Eelco Dolstra
0fdf4da0e9
NAR info files in binary caches can now have a cryptographic signature that Nix will verify before using the corresponding NAR file. To create a private/public key pair for signing and verifying a binary cache, do: $ openssl genrsa -out ./cache-key.sec 2048 $ openssl rsa -in ./cache-key.sec -pubout > ./cache-key.pub You should also come up with a symbolic name for the key, such as "cache.example.org-1". This will be used by clients to look up the public key. (It's a good idea to number keys, in case you ever need to revoke/replace one.) To create a binary cache signed with the private key: $ nix-push --dest /path/to/binary-cache --key ./cache-key.sec --key-name cache.example.org-1 The public key (cache-key.pub) should be distributed to the clients. They should have a nix.conf should contain something like: signed-binary-caches = * binary-cache-public-key-cache.example.org-1 = /path/to/cache-key.pub If all works well, then if Nix fetches something from the signed binary cache, you will see a message like: *** Downloading ‘http://cache.example.org/nar/7dppcj5sc1nda7l54rjc0g5l1hamj09j-subversion-1.7.11’ (signed by ‘cache.example.org-1’) to ‘/nix/store/7dppcj5sc1nda7l54rjc0g5l1hamj09j-subversion-1.7.11’... On the other hand, if the signature is wrong, you get a message like NAR info file `http://cache.example.org/7dppcj5sc1nda7l54rjc0g5l1hamj09j.narinfo' has an invalid signature; ignoring Signatures are implemented as a single line appended to the NAR info file, which looks like this: Signature: 1;cache.example.org-1;HQ9Xzyanq9iV...muQ== Thus the signature has 3 fields: a version (currently "1"), the ID of key, and the base64-encoded signature of the SHA-256 hash of the contents of the NAR info file up to but not including the Signature line. Issue #75.
Nix is a purely functional package manager. For installation and usage instructions, please read the manual, which can be found in `docs/manual/manual.html', and additionally at the Nix website at <http://nixos.org/>. Acknowledgments This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit (http://www.OpenSSL.org/).