Add cli to add and remove cards

Reviewed-on: #3

tg_client/tg_client.lua

@@ -1,3 +1,5 @@
+tg_server_name = "tg_server"
+
 local args = {...}
 
 local function split(str, divider)
@@ -13,18 +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, tg_server_name)
+function validate_clearance(computer_id, clearance_level)
     if establish_connection() then
-        tg_server_id = rednet.lookup("tg", tg_server_name)
-        rednet.send(tg_server_id, "validate_clearance,"..computer_id..","..clearance_level)
+        tg_server_id = rednet.lookup('tg', tg_server_name)
+        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
@@ -36,29 +36,61 @@ function validate_clearance(computer_id, clearance_level, tg_server_name)
     end
 end
 
-if fs.exists('/disk/key') then
-    key_file = fs.open('/disk/key', 'r')
-    key = key_file.readLine()
+function validate_key(minimum_clearance)
     if establish_connection() then
-        local tg_server_name = "tg_server"
+        if fs.exists("/disk/key") then
+            local key_file = fs.open("/disk/key","r")
+            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")
+            local id, msg, _ = rednet.receive("tg")
+            if msg == "authentication successful" then
+                return true
+            else
+                return false, "authentication error: "..msg
+            end
+        else
+            return false, "key file not found"
+        end
+    else
+        return false, "modem not found"
+    end
+end
 
+function authenticate()
+    if fs.exists('/disk/key') then
+        local key_file = fs.open('/disk/key', 'r')
+        local key = key_file.readLine()
+        if establish_connection() then
             tg_server_id = rednet.lookup("tg", tg_server_name)
             rednet.send(tg_server_id, "authenticate,"..key,"tg")
             local id, msg, proto = rednet.receive("tg")
 
             if msg == "authentication successful" then
-            key_parts = split(key,',')
+                local key_parts = split(key,',')
                 local card_holder = key_parts[1]
                 local card_clearance = key_parts[2]
-            print("Authentication was successful.")
-            print("Hello "..card_holder..", you were granted clearance level "..card_clearance.." for this computer.")
+                return true, _, card_holder, card_clearance
             else
                 print("Authentication failed.")
+                return false, "authentication failed"
             end
         else
             return false, "modem not found"
         end
         key_file.close()
-else
+    else
         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
 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/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)
-    local hash = 0
-    for i = 1, #str do
-        hash = (hash * 31 + string.byte(str, i)) % 65536
-    end
-    return string.format("%04X", hash)
-end
-
+dofile(dir..'hash.lua')
 
 local function check_for_outdated_sessions()
     local expired = 0
@@ -34,13 +28,34 @@ local function check_for_outdated_sessions()
           #clearances .. " active session(s) remain.")
 end
 
+local function validate_key(card_holder, card_clearance, random_chars)
+    local card_hash = hash(card_holder..','..card_clearance..','..random_chars)
+    local key_file = fs.open(dir..config.key_file, 'r')
+    local card_authentic = false
 
+    while true do
+        local trusted_hash = key_file.readLine()
+        if trusted_hash == card_hash then
+            print("Valid card "..card_hash)
+            card_authentic = true
+            return true, card_hash
+        end
+        if not line then break end -- Stop when EOF reached
+    end
 
-rednet.open(config.modem_side)
-rednet.host('tg', config.name)
-print("Server started, waiting for requests...")
+    key_file.close()
     
-while true do
+    if card_authentic == false then
+        print("Unknown card "..card_hash)
+        return false
+    end
+end
+
+if args[1] == "serve" then
+    rednet.open(config.modem_side)
+    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, ',')
@@ -69,28 +84,65 @@ while true do
             print("Beginning transaction for authentication with "..id)
             local card_holder = msg_parts[2]
             local card_clearance = msg_parts[3]
-        local card_hash = hash(card_holder..','..card_clearance..','..msg_parts[4])
-        local key_file = fs.open(dir..config.key_file, 'r')
-        local card_authentic = false
 
-        while true do
-            local trusted_hash = key_file.readLine()
-            if trusted_hash == card_hash then
+            local is_authentic, card_hash = validate_key(card_holder, card_clearance, msg_parts[4])
+
+            if is_authentic then
                     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)
-
-                card_authentic = true
-            end
-            if not line then break end -- Stop when EOF reached
-        end
-
-        key_file.close()
-        
-        if card_authentic == false then
+            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")
+            else
+                rednet.send(id, "authentication failed", "tg")
+            end
+            print("Transaction finished")
+        end
+    end
+elseif args[1] == "add_card" then
+    if args[2] then
+        local new_card = args[2]
+        local new_card_parts = split(new_card, ',')
+        local card_holder = new_card_parts[1]
+
+        local key_file = fs.open(card_holder..'.key', 'w')
+        key_file.write(new_card)
+        key_file.close()
+
+        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
+        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