Requesting auto-connection of personal-files to sam-cli


Hi all, I’m working on snapping the AWS SAM CLI. You can see the recipe etc. in this pull request.

The SAM CLI needs personal-files because it relies on the AWS CLI which users will almost certainly have pre-installed and which stores its configuration in ~/.aws.

[revoked] Requesting classic confinement for `sam-cli`

And while I’m doing a poke on the alias post for this, I might as well do this one too :slight_smile:


The readonly access is clearly needed and I’m inclined to vote in favor of granting an installation constraint for read-only access to ~/.aws, but I’m somewhat hesitant because sam-cli is not the clear owner of this directory and this directory contains very sensitive information that would give the snap access to run up charges in AWS. I may feel less concern about this if the snap were named after the upstream project, aws-sam-cli. That said, the snap’s description is (currently) “The AWS SAM CLI tool for the AWS Serverless Application Model” so it isn’t trying to hide anything. Also, @stilvoid is in the process of upstreaming the snap packaging:

@stilvoid - Why did you choose to name the project sam-cli instead of aws-sam-cli?

As for auto-connection, I’m disinclined to grant auto-connection because the snap is not the clear owner. It is also easy for the snap to determine if it has read access, understand that it is a snap, and tell the user “Access denied to ~/.aws. Please run: sudo snap connect sam-cli:personal-files”. Personally, that would actually build confidence that the project cares about the security of this very sensitive data. Before I vote, I’d like to hear what an architect has to say (cc @pedronis).

Note that personal-files is new and we are still defining the processes around it. We’ve identified that personal-files is being used by more than just ‘owners of the directory’ as can be seen from sam-cli, Kubicorn and kubefwd.

(@stilvoid - feel free to ignore my comments from here down)

@pedronis, @mvo (who created the interface) - should snapd be updated so that a snap declaration can express the interface reference in its policy? Ie, let’s say we dictate as a matter of process for snaps like this that a snap use a particular interface reference, like so:

name: foo
summary: application for building upon bar
    interface: personal-files
    read: [ $HOME/.foo ]

such that snap interfaces would list:

$ snap interfaces
:personal-files   foo:home-dot-bar

and users connect would snap connect foo:home-dot-bar. Currently, by design, there is no way to reference home-dot-bar in the snap declaration. Eg (written as yaml instead of json for easier reading):

  allow-auto-connection :  true
      read: \\$HOME/\\.bar
      interface-reference: home-dot-bar  # doesn't exist

@pedronis, I could introduce this in the review-tools with an override mechanism in the short term, but this isn’t scalable (not to mention, getting the changes into prod in the store takes days) and I feel this needs to be enforced by snapd. At what priority should this be implemented? Who would pick up that work? (that can of course be discussed elsewhere).

@pedronis - specific to this request, how do you feel about the installation constraint? manual vs auto connect? How does that change if the above were implemented, if at all?


We have plans to implement something like that, the spelling would be more like:

  allow-auto-connection :  true
      - home-dot-bar
      read: \\$HOME/\\.bar

About when it can happen, we need to see in a bit depending on progress on other things.


if this get upstreamed (as seems being worked on), well it have the same publisher as aws-cli ?


Hi folks, to answer a few points:

  • The review on GitHub has also expressed a preference to call the package aws-sam-cli and I completely agree. I’ll fix it later today.

  • For now, the package will be under my account but I am currently working with the owner of the aws publisher account to move a number of packages to that - this package will be part of that move :slight_smile:


Nice. Would you recommend I add some ad-hoc override tests to the review-tools so that we can define our processes and enforce them at the store level in the meantime?


All this is good news. I’d like to give this a little time to work itself out before casting my vote, because if it’s the same publisher and the name is changed to aws-sam-cli, I would vote in favor of auto-connect (new information notwithstanding).


It’s worked itself out :wink:

aws-sam-cli is now registered under the AWS publisher and the snapcraft.yaml is merged and using the correct name:


+1 for installation and auto-connection for read access to ~/.aws.

@reviewers - can others vote on this?

Interface autoconnection request for the glances snap

+1 from me. This makes sense given the publisher and the application.


it’s not a bad idea if you can fit that in, given I don’t have a timeline for you for when we can implement that in snapd itself yet.


FYI, I’ve implemented this in the review-tools. Please add to the snapd team’s roadmap since the check is limited and updating in the review-tools won’t scale.


2 votes for, 0 against. Granting installation and auto-connection for read access to ~/.aws to aws-sam-cli when the interface reference is ‘config-aws’. This is now live.

Note, you’ll need to update your snap to use:

    interface: personal-files
    - $HOME/.aws

In this manner, this can be manipulated via snap connect/disconnect with ‘aws:config-aws’