server.lua

local TEMP_FILE_PATH = "/scripts/ssh/.temp"

local localPrint = print
local oldPull = os.pullEvent
os.pullEvent = os.pullEventRaw
print = myPrint
function myPrint(str)
 local file = io.open(TEMP_FILE_PATH, "a")
 file:write(str.."\n")
 file:close()
end


local activeConnections = {}

function authenticateUser(username, password)
 return true
end

function waitForTermination()
 sleep(1)
 print("Enter the root password to terminate")
 while true do
  local password = read("*")
  if password == "teste" then
   localPrint("Session ended")
   return
  else
  localPrint("Wrong password")
  end
 end
end

function waitForConnections()
 local senderID, message = rednet.receive("ssh")
 local i = string.find(message, "|")
 if i ~= nil then
  local username = string.sub(message, 1, i-1)
  local password = string.sub(message, i+1)
  if authenticateUser(username, password) then
   rednet.send(senderID, {true, "Access granted"}, "ssh")
   localPrint("Client with id "..senderID.." connected")
   return senderID
  else
   rednet.send(senderID, {false,""}, "ssh")
   localPrint("Client with id "..senderID.." was not authorized")
   return waitForConnections()
  end
 else
  rednet.send(senderID, {false, "Wrong message format"}, "ssh")
  return waitForConnections()
 end
end

function shellServer()
 local clientID = nil
 rednet.open("left")
 localPrint("Running SSH host")
 clientID = waitForConnections()
 while true do
  local file = io.open(TEMP_FILE_PATH, "w")
  file:close()
  local senderID, command = rednet.receive("ssh")
  if senderID == clientID then
   --rednet.send(senderID, {true, "Access authorized"}, "ssh")
   shell.run(command)
   file = io.open(TEMP_FILE_PATH, "r")
   local content = file:read("*a")
   rednet.send(senderID, {true, content}, "ssh")
  else
   rednet.send(senderID, {false, "Access not authorized"}, "ssh")
  end
 end
end

parallel.waitForAny(waitForTermination, shellServer)

print = localPrint
os.pullEvent = oldPull