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-- SPDX-License-Identifier: GPL-3.0-or-later
--[[
Conventions:
- key = private+public key-pair in openssl.pkey format
- certs = lua list of certificates (at least one), each in openssl.x509 format,
ordered from leaf to almost-root
- panic('...') is used on bad problems instead of returning nils or such
--]]
local tls_cert = {}
local x509, pkey = require('openssl.x509'), require('openssl.pkey')
-- @function Create self-signed certificate; return certs, key
local function new_ephemeral(host)
-- Import luaossl directly
local name = require('openssl.x509.name')
local altname = require('openssl.x509.altname')
local openssl_bignum = require('openssl.bignum')
local openssl_rand = require('openssl.rand')
-- Create self-signed certificate
host = host or hostname()
local crt = x509.new()
local now = os.time()
crt:setVersion(3)
-- serial needs to be unique or browsers will show uninformative error messages
crt:setSerial(openssl_bignum.fromBinary(openssl_rand.bytes(16)))
-- use the host we're listening on as canonical name
local dn = name.new()
dn:add("CN", host)
crt:setSubject(dn)
crt:setIssuer(dn) -- should match subject for a self-signed
local alt = altname.new()
alt:add("DNS", host)
crt:setSubjectAlt(alt)
-- Valid for 90 days
crt:setLifetime(now, now + 90*60*60*24)
-- Can't be used as a CA
crt:setBasicConstraints{CA=false}
crt:setBasicConstraintsCritical(true)
-- Create and set key (default: EC/P-256 as a most "interoperable")
local key = pkey.new {type = 'EC', curve = 'prime256v1'}
crt:setPublicKey(key)
crt:sign(key)
return { crt }, key
end
-- @function Write certs and key to files
local function write_cert_files(certs, key, certfile, keyfile)
-- Write certs
local f = assert(io.open(certfile, 'w'), string.format('cannot open "%s" for writing', certfile))
for _, cert in ipairs(certs) do
f:write(tostring(cert))
end
f:close()
-- Write key as a pair
f = assert(io.open(keyfile, 'w'), string.format('cannot open "%s" for writing', keyfile))
local pub, priv = key:toPEM('public', 'private')
assert(f:write(pub .. priv))
f:close()
end
-- @function Start maintenance of a self-signed TLS context (at ephem_state.ctx).
-- Keep updating the ephem_state.servers table. Stop updating by calling _destroy().
-- TODO: each process maintains its own ephemeral cert ATM, and the files aren't ever read from.
function tls_cert.ephemeral_state_maintain(ephem_state, certfile, keyfile)
local certs, key = new_ephemeral()
write_cert_files(certs, key, certfile, keyfile)
ephem_state.ctx = tls_cert.new_tls_context(certs, key)
-- Each server needs to have its ctx updated.
for _, s in pairs(ephem_state.servers) do
s.server.ctx = ephem_state.ctx
s.config.ctx = ephem_state.ctx -- not required, but let's keep it synchonized
end
log('[http] created new ephemeral TLS certificate')
local _, expiry_stamp = certs[1]:getLifetime()
local wait_msec = 1000 * math.max(1, expiry_stamp - os.time() - 3 * 24 * 3600)
if not ephem_state.timer_id then
ephem_state.timer_id = event.after(wait_msec, function ()
tls_cert.ephemeral_state_maintain(ephem_state, certfile, keyfile)
end)
else
event.reschedule(ephem_state.timer_id, wait_msec)
end
end
function tls_cert.ephemeral_state_destroy(ephem_state)
if ephem_state and ephem_state.timer_id then
event.cancel(ephem_state.timer_id)
end
end
-- @function Read a certificate chain and a key from files; return certs, key
function tls_cert.load(certfile, keyfile)
-- get key
local f, err = io.open(keyfile, 'r')
if not f then
panic('[http] unable to open TLS key file: %s', err)
end
local key = pkey.new(f:read('*all'))
f:close()
if not key then
panic('[http] unable to parse TLS key file %s', keyfile)
end
-- get certs list
local certs = {}
local f, err = io.open(certfile, 'r')
if not f then
panic('[http] unable to read TLS certificate file: %s', err)
end
while true do
-- Get the next "block" = single certificate as PEM string.
local block = nil
local line
repeat
line = f:read()
if not line then break end
if block then
block = block .. '\n' .. line
else
block = line
end
-- separator: "posteb" in https://tools.ietf.org/html/rfc7468#section-3
until string.sub(line, 1, 9) == '-----END '
-- Empty block means clean EOF.
if not block then break end
if not line then
panic('[http] unable to parse TLS certificate file %s, certificate number %d', certfile, 1 + #certs)
end
-- Parse the cert and append to the list.
local cert = x509.new(block, 'PEM')
if not cert then
panic('[http] unable to parse TLS certificate file %s, certificate number %d', certfile, 1 + #certs)
end
table.insert(certs, cert)
end
f:close()
return certs, key
end
-- @function Prefer HTTP/2 or HTTP/1.1
local function alpnselect(_, protos)
for _, proto in ipairs(protos) do
if proto == 'h2' or proto == 'http/1.1' then
return proto
end
end
return nil
end
local warned_old_luaossl = false
-- @function Return a new TLS context for a server.
function tls_cert.new_tls_context(certs, key)
local ctx = require('http.tls').new_server_context()
if ctx.setAlpnSelect then
ctx:setAlpnSelect(alpnselect)
end
assert(ctx:setPrivateKey(key))
assert(ctx:setCertificate(certs[1]))
-- Set up certificate chain to be sent, if required and possible.
if #certs == 1 then return ctx end
if ctx.setCertificateChain then
local chain = require('openssl.x509.chain').new()
assert(chain)
for i = 2, #certs do
chain:add(certs[i])
assert(chain)
end
assert(ctx:setCertificateChain(chain))
elseif not warned_old_luaossl then
-- old luaossl version -> only final cert sent to clients
warn('[http] Warning: need luaossl >= 20181207 to support sending intermediary certificate to clients')
warned_old_luaossl = true
end
return ctx
end
return tls_cert
|
