Add namespace to expire_all auth signature

oxenss/rpc/client_rpc_endpoints.h

@@ -405,8 +405,10 @@ struct delete_before final : recursive {
 ///   namespace (namespace 0).
 /// - expiry -- the new expiry timestamp (milliseconds since unix epoch).  Should be >= now, but
 ///   tolerance acceptance allows >= 60s ago.
-/// - signature -- signature of ("expire_all" || expiry), signed by `pubkey`.  Must be base64
-///   encoded (json) or bytes (OMQ).
+/// - signature -- signature of ("expire_all" || namespace || expiry), signed by `pubkey`.  Must be
+///   base64 encoded (json) or bytes (OMQ).  namespace should be the stringified namespace for
+///   non-default namespace expiries (i.e. "42", "-99", "all"), or an empty string for the default
+///   namespace (whether or not explicitly provided).
 ///
 /// Returns dict of:
 /// - "swarms" dict mapping ed25519 pubkeys (in hex) of swarm members to dict values of:

oxenss/rpc/request_handler.cpp

@@ -968,6 +968,7 @@ void RequestHandler::process_client_req(rpc::expire_all&& req, std::function<voi
                 std::nullopt,  // no subkey allowed
                 req.signature,
                 "expire_all",
+                signature_value(req.msg_namespace),
                 req.expiry)) {
         OXEN_LOG(debug, "expire_all: signature verification failed");
         return cb(Response{http::UNAUTHORIZED, "expire_all signature verification failed"sv});