** Tags added: block-proposed-noble -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apt in Ubuntu. https://bugs.launchpad.net/bugs/2073126
Title: More nuanced public key algorithm revocation Status in apt package in Ubuntu: Fix Committed Status in apt source package in Noble: Fix Committed Status in apt source package in Oracular: Fix Committed Bug description: (This is uploaded to noble as 2.8.1 per https://wiki.ubuntu.com/AptUpdates) [Impact] We have received feedback from users that use NIST-P256 keys for their repositories that are upset about receiving a warning. APT 2.8.0 in noble-proposed would bump the warning to an error, breaking them. We also revoked additional ECC curves, which may still be considered trusted, so we should not bump them to errors. Also existing users may have third-party repositories that use 1024-bit RSA keys and we have not adequately informed them yet perhaps. [Solution] Hence we will restore all elliptic curve keys of 256 or more bit to trusted: ">=rsa2048,ed25519,ed448,nistp256,nistp384,nistp512,brainpoolP256r1,brainpoolP320r1,brainpoolP384r1,brainpoolP512r1,secp256k1"; At the same time we will also introduce a more nuanced approach to revocations by introducing a 'next' level that issues a warning if the key is not allowed in it and a 'future' level that will issue an audit message with the --audit option. For the next level, we will set it to: ">=rsa2048,ed25519,ed448,nistp256,nistp384,nistp512" This means we restrict warnings to Brainpool curves and the secp256k1 key, which we have not received any feedback about them being used yet. For the future level, we will take a strong approach to best practices as it is only seen when explictly running with --audit and the intention is to highlight best practices. It will be set to ">=rsa3072,ed25519,ed448"; Which corresponds to the NIST recommendations for 2031 (and as little curves as possible). We are also introducing a mitigation for existing 24.04 systems to not upgrade the policy yet; by creating an apt.conf.d configuration file that temporarily allows the 1024-bit RSA keys if upgraded from apt 2.7.x; with the plan to remove them in 24.04.2. [Test plan] Tests are included in the library unit tests for parsing the specification strings; we have also included a test for the gpgv method to ensure that it produces the correct outcome for both 'next' and 'future' revoked keys. A spot check with a 1024-bit RSA repository and a 4096 RSA repository would still be nice. Check a clean install of apt/an upgrade from mantic vs an existing noble system: - An existing noble system should create /etc/apt/apt.conf.d/00-temporary-rsa1024 and continue to trust weak RSA signatures with a warning - Bootstrap a new noble with proposed enabled using e.g. mmdebstrap and check that this is not the case - Also check upgrading from mantic directly to proposed and ensure that 1024R repositories are rejected. [Where problems could occur] There could of course be bugs in the implementation of the new feature; this could result in verification of files failing. This also happens if you specify an invalid `next` or `future` string. There cannot be any false positives: The new levels are only *additional* checks, anything not in the `Assert-Pubkey-Algo` list is still revoked. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/2073126/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
