37c9fb7a59
This commit adds the functionality necessary to transition from doing binary verification on the basis of a single signature to requiring a minimum threshold of trusted signatures. A signature can appear as "good" from GPG output, but it may not come from an identity the user trusts. We call these "good, untrusted" signatures. We report bad signatures but do not necessarily fail in their presence, since a bad signature might coexist with enough good, trusted signatures to fulfill our criteria. If "--import-keys" is enabled, we will prompt the user to optionally try to retrieve unknown keys. Marking them as trusted locally is a WIP, but keys which are retrieved successfully and appear on the builder-keys list will immediately count as being useful towards fulfilling the threshold. Logging is improved and an option to output JSON that summarizes the whole sum signature and binary verification processes has been added. Co-authored-by: Russ Yanofsky <russ@yanofsky.org> Co-authored-by: willcl-ark <will8clark@gmail.com>
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Verify Binaries
Preparation
As of Bitcoin Core v22.0, releases are signed by a number of public keys on the basis of the guix.sigs repository. When verifying binary downloads, you (the end user) decide which of these public keys you trust and then use that trust model to evaluate the signature on a file that contains hashes of the release binaries. The downloaded binaries are then hashed and compared to the signed checksum file.
First, you have to figure out which public keys to recognize. Browse the list of frequent builder-keys and decide which of these keys you would like to trust. For each key you want to trust, you must obtain that key for your local GPG installation.
You can obtain these keys by
- through a browser using a key server (e.g. keyserver.ubuntu.com),
- manually using the
gpg --keyserver <url> --recv-keys <key>command, or - you can run the packaged
verifybinaries.py ... --import-keysscript to have it automatically retrieve unrecognized keys.
Usage
This script attempts to download the checksum file (SHA256SUMS) and corresponding
signature file SHA256SUMS.asc from https://bitcoincore.org and https://bitcoin.org.
It first checks if the checksum file is valid based upon a plurality of signatures, and then downloads the release files specified in the checksum file, and checks if the hashes of the release files are as expected.
If we encounter pubkeys in the signature file that we do not recognize, the script
can prompt the user as to whether they'd like to download the pubkeys. To enable
this behavior, use the --import-keys flag.
The script returns 0 if everything passes the checks. It returns 1 if either the signature check or the hash check doesn't pass. An exit code of >2 indicates an error.
See the Config object for various options.
Examples
Validate releases with default settings:
./contrib/verifybinaries/verify.py 22.0
./contrib/verifybinaries/verify.py 22.0-rc2
./contrib/verifybinaries/verify.py bitcoin-core-23.0
./contrib/verifybinaries/verify.py bitcoin-core-23.0-rc1
Get JSON output and don't prompt for user input (no auto key import):
./contrib/verifybinaries/verify.py 22.0-x86 --json
Don't trust builder-keys by default, and rely only on local GPG state and manually specified keys, while requiring a threshold of at least 10 trusted signatures:
./contrib/verifybinaries/verify.py 22.0-x86 \
--no-trust-builder-keys \
--trusted-keys 74E2DEF5D77260B98BC19438099BAD163C70FBFA,9D3CC86A72F8494342EA5FD10A41BDC3F4FAFF1C \
--min-trusted-sigs 10
If you only want to download the binaries of certain platform, add the corresponding suffix, e.g.:
./contrib/verifybinaries/verify.py bitcoin-core-22.0-osx
./contrib/verifybinaries/verify.py bitcoin-core-22.0-rc2-win64
If you do not want to keep the downloaded binaries, specify anything as the second parameter.
./contrib/verifybinaries/verify.py bitcoin-core-22.0 delete