fix: http signatures errors are 500, not 401

if user provides an http signature and we fail to verify, bail out! if
our db didn't give us the local user its unlikely that we will be able
to serve anything anyway, just give up

upub/routes/src/auth.rs

@@ -120,22 +120,21 @@ where
 				.next().ok_or(ApiError::bad_request())?
 				.to_string();
 
-			match ctx.fetch_user(&user_id, ctx.db()).await {
+			let user = ctx.fetch_user(&user_id, ctx.db()).await?;
-				Err(e) => tracing::warn!("failed resolving http signature actor: {e}"),
+
-				Ok(user) => match http_signature
+			let valid = http_signature
 				.build_from_parts(parts)
-						.verify(&user.public_key)
+				.verify(&user.public_key)?;
-					{
+
-						Ok(true) => {
+			if !valid {
+				tracing::warn!("refusing mismatching http signature");
+				return Err(ApiError::unauthorized());
+			}
+
 			let internal = upub::model::instance::Entity::domain_to_internal(&user.domain, ctx.db())
 				.await?
 				.ok_or_else(ApiError::internal_server_error)?; // user but not their domain???
 			identity = Identity::Remote { user: user.id, domain: user.domain, internal };
-						},
-						Ok(false) => tracing::warn!("invalid signature: {http_signature:?}"),
-						Err(e) => tracing::error!("error verifying signature: {e}"),
-					},
-			}
 		}
 
 		Ok(AuthIdentity(identity))