diff --git a/inbox/host-meta-2.xml b/inbox/host-meta-2.xml index 5aa016bf..edd9e232 100644 --- a/inbox/host-meta-2.xml +++ b/inbox/host-meta-2.xml @@ -181,7 +181,7 @@

For the forseeable future you will need to maintain legacy SRV records in addition to this file, and you should provide DANE TLSA records too if possible.

To make your server as accessible to other clients/servers no matter how bad the network they are on, it is advised to use port 443 when possible, as it looks the most like HTTPS.

-

Extra care must be taken in updating "public-key-pins-sha-256" similar to that which is required of HPKP and DANE, summarized here, you MUST add the new key, wait until at least 2 TTL periods have passed, and only then remove the old key.

+

Extra care must be taken in updating "public-key-pins-sha-256" similar to that which is required of HPKP and DANE, summarized here, you MUST add the new key to the file, continue using the old key until least 2 TTL periods have passed, and only then remove the old key from the file and start using the new key.

To make connection discovery work in web clients (including those hosted on a different domain) the host service SHOULD set appropriate CORS headers for Web Host Metadata files. The exact headers and values are out of scope of this document but may include: Access-Control-Allow-Origin, Access-Control-Allow-Methods and Access-Control-Allow-Headers.

Due care has to be exercised in limiting the scope of Access-Control-Allow-Origin response header to Web Host Metadata files only.

It should be noted this allows your web host to hijack your XMPP connection, but that's actually been true for quite some time, they could already bypass the need for a certificate with POSH, or get one from LetsEncrypt if you didn't have the proper CAA records, or hijack it for websocket/bosh supporting clients, so this doesn't really open up new avenues of attack.

-

Please refer to the security considerations and warnings of &rfc7469; with regards to having a backup public key and being careful to not break your domain for the whole TTL

+

Please refer to the security considerations and warnings of &rfc7469; with regards to having a backup public key and being careful to not break your domain for the whole TTL. For this reason and others it is advised to put a max limit on TTL of 1 week (604800).

Validating certs is full of edge cases and must be done with the utmost of care and precision.