From 0fdf4da0e979f992db75cc17376e455ddc5a96d8 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 8 Jan 2014 15:23:41 +0100 Subject: Support cryptographically signed binary caches MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. --- tests/binary-cache.sh | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'tests/binary-cache.sh') diff --git a/tests/binary-cache.sh b/tests/binary-cache.sh index eb2ebbff8203..ed947a6620d5 100644 --- a/tests/binary-cache.sh +++ b/tests/binary-cache.sh @@ -40,6 +40,14 @@ nix-store --check-validity $outPath nix-store -qR $outPath | grep input-2 +# Test whether this unsigned cache is rejected if the user requires signed caches. +clearStore + +rm -f $NIX_STATE_DIR/binary-cache* + +nix-store --option binary-caches "file://$cacheDir" --option signed-binary-caches 1 -r $outPath + + # Test whether fallback works if we have cached info but the # corresponding NAR has disappeared. clearStore -- cgit 1.4.1