M go.mod → go.mod

@@ -10,6 +10,7 @@ github.com/gorilla/handlers v1.5.1
 	github.com/gorilla/sessions v1.2.1
 	github.com/kr/pretty v0.2.1 // indirect
 	github.com/mattn/go-sqlite3 v1.14.6
+	github.com/pkg/sftp v1.12.0
 	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad
 	golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c // indirect
 	golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf // indirect

M go.sum → go.sum

@@ -2,6 +2,7 @@ git.sr.ht/~adnano/go-gemini v0.1.14-0.20210214021019-595b0d049034 h1:duv1TxH0cWtX8IVffgOKIjO0qaRAaDce2MlTCoqk6V4=
 git.sr.ht/~adnano/go-gemini v0.1.14-0.20210214021019-595b0d049034/go.mod h1:hQ75Y0i5jSFL+FQ7AzWVAYr5LQsaFC7v3ZviNyj46dY=
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/felixge/httpsnoop v1.0.1 h1:lvB5Jl89CsZtGIWuTcDM1E/vkVs49/Ml7JJe07l8SPQ=
 github.com/felixge/httpsnoop v1.0.1/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
 github.com/gorilla/feeds v1.1.1 h1:HwKXxqzcRNg9to+BbvJog4+f3s/xzvtZXICcQGutYfY=
@@ -12,6 +13,8 @@ github.com/gorilla/securecookie v1.1.1 h1:miw7JPhV+b/lAHSXz4qd/nN9jRiAFV5FwjeKyCS8BvQ=
 github.com/gorilla/securecookie v1.1.1/go.mod h1:ra0sb63/xPlUeL+yeDciTfxMRAA+MP+HVt/4epWDjd4=
 github.com/gorilla/sessions v1.2.1 h1:DHd3rPN5lE3Ts3D8rKkQ8x/0kqfeNmBAaiSi+o7FsgI=
 github.com/gorilla/sessions v1.2.1/go.mod h1:dk2InVEVJ0sfLlnXv9EAgkf6ecYs/i80K/zI+bUmuGM=
+github.com/kr/fs v0.1.0 h1:Jskdu9ieNAYnjxsi0LbQp1ulIKZV1LAFgK1tWhpZgl8=
+github.com/kr/fs v0.1.0/go.mod h1:FFnZGqtBN9Gxj7eW1uZ42v5BccTP0vu6NEaFoC2HwRg=
 github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
@@ -19,7 +22,15 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/mattn/go-sqlite3 v1.14.6 h1:dNPt6NO46WmLVt2DLNpwczCmdV5boIZ6g/tlDrlRUbg=
 github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pkg/sftp v1.12.0 h1:/f3b24xrDhkhddlaobPe2JgBqfdt+gC/NYl0QY9IOuI=
+github.com/pkg/sftp v1.12.0/go.mod h1:fUqqXB5vEgVCZ131L+9say31RAri6aF6KDViawhxKK8=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad h1:DN0cp81fZ3njFcrLCytUHRSUkqBjfTo4Tx9RJTWs0EY=
 golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 h1:0GoQqolDA55aaLxZyTzK/Y2ePZzZTUrRacwib7cNsYQ=
@@ -27,6 +38,7 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20210119194325-5f4716e94777 h1:003p0dJM77cxMSyCPFphvZf/Y5/NXf5fzg6ufd1/Oew=
 golang.org/x/net v0.0.0-20210119194325-5f4716e94777/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c h1:VwygUrnw9jn88c4u8GD3rZQbqrP/tgas88tPUbBxQrk=
@@ -43,3 +55,5 @@ golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/time v0.0.0-20201208040808-7e3f01d25324 h1:Hir2P/De0WpUhtrKGGjvSb2YxUgyZ7EFOSLIcSSpiwE=
 golang.org/x/time v0.0.0-20201208040808-7e3f01d25324/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

M main.go → main.go

@@ -49,6 +49,7 @@ }
 
 	switch args[0] {
 	case "serve":
+		runSFTPServer()
 		// s1.StartAsync()
 		wg := new(sync.WaitGroup)
 		wg.Add(2)

A sftp.go

@@ -0,0 +1,213 @@
+// An example SFTP server implementation using the golang SSH package.
+// Serves the whole filesystem visible to the user, and has a hard-coded username and password,
+// so not for real use!
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net"
+	"os"
+	"path"
+	"path/filepath"
+
+	"github.com/pkg/sftp"
+	"golang.org/x/crypto/ssh"
+)
+
+type Connection struct {
+	User string
+}
+
+func (con *Connection) Fileread(request *sftp.Request) (io.ReaderAt, error) {
+	// check user perms -- cant read others hidden files
+	fullpath := path.Join(c.FilesDirectory, filepath.Clean(request.Filepath))
+	f, err := os.Open(fullpath)
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+func (con *Connection) Filewrite(request *sftp.Request) (io.WriterAt, error) {
+	// check user perms -- cant write others files
+	fullpath := path.Join(c.FilesDirectory, filepath.Clean(request.Filepath))
+	f, err := os.Open(fullpath)
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+func (conn *Connection) Filelist(request *sftp.Request) (sftp.ListerAt, error) {
+	fullpath := path.Join(c.FilesDirectory, filepath.Clean(request.Filepath))
+	switch request.Method {
+	case "List":
+		f, err := os.Open(fullpath)
+		if err != nil {
+			return nil, err
+		}
+		fileInfo, err := f.Readdir(-1)
+		if err != nil {
+			return nil, err
+		}
+		return listerat(fileInfo), nil
+	case "Stat":
+		stat, err := os.Stat(fullpath)
+		if err != nil {
+			return nil, err
+		}
+		return listerat([]os.FileInfo{stat}), nil
+	}
+	return nil, fmt.Errorf("Invalid command")
+}
+
+func (c *Connection) Filecmd(request *sftp.Request) error {
+	// remove, rename, setstat? find out
+	return nil
+}
+
+// TODO hide hidden folders
+// Users have write persm on their files, read perms on all
+
+func buildHandlers(connection *Connection) sftp.Handlers {
+	return sftp.Handlers{
+		connection,
+		connection,
+		connection,
+		connection,
+	}
+}
+
+// Based on example server code from golang.org/x/crypto/ssh and server_standalone
+func runSFTPServer() {
+
+	var (
+		readOnly    bool
+		debugStderr bool
+	)
+
+	flag.BoolVar(&readOnly, "R", false, "read-only server")
+	flag.BoolVar(&debugStderr, "e", false, "debug to stderr")
+	flag.Parse()
+
+	debugStream := ioutil.Discard
+	if debugStderr {
+		debugStream = os.Stderr
+	}
+
+	// An SSH server is represented by a ServerConfig, which holds
+	// certificate details and handles authentication of ServerConns.
+	config := &ssh.ServerConfig{
+		// PublicKeyCallback
+		PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
+			// Should use constant-time compare (or better, salt+hash) in
+			// a production setting.
+			fmt.Fprintf(debugStream, "Login: %s\n", c.User())
+			if c.User() == "alex" && string(pass) == "alex" {
+				return nil, nil
+			}
+			return nil, fmt.Errorf("password rejected for %q", c.User())
+		},
+	}
+
+	privateBytes, err := ioutil.ReadFile("id_rsa")
+	if err != nil {
+		log.Fatal("Failed to load private key", err)
+	}
+
+	private, err := ssh.ParsePrivateKey(privateBytes)
+	if err != nil {
+		log.Fatal("Failed to parse private key", err)
+	}
+
+	config.AddHostKey(private)
+
+	// Once a ServerConfig has been configured, connections can be
+	// accepted.
+	listener, err := net.Listen("tcp", "0.0.0.0:2024")
+	if err != nil {
+		log.Fatal("failed to listen for connection", err)
+	}
+	fmt.Printf("Listening on %v\n", listener.Addr())
+
+	nConn, err := listener.Accept()
+	if err != nil {
+		log.Fatal("failed to accept incoming connection", err)
+	}
+
+	// Before use, a handshake must be performed on the incoming net.Conn.
+	sconn, chans, reqs, err := ssh.NewServerConn(nConn, config)
+	if err != nil {
+		log.Fatal("failed to handshake", err)
+	}
+	log.Println("login detected:", sconn.User())
+	fmt.Fprintf(debugStream, "SSH server established\n")
+
+	// The incoming Request channel must be serviced.
+	go ssh.DiscardRequests(reqs)
+
+	// Service the incoming Channel channel.
+	for newChannel := range chans {
+		// Channels have a type, depending on the application level
+		// protocol intended. In the case of an SFTP session, this is "subsystem"
+		// with a payload string of "<length=4>sftp"
+		fmt.Fprintf(debugStream, "Incoming channel: %s\n", newChannel.ChannelType())
+		if newChannel.ChannelType() != "session" {
+			newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
+			fmt.Fprintf(debugStream, "Unknown channel type: %s\n", newChannel.ChannelType())
+			continue
+		}
+		channel, requests, err := newChannel.Accept()
+		if err != nil {
+			log.Fatal("could not accept channel.", err)
+		}
+		fmt.Fprintf(debugStream, "Channel accepted\n")
+
+		// Sessions have out-of-band requests such as "shell",
+		// "pty-req" and "env".  Here we handle only the
+		// "subsystem" request.
+		go func(in <-chan *ssh.Request) {
+			for req := range in {
+				fmt.Fprintf(debugStream, "Request: %v\n", req.Type)
+				ok := false
+				switch req.Type {
+				case "subsystem":
+					fmt.Fprintf(debugStream, "Subsystem: %s\n", req.Payload[4:])
+					if string(req.Payload[4:]) == "sftp" {
+						ok = true
+					}
+				}
+				fmt.Fprintf(debugStream, " - accepted: %v\n", ok)
+				req.Reply(ok, nil)
+			}
+		}(requests)
+		connection := Connection{"alex"}
+		root := buildHandlers(&connection)
+		server := sftp.NewRequestServer(channel, root)
+		if err := server.Serve(); err == io.EOF {
+			server.Close()
+			log.Print("sftp client exited session.")
+		} else if err != nil {
+			log.Fatal("sftp server completed with error:", err)
+		}
+	}
+}
+
+type listerat []os.FileInfo
+
+// Modeled after strings.Reader's ReadAt() implementation
+func (f listerat) ListAt(ls []os.FileInfo, offset int64) (int, error) {
+	var n int
+	if offset >= int64(len(f)) {
+		return 0, io.EOF
+	}
+	n = copy(ls, f[offset:])
+	if n < len(ls) {
+		return n, io.EOF
+	}
+	return n, nil
+}