ftpd: allow to ignore ASCII transfer types

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

go.mod

@@ -82,7 +82,7 @@ require (
 	cloud.google.com/go/auth v0.3.0 // indirect
 	cloud.google.com/go/auth/oauth2adapt v0.2.2 // indirect
 	cloud.google.com/go/compute/metadata v0.3.0 // indirect
-	cloud.google.com/go/iam v1.1.7 // indirect
+	cloud.google.com/go/iam v1.1.8 // indirect
 	filippo.io/edwards25519 v1.1.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/internal v1.6.0 // indirect
 	github.com/ajg/form v1.5.1 // indirect
@@ -143,7 +143,7 @@ require (
 	github.com/mitchellh/go-testing-interface v1.14.1 // indirect
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/oklog/run v1.1.0 // indirect
-	github.com/pelletier/go-toml/v2 v2.2.1 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.2 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/power-devops/perfstat v0.0.0-20240221224432-82ca36839d55 // indirect
 	github.com/prometheus/client_model v0.6.1 // indirect
@@ -183,7 +183,7 @@ require (
 )
 
 replace (
-	github.com/fclairamb/ftpserverlib => github.com/drakkan/ftpserverlib v0.0.0-20240430171908-06190249a088
+	github.com/fclairamb/ftpserverlib => github.com/drakkan/ftpserverlib v0.0.0-20240502162317-7bc57ede068a
 	github.com/jlaffaye/ftp => github.com/drakkan/ftp v0.0.0-20240430173938-7ba8270c8e7f
 	github.com/robfig/cron/v3 => github.com/drakkan/cron/v3 v3.0.0-20230222140221-217a1e4d96c0
 	golang.org/x/crypto => github.com/drakkan/crypto v0.0.0-20240405104909-a6b14455cac6

go.sum

@@ -9,6 +9,8 @@ cloud.google.com/go/compute/metadata v0.3.0 h1:Tz+eQXMEqDIKRsmY3cHTL6FVaynIjX2Qx
 cloud.google.com/go/compute/metadata v0.3.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k=
 cloud.google.com/go/iam v1.1.7 h1:z4VHOhwKLF/+UYXAJDFwGtNF0b6gjsW1Pk9Ml0U/IoM=
 cloud.google.com/go/iam v1.1.7/go.mod h1:J4PMPg8TtyurAUvSmPj8FF3EDgY1SPRZxcUGrn7WXGA=
+cloud.google.com/go/iam v1.1.8 h1:r7umDwhj+BQyz0ScZMp4QrGXjSTI3ZINnpgU2nlB/K0=
+cloud.google.com/go/iam v1.1.8/go.mod h1:GvE6lyMmfxXauzNq8NbgJbeVQNspG+tcdL/W8QO1+zE=
 cloud.google.com/go/kms v1.15.8 h1:szIeDCowID8th2i8XE4uRev5PMxQFqW+JjwYxL9h6xs=
 cloud.google.com/go/kms v1.15.8/go.mod h1:WoUHcDjD9pluCg7pNds131awnH429QGvRM3N/4MyoVs=
 cloud.google.com/go/storage v1.40.0 h1:VEpDQV5CJxFmJ6ueWNsKxcr1QAYOXEgxDa+sBbJahPw=
@@ -118,8 +120,8 @@ github.com/drakkan/crypto v0.0.0-20240405104909-a6b14455cac6 h1:XzaQu+jRDZWu+Cro
 github.com/drakkan/crypto v0.0.0-20240405104909-a6b14455cac6/go.mod h1:vr6Su+7cTlO45qkww3VDJlzDn0ctJvRgYbC2NvXHt+M=
 github.com/drakkan/ftp v0.0.0-20240430173938-7ba8270c8e7f h1:S9JUlrOzjK58UKoLqqb40YLyVlt0bcIFtYrvnanV3zc=
 github.com/drakkan/ftp v0.0.0-20240430173938-7ba8270c8e7f/go.mod h1:4p8lUl4vQ80L598CygL+3IFtm+3nggvvW/palOlViwE=
-github.com/drakkan/ftpserverlib v0.0.0-20240430171908-06190249a088 h1:M7X8bstrPumVbmxdtHxQMJghiYhFzk/y+LvmWJkihqw=
+github.com/drakkan/ftpserverlib v0.0.0-20240502162317-7bc57ede068a h1:IULpJkoPn+DlpbF0owSZDao1yCFuOaDrSnIEpvdxXM8=
-github.com/drakkan/ftpserverlib v0.0.0-20240430171908-06190249a088/go.mod h1:+9afJRWESpCq4/O8Vr00Q2jfinRxP6PiCpXph6CgGuc=
+github.com/drakkan/ftpserverlib v0.0.0-20240502162317-7bc57ede068a/go.mod h1:+9afJRWESpCq4/O8Vr00Q2jfinRxP6PiCpXph6CgGuc=
 github.com/drakkan/webdav v0.0.0-20240414072657-7c19d3cb5103 h1:jhcR8ixhpd3f8iBeH/6pJ9V3BNjY3Yjrb7Ipp8Cezmw=
 github.com/drakkan/webdav v0.0.0-20240414072657-7c19d3cb5103/go.mod h1:zOVb1QDhwwqWn2L2qZ0U3swMSO4GTSNyIwXCGO/UGWE=
 github.com/eikenb/pipeat v0.0.0-20210730190139-06b3e6902001 h1:/ZshrfQzayqRSBDodmp3rhNCHJCff+utvgBuWRbiqu4=
@@ -307,6 +309,8 @@ github.com/otiai10/mint v1.5.1 h1:XaPLeE+9vGbuyEHem1JNk3bYc7KKqyI/na0/mLd/Kks=
 github.com/otiai10/mint v1.5.1/go.mod h1:MJm72SBthJjz8qhefc4z1PYEieWmy8Bku7CjcAqyUSM=
 github.com/pelletier/go-toml/v2 v2.2.1 h1:9TA9+T8+8CUCO2+WYnDLCgrYi9+omqKXyjDtosvtEhg=
 github.com/pelletier/go-toml/v2 v2.2.1/go.mod h1:1t835xjRzz80PqgE6HHgN2JOsmgYu/h4qDAS4n929Rs=
+github.com/pelletier/go-toml/v2 v2.2.2 h1:aYUidT7k73Pcl9nb2gScu7NSrKCSHIDE89b3+6Wq+LM=
+github.com/pelletier/go-toml/v2 v2.2.2/go.mod h1:1t835xjRzz80PqgE6HHgN2JOsmgYu/h4qDAS4n929Rs=
 github.com/pires/go-proxyproto v0.7.0 h1:IukmRewDQFWC7kfnb66CSomk2q/seBuilHBYFwyq0Hs=
 github.com/pires/go-proxyproto v0.7.0/go.mod h1:Vz/1JPY/OACxWGQNIRY2BeyDmpoaWmEP40O9LbuiFR4=
 github.com/pkg/browser v0.0.0-20240102092130-5ac0b6a4141c h1:+mdjkGKdHQG3305AYmdv1U2eRNDiU2ErMBj1gwrq8eQ=
@@ -421,6 +425,7 @@ go.opentelemetry.io/otel/metric v1.26.0 h1:7S39CLuY5Jgg9CrnA9HHiEjGMF/X2VHvoXGgS
 go.opentelemetry.io/otel/metric v1.26.0/go.mod h1:SY+rHOI4cEawI9a7N1A4nIg/nTQXe1ccCNWYOJUrpX4=
 go.opentelemetry.io/otel/sdk v1.22.0 h1:6coWHw9xw7EfClIC/+O31R8IY3/+EiRFHevmHafB2Gw=
 go.opentelemetry.io/otel/sdk v1.22.0/go.mod h1:iu7luyVGYovrRpe2fmj3CVKouQNdTOkxtLzPvPz1DOc=
+go.opentelemetry.io/otel/sdk v1.24.0 h1:YMPPDNymmQN3ZgczicBY3B6sf9n62Dlj9pWD3ucgoDw=
 go.opentelemetry.io/otel/trace v1.26.0 h1:1ieeAUb4y0TE26jUFrCIXKpTuVK7uJGN9/Z/2LP5sQA=
 go.opentelemetry.io/otel/trace v1.26.0/go.mod h1:4iDxvGDQuUkHve82hJJ8UqrwswHYsZuWCBllGV2U2y0=
 go.uber.org/automaxprocs v1.5.3 h1:kWazyxZUrS3Gs4qUpbwo5kEIMGe/DAvi5Z4tl2NW4j8=

internal/config/config.go

@@ -1193,6 +1193,12 @@ func getFTPDBindingSecurityFromEnv(idx int, binding *ftpd.Binding) bool {
 		isSet = true
 	}
 
+	ignoreASCIITransferType, ok := lookupIntFromEnv(fmt.Sprintf("SFTPGO_FTPD__BINDINGS__%d__IGNORE_ASCII_TRANSFER_TYPE", idx), 0)
+	if ok {
+		binding.IgnoreASCIITransferType = int(ignoreASCIITransferType)
+		isSet = true
+	}
+
 	return isSet
 }
 

internal/config/config_test.go

@@ -926,6 +926,7 @@ func TestFTPDBindingsFromEnv(t *testing.T) {
 	os.Setenv("SFTPGO_FTPD__BINDINGS__9__CLIENT_AUTH_TYPE", "2")
 	os.Setenv("SFTPGO_FTPD__BINDINGS__9__DEBUG", "1")
 	os.Setenv("SFTPGO_FTPD__BINDINGS__9__ACTIVE_CONNECTIONS_SECURITY", "1")
+	os.Setenv("SFTPGO_FTPD__BINDINGS__9__IGNORE_ASCII_TRANSFER_TYPE", "1")
 	os.Setenv("SFTPGO_FTPD__BINDINGS__9__CERTIFICATE_FILE", "cert.crt")
 	os.Setenv("SFTPGO_FTPD__BINDINGS__9__CERTIFICATE_KEY_FILE", "cert.key")
 
@@ -950,6 +951,7 @@ func TestFTPDBindingsFromEnv(t *testing.T) {
 		os.Unsetenv("SFTPGO_FTPD__BINDINGS__9__CLIENT_AUTH_TYPE")
 		os.Unsetenv("SFTPGO_FTPD__BINDINGS__9__DEBUG")
 		os.Unsetenv("SFTPGO_FTPD__BINDINGS__9__ACTIVE_CONNECTIONS_SECURITY")
+		os.Unsetenv("SFTPGO_FTPD__BINDINGS__9__IGNORE_ASCII_TRANSFER_TYPE")
 		os.Unsetenv("SFTPGO_FTPD__BINDINGS__9__CERTIFICATE_FILE")
 		os.Unsetenv("SFTPGO_FTPD__BINDINGS__9__CERTIFICATE_KEY_FILE")
 	})
@@ -974,6 +976,7 @@ func TestFTPDBindingsFromEnv(t *testing.T) {
 	require.False(t, bindings[0].Debug)
 	require.Equal(t, 1, bindings[0].PassiveConnectionsSecurity)
 	require.Equal(t, 0, bindings[0].ActiveConnectionsSecurity)
+	require.Equal(t, 0, bindings[0].IgnoreASCIITransferType)
 	require.Equal(t, 2203, bindings[1].Port)
 	require.Equal(t, "127.0.1.1", bindings[1].Address)
 	require.True(t, bindings[1].ApplyProxyConfig) // default value
@@ -991,6 +994,7 @@ func TestFTPDBindingsFromEnv(t *testing.T) {
 	require.Nil(t, bindings[1].TLSCipherSuites)
 	require.Equal(t, 0, bindings[1].PassiveConnectionsSecurity)
 	require.Equal(t, 1, bindings[1].ActiveConnectionsSecurity)
+	require.Equal(t, 1, bindings[1].IgnoreASCIITransferType)
 	require.True(t, bindings[1].Debug)
 	require.Equal(t, "cert.crt", bindings[1].CertificateFile)
 	require.Equal(t, "cert.key", bindings[1].CertificateKeyFile)

internal/ftpd/ftpd.go

@@ -109,6 +109,11 @@ type Binding struct {
 	// Please note that disabling the security checks you will make the FTP service vulnerable to bounce attacks
 	// on active data connections, so change the default value only if you are on a trusted/internal network
 	ActiveConnectionsSecurity int `json:"active_connections_security" mapstructure:"active_connections_security"`
+	// Set to 1 to silently ignore any client requests to perform ASCII translations via the TYPE command.
+	// That is, FTP clients can request ASCII translations, and SFTPGo will respond as the client expects,
+	// but will not actually perform the translation for either uploads or downloads. This behavior can be
+	// useful in circumstances involving older/mainframe clients and EBCDIC files.
+	IgnoreASCIITransferType int `json:"ignore_ascii_transfer_type" mapstructure:"ignore_ascii_transfer_type"`
 	// Debug enables the FTP debug mode. In debug mode, every FTP command will be logged
 	Debug   bool `json:"debug" mapstructure:"debug"`
 	ciphers []uint16

internal/ftpd/server.go

@@ -133,6 +133,7 @@ func (s *Server) GetSettings() (*ftpserver.Settings, error) {
 		EnableHASH:               s.config.HASHSupport > 0,
 		EnableCOMB:               s.config.CombineSupport > 0,
 		DefaultTransferType:      ftpserver.TransferTypeBinary,
+		IgnoreASCIITranferType:   s.binding.IgnoreASCIITransferType == 1,
 		ActiveConnectionsCheck:   ftpserver.DataConnectionRequirement(s.binding.ActiveConnectionsSecurity),
 		PasvConnectionsCheck:     ftpserver.DataConnectionRequirement(s.binding.PassiveConnectionsSecurity),
 	}, nil

openapi/openapi.yaml

@@ -6446,6 +6446,15 @@ components:
             Active connections security:
               * `0` - require matching peer IP addresses of control and data connection
               * `1` - disable any checks
+        ignore_ascii_transfer_type:
+          type: integer
+          enum:
+            - 0
+            - 1
+          description: |
+            Ignore client requests to perform ASCII translations:
+              * `0` - ASCII translations are enabled
+              * `1` - ASCII translations are silently ignored
         debug:
           type: boolean
           description: 'If enabled any FTP command will be logged'

sftpgo.json

@@ -126,6 +126,7 @@
         "tls_cipher_suites": [],
         "passive_connections_security": 0,
         "active_connections_security": 0,
+        "ignore_ascii_transfer_type": 0,
         "debug": false
       }
     ],