method to the Signature and PublicKey types in the
btcec package to facilitate easy equivalence testing
* Allocate the signature cache map with the max number of entries in
order to avoid unnecessary map re-sizes/allocations
* Optimize evictions from the signature cache Delete the first entry
* seen which is safe from manipulation due to
the pre image resistance of the hash function
* Double the default maximum number of entries within the signature
cache due to the reduction in the size of a cache entry
* With this eviction scheme, removals are effectively O(1)
Fixes#575.
This modifies the conversion of the output index from the JSON-based
test data for valid and invalid transactions as well as the signature
hash type for signature hash tests to first convert to a signed int and
then to an unsigned int. This is necessary because the result of a
direct conversion of a float to an unsigned int is implementation
dependent and doesn't result in the expected value on all platforms.
Also, while here, change the function names in the error prints to match
the actual names.
Fixes#600.
500 tests with various transactions and scripts, verifying that
calcSignatureHash generates the expected hash in each case.
This requires changing SigHashType to uint32; that won't affect the
standard use-cases, but will make calcSignatureHash behave more like the
Core counterpart for non-standard SigHashType settings, like those in
some of these tests.
See https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki for
more information.
This commit mimics Bitcoin Core commit bc60b2b4b401f0adff5b8b9678903ff8feb5867b
and includes additional tests from Bitcoin Core commit
cb54d17355864fa08826d6511a0d7692b21ef2c9
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.
- Move reference tests to test package since they are intended to
exercise the engine as callers would
- Improve the short form script parsing to allow additional opcodes:
DATA_#, OP_#, FALSE, TRUE
- Make use of a function to decode hex strings rather than manually
defining byte slices
- Update the tests to make use of the short form script parsing logic
rather than manually defining byte slices
- Consistently replace all []byte{} and [][]byte{} with nil
- Define tests only used in a specific function inside that func
- Move invalid flag combination test to engine_test since that is what
it is testing
- Remove all redundant script tests in favor of the JSON-based tests in
the data directory.
- Move several functions from internal_test.go to the test files
associated with what the tests are checking
This commit exports a new map named OpcodeByName which can be used to
lookup an opcode value given a human-readable opcode name.
It also modifies the test function which does short form parsing to use
the new map instead of the internal array.
Closes#267.
This commit converts the opcode map to an array to improve performance.
Benchmark of executing a standard p2pk transaction:
New: BenchmarkExecute 2000 784349 ns/op
Old: BenchmarkExecute 2000 792600 ns/op
The time is dominated by the signature checking as expected, however there
is still an increase in speed.
This commit renames the Script type to Engine to better reflect its
purpose. It also renames the NewScript function to NewEngine to match.
This is being done because name Script for the engine is confusing since
it implies it is an actual script rather than the execution environment
for the script. It also paves the way for eventually supplying a
ParsedScript type which will be less likely to be confused with the
execution environment.
While moving the code, some additional variable names and comments have
been updated to better match the style used throughout the rest of the
code base. In addition, an attempt has been made to use consistent naming
of the engine as 'vm' instead of using different variables names as it was
previously.
Finally, the relevant engine code has been moved into a new file named
engine.go and related tests moved to engine_test.go.
This commit separates the test functions and associated helper functions
which are used to execute the reference transaction and script tests from
Bitcoin Core into a separate file named reference_test.go.
Also, add a few comments and fix a couple of typos along the way.
