Element fails to set up keys upon registration of new user

[nomelif]

Hi!

I have a freshly installed conduwuit instance and am attempting to create an account for it using Element desktop. Upon registration, element makes a request to /_matrix/client/v3/keys/device_signing/upload with the following payload (of which I have redacted keys and my server's domain for privacy reasons):

{
  "master_key": {
    "keys": {
      "ed25519:<snip>": "<snip>"
    },
    "signatures": {
      "@demotili2:<snip>": {
        "ed25519:<snip>": "<snip>",
        "ed25519:<snip>": "<snip>"
      }
    },
    "usage": [
      "master"
    ],
    "user_id": "@demotili2:<snip my server>"
  },
  "self_signing_key": {
    "keys": {
      "ed25519:<snip>": "<snip>"
    },
    "signatures": {
      "@demotili2:<snip>": {
        "ed25519:<snip>": "<snip>"
      }
    },
    "usage": [
      "self_signing"
    ],
    "user_id": "@demotili2:<snip>"
  },
  "user_signing_key": {
    "keys": {
      "ed25519:<snip>": "<snip>"
    },
    "signatures": {
      "@demotili2:<snip>": {
        "ed25519:<snip>": "<snip>"
      }
    },
    "usage": [
      "user_signing"
    ],
    "user_id": "@demotili2:<snip>"
  },
  "auth": {}
}

I receive the following response:

{
    "errcode": "M_BAD_JSON",
    "error": "M_BAD_JSON: deserialization failed: missing field `session` at line 1 column 2"
}

Element throws up this error:

I am reasonably confident this is the same issue that has been litigated here on Element's side: element-hq/element-web#27501 and here in upstream conduit: https://gitlab.com/famedly/conduit/-/issues/488 Conduit mentions it is transient, and Element seems to set itself up without complaining upon clicking on retry. I am not well enough versed in this to say, whether this was a clean setup upon retry or not.

As I understand it, the crux of the issue is that element sends an empty auth attribute, which conduwuit doesn't like. According to people in the Element bug report, the spec doesn't explicitly forbid sending an empty auth attribute as opposed to sending none at all.

Would it be difficult for conduwuit to accept and silently drop an empty auth response?

PS: I am running inside podman, but I am reasonably confident this is not podman-related. The exact container version I am using is https://hub.docker.com/layers/girlbossceo/conduwuit/latest/images/sha256-104ecefe731e4417128735dd6356cead491ef3a8c827e683467ebd1c70488485

[nomelif]

It would seem that this is fixed in https://github.com/girlbossceo/conduwuit/tree/msc3967. I'll leave this issue up until that is merged if that's ok by you.