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Launchpad-linked federated Matrix accounts

Published by ines-almeida January 22, 2024 in General

Users can now add their Matrix accounts to their profile in Launchpad, as requested by Canonical’s Community team.

We also took the chance to slightly rework the frontend and how we display social accounts in the user profiles. Instead of having different sections in the profile for each social account , all social accounts are now all under a “Social Accounts” section.

Adding a new matrix account to your profile works similarly to how it has always worked for other accounts. Under the “Social Accounts” section in your user profile, you should now see a “No matrix accounts registered” and an edit button that will lead you to the Matrix accounts edit page. To edit, remove or add new ones, you will see an edit button in front of your newly added accounts in your profile.

We also added new API endpoints Person.social_accounts and Person.getSocialAccountsByPlatform() that will list the social accounts for a user. For more information, see our API documentation.

Currently, only Matrix was added as a social platform. But during this process, we made it much easier for Launchpad developers to add new social platforms to Launchpad in the future.


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Self-service riscv64 builds

Published by Colin Watson November 22, 2023 in PPA

Launchpad has supported building for riscv64 for a while, since it was a requirement to get Ubuntu’s riscv64 port going. We don’t actually have riscv64 hardware in our datacentre, since we’d need server-class hardware with the hypervisor extension and that’s still in its infancy; instead, we do full-system emulation of riscv64 on beefy amd64 hardware using qemu. This has worked well enough for a while, although it isn’t exactly fast.

The biggest problem with our setup wasn’t so much performance, though; it was that we were just using a bunch of manually-provisioned virtual machines, and they weren’t being reset to a clean state between builds. As a result, it would have been possible for a malicious build to compromise future builds on the same builder: it would only need a chroot or container escape. This violated our standard security model for builders, in which each build runs in an isolated ephemeral VM, and each VM is destroyed and restarted from a clean image at the end of every build. As a result, we had to limit the set of people who were allowed to have riscv64 builds on Launchpad, and we had to restrict things like snap recipes to only use very tightly-pinned parts from elsewhere on the internet (pinning is often a good idea anyway, but at an infrastructural level it isn’t something we need to require on other architectures).

We’ve wanted to bring this onto the same footing as our other architectures for some time. In Canonical’s most recent product development cycle, we worked with the OpenStack team to get riscv64 emulation support into nova, and installed a backport of this on our newest internal cloud region. This almost took care of the problem. However, Launchpad builder images start out as standard Ubuntu cloud images, which on riscv64 are only available from Ubuntu 22.04 LTS onwards; in testing 22.04-based VMs on other relatively slow architectures we already knew that we were seeing some mysterious hangs in snap recipe builds. Figuring this out blocked us for some time, and involved some pretty intensive debugging of the “strace absolutely everything in sight and see if anything sensible falls out” variety. We eventually narrowed this down to a LXD bug and were at least able to provide a workaround, at which point bringing up new builders was easy.

As a result, you can now enable riscv64 builds for yourself in your PPAs or snap recipes. Visit the PPA and follow the “Change details” link, or visit the snap recipe and follow the “Edit snap package” link; you’ll see a list of checkboxes under “Processors”, and you can enable or disable any that aren’t greyed out, including riscv64. This now means that all Ubuntu architectures are fully virtualized and unrestricted in Launchpad, making it easier for developers to experiment.


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Introducing Project-Scoped Access Tokens

Published by ines-almeida November 20, 2023 in General

Access tokens can be used to access repositories on behalf of someone. They have scope limitations, optional expiry dates, and can be revoked at any time. They are a stricter and safer alternative to using real user authentication when needing to automate pushing and/or pulling from your git repositories.

This is a concept that has existed in Launchpad for a while now. If you have the right permissions in a git repository, you might have seen a “Manage Access Tokens” button in your repository’s page in the past.

These tokens can be extremely useful. But if you have multiple git repositories within a project, it can be a bit of a nuisance to create and manage access tokens for each repository.

So what’s new? We’ve now introduced project-scoped access tokens. These tokens reduce the trouble for the creation and maintenance of tokens for larger projects. A project access token will work as authentication for any git repository within that project.

Let’s say user A wants to run something in a remote server that requires pulling multiple git repositories from a project. User A can create a project access token, and restrict it to “repository pull” scope only. This token will then be valid authentication to pull from any repository within that project. And user A will be able to revoke that token once it’s no longer needed, keeping their real user authentication safe.

The same token will be invalid for pushing, or for accessing repositories within other projects. Also note that this is used for ‘authentication’, not ‘authorization’ – if the user doesn’t have access to a given git repository, their access token will not grant them permissions.

Anyone with permissions to edit a project will be able to create an access token, either through the UI or the API, using the same method as to create access tokens for git repositories. See Generating Access Tokens section in our documentation for instructions and other information.
This feature was implemented on request by our colleagues from the ROS team. We would love to get some feedback whether this also covers your use case. Please let us know.


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New domain names for PPAs

Published by Colin Watson February 16, 2022 in PPA

Since they were introduced in 2007, Launchpad’s Personal Package Archives (PPAs) have always been hosted on ppa.launchpad.net. This has generally worked well, but one significant snag became clear later on: it was difficult to add HTTPS support for PPAs due to the way that cookies work on the web.

Launchpad uses a cookie for your login session, which is of course security-critical, and because we use multiple domain names for the main web application (bugs.launchpad.net, code.launchpad.net, and so on), the session cookie domain has to be set to allow subdomains of launchpad.net. We set the “Secure” flag on session cookies to ensure that browsers only ever send them over HTTPS, as well as the “HttpOnly” flag to prevent direct access to it from JavaScript; but there are still ways in which arbitrary JS on an HTTPS subdomain of launchpad.net might be able to exfiltrate or abuse users’ session cookies. As a result, we can never allow any HTTPS subdomain of launchpad.net to publish completely user-generated HTML that we don’t process first.

We don’t currently know of a way to get ppa.launchpad.net to serve arbitrary HTML as Content-Type: text/html, but this is quite a brittle protection as there are certainly ways (used for things like installer uploads) to upload arbitrary files to ppa.launchpad.net under a user-controlled directory structure, and we don’t want the webapp’s security to depend on nobody figuring out how to convince a browser to interpret any of that as arbitrary HTML. The librarian is already on a separate launchpadlibrarian.net domain name for a similar reason.

To resolve this dilemma, we’ve added a new ppa.launchpadcontent.net domain name which supports both HTTP and HTTPS (and similarly private-ppa.launchpadcontent.net for private PPAs, which as before is HTTPS-only). add-apt-repository in Ubuntu 22.04 will use the new domain name by default.

The old names will carry on working indefinitely – we know they’re embedded in lots of configuration and scripts, and we have no inclination to break all of those – but we recommend moving to the new names where possible. ppa.launchpad.net will remain HTTP-only.

Some systems may need to be updated to support the new domain name, particularly things like HTTP(S) proxy configuration files and no_proxy environment variables.


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Comment editing is now possible

Published by Thiago F Pappacena May 28, 2021 in General

It took a while, but now Launchpad finally allows users to edit their comments on questions, bug reports and merge proposal pages.

The first request for this feature dates back from 2007. Since then, Launchpad increased a lot in terms of new features, and the other priorities took precedence over that request, but the request was still more than valid. More recently, we managed to bump the priority of this feature, and now we have it: users are now allowed to edit their comments on Launchpad answers, bugs and merge proposals!

This has been available in the API for a few days already, but today we finally released the fresh new pencil icon in the top-right corner of your messages. Once you click it, the message is turned into a small form that allows you to edit your message content.

For messages that were edited before, it is possible to see old versions of that edited message by clicking the “last edit …” link, also at the top of the message.

In case you introduce sensitive information by mistake in your comment and need to remove it from the message history after editing it, you can always use the API to do so. We plan to add a remove button to the message’s revision history UI soon, to make this work easier.

The Launchpad team is proud of this new feature, and we hope that it will be useful for everyone! Let us know if you have any feedback!


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Git Protocol v2 Available at Launchpad

Published by Thiago F Pappacena September 28, 2020 in Code, Performance

After a few weeks of development and testing, we are proud to finally announce that Git protocol v2 is available at Launchpad! But what are the improvements in the protocol itself, and how can you benefit from that?

The git v2 protocol was released a while ago, in May 2018, with the intent of simplifying git over HTTP transfer protocol, allowing extensibility of git capabilities, and reducing the network usage in some operations.

For the end user, the main clear benefit is the bandwidth reduction: in the previous version of the protocol, when one does a “git pull origin master”, for example, even if you have no new commits to fetch from the remote origin, git server would first “advertise” to the client all refs (branches and tags) available. In big repositories with hundreds or thousands of refs, this simple handshake operation could consume a lot of bandwidth and time to communicate a bunch of data that would potentially be discarded by the client after.

In the v2 protocol, this waste is no longer present: the client now has the ability to filter which refs it wants to know about before the server starts advertising it.

The v2 protocol is not the default on git clients yet, but if you are using a git version higher than 2.19, you can use v2: simply run git config --global protocol.version 2, and you will be using the most recent protocol version when communicating with servers that support this version. Including Launchpad, of course.

And even if you have repositories hosted in a server that is not yet compatible with v2, don’t worry: the git client is backward compatible. If the server does not support v2, git client should fall back gracefully to the previous version and everything should continue to work as expected. We hope you enjoy the new feature. And let us know if you have any feedback!


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Login regression for users with non-ASCII names

Published by Colin Watson August 20, 2020 in General

On 2020-08-13, we deployed an update that caused users whose full names contain non-ASCII characters (which is of course very common) to be unable to log into Launchpad. We heard about this serious regression from users on 2020-08-17, and rolled out a fix on 2020-08-18. We’re sorry about this; it doesn’t meet the standards of both inclusion and quality that we set for ourselves. This post aims to explain what happened, technical details of why it happened, and the steps we’ve taken to avoid it happening again.

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Bug emails now use the bug’s address in the From: header

Published by Colin Watson May 20, 2020 in Notifications

The From: addresses used by Launchpad’s bug notifications have changed, to improve the chances of our messages being delivered over modern internet email.

Launchpad sends a lot of email, most of which is the result of Launchpad users performing some kind of action. For example, when somebody adds a comment to a bug, Launchpad sends that comment by email to everyone who’s subscribed to the bug.

Most of Launchpad was designed in an earlier era of internet email. In that era, it was perfectly reasonable to take the attitude that we were sending email on behalf of the user – in effect, being a fancy mail user agent or perhaps a little like a mailing list – and so if we generated an email that’s a direct result of something that a user did and consisting mostly of text they wrote, it made sense to put their email address in the From: header. Reply-To: was set so that replies would normally go to the appropriate place (the bug, in the case of bug notifications), but if somebody wanted to go to a bit of effort to start a private side conversation then it was easy to do so; and if email clients had automatic address books then those wouldn’t get confused because the address being used was a legitimate address belonging to the user in question.

Of course, some people always wanted to hide their addresses for obvious privacy reasons, so since 2006 Launchpad has had a “Hide my email address from other Launchpad users” switch (which you can set on your Change your personal details page), and since 2010 Launchpad has honoured this for bug notifications, so if you have that switch set then your bug comments will be sent out as something like “From: Your Name <bug-id@bugs.launchpad.net>“. This compromise worked tolerably well for a while.

But spammers and other bad actors ruin everything, and the internet email landscape has changed. It’s reasonably common now for operators of email domains to publish DMARC policies that require emails whose From: headers are within that domain to be authenticated in some way, and this is incompatible with the older approach. As a result, it’s been getting increasingly common for Launchpad bug notifications not to be delivered because they failed these authentication checks. Regardless of how justifiable our notification-sending practices were, we have to exist within the reality of internet email as it’s actually deployed.

So, thanks to a contribution from Thomas Ward, Launchpad now sends all its bug notifications as if the user in question had the “Hide my email address from other Launchpad users” switch set: that is, they’ll all appear as something like “From: Your Name <bug-id@bugs.launchpad.net>“. Over time we expect to extend this sort of approach to the other types of email that we send, possibly with different details depending on the situation.

Please let us know if this causes any strange behaviour in your email client. We may not be able to fix all of them, depending on how they interact with DMARC’s requirements, but we’d like to be aware of what’s going on.


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Launchpad news, March 2019 – July 2019

Published by Colin Watson August 6, 2019 in General

Here’s a brief changelog of what we’ve been up to since our last general update.

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Launchpad news, February 2019

Published by Colin Watson March 7, 2019 in General

Here’s a brief changelog for this month.

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