SSH_AUTH_METHOD_PASSWORD does not seem to be working

[bschulth]

• There seems to be a problem with SSH_AUTH_METHOD_PASSWORD...it fails to authenticate in this block of code:
  • https://github.com/ropensci/ssh/blob/master/src/session.c#L102-L120
• When I change this function:

/* authenticate client */
static void auth_or_disconnect(ssh_session ssh, ssh_key privkey, SEXP rpass, const char *user){
  if(ssh_userauth_none(ssh, NULL) == SSH_AUTH_SUCCESS)
    return;
  int method = ssh_userauth_list(ssh, NULL);
  if (method & SSH_AUTH_METHOD_PUBLICKEY){
    if(privkey != NULL && ssh_userauth_publickey(ssh, NULL, privkey) == SSH_AUTH_SUCCESS)
      return;
    // ssh_userauth_publickey_auto() tries both ssh-agent and standard keys in ~/.ssh
    // it also automatically picks up SSH_ASKPASS env var set by 'askpass' package
    if(privkey == NULL && ssh_userauth_publickey_auto(ssh, NULL, NULL) == SSH_AUTH_SUCCESS)
      return;
  }
  if (method & SSH_AUTH_METHOD_INTERACTIVE && auth_interactive(ssh, rpass, user) == SSH_AUTH_SUCCESS)
    return;
  if (method & SSH_AUTH_METHOD_PASSWORD && auth_password(ssh, rpass, user) == SSH_AUTH_SUCCESS)
    return;
  ssh_disconnect(ssh);
  Rf_errorcall(R_NilValue, "Authentication with ssh server failed");
}

• To have a retry loop, it works on second attempt. Not sure if this is a timeout issue or not waiting for a socket response.

/* authenticate client */
static void auth_or_disconnect(ssh_session ssh, ssh_key privkey, SEXP rpass, const char *user){
  if(ssh_userauth_none(ssh, NULL) == SSH_AUTH_SUCCESS)
    return;
  int method = ssh_userauth_list(ssh, NULL);
  if (method & SSH_AUTH_METHOD_PUBLICKEY){
    if(privkey != NULL && ssh_userauth_publickey(ssh, NULL, privkey) == SSH_AUTH_SUCCESS)
      return;
    // ssh_userauth_publickey_auto() tries both ssh-agent and standard keys in ~/.ssh
    // it also automatically picks up SSH_ASKPASS env var set by 'askpass' package
    if(privkey == NULL && ssh_userauth_publickey_auto(ssh, NULL, NULL) == SSH_AUTH_SUCCESS)
      return;
  }
  if (method & SSH_AUTH_METHOD_INTERACTIVE && auth_interactive(ssh, rpass, user) == SSH_AUTH_SUCCESS)
    return;
  // CHANGE START+++++++++++++++++++++++++++++++++++++
  if (method & SSH_AUTH_METHOD_PASSWORD) {
    int tries;
    int rc;
    rc = SSH_AUTH_AGAIN;
    while (rc != SSH_AUTH_SUCCESS) {
      tries += 1;
      REprintf("\nTrying password...via auth_password...attempt %i\n", tries);
      rc = auth_password(ssh, rpass, user);
      REprintf("   rc = %i\n", rc);
      if (rc == SSH_AUTH_SUCCESS) {
        return;
      }
      if (tries > 5) {
        break;
      }
    }
  }
  // CHANGE END+++++++++++++++++++++++++++++++++++++
  ssh_disconnect(ssh);
  Rf_errorcall(R_NilValue, "Authentication with ssh server failed");
}

• Example output from my tweaked code:

ssh_userauth_publickey_auto: Private key /home/bschulth/.ssh/identity doesn't exist.
ssh_userauth_publickey_auto: Tried every public key, none matched

Trying password...via auth_password...attempt 1
ssh_socket_unbuffered_write: Enabling POLLOUT for socket
packet_send2: packet: wrote [len=76,padding=19,comp=56,payload=56]
ssh_socket_pollcallback: Poll callback on socket 29 (POLLOUT ), out buffer 0
ssh_socket_pollcallback: sending control flow event
ssh_packet_socket_controlflow_callback: sending channel_write_wontblock callback
   rc = 1

Trying password...via auth_password...attempt 2
ssh_socket_pollcallback: Poll callback on socket 29 (POLLIN ), out buffer 0
ssh_packet_socket_callback: packet: read type 52 [len=12,padding=10,comp=1,payload=1]
ssh_packet_process: Dispatching handler for packet type 52
ssh_packet_userauth_success: Authentication successful
ssh_packet_userauth_success: Received SSH_USERAUTH_SUCCESS
   rc = 0