[Haskell-cafe] Improvements to package hosting and security

Dennis J. McWherter, Jr. dennis at deathbytape.com
Mon Apr 13 14:55:31 UTC 2015

This proposal looks great. The one thing I am failing to understand (and I 
recognize the proposal is in early stages) is how to ensure redundancy in 
the system. As far as I can tell, much of this proposal discusses the 
centralized authority of the system (i.e. ensuring secure distribution) and 
only references (with little detail) the distributed store. For instance, 
say I host a package on a personal server and one day I decide to shut that 
server down; is this package now lost forever? I do see this line: "backup 
download links to S3" but this implies that the someone is willing to pay 
for S3 storage for all of the packages.

Are there plans to adopt a P2P-like model or something similar to support 
any sort of replication? Public resources like this seem to come and go, so 
it would be nice to avoid some of the problems associated with high churn 
in the network. That said, there is an obvious cost to replication. 
Likewise, the central authority would have to be updated with new, relevant 
locations to find the file (as it is currently proposed).

In any case, as I said before, the proposal looks great! I am looking 
forward to this.

On Monday, April 13, 2015 at 5:02:46 AM UTC-5, Michael Snoyman wrote:
> Many of you saw the blog post Mathieu wrote[1] about having more 
> composable community infrastructure, which in particular focused on 
> improvements to Hackage. I've been discussing some of these ideas with both 
> Mathieu and others in the community working on some similar thoughts. I've 
> also separately spent some time speaking with Chris about package 
> signing[2]. Through those discussions, it's become apparent to me that 
> there are in fact two core pieces of functionality we're relying on Hackage 
> for today:
> * A centralized location for accessing package metadata (i.e., the cabal 
> files) and the package contents themselves (i.e., the sdist tarballs)
> * A central authority for deciding who is allowed to make releases of 
> packages, and make revisions to cabal files
> In my opinion, fixing the first problem is in fact very straightforward to 
> do today using existing tools. FP Complete already hosts a full Hackage 
> mirror[3] backed by S3, for instance, and having the metadata mirrored to a 
> Git repository as well is not a difficult technical challenge. This is the 
> core of what Mathieu was proposing as far as composable infrastructure, 
> corresponding to next actions 1 and 3 at the end of his blog post (step 2, 
> modifying Hackage, is not a prerequesite). In my opinion, such a system 
> would far surpass in usability, reliability, and extensibility our current 
> infrastructure, and could be rolled out in a few days at most.
> However, that second point- the central authority- is the more interesting 
> one. As it stands, our entire package ecosystem is placing a huge level of 
> trust in Hackage, without any serious way to vet what's going on there. 
> Attack vectors abound, e.g.:
> * Man in the middle attacks: as we are all painfully aware, cabal-install 
> does not support HTTPS, so a MITM attack on downloads from Hackage is 
> trivial
> * A breach of the Hackage Server codebase would allow anyone to upload 
> nefarious code[4]
> * Any kind of system level vulnerability could allow an attacker to 
> compromise the server in the same way
> Chris's package signing work addresses most of these vulnerabilities, by 
> adding a layer of cryptographic signatures on top of Hackage as the central 
> authority. I'd like to propose taking this a step further: removing Hackage 
> as the central authority, and instead relying entirely on cryptographic 
> signatures to release new packages.
> I wrote up a strawman proposal last week[5] which clearly needs work to be 
> a realistic option. My question is: are people interested in moving forward 
> on this? If there's no interest, and everyone is satisfied with continuing 
> with the current Hackage-central-authority, then we can proceed with having 
> reliable and secure services built around Hackage. But if others- like me- 
> would like to see a more secure system built from the ground up, please say 
> so and let's continue that conversation.
> [1] 
> https://www.fpcomplete.com/blog/2015/03/composable-community-infrastructure 
> [2] 
> https://github.com/commercialhaskell/commercialhaskell/wiki/Package-signing-detailed-propsal 
> [3] https://www.fpcomplete.com/blog/2015/03/hackage-mirror  
> [4] I don't think this is just a theoretical possibility for some point in 
> the future. I have reported an easily trigerrable DoS attack on the current 
> Hackage Server codebase, which has been unresolved for 1.5 months now  
> [5] https://gist.github.com/snoyberg/732aa47a5dd3864051b9  
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