diff options
Diffstat (limited to 'pkg/api/api0')
| -rw-r--r-- | pkg/api/api0/serverlist.go | 58 |
1 files changed, 49 insertions, 9 deletions
diff --git a/pkg/api/api0/serverlist.go b/pkg/api/api0/serverlist.go index 7ae8f89..83fb283 100644 --- a/pkg/api/api0/serverlist.go +++ b/pkg/api/api0/serverlist.go @@ -3,6 +3,9 @@ package api0 import ( "bytes" "compress/gzip" + "crypto/sha256" + "encoding/binary" + "encoding/hex" "errors" "fmt" "io" @@ -52,6 +55,18 @@ type ServerList struct { } type ServerListConfig struct { + // ExperimentalDeterministicServerIDSecret, if provided, is a secret to + // combine with the server metadata upon registration to deterministically + // generate a server ID. The secret is used to prevent brute-forcing server + // IDs from the ID and known server info. + // + // This is NOT to be used for uniquely and/or persistently identifying + // servers, and may change at any time. It is intended to allow servers to + // have the same IDs on a best-effort basis when re-registering after + // masterserver (this will reduce pdata update unauthorized errors after + // restarting the masterserver) or server restart. Notable, if a server + // changes their name or description, the ID will not be the same anymore. + ExperimentalDeterministicServerIDSecret string } type Server struct { @@ -843,17 +858,42 @@ func (s *ServerList) ServerHybridUpdatePut(u *ServerUpdate, c *Server, l ServerL nsrv.ServerAuthToken = tok } - // allocate a new server ID, skipping any which already exist - for { - sid, err := cryptoRandHex(32) - if err != nil { - return nil, fmt.Errorf("generate new server id: %w", err) + // we'll allocate a new server ID + nsrv.ID = "" + + // attempt to generate a deterministic server ID + if s.cfg.ExperimentalDeterministicServerIDSecret != "" { + ss := sha256.New() + if x, err := nsrv.Addr.Addr().MarshalBinary(); err == nil { + binary.Write(ss, binary.LittleEndian, x) } - if _, exists := s.servers2[sid]; exists { - continue // try another id since another server already used it + binary.Write(ss, binary.LittleEndian, nsrv.Addr.Port()) + binary.Write(ss, binary.LittleEndian, nsrv.AuthPort) + binary.Write(ss, binary.LittleEndian, uint64(len(nsrv.Name))) + ss.Write([]byte(nsrv.Name)) + binary.Write(ss, binary.LittleEndian, uint64(len(nsrv.Description))) + ss.Write([]byte(nsrv.Description)) + binary.Write(ss, binary.LittleEndian, uint64(len(s.cfg.ExperimentalDeterministicServerIDSecret))) + ss.Write([]byte(s.cfg.ExperimentalDeterministicServerIDSecret)) + sid := hex.EncodeToString(ss.Sum(nil))[:32] + if _, exists := s.servers2[sid]; !exists { + nsrv.ID = sid + } + } + + // fall back to a random one + if nsrv.ID == "" { + for { + sid, err := cryptoRandHex(32) + if err != nil { + return nil, fmt.Errorf("generate new server id: %w", err) + } + if _, exists := s.servers2[sid]; exists { + continue // try another id since another server already used it + } + nsrv.ID = sid + break } - nsrv.ID = sid - break } // set the server order |