Short:        SSH2 server and client suite with SFTP
Author:       Stefan Franke (BebboSSH), Michele Dipace (AROS port)
Uploader:     michele dipace kaffeine net (Michele Dipace)
Type:         comm/net
Version:      1.0.6
Replaces:     comm/net/bebbossh.x86_64-aros.lha
Requires:     AROS One x86_64 (ABIv11) with a TCP/IP stack (AROSTCP)
Architecture: i386-aros

WHAT IS THIS?

BebboSSH is an SSH2 implementation for Amiga systems by Stefan "Bebbo"
Franke. This archive is its port to
AROS x86_64 (AROS One 64-bit, ABIv11).
With it you can log in to an AROS machine from any SSH client, run
commands, and copy files with scp and sftp; the native clients connect
from AROS to other SSH servers. The original 68k version is
comm/net/bebbossh.lha;
the AROS i386 build is comm/net/bebbossh.i386-aros.lha,
the AROS aarch64 build is comm/net/bebbossh.aarch64-aros.lha.

PROGRAMS

  bebbosshd       SSH2 server: remote commands, SFTP, SCP, TCP port
                  forwarding (direct-tcpip), password and public-key login
  bebbossh        SSH2 client, with -L local port forwarding
  bebboscp        SCP client
  bebbosshkeygen  Ed25519 key generator

Algorithms: curve25519-sha256 key exchange, ssh-ed25519 host and user
keys, aes128-gcm@openssh.com and chacha20-poly1305@openssh.com ciphers.
AES-GCM uses AES-NI and PCLMULQDQ when the CPU provides them.

REQUIREMENTS

- AROS One x86_64 (ABIv11).
- A configured TCP/IP stack (AROSTCP, bsdsocket.library).
- No extra libraries: the crypto code is linked into each program.
- In a virtual machine, use an rtl8139 or pcnet network card, not
  e1000 (see KNOWN LIMITS).

CONTENTS

  BebboSSH/bebbosshd, bebbossh, bebboscp, bebbosshkeygen
  BebboSSH/sshd_config.example, passwd.example
  BebboSSH/README.AROS.txt   install and configuration guide
  BebboSSH/README.md, AROS_PORTING.md, docs/, scripts/
  BebboSSH/COPYING, LICENSE  license texts (GNU GPL v3)
  BebboSSH/SHA256SUMS        checksums of the files above

INSTALLATION

1. Extract the archive to a persistent volume, for example DH0:.
2. In an AROS Shell, create the configuration and a host key:

     cd DH0:BebboSSH
     copy sshd_config.example sshd_config
     copy passwd.example passwd
     bebbosshkeygen -f ssh_host_ed25519_key

3. Edit passwd: one "username password" pair per line. The test/test
   entry of the example is for a first test only; replace it.
4. Start the server:

     stack 262144
     bebbosshd

5. From another machine: ssh username@<address of the AROS machine>

To start the server at boot, add these lines to S:User-Startup:

  Stack 262144
  If EXISTS DH0:BebboSSH/bebbosshd
      Run DH0:BebboSSH/bebbosshd
  EndIf

To call the clients from anywhere, copy bebbossh, bebboscp and
bebbosshkeygen to C:. Keep bebbosshd in its own directory: the example
configuration finds its files through PROGDIR:.

CONFIGURATION

bebbosshd reads ENVARC:ssh/sshd_config if it exists, otherwise
PROGDIR:sshd_config. The main directives of the example:

  Port 22                 TCP port
  ListenAddress 0.0.0.0   address to listen on (0.0.0.0 = all)
  HostKey PROGDIR:ssh_host_ed25519_key
  Passwords PROGDIR:passwd
  HomeDir DH0:            start directory of commands and SFTP
                          (on x86_64 only with BEBBOSSH_AROS_X64_CD set)
  Stack 262144            stack of command tasks (default 1 MiB)
  DebugLevel 1            log level: 0 none to 8 ultra, or a name such
                          as error or debug
  SendNoop some           keepalive messages to idle sessions
  Ciphers aes128-gcm@openssh.com,chacha20-poly1305@openssh.com
                          ciphers offered (both by default)
  AllowTcpForwarding yes  direct-tcpip forwarding (ssh -L); no refuses it

Command-line options override the file: -p port, -A password file,
-K host key, -H home directory, -v log level (for example -v5).
Public-key login reads ENVARC:.ssh/authorized_keys (OpenSSH format,
one key per line). README.AROS.txt describes every file in detail.

USAGE

From a PC with OpenSSH:

  ssh user@aros-host version
  scp file.txt user@aros-host:DH0:
  sftp user@aros-host

From AROS:

  bebbossh user@host
  bebbossh -i DH0:keys/id_ed25519 user@host command
  bebbossh -L 8080:localhost:80 user@host
  bebboscp localfile user@host:remotefile
  bebbosshkeygen -f DH0:keys/id_ed25519

The first connection to a host asks, in a console window, whether to
trust its key: answer yes. The key is then kept in
ENVARC:.ssh/known_hosts. Without a console (for example in a remote
command) an unknown host is refused. A host whose key differs from the
stored one is always refused with a warning; if the change is
expected, remove its line from known_hosts.

KNOWN LIMITS

- No full interactive PTY programs: the interactive shell runs simple
  commands, and programs that read their input are rejected with exit
  status 2.
- No redirection or pipes (>, <, |) in remote commands.
- Remote commands run one at a time and block the server until they
  end, also when typed in an interactive session, and Ctrl-C does not
  stop them: keep them short.
- An SFTP path on a volume that is not mounted opens an "insert
  volume" requester and blocks the server until it is closed.
- With an Intel e1000 network card and heavy network load, AROS One
  x86_64 can halt or reboot. The cause is the AROS e1000.device; it is
  fixed upstream (deadwood2/AROS issue 274). Until AROS One ships the
  fix, use an rtl8139 or pcnet card.
- Some features are off unless set before starting bebbosshd
  (setenv NAME 1): BEBBOSSH_AROS_X64_CD (cd and pwd in the interactive
  shell), BEBBOSSH_AROS_X64_SFTP_MTIME (keep upload times),
  BEBBOSSH_AROS_X64_SFTP_LINKS (SFTP readlink and symlink).
- OpenSSH "put -p" sets the file time before it closes the file, and
  AROS updates the date on close, so that time is not kept.
- passwd.example contains a test password: change it.

WHAT IS NEW IN 1.0.6

- Security fixes ported from bebbossh 1.46.1, an unofficial build by
  Matthias Muench: the server accepts only login requests until a
  client has logged in, and a public-key query without a signature no
  longer logs in; packet parsing in the server and in the clients is
  bounded to the received packet; SFTP requests are bounds-checked;
  the Ed25519 code and bebbosshkeygen no longer write out of bounds;
  authentication tags are compared in constant time, and the clients
  wipe their keys on exit. Updating is recommended.
- The clients refuse a host whose key changed, and ask about an
  unknown host only in a console window.
- New sshd_config directive AllowTcpForwarding (default yes).
- Uploads of 2 MiB or more with scp or sftp no longer stop at 2 MiB.

TESTED

On AROS One x86_64 under QEMU with an rtl8139 card, with the programs
of this archive: OpenSSH ssh, scp and sftp; 100 logins in a row; 80
file transfers without pauses; two servers at once; Ctrl-C and
restart; a connection dropped during an interactive command; TAB
completion; uploads up to 16 MiB; the login and host key checks of
this release; the native clients, also on the AROS console; with
and without AES-NI.

SOURCE AND LICENSE

GNU GPL v3 or later (see COPYING). Source of this release:
  https://github.com/kaffeine1/bebbossh-aros/tree/v1.0.6-aros-x86_64
Original BebboSSH: https://franke.ms/git/bebbo/bebbossh
Bug reports: https://github.com/kaffeine1/bebbossh-aros/issues

Port by Michele Dipace <michele.dipace@kaffeine.net>.