On Wed, May 22, 2013 at 05:12:20PM +0200, Ludovic Courtès wrote: > Hello, > > Currently the “binary cache” substituter relies on DNS to authenticate > downloaded binaries: anything coming from, say, hydra.nixos.org is > considered authentic, because hydra.nixos.org is listed in the > ‘trusted-binary-cache’ list. > > This is obviously subject to person-in-the-middle attacks: one could > connect over Wifi to somebody else’s network, which happens to redirect > hydra.nixos.org to evil.example.com, and end up downloading evil binaries. > > I was thinking of a simple extension to solve that: > > 1a. The /nix-cache-info file would contain an (optional) > ‘OpenPGPFingerprint’ field, to announce the fingerprint of the > OpenPGP key used to sign Nars. > > 1b. In addition to, or alternatively, a /nix-signing-key file would be > served, containing the OpenPGP key used to sign Nars. > > 2. In addition to serving, say, > /nar/zwpx7d0sv36fi4xpwqx2dak0axx5nji8-gmp-5.1.1, the server would > also serve /nar/zwpx7d0sv36fi4xpwqx2dak0axx5nji8-gmp-5.1.1.sig, an > OpenPGP binary signature of the uncompressed Nar. > > WDYT? Could this be implemented in Hydra?
I add myself to the request. The /nix-cache-info or /nix-signing-key files should be requested only once and stored in the local system, unless the user deletes them. If they are fetched at every run, we are doomed again.
