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#51 send serialized data to properly MAC

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This commit is contained in:
Mikayla Fischler
2023-06-27 18:36:16 -04:00
parent fb3c7ded06
commit a8071db08e
5 changed files with 144 additions and 48 deletions
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49
scada-common/network.lua
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@@ -55,7 +55,7 @@ end
---@nodiscard
---@param message string initial value concatenated with ciphertext
local function compute_hmac(message)
local start = util.time_ms()
-- local start = util.time_ms()
c_eng.hmac.init()
c_eng.hmac.update(stream.fromString(message))
@@ -63,7 +63,7 @@ local function compute_hmac(message)
local hash = c_eng.hmac.asHex()
log.debug("compute_hmac(): hmac-md5 = " .. util.strval(hash) .. " (took " .. (util.time_ms() - start) .. "ms)")
-- log.debug("compute_hmac(): hmac-md5 = " .. util.strval(hash) .. " (took " .. (util.time_ms() - start) .. "ms)")
return hash
end
@@ -166,20 +166,22 @@ function network.nic(modem)
-- send a packet, with message authentication if configured
---@param dest_channel integer destination channel
---@param local_channel integer local channel
---@param packet scada_packet packet raw_sendable
---@param packet scada_packet packet
function public.transmit(dest_channel, local_channel, packet)
if self.connected then
local tx_packet = packet ---@type authd_packet|scada_packet
if c_eng.hmac ~= nil then
local start = util.time_ms()
local message = textutils.serialize(packet.raw_verifiable(), { allow_repetitions = true, compact = true })
local computed_hmac = compute_hmac(message)
-- local start = util.time_ms()
tx_packet = comms.authd_packet()
packet.set_mac(computed_hmac)
---@cast tx_packet authd_packet
tx_packet.make(packet, compute_hmac)
log.debug("crypto.modem.transmit: data processing took " .. (util.time_ms() - start) .. "ms")
-- log.debug("crypto.modem.transmit: data processing took " .. (util.time_ms() - start) .. "ms")
end
modem.transmit(dest_channel, local_channel, packet.raw_sendable())
modem.transmit(dest_channel, local_channel, tx_packet.raw_sendable())
end
end
@@ -197,25 +199,30 @@ function network.nic(modem)
if self.connected then
local s_packet = comms.scada_packet()
-- parse packet as generic SCADA packet
s_packet.receive(side, sender, reply_to, message, distance)
if c_eng.hmac ~= nil then
-- parse packet as an authenticated SCADA packet
local a_packet = comms.authd_packet()
a_packet.receive(side, sender, reply_to, message, distance)
if s_packet.is_valid() then
if c_eng.hmac ~= nil then
local start = util.time_ms()
local packet_hmac = s_packet.mac()
local computed_hmac = compute_hmac(textutils.serialize(s_packet.raw_verifiable(), { allow_repetitions = true, compact = true }))
if a_packet.is_valid() then
-- local start = util.time_ms()
local packet_hmac = a_packet.mac()
local msg = a_packet.data()
local computed_hmac = compute_hmac(msg)
if packet_hmac == computed_hmac then
log.debug("crypto.modem.receive: HMAC verified in " .. (util.time_ms() - start) .. "ms")
packet = s_packet
-- log.debug("crypto.modem.receive: HMAC verified in " .. (util.time_ms() - start) .. "ms")
s_packet.receive(side, sender, reply_to, textutils.unserialize(msg), distance)
else
log.debug("crypto.modem.receive: HMAC failed verification in " .. (util.time_ms() - start) .. "ms")
-- log.debug("crypto.modem.receive: HMAC failed verification in " .. (util.time_ms() - start) .. "ms")
end
else
packet = s_packet
end
else
-- parse packet as a generic SCADA packet
s_packet.receive(side, sender, reply_to, message, distance)
end
if s_packet.is_valid() then packet = s_packet end
end
return packet