Merge pull request 'issue-2 Resolves #2' (#4) from issue-2 into main

Reviewed-on: #4

tg_client/tg_client.lua

@@ -15,18 +15,16 @@ local function establish_connection()
     for _, side in ipairs(peripherals) do
         if peripheral.getType(side) == "modem" then
             rednet.open(side)
-            print("Opened modem: "..side)
             return true
         end
     end
-    print("No modem found!")
     return false
 end
 
 function validate_clearance(computer_id, clearance_level)
     if establish_connection() then
-        tg_server_id = rednet.lookup("tg", tg_server_name)
+        tg_server_id = rednet.lookup('tg', tg_server_name)
-        rednet.send(tg_server_id, "validate_clearance,"..computer_id..","..clearance_level)
+        rednet.send(tg_server_id, "validate_clearance,"..computer_id..","..clearance_level,"tg")
         local id, msg, proto = rednet.receive("tg")
         if msg == "granted" then
             return true
@@ -41,11 +39,11 @@ end
 function validate_key(minimum_clearance)
     if establish_connection() then
         if fs.exists("/disk/key") then
-            key_file = fs.open("/disk/key","r")
+            local key_file = fs.open("/disk/key","r")
-            key = key_file.readLine()
+            local key = key_file.readLine()
             tg_server_id = rednet.lookup('tg', tg_server_name)
             rednet.send(tg_server_id, "validate_key,"..key..","..minimum_clearance, "tg")
-            id, msg, _ = rednet.receive("tg")
+            local id, msg, _ = rednet.receive("tg")
             if msg == "authentication successful" then
                 return true
             else
@@ -59,27 +57,40 @@ function validate_key(minimum_clearance)
     end
 end
 
-if fs.exists('/disk/key') then
+function authenticate()
-    key_file = fs.open('/disk/key', 'r')
+    if fs.exists('/disk/key') then
-    key = key_file.readLine()
+        local key_file = fs.open('/disk/key', 'r')
-    if establish_connection() then
+        local key = key_file.readLine()
-        tg_server_id = rednet.lookup("tg", tg_server_name)
+        if establish_connection() then
-        rednet.send(tg_server_id, "authenticate,"..key,"tg")
+            tg_server_id = rednet.lookup("tg", tg_server_name)
-        local id, msg, proto = rednet.receive("tg")
+            rednet.send(tg_server_id, "authenticate,"..key,"tg")
+            local id, msg, proto = rednet.receive("tg")
 
-        if msg == "authentication successful" then
+            if msg == "authentication successful" then
-            key_parts = split(key,',')
+                local key_parts = split(key,',')
-            local card_holder = key_parts[1]
+                local card_holder = key_parts[1]
-            local card_clearance = key_parts[2]
+                local card_clearance = key_parts[2]
-            print("Authentication was successful.")
+                return true, _, card_holder, card_clearance
-            print("Hello "..card_holder..", you were granted clearance level "..card_clearance.." for this computer.")
+            else
+                print("Authentication failed.")
+                return false, "authentication failed"
+            end
         else
-            print("Authentication failed.")
+            return false, "modem not found"
         end
+        key_file.close()
     else
-        return false, "modem not found"
+        print("Key file not found. Aborting.")
+        return false, "key file not found"
+    end
+end
+
+if args[1] == "auth" or args[1] == "authenticate" then
+    local success, error, card_holder, card_clearance = authenticate()
+    if success then
+        print("Authentication was successful.")
+        print("Hello "..card_holder..", you were granted clearance level "..card_clearance.." for this computer.")
+    else
+        print("Authentication failed: "..error)
     end
-    key_file.close()
-else
-    print("Key file not found. Aborting.")
 end

tg_server/hash.lua

@@ -0,0 +1,7 @@
+function hash(str)
+    local hash = 0
+    for i = 1, #str do
+        hash = (hash * 31 + string.byte(str, i)) % 65536
+    end
+    return string.format("%04X", hash)
+end

tg_server/taskguard.cfg

@@ -1,7 +1,7 @@
 local config = {
     name = "tg_server",
     modem_side = "top",
-    clearance_expiry = 600, -- Minutes until clearance will expire
+    clearance_expiry = 600, -- Seconds until clearance will expire
     key_file = "verified_keys.txt", -- Name of the key file, relative to tg_server.lua
 }
 return config

tg_server/tg_server.lua

@@ -1,9 +1,10 @@
 local fullPath = shell.getRunningProgram()
 local dir = fullPath:match("^(.*/)") or ""
+local args = {...}
 
 local config = dofile(dir..'taskguard.cfg')
 
-local clearances = { { computer_id = 1, clearance_level = 1, time_granted = os.clock() } }
+local clearances = { } -- { computer_id = 1, clearance_level = 1, time_granted = os.clock() }
 
 local function split(str, divider)
     local t = {}
@@ -13,14 +14,7 @@ local function split(str, divider)
     return t
 end
 
-local function hash(str)
+dofile(dir..'hash.lua')
-    local hash = 0
-    for i = 1, #str do
-        hash = (hash * 31 + string.byte(str, i)) % 65536
-    end
-    return string.format("%04X", hash)
-end
-
 
 local function check_for_outdated_sessions()
     local expired = 0
@@ -57,62 +51,98 @@ local function validate_key(card_holder, card_clearance, random_chars)
     end
 end
 
-rednet.open(config.modem_side)
+if args[1] == "serve" then
-rednet.host('tg', config.name)
+    rednet.open(config.modem_side)
-print("Server started, waiting for requests...")
+    rednet.host('tg', config.name)
+    print("Server started, waiting for requests...")
+    while true do
+        local id, msg, proto = rednet.receive('tg')
+        check_for_outdated_sessions()
+        msg_parts = split(msg, ',')
+        if msg_parts[1] == 'validate_clearance' then
+            print("Beginning transaction for clearance query with "..id)
+            local target_id = tonumber(msg_parts[2])
+            local requested_clearance = tonumber(msg_parts[3])
+            local has_clearance = false
 
-while true do
+            for i, entry in ipairs(clearances) do
-    local id, msg, proto = rednet.receive('tg')
+                if entry.computer_id == target_id and entry.clearance_level >= requested_clearance then
-    check_for_outdated_sessions()
+                    -- Auth granted
-    msg_parts = split(msg, ',')
+                    rednet.send(id, 'granted', 'tg')
-    if msg_parts[1] == 'validate_clearance' then
+                    print('Finished transaction, granted')
-        print("Beginning transaction for clearance query with "..id)
+                    has_clearance = true
-        local target_id = tonumber(msg_parts[2])
+                end
-        local requested_clearance = tonumber(msg_parts[3])
-        local has_clearance = false
-
-        for i, entry in ipairs(clearances) do
-            if entry.computer_id == target_id and entry.clearance_level >= requested_clearance then
-                -- Auth granted
-                rednet.send(id, 'granted', 'tg')
-                print('Finished transaction, granted')
-                has_clearance = true
             end
-        end
 
-        if has_clearance == false then
+            if has_clearance == false then
-            -- Auth not granted
+                -- Auth not granted
-            rednet.send(id, 'failed', 'tg')
+                rednet.send(id, 'failed', 'tg')
-            print('Finished transaction, failed')
+                print('Finished transaction, failed')
-        end
+            end
-        print("EOP")
+            print("EOP")
-    elseif  msg_parts[1] == 'authenticate' then
+        elseif  msg_parts[1] == 'authenticate' then
-        print("Beginning transaction for authentication with "..id)
+            print("Beginning transaction for authentication with "..id)
-        local card_holder = msg_parts[2]
+            local card_holder = msg_parts[2]
-        local card_clearance = msg_parts[3]
+            local card_clearance = msg_parts[3]
 
-        local is_authentic, card_hash = validate_key(card_holder, card_clearance, msg_parts[4])
+            local is_authentic, card_hash = validate_key(card_holder, card_clearance, msg_parts[4])
 
-        if is_authentic then
+            if is_authentic then
-                table.insert(clearances, { computer_id = tonumber(id), clearance_level = tonumber(card_clearance), time_granted = os.clock() })
+                    table.insert(clearances, { computer_id = tonumber(id), clearance_level = tonumber(card_clearance), time_granted = os.clock() })
+                    rednet.send(id, "authentication successful", "tg")
+                    print("Granted card "..card_hash.." clearance level "..card_clearance)
+            else
+                print("Unknown card "..card_hash)
+                rednet.send(id, "authentication failed", "tg")
+            end
+            print("Transaction finished")
+        elseif msg_parts[1] == 'validate_key' then
+            print("Beginning transaction for single-validation with "..id)
+            local card_holder = msg_parts[2]
+            local card_clearance = msg_parts[3]
+            local minimum_clearance = msg_parts[5]
+
+            if validate_key(card_holder, card_clearance, msg_parts[4]) and tonumber(card_clearance) >= tonumber(minimum_clearance) then
                 rednet.send(id, "authentication successful", "tg")
-                print("Granted card "..card_hash.." clearance level "..card_clearance)
+            else
-        else
+                rednet.send(id, "authentication failed", "tg")
-            print("Unknown card "..card_hash)
+            end
-            rednet.send(id, "authentication failed", "tg")
+            print("Transaction finished")
         end
-        print("Transaction finished")
+    end
-    elseif msg_parts[1] == 'validate_key' then
+elseif args[1] == "add_card" then
-        print("Beginning transaction for single-validation with "..id)
+    if args[2] then
-        local card_holder = msg_parts[2]
+        local new_card = args[2]
-        local card_clearance = msg_parts[3]
+        local new_card_parts = split(new_card, ',')
-        local minimum_clearance = msg_parts[5]
+        local card_holder = new_card_parts[1]
 
-        if validate_key(card_holder, card_clearance, msg_parts[4]) and tonumber(card_clearance) >= tonumber(minimum_clearance) then
+        local key_file = fs.open(card_holder..'.key', 'w')
-            rednet.send(id, "authentication successful", "tg")
+        key_file.write(new_card)
-        else
+        key_file.close()
-            rednet.send(id, "authentication failed", "tg")
+
+        local trusted_keys = fs.open(dir..config.key_file, 'a')
+        local card_hash = hash(new_card)
+        trusted_keys.write(card_hash)
+        trusted_keys.close()
+    end
+elseif args[1] == "remove_card" then
+    if args[2] then
+        local key_hash = args[2]
+        local trusted_keys = fs.open(dir..config.key_file, 'r')
+        local new_key_table = {}
+        while true do
+            local trusted_hash = trusted_keys.readLine()
+            if trusted_hash ~= key_hash then
+                table.insert(new_key_table, trusted_hash)
+            end
+            if not trusted_hash then break end -- Stop when EOF reached
         end
-        print("Transaction finished")
+        trusted_keys.close()
+
+        local trusted_keys = fs.open(dir..config.key_file, 'w+')
+        for _, entry in ipairs(new_key_table) do
+            trusted_keys.write(entry .. '\n')
+        end
+        trusted_keys.close()
     end
 end