SFTPGo

Full featured and highly configurable SFTP server software

Features

• Each account is chrooted to his Home Dir
• SFTP accounts are virtual accounts stored in a "data provider"
• SQLite, MySQL and PostgreSQL data providers are supported. The Provider interface could be extended to support non SQL backends too
• Public key and password authentication
• Quota support: accounts can have individual quota expressed as max number of files and max total size
• Bandwidth throttling is supported, with distinct settings for upload and download
• Per user maximum concurrent sessions
• Per user permissions: list directories content, upload, download, delete, rename, create directories, create symlinks can be enabled or disabled
• Per user files/folders ownership: you can map all the users to the system account that runs SFTPGo (all platforms are supported) or you can run SFTPGo as root user and map each user or group of users to a different system account (*NIX only)
• Configurable custom commands and/or HTTP notifications on SFTP upload, download, delete or rename
• REST API for users and quota management and real time reports for the active connections with possibility of forcibly closing a connection
• Log files are accurate and they are saved in the easily parsable JSON format
• Automatically terminating idle connections

Platforms

SFTPGo is developed and tested on Linux, regularly the test cases are executed and pass on macOS and Windows. Other UNIX variants such as *BSD should work too.

Requirements

• Go 1.12 or higher
• A suitable SQL server to use as data provider: MySQL (4.1+) or SQLite 3.x or PostreSQL (9+)

Installation

Simple install the package to your $GOPATH with the go tool from shell:

$ go get -u github.com/drakkan/sftpgo

Make sure Git is installed on your machine and in your system's PATH.

A systemd sample service can be found inside the source tree.

Alternately you can use distro packages:

• Arch Linux PKGBUILD is available on AUR

Configuration

The sftpgo executable supports the following command line flags:

• -config-dir string. Location of the config dir. This directory should contain the sftpgo.conf configuration file, the private key for the SFTP server (id_rsa file) and the SQLite database if you use SQLite as data provider. The server private key will be autogenerated if the user that executes SFTPGo has write access to the config-dir. The default value is "."
• -log-file-path string. Location for the log file, default "sftpgo.log"

Before starting sftpgo a dataprovider must be configured.

Sample SQL scripts to create the required database structure can be found insite the source tree sql directory.

The sftpgo.conf configuration file contains the following sections:

• "sftpd", the configuration for the SFTP server
  • bind_port, integer the port used for serving SFTP requests. Default: 2022
  • bind_address, string. Leave blank to listen on all available network interfaces. Default: ""
  • idle_timeout, integer. Time in minutes after which an idle client will be disconnected. Default: 15
  • max_auth_tries integer. Maximum number of authentication attempts permitted per connection. If set to a negative number, the number of attempts are unlimited. If set to zero, the number of attempts are limited to 6.
  • umask, string. Umask for the new files and directories. This setting has no effect on Windows. Default: "0022"
  • actions, struct. It contains the command to execute and/or the HTTP URL to notify and the trigger conditions
    • execute_on, list of strings. Valid values are download, upload, delete, rename. On folder deletion a delete notification will be sent for each deleted file. Leave empty to disable actions.
    • command, string. Absolute path to the command to execute. Leave empty to disable. The command is invoked with the following arguments:
      • action, any valid execute_on string
      • username, user who did the action
      • path to the affected file. For rename action this is the old file name
      • target_path, non empty for rename action, this is the new file name
    • http_notification_url, a valid URL. An HTTP GET request will be executed to this URL. Leave empty to disable. The query string will contain the following parameters that have the same meaning of the command's arguments:
      • action
      • username
      • path
      • target_path, added for rename action only
• "data_provider", the configuration for the data provider
  • driver, string. Supported drivers are sqlite, mysql, postgresql
  • name, string. Database name
  • host, string. Database host. Leave empty for driver sqlite
  • port, integer. Database port. Leave empty for driver sqlite
  • username, string. Database user. Leave empty for driver sqlite
  • password, string. Database password. Leave empty for driver sqlite
  • sslmode, integer. Used for drivers mysql and postgresql. 0 disable SSL/TLS connections, 1 require ssl, 2 set ssl mode to verify-ca for driver postgresql and skip-verify for driver mysql, 3 set ssl mode to verify-full for driver postgresql and preferred for driver mysql
  • connectionstring, string. Provide a custom database connection string. If not empty this connection string will be used instead of build one using the previous parameters
  • users_table, string. Database table for SFTP users
  • manage_users, integer. Set to 0 to disable users management, 1 to enable
  • track_quota, integer. Set to 0 to disable quota tracking, 1 to update the used quota each time a user upload or delete a file
• "httpd", the configuration for the HTTP server used to serve REST API
  • bind_port, integer the port used for serving HTTP requests. Default: 8080
  • bind_address, string. Leave blank to listen on all available network interfaces. Default: "127.0.0.1"

Here is a full example showing the default config:

   "sftpd":{
        "bind_port":2022,
        "bind_address":"",
        "idle_timeout":15,
        "max_auth_tries":0,
        "umask":"0022",
        "actions":{
            "execute_on":[],
            "command":"",
            "http_notification_url":""
        }
   },
   "data_provider":{
        "driver":"sqlite",
        "name":"sftpgo.db",
        "host":"",
        "port":5432,
        "username":"",
        "password":"",
        "sslmode":0,
        "connection_string":"",
        "users_table":"users",
        "manage_users":1,
        "track_quota":1
    },
    "httpd":{
        "bind_port":8080,
        "bind_address":"127.0.0.1"
    }
}

Account's configuration properties

For each account the following properties can be configured:

• username
• password used for password authentication. The password will be stored using argon2id hashing algo
• public_key used for public key authentication. At least one between password and public key is mandatory
• home_dir The user cannot upload or download files outside this directory. Must be an absolute path
• uid, gid. If sftpgo runs as root then the created files and directories will be assigned to this system uid/gid. Ignored on windows and if sftpgo runs as non root user: in this case files and directories for all SFTP users will be owned by the system user that runs sftpgo.
• max_sessions maximum concurrent sessions. 0 means unlimited
• quota_size maximum size allowed. 0 means unlimited
• quota_files maximum number of files allowed. 0 means unlimited
• permissions the following permissions are supported:
  • * all permission are granted
  • list list items is allowed
  • download download files is allowed
  • upload upload files is allowed
  • delete delete files or directories is allowed
  • rename rename files or directories is allowed
  • create_dirs create directories is allowed
  • create_symlinks create links is allowed
• upload_bandwidth maximum upload bandwidth as KB/s, 0 means unlimited
• download_bandwidth maximum download bandwidth as KB/s, 0 means unlimited

These properties are stored inside the data provider. If you want to use your existing accounts, you can create a database view. Since a view is read only, you have to disable user management and quota tracking so sftpgo will never try to write to the view.

REST API

SFTPGo exposes REST API to manage users and quota and to get real time reports for the active connections with possibility of forcibly closing a connection.

If quota tracking is enabled in sftpgo.conf configuration file, then the used size and number of files are updated each time a file is added/removed. If files are added/removed not using SFTP, you can rescan the user home dir and update the used quota using the REST API.

REST API is designed to run on localhost or on a trusted network, if you need https or authentication you can setup a reverse proxy using an HTTP Server such as Apache or NGNIX.

The OpenAPI 3 schema for the exposed API can be found inside the source tree: openapi.yaml.

Logs

Inside the log file each line is a JSON struct, each struct has a sender fields that identify the log type.

The logs can be divided into the following categories:

• "app logs", internal logs used to debug sftpgo:
  • sender string. This is generally the package name that emits the log
  • time string. Date/time with millisecond precision
  • level string
  • message string
• "transfer logs", SFTP transfer logs:
  • sender string. SFTPUpload or SFTPDownload
  • time string. Date/time with millisecond precision
  • level string
  • elapsed_ms, int64. Elapsed time, as milliseconds, for the upload/download
  • size_bytes, int64. Size, as bytes, of the download/upload
  • username, string
  • file_path string
  • connection_id string. Unique SFTP connection identifier
• "command logs", SFTP command logs:
  • sender string. SFTPRename, SFTPRmdir, SFTPMkdir, SFTPSymlink, SFTPRemove
  • level string
  • username, string
  • file_path string
  • target_path string
  • connection_id string. Unique SFTP connection identifier
• "http logs", REST API logs:
  • sender string. httpd
  • level string
  • remote_addr string. IP and port of the remote client
  • proto string, for example HTTP/1.1
  • method string. HTTP method (GET, POST, PUT, DELETE etc.)
  • user_agent string
  • uri string. Full uri
  • resp_status integer. HTTP response status code
  • resp_size integer. Size in bytes of the HTTP response
  • elapsed_ms int64. Elapsed time, as milliseconds, to complete the request
  • request_id string. Unique request identifier

Acknowledgements

• pkg/sftp
• go-chi
• zerolog
• lumberjack
• argon2id
• go-sqlite3
• go-sql-driver/mysql
• lib/pq

Some code was initially taken from Pterodactyl sftp server

License

GNU GPLv3