Linking the identity that delegates to the hub; New drop form full width (closes #281) 787632570bf9

- **Linking the identity that delegates to the hub (#281):** the notice on pages that commit for you (New drop, web edits) read as if the hub's key file was what to link under Settings › Keys, which then asked for a signature nobody but the hub can make. It now says to export your own identity again after `oxy identity delegate add` and upload that; uploading the hub's own key is refused saying so, uploading an already linked key says to export again after delegating, and a challenge signed by another key than the one uploaded names both keys. The New drop form runs the page's width, and CREATE DROP and CANCEL are the same height in one row.

        "You have not delegated to this hub's key yet. In a checkout with your identity, download the hub's key from /.well-known/oxyhub-key and run `oxy identity delegate add oxyhub-key.identity --scope changes,refs`. That makes a new version of your own identity: export it there (`oxy identity export`), upload that file under Settings › Keys and sign the challenge in the same checkout. The hub's key file is not the one to upload.".to_string()

    if identity.hash() == app.hub_key.key {

        let msg = "That is this hub's own key, which only the hub holds. Upload your identity: after `oxy identity delegate add` with the hub's key, run `oxy identity export` in that checkout and upload the file it writes.";

        return keys_page(&app, shell, me.account, None, Some(msg.into()), None).await;

    }

            "That key is already linked to you. If you have delegated since (`oxy identity delegate add`), export again: a delegation makes a new version of your identity."

        // Signed by another key than the one uploaded: say which, as it is

        // usually the wrong checkout or an `author.signer` set there.

        let msg = match sigs.first() {

            Some(sig) if sig.key != identity.hash() => format!(

                "That signature is by key {}, but the identity uploaded is {} ({}). Sign in a checkout whose `oxy identity export` gives that identity, without an `author.signer` set, or upload the identity that checkout exports.",

                sig.key.short(12),

                identity.hash().short(12),

                identity.name

            ),

            _ => "The signature does not verify against that identity and challenge.".into(),

        };

        return keys_page(&app, shell, me.account, None, Some(msg), None).await;

/// Upload an identity under Settings › Keys; the page it answers with.

async fn upload_identity(app: &Shared, cookie: &str, csrf: &str, object: &[u8]) -> String {

    let boundary = "XYZ";

    let mut multipart = Vec::new();

    multipart.extend_from_slice(format!("--{boundary}\r\nContent-Disposition: form-data; name=\"_csrf\"\r\n\r\n{csrf}\r\n").as_bytes());

    multipart.extend_from_slice(format!("--{boundary}\r\nContent-Disposition: form-data; name=\"identity\"; filename=\"me.identity\"\r\nContent-Type: application/octet-stream\r\n\r\n").as_bytes());

    multipart.extend_from_slice(object);

    multipart.extend_from_slice(format!("\r\n--{boundary}--\r\n").as_bytes());

    let req = Request::builder()

        .method("POST")

        .uri("/settings/keys/upload")

        .header(header::COOKIE, format!("oxyhub={cookie}"))

        .header(header::CONTENT_TYPE, format!("multipart/form-data; boundary={boundary}"))

        .body(Body::from(multipart))

        .unwrap();

    let res = oxygenhub::router(app.clone()).oneshot(req).await.unwrap();

    assert_eq!(res.status(), StatusCode::OK);

    String::from_utf8_lossy(&res.into_body().collect().await.unwrap().to_bytes()).into_owned()

}

    let body = upload_identity(app, &andy, &csrf, &identity.encode()).await;

    // oxygenhub#281: the hub's own key is refused with what to upload

    // instead, and a challenge signed by another key names both keys.

    let body = upload_identity(app, &andy, &csrf, &app.hub_key.identity.encode()).await;

    assert!(body.contains("this hub's own key") || body.contains("this hub's own key"), "{body}");

    assert!(!body.contains("sign-challenge "), "no challenge for the hub's key: {body}");

    let other = oxy_core::identity::SecretKey::generate().identity("Other", "[email protected]", 1);

    let body = upload_identity(app, &andy, &csrf, &other.encode()).await;

    let challenge_hex = body.split("sign-challenge ").nth(1).unwrap().split('<').next().unwrap().trim().to_string();

    let challenge_id = body.split("name=\"challenge\" value=\"").nth(1).unwrap().split('"').next().unwrap().to_string();

    let sig = sk.sign_challenge(&key, &hex::decode(&challenge_hex).unwrap()).unwrap();

    let sig_hex = hex::encode(oxy_core::identity::Signature::encode_list(&[sig]));

    let r = post(app, "/settings/keys/verify", Some(&andy), &format!("_csrf={csrf}&challenge={challenge_id}&signature={sig_hex}")).await;

    assert!(

        r.body.contains(&format!("That signature is by key {}", key.short(12))) && r.body.contains(&other.hash().short(12)),

        "{}",

        r.body

    );

form .actions { display: flex; gap: 10px; align-items: stretch; flex-wrap: wrap; margin: 12px 0 0; }

form .actions > *, form.card .actions > button[type=submit] { margin: 0; }

form .actions > a.go { display: inline-flex; align-items: center; }

/* A drop's form takes the page's width, as the notice above it does. */

form.card.drop-form { max-width: none; }