refinement

.dockerignore

@@ -6,6 +6,7 @@ bin
 *.pyc
 *.egg-info
 .vagrant
+.git
 .tmp
 bower_components
 node_modules

.golangci.yml

@@ -18,3 +18,7 @@ issues:
   max-same-issues: 0
   new: false
   exclude-use-default: false
+  exclude-rules:
+    - linters:
+        - staticcheck
+      text: "SA1019:"

README.md

@@ -47,6 +47,16 @@ $ curl --upload-file ./hello.txt https://transfer.sh/hello.txt -H "Max-Downloads
 $ curl --upload-file ./hello.txt https://transfer.sh/hello.txt -H "Max-Days: 1" # Set the number of days before deletion
 ```
 
+### X-Encrypt-Password
+```bash
+$ curl --upload-file ./hello.txt https://transfer.sh/hello.txt -H "X-Encrypt-Password: test" # Encrypt the content sever side with AES265 using "test" as password
+```
+
+### X-Decrypt-Password
+```bash
+$ curl https://transfer.sh/BAYh0/hello.txt -H "X-Decrypt-Password: test" # Decrypt the content sever side with AES265 using "test" as password
+```
+
 ## Response Headers
 
 ### X-Url-Delete

server/handlers.go

@@ -58,6 +58,12 @@ import (
 	"github.com/microcosm-cc/bluemonday"
 	blackfriday "github.com/russross/blackfriday/v2"
 	"github.com/skip2/go-qrcode"
+	//lint:ignore SA1019 Ignore the deprecation warnings
+	"golang.org/x/crypto/openpgp"
+	//lint:ignore SA1019 Ignore the deprecation warnings
+	"golang.org/x/crypto/openpgp/armor"
+	//lint:ignore SA1019 Ignore the deprecation warnings
+	"golang.org/x/crypto/openpgp/packet"
 )
 
 const getPathPart = "get"
@@ -65,6 +71,10 @@ const getPathPart = "get"
 var (
 	htmlTemplates = initHTMLTemplates()
 	textTemplates = initTextTemplates()
+
+	packetConfig = &packet.Config{
+		DefaultCipher: packet.CipherAES256,
+	}
 )
 
 func stripPrefix(path string) string {
@@ -88,6 +98,96 @@ func initHTMLTemplates() *html_template.Template {
 	return templates
 }
 
+func transformEncryptionReader(reader io.ReadCloser, password string) (io.Reader, error) {
+	if len(password) == 0 {
+		return reader, nil
+	}
+
+	return encrypt(reader, password, packetConfig)
+}
+
+func transformDecryptionReader(reader io.ReadCloser, password string) (io.Reader, error) {
+	if len(password) == 0 {
+		return reader, nil
+	}
+
+	return decrypt(reader, password, packetConfig)
+}
+
+func decrypt(ciphertext io.ReadCloser, password string, packetConfig *packet.Config) (plaintext io.Reader, err error) {
+	content, err := ioutil.ReadAll(ciphertext)
+	if err != nil {
+		return
+	}
+
+	decbuf := bytes.NewBuffer(content)
+
+	armorBlock, err := armor.Decode(decbuf)
+	if err != nil {
+		return
+	}
+
+	failed := false
+	prompt := func(keys []openpgp.Key, symmetric bool) ([]byte, error) {
+		// If the given passphrase isn't correct, the function will be called again, forever.
+		// This method will fail fast.
+		// Ref: https://godoc.org/golang.org/x/crypto/openpgp#PromptFunction
+		if failed {
+			return nil, errors.New("decryption failed")
+		}
+		failed = true
+		return []byte(password), nil
+	}
+
+	md, err := openpgp.ReadMessage(armorBlock.Body, nil, prompt, packetConfig)
+	if err != nil {
+		return
+	}
+
+	plaintext = md.UnverifiedBody
+
+	return
+}
+
+func encrypt(plaintext io.ReadCloser, password string, packetConfig *packet.Config) (ciphertext io.Reader, err error) {
+	encbuf := bytes.NewBuffer(nil)
+
+	w, err := armor.Encode(encbuf, "PGP MESSAGE", nil)
+	if err != nil {
+		safeClose(w)
+		return
+	}
+
+	pt, err := openpgp.SymmetricallyEncrypt(w, []byte(password), nil, packetConfig)
+
+	if err != nil {
+		safeClose(pt)
+		safeClose(w)
+		return
+	}
+
+	content, err := ioutil.ReadAll(plaintext)
+	if err != nil {
+		safeClose(pt)
+		safeClose(w)
+		return
+	}
+
+	_, err = pt.Write(content)
+	if err != nil {
+		safeClose(pt)
+		safeClose(w)
+		return
+	}
+
+	// Close writers to force-flush their buffer
+	safeClose(pt)
+	safeClose(w)
+	ciphertext = bytes.NewReader(encbuf.Bytes())
+
+	return
+}
+
 func healthHandler(w http.ResponseWriter, r *http.Request) {
 	_, _ = w.Write([]byte("Approaching Neutral Zone, all systems normal and functioning."))
 }
@@ -360,7 +460,7 @@ func (s *Server) postHandler(w http.ResponseWriter, r *http.Request) {
 				}
 			}
 
-			metadata := metadataForRequest(contentType, s.randomTokenLength, r)
+			metadata := metadataForRequest(contentType, contentLength, s.randomTokenLength, r)
 
 			buffer := &bytes.Buffer{}
 			if err := json.NewEncoder(buffer).Encode(metadata); err != nil {
@@ -377,7 +477,13 @@ func (s *Server) postHandler(w http.ResponseWriter, r *http.Request) {
 
 			s.logger.Printf("Uploading %s %s %d %s", token, filename, contentLength, contentType)
 
-			if err = s.storage.Put(r.Context(), token, filename, file, contentType, uint64(contentLength)); err != nil {
+			reader, err := transformEncryptionReader(file, r.Header.Get("X-Encrypt-Password"))
+			if err != nil {
+				http.Error(w, "Could not crypt file", http.StatusInternalServerError)
+				return
+			}
+
+			if err = s.storage.Put(r.Context(), token, filename, reader, contentType, uint64(contentLength)); err != nil {
 				s.logger.Printf("Backend storage error: %s", err.Error())
 				http.Error(w, err.Error(), http.StatusInternalServerError)
 				return
@@ -415,8 +521,8 @@ func (s *Server) cleanTmpFile(f *os.File) {
 type metadata struct {
 	// ContentType is the original uploading content type
 	ContentType string
-	// Secret as knowledge to delete file
+	// ContentLength is is the original uploading content length
-	// Secret string
+	ContentLength int64
 	// Downloads is the actual number of downloads
 	Downloads int
 	// MaxDownloads contains the maximum numbers of downloads
@@ -425,11 +531,16 @@ type metadata struct {
 	MaxDate time.Time
 	// DeletionToken contains the token to match against for deletion
 	DeletionToken string
+	// Encrypted contains if the file was encrypted
+	Encrypted bool
+	// DecryptedContentType is the original uploading content type
+	DecryptedContentType string
 }
 
-func metadataForRequest(contentType string, randomTokenLength int, r *http.Request) metadata {
+func metadataForRequest(contentType string, contentLength int64, randomTokenLength int, r *http.Request) metadata {
 	metadata := metadata{
 		ContentType:   strings.ToLower(contentType),
+		ContentLength: contentLength,
 		MaxDate:       time.Time{},
 		Downloads:     0,
 		MaxDownloads:  -1,
@@ -448,6 +559,14 @@ func metadataForRequest(contentType string, randomTokenLength int, r *http.Reque
 		metadata.MaxDate = time.Now().Add(time.Hour * 24 * time.Duration(v))
 	}
 
+	if password := r.Header.Get("X-Encrypt-Password"); password != "" {
+		metadata.Encrypted = true
+		metadata.ContentType = "text/plain; charset=utf-8"
+		metadata.DecryptedContentType = contentType
+	} else {
+		metadata.Encrypted = false
+	}
+
 	return metadata
 }
 
@@ -458,7 +577,7 @@ func (s *Server) putHandler(w http.ResponseWriter, r *http.Request) {
 
 	contentLength := r.ContentLength
 
-	defer CloseCheck(r.Body.Close)
+	defer safeClose(r.Body)
 
 	file, err := ioutil.TempFile(s.tempPath, "transfer-")
 	defer s.cleanTmpFile(file)
@@ -521,7 +640,7 @@ func (s *Server) putHandler(w http.ResponseWriter, r *http.Request) {
 
 	token := token(s.randomTokenLength)
 
-	metadata := metadataForRequest(contentType, s.randomTokenLength, r)
+	metadata := metadataForRequest(contentType, contentLength, s.randomTokenLength, r)
 
 	buffer := &bytes.Buffer{}
 	if err := json.NewEncoder(buffer).Encode(metadata); err != nil {
@@ -540,7 +659,13 @@ func (s *Server) putHandler(w http.ResponseWriter, r *http.Request) {
 
 	s.logger.Printf("Uploading %s %s %d %s", token, filename, contentLength, contentType)
 
-	if err = s.storage.Put(r.Context(), token, filename, file, contentType, uint64(contentLength)); err != nil {
+	reader, err := transformEncryptionReader(file, r.Header.Get("X-Encrypt-Password"))
+	if err != nil {
+		http.Error(w, "Could not crypt file", http.StatusInternalServerError)
+		return
+	}
+
+	if err = s.storage.Put(r.Context(), token, filename, reader, contentType, uint64(contentLength)); err != nil {
 		s.logger.Printf("Error putting new file: %s", err.Error())
 		http.Error(w, "Could not save file", http.StatusInternalServerError)
 		return
@@ -651,6 +776,7 @@ func (metadata metadata) remainingLimitHeaderValues() (remainingDownloads, remai
 		remainingDays = strconv.Itoa(int(timeDifference.Hours()/24) + 1)
 	}
 
+
 	if metadata.MaxDownloads == -1 {
 		remainingDownloads = "n/a"
 	} else {
@@ -683,7 +809,7 @@ func (s *Server) checkMetadata(ctx context.Context, token, filename string, incr
 	var metadata metadata
 
 	r, _, err := s.storage.Get(ctx, token, fmt.Sprintf("%s.metadata", filename))
-	defer CloseCheck(r.Close)
+	defer safeClose(r)
 
 	if err != nil {
 		return metadata, err
@@ -719,7 +845,7 @@ func (s *Server) checkDeletionToken(ctx context.Context, deletionToken, token, f
 	var metadata metadata
 
 	r, _, err := s.storage.Get(ctx, token, fmt.Sprintf("%s.metadata", filename))
-	defer CloseCheck(r.Close)
+	defer safeClose(r)
 
 	if s.storage.IsNotExist(err) {
 		return errors.New("metadata doesn't exist")
@@ -798,7 +924,7 @@ func (s *Server) zipHandler(w http.ResponseWriter, r *http.Request) {
 		}
 
 		reader, _, err := s.storage.Get(r.Context(), token, filename)
-		defer CloseCheck(reader.Close)
+		defer safeClose(reader)
 
 		if err != nil {
 			if s.storage.IsNotExist(err) {
@@ -852,10 +978,10 @@ func (s *Server) tarGzHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Connection", "close")
 
 	gw := gzip.NewWriter(w)
-	defer CloseCheck(gw.Close)
+	defer safeClose(gw)
 
 	zw := tar.NewWriter(gw)
-	defer CloseCheck(zw.Close)
+	defer safeClose(zw)
 
 	for _, key := range strings.Split(files, ",") {
 		key = resolveKey(key, s.proxyPath)
@@ -869,7 +995,7 @@ func (s *Server) tarGzHandler(w http.ResponseWriter, r *http.Request) {
 		}
 
 		reader, contentLength, err := s.storage.Get(r.Context(), token, filename)
-		defer CloseCheck(reader.Close)
+		defer safeClose(reader)
 
 		if err != nil {
 			if s.storage.IsNotExist(err) {
@@ -914,7 +1040,7 @@ func (s *Server) tarHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Connection", "close")
 
 	zw := tar.NewWriter(w)
-	defer CloseCheck(zw.Close)
+	defer safeClose(zw)
 
 	for _, key := range strings.Split(files, ",") {
 		key = resolveKey(key, s.proxyPath)
@@ -928,7 +1054,7 @@ func (s *Server) tarHandler(w http.ResponseWriter, r *http.Request) {
 		}
 
 		reader, contentLength, err := s.storage.Get(r.Context(), token, filename)
-		defer CloseCheck(reader.Close)
+		defer safeClose(reader)
 
 		if err != nil {
 			if s.storage.IsNotExist(err) {
@@ -1012,7 +1138,7 @@ func (s *Server) getHandler(w http.ResponseWriter, r *http.Request) {
 
 	contentType := metadata.ContentType
 	reader, contentLength, err := s.storage.Get(r.Context(), token, filename)
-	defer CloseCheck(reader.Close)
+	defer safeClose(reader)
 
 	if s.storage.IsNotExist(err) {
 		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
@@ -1024,7 +1150,6 @@ func (s *Server) getHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	var disposition string
-
 	if action == "inline" {
 		disposition = "inline"
 	} else {
@@ -1033,9 +1158,7 @@ func (s *Server) getHandler(w http.ResponseWriter, r *http.Request) {
 
 	remainingDownloads, remainingDays := metadata.remainingLimitHeaderValues()
 
-	w.Header().Set("Content-Type", contentType)
+	w.Header().Set("Content-Disposition", fmt.Sprintf(`%s; filename="%s"`, disposition, filename))
-	w.Header().Set("Content-Length", strconv.FormatUint(contentLength, 10))
-	w.Header().Set("Content-Disposition", fmt.Sprintf("%s; filename=\"%s\"", disposition, filename))
 	w.Header().Set("Connection", "keep-alive")
 	w.Header().Set("X-Remaining-Downloads", remainingDownloads)
 	w.Header().Set("X-Remaining-Days", remainingDays)
@@ -1065,7 +1188,22 @@ func (s *Server) getHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if _, err = io.Copy(w, reader); err != nil {
+	password := r.Header.Get("X-Decrypt-Password");
+	decryptionReader, err := transformDecryptionReader(reader, password)
+	if err != nil {
+		http.Error(w, "Could not decrypt file", http.StatusInternalServerError)
+		return
+	}
+
+	if metadata.Encrypted && len(password) > 0 {
+		contentType = metadata.DecryptedContentType
+		contentLength = uint64(metadata.ContentLength)
+	}
+
+	w.Header().Set("Content-Type", contentType)
+	w.Header().Set("Content-Length", strconv.FormatUint(contentLength, 10))
+
+	if _, err = io.Copy(w, decryptionReader); err != nil {
 		s.logger.Printf("%s", err.Error())
 		http.Error(w, "Error occurred copying to output stream", http.StatusInternalServerError)
 		return

server/storage.go

@@ -151,7 +151,7 @@ func (s *LocalStorage) Put(ctx context.Context, token string, filename string, r
 	}
 
 	f, err = os.OpenFile(filepath.Join(path, filename), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
-	defer CloseCheck(f.Close)
+	defer safeClose(f)
 
 	if err != nil {
 		return err
@@ -650,7 +650,7 @@ func getGDriveTokenFromWeb(ctx context.Context, config *oauth2.Config, logger *l
 // Retrieves a token from a local file.
 func gDriveTokenFromFile(file string) (*oauth2.Token, error) {
 	f, err := os.Open(file)
-	defer CloseCheck(f.Close)
+	defer safeClose(f)
 	if err != nil {
 		return nil, err
 	}
@@ -663,7 +663,7 @@ func gDriveTokenFromFile(file string) (*oauth2.Token, error) {
 func saveGDriveToken(path string, token *oauth2.Token, logger *log.Logger) {
 	logger.Printf("Saving credential file to: %s\n", path)
 	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
-	defer CloseCheck(f.Close)
+	defer safeClose(f)
 	if err != nil {
 		logger.Fatalf("Unable to cache oauth token: %v", err)
 	}

server/utils.go

@@ -28,6 +28,7 @@ package server
 
 import (
 	"fmt"
+	"io"
 	"math"
 	"net/http"
 	"net/mail"
@@ -280,8 +281,12 @@ func formatSize(size int64) string {
 	return fmt.Sprintf("%s %s", strconv.FormatFloat(newVal, 'f', -1, 64), getSuffix)
 }
 
-func CloseCheck(f func() error) {
+func safeClose(c io.Closer) {
-	if err := f(); err != nil {
+	if c == nil {
+		return
+	}
+
+	if err := c.Close(); err != nil {
 		fmt.Println("Received close error:", err)
 	}
 }