FTP: try to return more specific error codes/messages for some errors

We now return 552 code for quota exceeded errors and 553 in the following
cases:

- filename denied by a filter
- no upload permission
- no overwrite permission
- pre upload hook error

Fixes #442

common/connection.go

@@ -10,6 +10,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	ftpserver "github.com/fclairamb/ftpserverlib"
 	"github.com/pkg/sftp"
 
 	"github.com/drakkan/sftpgo/v2/dataprovider"
@@ -796,7 +797,7 @@ func (c *BaseConnection) GetMaxWriteSize(quotaResult vfs.QuotaCheckResult, isRes
 			return 0, c.GetOpUnsupportedError()
 		}
 		if c.User.Filters.MaxUploadFileSize > 0 && c.User.Filters.MaxUploadFileSize <= fileSize {
-			return 0, ErrQuotaExceeded
+			return 0, c.GetQuotaExceededError()
 		}
 		if c.User.Filters.MaxUploadFileSize > 0 {
 			maxUploadSize := c.User.Filters.MaxUploadFileSize - fileSize
@@ -1058,6 +1059,26 @@ func (c *BaseConnection) GetOpUnsupportedError() error {
 	}
 }
 
+// GetQuotaExceededError returns an appropriate storage limit exceeded error for the connection protocol
+func (c *BaseConnection) GetQuotaExceededError() error {
+	switch c.protocol {
+	case ProtocolFTP:
+		return ftpserver.ErrStorageExceeded
+	default:
+		return ErrQuotaExceeded
+	}
+}
+
+// IsQuotaExceededError returns true if the given error is a quota exceeded error
+func (c *BaseConnection) IsQuotaExceededError(err error) bool {
+	switch c.protocol {
+	case ProtocolFTP:
+		return errors.Is(err, ftpserver.ErrStorageExceeded)
+	default:
+		return errors.Is(err, ErrQuotaExceeded)
+	}
+}
+
 // GetGenericError returns an appropriate generic error for the connection protocol
 func (c *BaseConnection) GetGenericError(err error) error {
 	switch c.protocol {

common/connection_test.go

@@ -259,6 +259,8 @@ func TestErrorsMapping(t *testing.T) {
 		} else {
 			assert.EqualError(t, err, vfs.ErrStorageSizeUnavailable.Error())
 		}
+		err = conn.GetQuotaExceededError()
+		assert.True(t, conn.IsQuotaExceededError(err))
 		err = conn.GetFsError(fs, nil)
 		assert.NoError(t, err)
 		err = conn.GetOpUnsupportedError()
@@ -307,7 +309,7 @@ func TestMaxWriteSize(t *testing.T) {
 	quotaResult.QuotaSize = 0
 	quotaResult.UsedSize = 0
 	size, err = conn.GetMaxWriteSize(quotaResult, true, 100, fs.IsUploadResumeSupported())
-	assert.EqualError(t, err, ErrQuotaExceeded.Error())
+	assert.True(t, conn.IsQuotaExceededError(err))
 	assert.Equal(t, int64(0), size)
 
 	size, err = conn.GetMaxWriteSize(quotaResult, true, 10, fs.IsUploadResumeSupported())

common/transfer.go

@@ -207,7 +207,7 @@ func (t *BaseTransfer) Close() error {
 		numFiles = 1
 	}
 	metrics.TransferCompleted(atomic.LoadInt64(&t.BytesSent), atomic.LoadInt64(&t.BytesReceived), t.transferType, t.ErrTransfer)
-	if t.ErrTransfer == ErrQuotaExceeded && t.File != nil {
+	if t.File != nil && t.Connection.IsQuotaExceededError(t.ErrTransfer) {
 		// if quota is exceeded we try to remove the partial file for uploads to local filesystem
 		err = t.Fs.Remove(t.File.Name(), false)
 		if err == nil {

ftpd/ftpd_test.go

@@ -19,6 +19,7 @@ import (
 	"testing"
 	"time"
 
+	ftpserver "github.com/fclairamb/ftpserverlib"
 	"github.com/jlaffaye/ftp"
 	"github.com/rs/zerolog"
 	"github.com/stretchr/testify/assert"
@@ -819,11 +820,11 @@ func TestPreUploadHook(t *testing.T) {
 		assert.NoError(t, err)
 		err = ftpUploadFile(testFilePath, testFileName, testFileSize, client, 0)
 		if assert.Error(t, err) {
-			assert.Contains(t, err.Error(), "permission denied")
+			assert.Contains(t, err.Error(), ftpserver.ErrFileNameNotAllowed.Error())
 		}
 		err = ftpUploadFile(testFilePath, testFileName+"1", testFileSize, client, 0)
 		if assert.Error(t, err) {
-			assert.Contains(t, err.Error(), "permission denied")
+			assert.Contains(t, err.Error(), ftpserver.ErrFileNameNotAllowed.Error())
 		}
 		err := client.Quit()
 		assert.NoError(t, err)

ftpd/handler.go

@@ -2,6 +2,7 @@ package ftpd
 
 import (
 	"errors"
+	"fmt"
 	"io"
 	"os"
 	"path"
@@ -318,7 +319,7 @@ func (c *Connection) downloadFile(fs vfs.Fs, fsPath, ftpPath string, offset int6
 func (c *Connection) uploadFile(fs vfs.Fs, fsPath, ftpPath string, flags int) (ftpserver.FileTransfer, error) {
 	if !c.User.IsFileAllowed(ftpPath) {
 		c.Log(logger.LevelWarn, "writing file %#v is not allowed", ftpPath)
-		return nil, c.GetPermissionDeniedError()
+		return nil, ftpserver.ErrFileNameNotAllowed
 	}
 
 	filePath := fsPath
@@ -329,7 +330,7 @@ func (c *Connection) uploadFile(fs vfs.Fs, fsPath, ftpPath string, flags int) (f
 	stat, statErr := fs.Lstat(fsPath)
 	if (statErr == nil && stat.Mode()&os.ModeSymlink != 0) || fs.IsNotExist(statErr) {
 		if !c.User.HasPerm(dataprovider.PermUpload, path.Dir(ftpPath)) {
-			return nil, c.GetPermissionDeniedError()
+			return nil, fmt.Errorf("%w, no upload permission", ftpserver.ErrFileNameNotAllowed)
 		}
 		return c.handleFTPUploadToNewFile(fs, fsPath, filePath, ftpPath)
 	}
@@ -346,7 +347,7 @@ func (c *Connection) uploadFile(fs vfs.Fs, fsPath, ftpPath string, flags int) (f
 	}
 
 	if !c.User.HasPerm(dataprovider.PermOverwrite, path.Dir(ftpPath)) {
-		return nil, c.GetPermissionDeniedError()
+		return nil, fmt.Errorf("%w, no overwrite permission", ftpserver.ErrFileNameNotAllowed)
 	}
 
 	return c.handleFTPUploadToExistingFile(fs, flags, fsPath, filePath, stat.Size(), ftpPath)
@@ -356,11 +357,11 @@ func (c *Connection) handleFTPUploadToNewFile(fs vfs.Fs, resolvedPath, filePath,
 	quotaResult := c.HasSpace(true, false, requestPath)
 	if !quotaResult.HasSpace {
 		c.Log(logger.LevelInfo, "denying file write due to quota limits")
-		return nil, common.ErrQuotaExceeded
+		return nil, ftpserver.ErrStorageExceeded
 	}
 	if err := common.ExecutePreAction(&c.User, common.OperationPreUpload, resolvedPath, requestPath, c.GetProtocol(), 0, 0); err != nil {
 		c.Log(logger.LevelDebug, "upload for file %#v denied by pre action: %v", requestPath, err)
-		return nil, c.GetPermissionDeniedError()
+		return nil, fmt.Errorf("%w, denied by pre-upload action", ftpserver.ErrFileNameNotAllowed)
 	}
 	file, w, cancelFn, err := fs.Create(filePath, 0)
 	if err != nil {
@@ -386,7 +387,7 @@ func (c *Connection) handleFTPUploadToExistingFile(fs vfs.Fs, flags int, resolve
 	quotaResult := c.HasSpace(false, false, requestPath)
 	if !quotaResult.HasSpace {
 		c.Log(logger.LevelInfo, "denying file write due to quota limits")
-		return nil, common.ErrQuotaExceeded
+		return nil, ftpserver.ErrStorageExceeded
 	}
 	minWriteOffset := int64(0)
 	// ftpserverlib sets:
@@ -404,7 +405,7 @@ func (c *Connection) handleFTPUploadToExistingFile(fs vfs.Fs, flags int, resolve
 	}
 	if err := common.ExecutePreAction(&c.User, common.OperationPreUpload, resolvedPath, requestPath, c.GetProtocol(), fileSize, flags); err != nil {
 		c.Log(logger.LevelDebug, "upload for file %#v denied by pre action: %v", requestPath, err)
-		return nil, c.GetPermissionDeniedError()
+		return nil, fmt.Errorf("%w, denied by pre-upload action", ftpserver.ErrFileNameNotAllowed)
 	}
 
 	if common.Config.IsAtomicUploadEnabled() && fs.IsAtomicUploadSupported() {

ftpd/transfer.go

@@ -65,7 +65,7 @@ func (t *transfer) Write(p []byte) (n int, err error) {
 	atomic.AddInt64(&t.BytesReceived, int64(n))
 
 	if t.MaxWriteSize > 0 && err == nil && atomic.LoadInt64(&t.BytesReceived) > t.MaxWriteSize {
-		err = common.ErrQuotaExceeded
+		err = t.Connection.GetQuotaExceededError()
 	}
 	if err != nil {
 		t.TransferError(err)

go.mod

@@ -11,7 +11,7 @@ require (
 	github.com/aws/aws-sdk-go v1.38.68
 	github.com/cockroachdb/cockroach-go/v2 v2.1.1
 	github.com/eikenb/pipeat v0.0.0-20210603033007-44fc3ffce52b
-	github.com/fclairamb/ftpserverlib v0.13.3-0.20210614220040-27dccea41813
+	github.com/fclairamb/ftpserverlib v0.13.3-0.20210627202858-3bf551007432
 	github.com/frankban/quicktest v1.13.0 // indirect
 	github.com/go-chi/chi/v5 v5.0.3
 	github.com/go-chi/jwtauth/v5 v5.0.1

go.sum

@@ -233,8 +233,8 @@ github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7
 github.com/fatih/color v1.7.0 h1:DkWD4oS2D8LGGgTQ6IvwJJXSL5Vp2ffcQg58nFV38Ys=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/structs v1.1.0/go.mod h1:9NiDSp5zOcgEDl+j00MP/WkGVPOlPRLejGD8Ga6PJ7M=
-github.com/fclairamb/ftpserverlib v0.13.3-0.20210614220040-27dccea41813 h1:wXDgbyHQT62eyVff37ocEXSp0N5RiTLdoOmugP/tRRU=
+github.com/fclairamb/ftpserverlib v0.13.3-0.20210627202858-3bf551007432 h1:UtF6df4idbDpc/x9lMyJT/fLmu6YLRZG6nFyz7qi81Y=
-github.com/fclairamb/ftpserverlib v0.13.3-0.20210614220040-27dccea41813/go.mod h1:T7GFWYWSREftxINf3ielPlaQ+aiE04/elEH0zLwkxBA=
+github.com/fclairamb/ftpserverlib v0.13.3-0.20210627202858-3bf551007432/go.mod h1:ATLgn4bHgiM9+vfZbK+rMu/dqgkxO5nk94x/9f8ffDI=
 github.com/form3tech-oss/jwt-go v3.2.2+incompatible h1:TcekIExNqud5crz4xD2pavyTgWiPvpYe4Xau31I0PRk=
 github.com/form3tech-oss/jwt-go v3.2.2+incompatible/go.mod h1:pbq4aXjuKjdthFRnoDwaVPLA+WlJuPGy+QneDUgJi2k=
 github.com/fortytw2/leaktest v1.3.0/go.mod h1:jDsjWgpAGjm2CA7WthBh/CdZYEPF31XHquHwclZch5g=
@@ -294,8 +294,6 @@ github.com/gobwas/httphead v0.0.0-20180130184737-2c6c146eadee/go.mod h1:L0fX3K22
 github.com/gobwas/pool v0.2.0/go.mod h1:q8bcK0KcYlCgd9e7WYLm9LpyS+YeLd8JVDW6WezmKEw=
 github.com/gobwas/ws v1.0.2/go.mod h1:szmBTxLgaFppYjEmNtny/v3w89xOydFnnZMcgRRu/EM=
 github.com/goccy/go-json v0.4.8/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
-github.com/goccy/go-json v0.7.1 h1:VMhnh5gcc8De8f6m2DLvSqY1x8Jwl3btet+EqMP0QNs=
-github.com/goccy/go-json v0.7.1/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
 github.com/goccy/go-json v0.7.2 h1:MY1gMmtCxRpaI8YGpeHCvXUb+FVIo09pnjqF9Rhh274=
 github.com/goccy/go-json v0.7.2/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
 github.com/godbus/dbus v0.0.0-20190422162347-ade71ed3457e/go.mod h1:bBOAhwG1umN6/6ZUMtDFBMQR8jRg9O75tm9K00oMsK4=
@@ -843,7 +841,6 @@ github.com/streadway/amqp v0.0.0-20190827072141-edfb9018d271/go.mod h1:AZpEONHx3
 github.com/streadway/handy v0.0.0-20190108123426-d5acb3125c2a/go.mod h1:qNTQ5P5JnDBl6z3cMAg/SywNDC5ABu5ApDIw6lUbRmI=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.2.0 h1:Hbg2NidpLE8veEBkEZTL3CvlkUIVzuU9jDplZO54c48=
 github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=