7c0cfce20d
f6b782f3aadoc: Improve m_best_header documentation (Martin Zumsande)ee673b9aa0validation: remove m_failed_blocks (Martin Zumsande)ed764ea2b4validation: Add more checks to CheckBlockIndex() (Martin Zumsande)9a70883002validation: in invalidateblock, calculate m_best_header right away (Martin Zumsande)8e39f2d20dvalidation: in invalidateblock, mark children as invalid right away (Martin Zumsande)4c29326183validation: cache all headers with enough PoW in invalidateblock (Martin Zumsande)15fa5b5a90validation: call InvalidBlockFound also from AcceptBlock (Martin Zumsande) Pull request description: Some fields in validation are set opportunistically by "best effort": - The `BLOCK_FAILED_CHILD` status (which means that the block index has an invalid predecessor) - `m_best_header` (the most-work header not known to be invalid). This means that there are known situations in which these fields are not set when they should be, or set to wrong values. This is tolerated because the fields are not used for anything consensus-critical and triggering these situations involved creating invalid blocks with valid PoW header, so would have a cost attached. Also, having stricter guarantees for these fields requires iterating over the entire block index, which has some DoS potential, especially with any header above the checkpoint being accepted int he past (see e.g. #11531). However, there are reasons to change this now: - RPCs use these fields and can report wrong results - There is the constant possibility that someone could add code that expects these fields to be correct, especially because it is not well documented that these fields cannot always be relied upon. - DoS concerns have become less of an issue after #25717 - now an attacker would need to invest much more work because they can't fork off the last checkpoint anymore This PR continues the work from #30666 to ensure that `BLOCK_FAILED_CHILD` status and `m_best_header` are always correct: - it adds a call to `InvalidChainFound()` in `AcceptBlock()`. - it adds checks for `BLOCK_FAILED_CHILD` and `m_best_header` to `CheckBlockIndex()`. In order to be able to do this, the existing cache in the RPC-only `InvalidateBlock()` is adjusted to handle these as well. These are performance optimizations with the goal of avoiding having a call of `InvalidChainFound()` / looping over the block index after each disconnected block. I also wrote a fuzz test to find possible edge cases violating `CheckBlockIndex`, which I will PR separately soon. - it removes the `m_failed_blocks` set, which was a heuristic necessary when we couldn't be sure if a given block index had an invalid predecessor or not. Now that we have that guarantee, the set is no longer needed. ACKs for top commit: stickies-v: re-ACKf6b782f3aaachow101: reACKf6b782f3aaryanofsky: Code review ACKf6b782f3aawith only minor code & comment updates TheCharlatan: Re-ACKf6b782f3aaTree-SHA512: 1bee324216eeee6af401abdb683abd098b18212833f9600dbc0a46244e634cb0e6f2a320c937a5675a12af7ec4a7d10fabc1db9e9bc0d9d0712e6e6ca72d084f
Bitcoin Core integration/staging tree
For an immediately usable, binary version of the Bitcoin Core software, see https://bitcoincore.org/en/download/.
What is Bitcoin Core?
Bitcoin Core connects to the Bitcoin peer-to-peer network to download and fully validate blocks and transactions. It also includes a wallet and graphical user interface, which can be optionally built.
Further information about Bitcoin Core is available in the doc folder.
License
Bitcoin Core is released under the terms of the MIT license. See COPYING for more information or see https://opensource.org/license/MIT.
Development Process
The master branch is regularly built (see doc/build-*.md for instructions) and tested, but it is not guaranteed to be
completely stable. Tags are created
regularly from release branches to indicate new official, stable release versions of Bitcoin Core.
The https://github.com/bitcoin-core/gui repository is used exclusively for the development of the GUI. Its master branch is identical in all monotree repositories. Release branches and tags do not exist, so please do not fork that repository unless it is for development reasons.
The contribution workflow is described in CONTRIBUTING.md and useful hints for developers can be found in doc/developer-notes.md.
Testing
Testing and code review is the bottleneck for development; we get more pull requests than we can review and test on short notice. Please be patient and help out by testing other people's pull requests, and remember this is a security-critical project where any mistake might cost people lots of money.
Automated Testing
Developers are strongly encouraged to write unit tests for new code, and to
submit new unit tests for old code. Unit tests can be compiled and run
(assuming they weren't disabled during the generation of the build system) with: ctest. Further details on running
and extending unit tests can be found in /src/test/README.md.
There are also regression and integration tests, written
in Python.
These tests can be run (if the test dependencies are installed) with: build/test/functional/test_runner.py
(assuming build is your build directory).
The CI (Continuous Integration) systems make sure that every pull request is tested on Windows, Linux, and macOS. The CI must pass on all commits before merge to avoid unrelated CI failures on new pull requests.
Manual Quality Assurance (QA) Testing
Changes should be tested by somebody other than the developer who wrote the code. This is especially important for large or high-risk changes. It is useful to add a test plan to the pull request description if testing the changes is not straightforward.
Translations
Changes to translations as well as new translations can be submitted to Bitcoin Core's Transifex page.
Translations are periodically pulled from Transifex and merged into the git repository. See the translation process for details on how this works.
Important: We do not accept translation changes as GitHub pull requests because the next pull from Transifex would automatically overwrite them again.