package server import ( "bytes" "crypto/rand" "crypto/sha256" "encoding/hex" "encoding/json" "errors" "fmt" "io" "io/ioutil" "sync" "github.com/restic/restic/backend" "github.com/restic/restic/chunker" "github.com/restic/restic/crypto" "github.com/restic/restic/debug" "github.com/restic/restic/pack" ) // Config contains the configuration for a repository. type Config struct { Version uint `json:"version"` ID string `json:"id"` ChunkerPolynomial chunker.Pol `json:"chunker_polynomial"` } // Server is used to access a repository in a backend. type Server struct { be backend.Backend Config Config key *crypto.Key keyName string idx *Index pm sync.Mutex packs []*pack.Packer } func NewServer(be backend.Backend) *Server { return &Server{ be: be, idx: NewIndex(), } } // Find loads the list of all blobs of type t and searches for names which start // with prefix. If none is found, nil and ErrNoIDPrefixFound is returned. If // more than one is found, nil and ErrMultipleIDMatches is returned. func (s *Server) Find(t backend.Type, prefix string) (string, error) { return backend.Find(s.be, t, prefix) } // FindSnapshot takes a string and tries to find a snapshot whose ID matches // the string as closely as possible. func (s *Server) FindSnapshot(name string) (string, error) { return backend.FindSnapshot(s.be, name) } // PrefixLength returns the number of bytes required so that all prefixes of // all IDs of type t are unique. func (s *Server) PrefixLength(t backend.Type) (int, error) { return backend.PrefixLength(s.be, t) } // Load tries to load and decrypt content identified by t and id from the // backend. func (s *Server) Load(t backend.Type, id backend.ID) ([]byte, error) { debug.Log("Server.Load", "load %v with id %v", t, id.Str()) // load blob from pack rd, err := s.be.Get(t, id.String()) if err != nil { debug.Log("Server.Load", "error loading %v: %v", id.Str(), err) return nil, err } buf, err := ioutil.ReadAll(rd) if err != nil { return nil, err } err = rd.Close() if err != nil { return nil, err } // check hash if !backend.Hash(buf).Equal(id) { return nil, errors.New("invalid data returned") } // decrypt plain, err := s.Decrypt(buf) if err != nil { return nil, err } return plain, nil } // LoadBlob tries to load and decrypt content identified by t and id from a // pack from the backend. func (s *Server) LoadBlob(t pack.BlobType, id backend.ID) ([]byte, error) { debug.Log("Server.LoadBlob", "load %v with id %v", t, id.Str()) // lookup pack packID, tpe, offset, length, err := s.idx.Lookup(id) if err != nil { debug.Log("Server.LoadBlob", "id %v not found in index: %v", id.Str(), err) return nil, err } if tpe != t { debug.Log("Server.LoadBlob", "wrong type returned for %v: wanted %v, got %v", id.Str(), t, tpe) return nil, fmt.Errorf("blob has wrong type %v (wanted: %v)", tpe, t) } debug.Log("Server.LoadBlob", "id %v found in pack %v at offset %v (length %d)", id.Str(), packID.Str(), offset, length) // load blob from pack rd, err := s.be.GetReader(backend.Data, packID.String(), offset, length) if err != nil { debug.Log("Server.LoadBlob", "error loading pack %v for %v: %v", packID.Str(), id.Str(), err) return nil, err } buf, err := ioutil.ReadAll(rd) if err != nil { return nil, err } err = rd.Close() if err != nil { return nil, err } // decrypt plain, err := s.Decrypt(buf) if err != nil { return nil, err } // check hash if !backend.Hash(plain).Equal(id) { return nil, errors.New("invalid data returned") } return plain, nil } // LoadJSONUnpacked decrypts the data and afterwards calls json.Unmarshal on // the item. func (s *Server) LoadJSONUnpacked(t backend.Type, id backend.ID, item interface{}) error { // load blob from backend rd, err := s.be.Get(t, id.String()) if err != nil { return err } defer rd.Close() // decrypt decryptRd, err := crypto.DecryptFrom(s.key, rd) defer decryptRd.Close() if err != nil { return err } // decode decoder := json.NewDecoder(decryptRd) err = decoder.Decode(item) if err != nil { return err } return nil } // LoadJSONPack calls LoadBlob() to load a blob from the backend, decrypt the // data and afterwards call json.Unmarshal on the item. func (s *Server) LoadJSONPack(t pack.BlobType, id backend.ID, item interface{}) error { // lookup pack packID, _, offset, length, err := s.idx.Lookup(id) if err != nil { return err } // load blob from pack rd, err := s.be.GetReader(backend.Data, packID.String(), offset, length) if err != nil { return err } defer rd.Close() // decrypt decryptRd, err := crypto.DecryptFrom(s.key, rd) defer decryptRd.Close() if err != nil { return err } // decode decoder := json.NewDecoder(decryptRd) err = decoder.Decode(item) if err != nil { return err } return nil } const minPackSize = 4 * chunker.MiB const maxPackSize = 16 * chunker.MiB const maxPackers = 200 // findPacker returns a packer for a new blob of size bytes. Either a new one is // created or one is returned that already has some blobs. func (s *Server) findPacker(size uint) (*pack.Packer, error) { s.pm.Lock() defer s.pm.Unlock() // search for a suitable packer if len(s.packs) > 0 { debug.Log("Server.findPacker", "searching packer for %d bytes\n", size) for i, p := range s.packs { if p.Size()+size < maxPackSize { debug.Log("Server.findPacker", "found packer %v", p) // remove from list s.packs = append(s.packs[:i], s.packs[i+1:]...) return p, nil } } } // no suitable packer found, return new blob, err := s.be.Create() if err != nil { return nil, err } debug.Log("Server.findPacker", "create new pack %p", blob) return pack.NewPacker(s.key, blob), nil } // insertPacker appends p to s.packs. func (s *Server) insertPacker(p *pack.Packer) { s.pm.Lock() defer s.pm.Unlock() s.packs = append(s.packs, p) debug.Log("Server.insertPacker", "%d packers\n", len(s.packs)) } // savePacker stores p in the backend. func (s *Server) savePacker(p *pack.Packer) error { debug.Log("Server.savePacker", "save packer with %d blobs\n", p.Count()) _, err := p.Finalize() if err != nil { return err } // move file to the final location sid := p.ID() err = p.Writer().(backend.Blob).Finalize(backend.Data, sid.String()) if err != nil { debug.Log("Server.savePacker", "blob Finalize() error: %v", err) return err } debug.Log("Server.savePacker", "saved as %v", sid.Str()) // update blobs in the index for _, b := range p.Blobs() { debug.Log("Server.savePacker", " updating blob %v to pack %v", b.ID.Str(), sid.Str()) s.idx.Store(b.Type, b.ID, sid, b.Offset, uint(b.Length)) } return nil } // countPacker returns the number of open (unfinished) packers. func (s *Server) countPacker() int { s.pm.Lock() defer s.pm.Unlock() return len(s.packs) } // Save encrypts data and stores it to the backend as type t. If data is small // enough, it will be packed together with other small blobs. func (s *Server) Save(t pack.BlobType, data []byte, id backend.ID) (backend.ID, error) { if id == nil { // compute plaintext hash id = backend.Hash(data) } debug.Log("Server.Save", "save id %v (%v, %d bytes)", id.Str(), t, len(data)) // get buf from the pool ciphertext := getBuf() defer freeBuf(ciphertext) // encrypt blob ciphertext, err := s.Encrypt(ciphertext, data) if err != nil { return nil, err } // find suitable packer and add blob packer, err := s.findPacker(uint(len(ciphertext))) if err != nil { return nil, err } // save ciphertext packer.Add(t, id, bytes.NewReader(ciphertext)) // add this id to the index, although we don't know yet in which pack it // will be saved, the entry will be updated when the pack is written. s.idx.Store(t, id, nil, 0, 0) debug.Log("Server.Save", "saving stub for %v (%v) in index", id.Str, t) // if the pack is not full enough and there are less than maxPackers // packers, put back to the list if packer.Size() < minPackSize && s.countPacker() < maxPackers { debug.Log("Server.Save", "pack is not full enough (%d bytes)", packer.Size()) s.insertPacker(packer) return id, nil } // else write the pack to the backend return id, s.savePacker(packer) } // SaveFrom encrypts data read from rd and stores it in a pack in the backend as type t. func (s *Server) SaveFrom(t pack.BlobType, id backend.ID, length uint, rd io.Reader) error { debug.Log("Server.SaveFrom", "save id %v (%v, %d bytes)", id.Str(), t, length) if id == nil { return errors.New("id is nil") } buf, err := ioutil.ReadAll(rd) if err != nil { return err } _, err = s.Save(t, buf, id) if err != nil { return err } return nil } // SaveJSON serialises item as JSON and encrypts and saves it in a pack in the // backend as type t. func (s *Server) SaveJSON(t pack.BlobType, item interface{}) (backend.ID, error) { debug.Log("Server.SaveJSON", "save %v blob", t) buf := getBuf()[:0] defer freeBuf(buf) wr := bytes.NewBuffer(buf) enc := json.NewEncoder(wr) err := enc.Encode(item) if err != nil { return nil, fmt.Errorf("json.Encode: %v", err) } buf = wr.Bytes() return s.Save(t, buf, nil) } // SaveJSONUnpacked serialises item as JSON and encrypts and saves it in the // backend as type t, without a pack. It returns the storage hash. func (s *Server) SaveJSONUnpacked(t backend.Type, item interface{}) (backend.ID, error) { // create file blob, err := s.be.Create() if err != nil { return nil, err } debug.Log("Server.SaveJSONUnpacked", "create new file %p", blob) // hash hw := backend.NewHashingWriter(blob, sha256.New()) // encrypt blob ewr := crypto.EncryptTo(s.key, hw) enc := json.NewEncoder(ewr) err = enc.Encode(item) if err != nil { return nil, fmt.Errorf("json.Encode: %v", err) } err = ewr.Close() if err != nil { return nil, err } // finalize blob in the backend sid := backend.ID(hw.Sum(nil)) err = blob.Finalize(t, sid.String()) if err != nil { return nil, err } return sid, nil } // Flush saves all remaining packs. func (s *Server) Flush() error { s.pm.Lock() defer s.pm.Unlock() debug.Log("Server.Flush", "manually flushing %d packs", len(s.packs)) for _, p := range s.packs { err := s.savePacker(p) if err != nil { return err } } s.packs = s.packs[:0] return nil } func (s *Server) Backend() backend.Backend { return s.be } func (s *Server) Index() *Index { return s.idx } // SetIndex instructs the server to use the given index. func (s *Server) SetIndex(i *Index) { s.idx = i } // SaveIndex saves all new packs in the index in the backend, returned is the // storage ID. func (s *Server) SaveIndex() (backend.ID, error) { debug.Log("Server.SaveIndex", "Saving index") // create blob blob, err := s.be.Create() if err != nil { return nil, err } debug.Log("Server.SaveIndex", "create new pack %p", blob) // hash hw := backend.NewHashingWriter(blob, sha256.New()) // encrypt blob ewr := crypto.EncryptTo(s.key, hw) err = s.idx.Encode(ewr) if err != nil { return nil, err } err = ewr.Close() if err != nil { return nil, err } // finalize blob in the backend sid := backend.ID(hw.Sum(nil)) err = blob.Finalize(backend.Index, sid.String()) if err != nil { return nil, err } debug.Log("Server.SaveIndex", "Saved index as %v", sid.Str()) return sid, nil } // LoadIndex loads all index files from the backend and merges them with the // current index. func (s *Server) LoadIndex() error { debug.Log("Server.LoadIndex", "Loading index") done := make(chan struct{}) defer close(done) for id := range s.be.List(backend.Index, done) { err := s.loadIndex(id) if err != nil { return err } } return nil } // loadIndex loads the index id and merges it with the currently used index. func (s *Server) loadIndex(id string) error { debug.Log("Server.loadIndex", "Loading index %v", id[:8]) before := len(s.idx.pack) rd, err := s.be.Get(backend.Index, id) defer rd.Close() if err != nil { return err } // decrypt decryptRd, err := crypto.DecryptFrom(s.key, rd) defer decryptRd.Close() if err != nil { return err } idx, err := DecodeIndex(decryptRd) if err != nil { debug.Log("Server.loadIndex", "error while decoding index %v: %v", id, err) return err } s.idx.Merge(idx) after := len(s.idx.pack) debug.Log("Server.loadIndex", "Loaded index %v, added %v blobs", id[:8], after-before) return nil } const repositoryIDSize = sha256.Size const RepositoryVersion = 1 func createConfig(s *Server) (err error) { s.Config.ChunkerPolynomial, err = chunker.RandomPolynomial() if err != nil { return err } newID := make([]byte, repositoryIDSize) _, err = io.ReadFull(rand.Reader, newID) if err != nil { return err } s.Config.ID = hex.EncodeToString(newID) s.Config.Version = RepositoryVersion debug.Log("Server.createConfig", "New config: %#v", s.Config) _, err = s.SaveJSONUnpacked(backend.Config, s.Config) return err } func (s *Server) loadConfig(cfg *Config) error { err := s.LoadJSONUnpacked(backend.Config, nil, cfg) if err != nil { return err } if cfg.Version != RepositoryVersion { return errors.New("unsupported repository version") } if !cfg.ChunkerPolynomial.Irreducible() { return errors.New("invalid chunker polynomial") } return nil } // SearchKey finds a key with the supplied password, afterwards the config is // read and parsed. func (s *Server) SearchKey(password string) error { key, err := SearchKey(s, password) if err != nil { return err } s.key = key.master s.keyName = key.Name() return s.loadConfig(&s.Config) } // Init creates a new master key with the supplied password and initializes the // repository config. func (s *Server) Init(password string) error { has, err := s.Test(backend.Config, "") if err != nil { return err } if has { return errors.New("repository master key and config already initialized") } key, err := createMasterKey(s, password) if err != nil { return err } s.key = key.master s.keyName = key.Name() return createConfig(s) } func (s *Server) Decrypt(ciphertext []byte) ([]byte, error) { if s.key == nil { return nil, errors.New("key for server not set") } return crypto.Decrypt(s.key, nil, ciphertext) } func (s *Server) Encrypt(ciphertext, plaintext []byte) ([]byte, error) { if s.key == nil { return nil, errors.New("key for server not set") } return crypto.Encrypt(s.key, ciphertext, plaintext) } func (s *Server) Key() *crypto.Key { return s.key } func (s *Server) KeyName() string { return s.keyName } // Count returns the number of blobs of a given type in the backend. func (s *Server) Count(t backend.Type) (n uint) { for _ = range s.be.List(t, nil) { n++ } return } // Proxy methods to backend func (s *Server) Get(t backend.Type, name string) (io.ReadCloser, error) { return s.be.Get(t, name) } func (s *Server) List(t backend.Type, done <-chan struct{}) <-chan string { return s.be.List(t, done) } func (s *Server) Test(t backend.Type, name string) (bool, error) { return s.be.Test(t, name) } func (s *Server) Remove(t backend.Type, name string) error { return s.be.Remove(t, name) } func (s *Server) Close() error { return s.be.Close() } func (s *Server) Delete() error { if b, ok := s.be.(backend.Deleter); ok { return b.Delete() } return errors.New("Delete() called for backend that does not implement this method") } func (s *Server) Location() string { return s.be.Location() }