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sftp.go
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sftp.go
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//go:build !plan9
// Package sftp provides a filesystem interface using github.com/pkg/sftp
package sftp
import (
"bytes"
"context"
"errors"
"fmt"
"io"
iofs "io/fs"
"os"
"path"
"regexp"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/pkg/sftp"
"github.com/rclone/rclone/fs"
"github.com/rclone/rclone/fs/accounting"
"github.com/rclone/rclone/fs/config"
"github.com/rclone/rclone/fs/config/configmap"
"github.com/rclone/rclone/fs/config/configstruct"
"github.com/rclone/rclone/fs/config/obscure"
"github.com/rclone/rclone/fs/hash"
"github.com/rclone/rclone/lib/env"
"github.com/rclone/rclone/lib/pacer"
"github.com/rclone/rclone/lib/readers"
sshagent "github.com/xanzy/ssh-agent"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/knownhosts"
)
const (
defaultShellType = "unix"
shellTypeNotSupported = "none"
hashCommandNotSupported = "none"
minSleep = 100 * time.Millisecond
maxSleep = 2 * time.Second
decayConstant = 2 // bigger for slower decay, exponential
keepAliveInterval = time.Minute // send keepalives every this long while running commands
)
var (
currentUser = env.CurrentUser()
posixWinAbsPathRegex = regexp.MustCompile(`^/[a-zA-Z]\:($|/)`) // E.g. "/C:" or anything starting with "/C:/"
unixShellEscapeRegex = regexp.MustCompile("[^A-Za-z0-9_.,:/\\@\u0080-\uFFFFFFFF\n-]")
)
func init() {
fsi := &fs.RegInfo{
Name: "sftp",
Description: "SSH/SFTP",
NewFs: NewFs,
Options: []fs.Option{{
Name: "host",
Help: "SSH host to connect to.\n\nE.g. \"example.com\".",
Required: true,
Sensitive: true,
}, {
Name: "user",
Help: "SSH username.",
Default: currentUser,
Sensitive: true,
}, {
Name: "port",
Help: "SSH port number.",
Default: 22,
}, {
Name: "pass",
Help: "SSH password, leave blank to use ssh-agent.",
IsPassword: true,
}, {
Name: "key_pem",
Help: `Raw PEM-encoded private key.
Note that this should be on a single line with line endings replaced with '\n', eg
key_pem = -----BEGIN RSA PRIVATE KEY-----\nMaMbaIXtE\n0gAMbMbaSsd\nMbaass\n-----END RSA PRIVATE KEY-----
This will generate the single line correctly:
awk '{printf "%s\\n", $0}' < ~/.ssh/id_rsa
If specified, it will override the key_file parameter.`,
Sensitive: true,
}, {
Name: "key_file",
Help: "Path to PEM-encoded private key file.\n\nLeave blank or set key-use-agent to use ssh-agent." + env.ShellExpandHelp,
}, {
Name: "key_file_pass",
Help: `The passphrase to decrypt the PEM-encoded private key file.
Only PEM encrypted key files (old OpenSSH format) are supported. Encrypted keys
in the new OpenSSH format can't be used.`,
IsPassword: true,
Sensitive: true,
}, {
Name: "pubkey_file",
Help: `Optional path to public key file.
Set this if you have a signed certificate you want to use for authentication.` + env.ShellExpandHelp,
}, {
Name: "known_hosts_file",
Help: `Optional path to known_hosts file.
Set this value to enable server host key validation.` + env.ShellExpandHelp,
Advanced: true,
Examples: []fs.OptionExample{{
Value: "~/.ssh/known_hosts",
Help: "Use OpenSSH's known_hosts file.",
}},
}, {
Name: "key_use_agent",
Help: `When set forces the usage of the ssh-agent.
When key-file is also set, the ".pub" file of the specified key-file is read and only the associated key is
requested from the ssh-agent. This allows to avoid ` + "`Too many authentication failures for *username*`" + ` errors
when the ssh-agent contains many keys.`,
Default: false,
}, {
Name: "use_insecure_cipher",
Help: `Enable the use of insecure ciphers and key exchange methods.
This enables the use of the following insecure ciphers and key exchange methods:
- aes128-cbc
- aes192-cbc
- aes256-cbc
- 3des-cbc
- diffie-hellman-group-exchange-sha256
- diffie-hellman-group-exchange-sha1
Those algorithms are insecure and may allow plaintext data to be recovered by an attacker.
This must be false if you use either ciphers or key_exchange advanced options.
`,
Default: false,
Examples: []fs.OptionExample{
{
Value: "false",
Help: "Use default Cipher list.",
}, {
Value: "true",
Help: "Enables the use of the aes128-cbc cipher and diffie-hellman-group-exchange-sha256, diffie-hellman-group-exchange-sha1 key exchange.",
},
},
}, {
Name: "disable_hashcheck",
Default: false,
Help: "Disable the execution of SSH commands to determine if remote file hashing is available.\n\nLeave blank or set to false to enable hashing (recommended), set to true to disable hashing.",
}, {
Name: "ask_password",
Default: false,
Help: `Allow asking for SFTP password when needed.
If this is set and no password is supplied then rclone will:
- ask for a password
- not contact the ssh agent
`,
Advanced: true,
}, {
Name: "path_override",
Default: "",
Help: `Override path used by SSH shell commands.
This allows checksum calculation when SFTP and SSH paths are
different. This issue affects among others Synology NAS boxes.
E.g. if shared folders can be found in directories representing volumes:
rclone sync /home/local/directory remote:/directory --sftp-path-override /volume2/directory
E.g. if home directory can be found in a shared folder called "home":
rclone sync /home/local/directory remote:/home/directory --sftp-path-override /volume1/homes/USER/directory
To specify only the path to the SFTP remote's root, and allow rclone to add any relative subpaths automatically (including unwrapping/decrypting remotes as necessary), add the '@' character to the beginning of the path.
E.g. the first example above could be rewritten as:
rclone sync /home/local/directory remote:/directory --sftp-path-override @/volume2
Note that when using this method with Synology "home" folders, the full "/homes/USER" path should be specified instead of "/home".
E.g. the second example above should be rewritten as:
rclone sync /home/local/directory remote:/homes/USER/directory --sftp-path-override @/volume1`,
Advanced: true,
}, {
Name: "set_modtime",
Default: true,
Help: "Set the modified time on the remote if set.",
Advanced: true,
}, {
Name: "shell_type",
Default: "",
Help: "The type of SSH shell on remote server, if any.\n\nLeave blank for autodetect.",
Advanced: true,
Examples: []fs.OptionExample{
{
Value: shellTypeNotSupported,
Help: "No shell access",
}, {
Value: "unix",
Help: "Unix shell",
}, {
Value: "powershell",
Help: "PowerShell",
}, {
Value: "cmd",
Help: "Windows Command Prompt",
},
},
}, {
Name: "md5sum_command",
Default: "",
Help: "The command used to read md5 hashes.\n\nLeave blank for autodetect.",
Advanced: true,
}, {
Name: "sha1sum_command",
Default: "",
Help: "The command used to read sha1 hashes.\n\nLeave blank for autodetect.",
Advanced: true,
}, {
Name: "skip_links",
Default: false,
Help: "Set to skip any symlinks and any other non regular files.",
Advanced: true,
}, {
Name: "subsystem",
Default: "sftp",
Help: "Specifies the SSH2 subsystem on the remote host.",
Advanced: true,
}, {
Name: "server_command",
Default: "",
Help: `Specifies the path or command to run a sftp server on the remote host.
The subsystem option is ignored when server_command is defined.
If adding server_command to the configuration file please note that
it should not be enclosed in quotes, since that will make rclone fail.
A working example is:
[remote_name]
type = sftp
server_command = sudo /usr/libexec/openssh/sftp-server`,
Advanced: true,
}, {
Name: "use_fstat",
Default: false,
Help: `If set use fstat instead of stat.
Some servers limit the amount of open files and calling Stat after opening
the file will throw an error from the server. Setting this flag will call
Fstat instead of Stat which is called on an already open file handle.
It has been found that this helps with IBM Sterling SFTP servers which have
"extractability" level set to 1 which means only 1 file can be opened at
any given time.
`,
Advanced: true,
}, {
Name: "disable_concurrent_reads",
Default: false,
Help: `If set don't use concurrent reads.
Normally concurrent reads are safe to use and not using them will
degrade performance, so this option is disabled by default.
Some servers limit the amount number of times a file can be
downloaded. Using concurrent reads can trigger this limit, so if you
have a server which returns
Failed to copy: file does not exist
Then you may need to enable this flag.
If concurrent reads are disabled, the use_fstat option is ignored.
`,
Advanced: true,
}, {
Name: "disable_concurrent_writes",
Default: false,
Help: `If set don't use concurrent writes.
Normally rclone uses concurrent writes to upload files. This improves
the performance greatly, especially for distant servers.
This option disables concurrent writes should that be necessary.
`,
Advanced: true,
}, {
Name: "idle_timeout",
Default: fs.Duration(60 * time.Second),
Help: `Max time before closing idle connections.
If no connections have been returned to the connection pool in the time
given, rclone will empty the connection pool.
Set to 0 to keep connections indefinitely.
`,
Advanced: true,
}, {
Name: "chunk_size",
Help: `Upload and download chunk size.
This controls the maximum size of payload in SFTP protocol packets.
The RFC limits this to 32768 bytes (32k), which is the default. However,
a lot of servers support larger sizes, typically limited to a maximum
total package size of 256k, and setting it larger will increase transfer
speed dramatically on high latency links. This includes OpenSSH, and,
for example, using the value of 255k works well, leaving plenty of room
for overhead while still being within a total packet size of 256k.
Make sure to test thoroughly before using a value higher than 32k,
and only use it if you always connect to the same server or after
sufficiently broad testing. If you get errors such as
"failed to send packet payload: EOF", lots of "connection lost",
or "corrupted on transfer", when copying a larger file, try lowering
the value. The server run by [rclone serve sftp](/commands/rclone_serve_sftp)
sends packets with standard 32k maximum payload so you must not
set a different chunk_size when downloading files, but it accepts
packets up to the 256k total size, so for uploads the chunk_size
can be set as for the OpenSSH example above.
`,
Default: 32 * fs.Kibi,
Advanced: true,
}, {
Name: "concurrency",
Help: `The maximum number of outstanding requests for one file
This controls the maximum number of outstanding requests for one file.
Increasing it will increase throughput on high latency links at the
cost of using more memory.
`,
Default: 64,
Advanced: true,
}, {
Name: "connections",
Help: strings.ReplaceAll(`Maximum number of SFTP simultaneous connections, 0 for unlimited.
Note that setting this is very likely to cause deadlocks so it should
be used with care.
If you are doing a sync or copy then make sure connections is one more
than the sum of |--transfers| and |--checkers|.
If you use |--check-first| then it just needs to be one more than the
maximum of |--checkers| and |--transfers|.
So for |connections 3| you'd use |--checkers 2 --transfers 2
--check-first| or |--checkers 1 --transfers 1|.
`, "|", "`"),
Default: 0,
Advanced: true,
}, {
Name: "set_env",
Default: fs.SpaceSepList{},
Help: `Environment variables to pass to sftp and commands
Set environment variables in the form:
VAR=value
to be passed to the sftp client and to any commands run (eg md5sum).
Pass multiple variables space separated, eg
VAR1=value VAR2=value
and pass variables with spaces in quotes, eg
"VAR3=value with space" "VAR4=value with space" VAR5=nospacehere
`,
Advanced: true,
}, {
Name: "ciphers",
Default: fs.SpaceSepList{},
Help: `Space separated list of ciphers to be used for session encryption, ordered by preference.
At least one must match with server configuration. This can be checked for example using ssh -Q cipher.
This must not be set if use_insecure_cipher is true.
Example:
aes128-ctr aes192-ctr aes256-ctr aes128-gcm@openssh.com aes256-gcm@openssh.com
`,
Advanced: true,
}, {
Name: "key_exchange",
Default: fs.SpaceSepList{},
Help: `Space separated list of key exchange algorithms, ordered by preference.
At least one must match with server configuration. This can be checked for example using ssh -Q kex.
This must not be set if use_insecure_cipher is true.
Example:
sntrup761x25519-sha512@openssh.com curve25519-sha256 curve25519-sha256@libssh.org ecdh-sha2-nistp256
`,
Advanced: true,
}, {
Name: "macs",
Default: fs.SpaceSepList{},
Help: `Space separated list of MACs (message authentication code) algorithms, ordered by preference.
At least one must match with server configuration. This can be checked for example using ssh -Q mac.
Example:
umac-64-etm@openssh.com umac-128-etm@openssh.com hmac-sha2-256-etm@openssh.com
`,
Advanced: true,
}, {
Name: "host_key_algorithms",
Default: fs.SpaceSepList{},
Help: `Space separated list of host key algorithms, ordered by preference.
At least one must match with server configuration. This can be checked for example using ssh -Q HostKeyAlgorithms.
Note: This can affect the outcome of key negotiation with the server even if server host key validation is not enabled.
Example:
ssh-ed25519 ssh-rsa ssh-dss
`,
Advanced: true,
}, {
Name: "ssh",
Default: fs.SpaceSepList{},
Help: `Path and arguments to external ssh binary.
Normally rclone will use its internal ssh library to connect to the
SFTP server. However it does not implement all possible ssh options so
it may be desirable to use an external ssh binary.
Rclone ignores all the internal config if you use this option and
expects you to configure the ssh binary with the user/host/port and
any other options you need.
**Important** The ssh command must log in without asking for a
password so needs to be configured with keys or certificates.
Rclone will run the command supplied either with the additional
arguments "-s sftp" to access the SFTP subsystem or with commands such
as "md5sum /path/to/file" appended to read checksums.
Any arguments with spaces in should be surrounded by "double quotes".
An example setting might be:
ssh -o ServerAliveInterval=20 user@example.com
Note that when using an external ssh binary rclone makes a new ssh
connection for every hash it calculates.
`,
}, {
Name: "socks_proxy",
Default: "",
Help: `Socks 5 proxy host.
Supports the format user:pass@host:port, user@host:port, host:port.
Example:
myUser:myPass@localhost:9005
`,
Advanced: true,
}, {
Name: "copy_is_hardlink",
Default: false,
Help: `Set to enable server side copies using hardlinks.
The SFTP protocol does not define a copy command so normally server
side copies are not allowed with the sftp backend.
However the SFTP protocol does support hardlinking, and if you enable
this flag then the sftp backend will support server side copies. These
will be implemented by doing a hardlink from the source to the
destination.
Not all sftp servers support this.
Note that hardlinking two files together will use no additional space
as the source and the destination will be the same file.
This feature may be useful backups made with --copy-dest.`,
Advanced: true,
}},
}
fs.Register(fsi)
}
// Options defines the configuration for this backend
type Options struct {
Host string `config:"host"`
User string `config:"user"`
Port string `config:"port"`
Pass string `config:"pass"`
KeyPem string `config:"key_pem"`
KeyFile string `config:"key_file"`
KeyFilePass string `config:"key_file_pass"`
PubKeyFile string `config:"pubkey_file"`
KnownHostsFile string `config:"known_hosts_file"`
KeyUseAgent bool `config:"key_use_agent"`
UseInsecureCipher bool `config:"use_insecure_cipher"`
DisableHashCheck bool `config:"disable_hashcheck"`
AskPassword bool `config:"ask_password"`
PathOverride string `config:"path_override"`
SetModTime bool `config:"set_modtime"`
ShellType string `config:"shell_type"`
Md5sumCommand string `config:"md5sum_command"`
Sha1sumCommand string `config:"sha1sum_command"`
SkipLinks bool `config:"skip_links"`
Subsystem string `config:"subsystem"`
ServerCommand string `config:"server_command"`
UseFstat bool `config:"use_fstat"`
DisableConcurrentReads bool `config:"disable_concurrent_reads"`
DisableConcurrentWrites bool `config:"disable_concurrent_writes"`
IdleTimeout fs.Duration `config:"idle_timeout"`
ChunkSize fs.SizeSuffix `config:"chunk_size"`
Concurrency int `config:"concurrency"`
Connections int `config:"connections"`
SetEnv fs.SpaceSepList `config:"set_env"`
Ciphers fs.SpaceSepList `config:"ciphers"`
KeyExchange fs.SpaceSepList `config:"key_exchange"`
MACs fs.SpaceSepList `config:"macs"`
HostKeyAlgorithms fs.SpaceSepList `config:"host_key_algorithms"`
SSH fs.SpaceSepList `config:"ssh"`
SocksProxy string `config:"socks_proxy"`
CopyIsHardlink bool `config:"copy_is_hardlink"`
}
// Fs stores the interface to the remote SFTP files
type Fs struct {
name string
root string
absRoot string
shellRoot string
shellType string
opt Options // parsed options
ci *fs.ConfigInfo // global config
m configmap.Mapper // config
features *fs.Features // optional features
config *ssh.ClientConfig
url string
mkdirLock *stringLock
cachedHashes *hash.Set
poolMu sync.Mutex
pool []*conn
drain *time.Timer // used to drain the pool when we stop using the connections
pacer *fs.Pacer // pacer for operations
savedpswd string
sessions atomic.Int32 // count in use sessions
tokens *pacer.TokenDispenser
}
// Object is a remote SFTP file that has been stat'd (so it exists, but is not necessarily open for reading)
type Object struct {
fs *Fs
remote string
size int64 // size of the object
modTime uint32 // modification time of the object as unix time
mode os.FileMode // mode bits from the file
md5sum *string // Cached MD5 checksum
sha1sum *string // Cached SHA1 checksum
}
// conn encapsulates an ssh client and corresponding sftp client
type conn struct {
sshClient sshClient
sftpClient *sftp.Client
err chan error
}
// Wait for connection to close
func (c *conn) wait() {
c.err <- c.sshClient.Wait()
}
// Send keepalives every interval over the ssh connection until done is closed
func (c *conn) sendKeepAlives(interval time.Duration) (done chan struct{}) {
done = make(chan struct{})
go func() {
t := time.NewTicker(interval)
defer t.Stop()
for {
select {
case <-t.C:
c.sshClient.SendKeepAlive()
case <-done:
return
}
}
}()
return done
}
// Closes the connection
func (c *conn) close() error {
sftpErr := c.sftpClient.Close()
sshErr := c.sshClient.Close()
if sftpErr != nil {
return sftpErr
}
return sshErr
}
// Returns an error if closed
func (c *conn) closed() error {
select {
case err := <-c.err:
return err
default:
}
return nil
}
// Show that we are using an ssh session
//
// Call removeSession() when done
func (f *Fs) addSession() {
f.sessions.Add(1)
}
// Show the ssh session is no longer in use
func (f *Fs) removeSession() {
f.sessions.Add(-1)
}
// getSessions shows whether there are any sessions in use
func (f *Fs) getSessions() int32 {
return f.sessions.Load()
}
// Open a new connection to the SFTP server.
func (f *Fs) sftpConnection(ctx context.Context) (c *conn, err error) {
// Rate limit rate of new connections
c = &conn{
err: make(chan error, 1),
}
if len(f.opt.SSH) == 0 {
c.sshClient, err = f.newSSHClientInternal(ctx, "tcp", f.opt.Host+":"+f.opt.Port, f.config)
} else {
c.sshClient, err = f.newSSHClientExternal()
}
if err != nil {
return nil, fmt.Errorf("couldn't connect SSH: %w", err)
}
c.sftpClient, err = f.newSftpClient(c.sshClient)
if err != nil {
_ = c.sshClient.Close()
return nil, fmt.Errorf("couldn't initialise SFTP: %w", err)
}
go c.wait()
return c, nil
}
// Set any environment variables on the ssh.Session
func (f *Fs) setEnv(s sshSession) error {
for _, env := range f.opt.SetEnv {
equal := strings.IndexRune(env, '=')
if equal < 0 {
return fmt.Errorf("no = found in env var %q", env)
}
// fs.Debugf(f, "Setting env %q = %q", env[:equal], env[equal+1:])
err := s.Setenv(env[:equal], env[equal+1:])
if err != nil {
return fmt.Errorf("failed to set env var %q: %w", env[:equal], err)
}
}
return nil
}
// Creates a new SFTP client on conn, using the specified subsystem
// or sftp server, and zero or more option functions
func (f *Fs) newSftpClient(client sshClient, opts ...sftp.ClientOption) (*sftp.Client, error) {
s, err := client.NewSession()
if err != nil {
return nil, err
}
err = f.setEnv(s)
if err != nil {
return nil, err
}
pw, err := s.StdinPipe()
if err != nil {
return nil, err
}
pr, err := s.StdoutPipe()
if err != nil {
return nil, err
}
if f.opt.ServerCommand != "" {
if err := s.Start(f.opt.ServerCommand); err != nil {
return nil, err
}
} else {
if err := s.RequestSubsystem(f.opt.Subsystem); err != nil {
return nil, err
}
}
opts = opts[:len(opts):len(opts)] // make sure we don't overwrite the callers opts
opts = append(opts,
sftp.UseFstat(f.opt.UseFstat),
sftp.UseConcurrentReads(!f.opt.DisableConcurrentReads),
sftp.UseConcurrentWrites(!f.opt.DisableConcurrentWrites),
sftp.MaxPacketUnchecked(int(f.opt.ChunkSize)),
sftp.MaxConcurrentRequestsPerFile(f.opt.Concurrency),
)
return sftp.NewClientPipe(pr, pw, opts...)
}
// Get an SFTP connection from the pool, or open a new one
func (f *Fs) getSftpConnection(ctx context.Context) (c *conn, err error) {
accounting.LimitTPS(ctx)
if f.opt.Connections > 0 {
f.tokens.Get()
}
f.poolMu.Lock()
for len(f.pool) > 0 {
c = f.pool[0]
f.pool = f.pool[1:]
err := c.closed()
if err == nil {
break
}
fs.Errorf(f, "Discarding closed SSH connection: %v", err)
c = nil
}
f.poolMu.Unlock()
if c != nil {
return c, nil
}
err = f.pacer.Call(func() (bool, error) {
c, err = f.sftpConnection(ctx)
if err != nil {
return true, err
}
return false, nil
})
if f.opt.Connections > 0 && c == nil {
f.tokens.Put()
}
return c, err
}
// Return an SFTP connection to the pool
//
// It nils the pointed to connection out so it can't be reused
//
// if err is not nil then it checks the connection is alive using a
// Getwd request
func (f *Fs) putSftpConnection(pc **conn, err error) {
if f.opt.Connections > 0 {
defer f.tokens.Put()
}
c := *pc
if !c.sshClient.CanReuse() {
return
}
*pc = nil
if err != nil {
// work out if this is an expected error
isRegularError := false
var statusErr *sftp.StatusError
var pathErr *os.PathError
switch {
case errors.Is(err, os.ErrNotExist):
isRegularError = true
case errors.As(err, &statusErr):
isRegularError = true
case errors.As(err, &pathErr):
isRegularError = true
}
// If not a regular SFTP error code then check the connection
if !isRegularError {
_, nopErr := c.sftpClient.Getwd()
if nopErr != nil {
fs.Debugf(f, "Connection failed, closing: %v", nopErr)
_ = c.close()
return
}
fs.Debugf(f, "Connection OK after error: %v", err)
}
}
f.poolMu.Lock()
f.pool = append(f.pool, c)
if f.opt.IdleTimeout > 0 {
f.drain.Reset(time.Duration(f.opt.IdleTimeout)) // nudge on the pool emptying timer
}
f.poolMu.Unlock()
}
// Drain the pool of any connections
func (f *Fs) drainPool(ctx context.Context) (err error) {
f.poolMu.Lock()
defer f.poolMu.Unlock()
if sessions := f.getSessions(); sessions != 0 {
fs.Debugf(f, "Not closing %d unused connections as %d sessions active", len(f.pool), sessions)
if f.opt.IdleTimeout > 0 {
f.drain.Reset(time.Duration(f.opt.IdleTimeout)) // nudge on the pool emptying timer
}
return nil
}
if f.opt.IdleTimeout > 0 {
f.drain.Stop()
}
if len(f.pool) != 0 {
fs.Debugf(f, "Closing %d unused connections", len(f.pool))
}
for i, c := range f.pool {
if cErr := c.closed(); cErr == nil {
cErr = c.close()
if cErr != nil {
fs.Debugf(f, "Ignoring error closing connection: %v", cErr)
}
}
f.pool[i] = nil
}
f.pool = nil
return nil
}
// NewFs creates a new Fs object from the name and root. It connects to
// the host specified in the config file.
func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, error) {
// This will hold the Fs object. We need to create it here
// so we can refer to it in the SSH callback, but it's populated
// in NewFsWithConnection
f := &Fs{
ci: fs.GetConfig(ctx),
}
// Parse config into Options struct
opt := new(Options)
err := configstruct.Set(m, opt)
if err != nil {
return nil, err
}
if len(opt.SSH) != 0 && ((opt.User != currentUser && opt.User != "") || opt.Host != "" || (opt.Port != "22" && opt.Port != "")) {
fs.Logf(name, "--sftp-ssh is in use - ignoring user/host/port from config - set in the parameters to --sftp-ssh (remove them from the config to silence this warning)")
}
f.tokens = pacer.NewTokenDispenser(opt.Connections)
if opt.User == "" {
opt.User = currentUser
}
if opt.Port == "" {
opt.Port = "22"
}
sshConfig := &ssh.ClientConfig{
User: opt.User,
Auth: []ssh.AuthMethod{},
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
Timeout: f.ci.ConnectTimeout,
ClientVersion: "SSH-2.0-" + f.ci.UserAgent,
}
if len(opt.HostKeyAlgorithms) != 0 {
sshConfig.HostKeyAlgorithms = []string(opt.HostKeyAlgorithms)
}
if opt.KnownHostsFile != "" {
hostcallback, err := knownhosts.New(env.ShellExpand(opt.KnownHostsFile))
if err != nil {
return nil, fmt.Errorf("couldn't parse known_hosts_file: %w", err)
}
sshConfig.HostKeyCallback = hostcallback
}
if opt.UseInsecureCipher && (opt.Ciphers != nil || opt.KeyExchange != nil) {
return nil, fmt.Errorf("use_insecure_cipher must be false if ciphers or key_exchange are set in advanced configuration")
}
sshConfig.Config.SetDefaults()
if opt.UseInsecureCipher {
sshConfig.Config.Ciphers = append(sshConfig.Config.Ciphers, "aes128-cbc", "aes192-cbc", "aes256-cbc", "3des-cbc")
sshConfig.Config.KeyExchanges = append(sshConfig.Config.KeyExchanges, "diffie-hellman-group-exchange-sha1", "diffie-hellman-group-exchange-sha256")
} else {
if opt.Ciphers != nil {
sshConfig.Config.Ciphers = opt.Ciphers
}
if opt.KeyExchange != nil {
sshConfig.Config.KeyExchanges = opt.KeyExchange
}
}
if opt.MACs != nil {
sshConfig.Config.MACs = opt.MACs
}
keyFile := env.ShellExpand(opt.KeyFile)
pubkeyFile := env.ShellExpand(opt.PubKeyFile)
//keyPem := env.ShellExpand(opt.KeyPem)
// Add ssh agent-auth if no password or file or key PEM specified
if (len(opt.SSH) == 0 && opt.Pass == "" && keyFile == "" && !opt.AskPassword && opt.KeyPem == "") || opt.KeyUseAgent {
sshAgentClient, _, err := sshagent.New()
if err != nil {
return nil, fmt.Errorf("couldn't connect to ssh-agent: %w", err)
}
signers, err := sshAgentClient.Signers()
if err != nil {
return nil, fmt.Errorf("couldn't read ssh agent signers: %w", err)
}
if keyFile != "" {
// If `opt.KeyUseAgent` is false, then it's expected that `opt.KeyFile` contains the private key
// and `${opt.KeyFile}.pub` contains the public key.
//
// If `opt.KeyUseAgent` is true, then it's expected that `opt.KeyFile` contains the public key.
// This is how it works with openssh; the `IdentityFile` in openssh config points to the public key.
// It's not necessary to specify the public key explicitly when using ssh-agent, since openssh and rclone
// will try all the keys they find in the ssh-agent until they find one that works. But just like
// `IdentityFile` is used in openssh config to limit the search to one specific key, so does
// `opt.KeyFile` in rclone config limit the search to that specific key.
//
// However, previous versions of rclone would always expect to find the public key in
// `${opt.KeyFile}.pub` even if `opt.KeyUseAgent` was true. So for the sake of backward compatibility
// we still first attempt to read the public key from `${opt.KeyFile}.pub`. But if it fails with
// an `fs.ErrNotExist` then we also try to read the public key from `opt.KeyFile`.
pubBytes, err := os.ReadFile(keyFile + ".pub")
if err != nil {
if errors.Is(err, iofs.ErrNotExist) && opt.KeyUseAgent {
pubBytes, err = os.ReadFile(keyFile)
if err != nil {
return nil, fmt.Errorf("failed to read public key file: %w", err)
}
} else {
return nil, fmt.Errorf("failed to read public key file: %w", err)
}
}
pub, _, _, _, err := ssh.ParseAuthorizedKey(pubBytes)
if err != nil {
return nil, fmt.Errorf("failed to parse public key file: %w", err)
}
pubM := pub.Marshal()
found := false
for _, s := range signers {
if bytes.Equal(pubM, s.PublicKey().Marshal()) {
sshConfig.Auth = append(sshConfig.Auth, ssh.PublicKeys(s))
found = true
break
}
}
if !found {
return nil, errors.New("private key not found in the ssh-agent")
}
} else {
sshConfig.Auth = append(sshConfig.Auth, ssh.PublicKeys(signers...))
}
}
// Load key file as a private key, if specified. This is only needed when not using an ssh agent.
if (keyFile != "" && !opt.KeyUseAgent) || opt.KeyPem != "" {
var key []byte
if opt.KeyPem == "" {
key, err = os.ReadFile(keyFile)
if err != nil {
return nil, fmt.Errorf("failed to read private key file: %w", err)
}
} else {
// wrap in quotes because the config is a coming as a literal without them.
opt.KeyPem, err = strconv.Unquote("\"" + opt.KeyPem + "\"")
if err != nil {
return nil, fmt.Errorf("pem key not formatted properly: %w", err)
}
key = []byte(opt.KeyPem)
}
clearpass := ""
if opt.KeyFilePass != "" {
clearpass, err = obscure.Reveal(opt.KeyFilePass)
if err != nil {
return nil, err
}
}
var signer ssh.Signer
if clearpass == "" {
signer, err = ssh.ParsePrivateKey(key)
} else {
signer, err = ssh.ParsePrivateKeyWithPassphrase(key, []byte(clearpass))
}
if err != nil {
return nil, fmt.Errorf("failed to parse private key file: %w", err)
}
// If a public key has been specified then use that
if pubkeyFile != "" {