1d827e0347
In this commit, we fix a policy-level divergence with Bitcoin Core when handling OP_CODESEPARATOR inside unexecuted OP_IF branches in non-segwit scripts with the ScriptVerifyConstScriptCode flag. Bitcoin Core's EvalScript (interpreter.cpp:474-476) places the SCRIPT_VERIFY_CONST_SCRIPTCODE check for OP_CODESEPARATOR before the fExec branch-execution gate, causing it to fire unconditionally on every OP_CODESEPARATOR encountered during script iteration -- even inside OP_FALSE OP_IF ... OP_ENDIF envelopes. Previously, btcd's equivalent check lived inside the opcodeCodeSeparator handler, which was never reached for opcodes in unexecuted branches due to the early return in executeOpcode that skips non-conditional opcodes when isBranchExecuting() is false. This meant a script like: OP_FALSE OP_IF OP_CODESEPARATOR OP_ENDIF <validation> would be rejected by Bitcoin Core's mempool but accepted by btcd's. The fix moves the check before the branch-execution gate in executeOpcode, matching Bitcoin Core's structure. This follows the existing pattern in btcd where isOpcodeDisabled and isOpcodeAlwaysIllegal checks already fire regardless of branch execution state. Note: SCRIPT_VERIFY_CONST_SCRIPTCODE is purely a policy flag (included in STANDARD_SCRIPT_VERIFY_FLAGS but not MANDATORY_SCRIPT_VERIFY_FLAGS), so this was not a consensus divergence. Both implementations would accept such transactions if mined in a block. Found via differential fuzzing by Bruno from bitcoinfuzz. |
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|---|---|---|
| .. | ||
| data | ||
| bench_test.go | ||
| consensus.go | ||
| doc.go | ||
| engine.go | ||
| engine_debug_test.go | ||
| engine_test.go | ||
| error.go | ||
| error_test.go | ||
| example_test.go | ||
| hashcache.go | ||
| hashcache_test.go | ||
| log.go | ||
| opcode.go | ||
| opcode_test.go | ||
| pkscript.go | ||
| pkscript_test.go | ||
| README.md | ||
| reference_test.go | ||
| script.go | ||
| script_test.go | ||
| scriptbuilder.go | ||
| scriptbuilder_test.go | ||
| scriptnum.go | ||
| scriptnum_test.go | ||
| sigcache.go | ||
| sigcache_test.go | ||
| sighash.go | ||
| sign.go | ||
| sign_test.go | ||
| sigvalidate.go | ||
| stack.go | ||
| stack_test.go | ||
| standard.go | ||
| standard_test.go | ||
| taproot.go | ||
| taproot_test.go | ||
| template.go | ||
| template_test.go | ||
| tokenizer.go | ||
| tokenizer_test.go | ||
txscript
Package txscript implements the bitcoin transaction script language. There is a comprehensive test suite.
This package has intentionally been designed so it can be used as a standalone package for any projects needing to use or validate bitcoin transaction scripts.
Bitcoin Scripts
Bitcoin provides a stack-based, FORTH-like language for the scripts in the bitcoin transactions. This language is not turing complete although it is still fairly powerful. A description of the language can be found at https://en.bitcoin.it/wiki/Script
Installation and Updating
$ go get -u github.com/btcsuite/btcd/txscript
Examples
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Standard Pay-to-pubkey-hash Script
Demonstrates creating a script which pays to a bitcoin address. It also prints the created script hex and uses the DisasmString function to display the disassembled script. -
Extracting Details from Standard Scripts
Demonstrates extracting information from a standard public key script. -
Manually Signing a Transaction Output
Demonstrates manually creating and signing a redeem transaction. -
Counting Opcodes in Scripts
Demonstrates creating a script tokenizer instance and using it to count the number of opcodes a script contains.
GPG Verification Key
All official release tags are signed by Conformal so users can ensure the code has not been tampered with and is coming from the btcsuite developers. To verify the signature perform the following:
-
Download the public key from the Conformal website at https://opensource.conformal.com/GIT-GPG-KEY-conformal.txt
-
Import the public key into your GPG keyring:
gpg --import GIT-GPG-KEY-conformal.txt -
Verify the release tag with the following command where
TAG_NAMEis a placeholder for the specific tag:git tag -v TAG_NAME
License
Package txscript is licensed under the copyfree ISC License.