Bump version

[ps-cgit] / filters / gentoo-ldap-authentication.lua

diff --git a/filters/gentoo-ldap-authentication.lua b/filters/gentoo-ldap-authentication.lua
index 3b6564b42983fc6996583495667ca2d8d93a99a0..673c88d1021cd19074a748fc2763bc5a3bd79480 100644 (file)
--- a/filters/gentoo-ldap-authentication.lua
+++ b/filters/gentoo-ldap-authentication.lua
@@ -1,12 +1,18 @@
 -- This script may be used with the auth-filter. Be sure to configure it as you wish.
 --
 -- Requirements:
---     luacrypto >= 0.3
---     <http://mkottman.github.io/luacrypto/>
+--     luaossl
+--     <http://25thandclement.com/~william/projects/luaossl.html>
 --     lualdap >= 1.2
 --     <https://git.zx2c4.com/lualdap/about/>
+--     luaposix
+--     <https://github.com/luaposix/luaposix>
 --
-
+local sysstat = require("posix.sys.stat")
+local unistd = require("posix.unistd")
+local lualdap = require("lualdap")
+local rand = require("openssl.rand")
+local hmac = require("openssl.hmac")
 
 --
 --
@@ -21,11 +27,9 @@ local protected_repos = {
        portage = "dev"
 }
 
-
--- All cookies will be authenticated based on this secret. Make it something
--- totally random and impossible to guess. It should be large.
-local secret = "BE SURE TO CUSTOMIZE THIS STRING TO SOMETHING BIG AND RANDOM"
-
+-- Set this to a path this script can write to for storing a persistent
+-- cookie secret, which should be guarded.
+local secret_filename = "/var/cache/cgit/auth-secret"
 
 
 --
@@ -102,8 +106,6 @@ end
 --
 --
 
-local lualdap = require("lualdap")
-
 function gentoo_ldap_user_groups(username, password)
        -- Ensure the user is alphanumeric
        if username == nil or username:match("%W") then
@@ -224,6 +226,13 @@ function get_cookie(cookies, name)
        return string.match(cookies, ";" .. name .. "=(.-);")
 end
 
+function tohex(b)
+       local x = ""
+       for i = 1, #b do
+               x = x .. string.format("%.2x", string.byte(b, i))
+       end
+       return x
+end
 
 --
 --
@@ -231,7 +240,38 @@ end
 --
 --
 
-local crypto = require("crypto")
+local secret = nil
+
+-- Loads a secret from a file, creates a secret, or returns one from memory.
+function get_secret()
+       if secret ~= nil then
+               return secret
+       end
+       local secret_file = io.open(secret_filename, "r")
+       if secret_file == nil then
+               local old_umask = sysstat.umask(63)
+               local temporary_filename = secret_filename .. ".tmp." .. tohex(rand.bytes(16))
+               local temporary_file = io.open(temporary_filename, "w")
+               if temporary_file == nil then
+                       os.exit(177)
+               end
+               temporary_file:write(tohex(rand.bytes(32)))
+               temporary_file:close()
+               unistd.link(temporary_filename, secret_filename) -- Intentionally fails in the case that another process is doing the same.
+               unistd.unlink(temporary_filename)
+               sysstat.umask(old_umask)
+               secret_file = io.open(secret_filename, "r")
+       end
+       if secret_file == nil then
+               os.exit(177)
+       end
+       secret = secret_file:read()
+       secret_file:close()
+       if secret:len() ~= 64 then
+               os.exit(177)
+       end
+       return secret
+end
 
 -- Returns value of cookie if cookie is valid. Otherwise returns nil.
 function validate_value(expected_field, cookie)
@@ -240,7 +280,7 @@ function validate_value(expected_field, cookie)
        local field = ""
        local expiration = 0
        local salt = ""
-       local hmac = ""
+       local chmac = ""
 
        if cookie == nil or cookie:len() < 3 or cookie:sub(1, 1) == "|" then
                return nil
@@ -259,19 +299,19 @@ function validate_value(expected_field, cookie)
                elseif i == 3 then
                        salt = component
                elseif i == 4 then
-                       hmac = component
+                       chmac = component
                else
                        break
                end
                i = i + 1
        end
 
-       if hmac == nil or hmac:len() == 0 then
+       if chmac == nil or chmac:len() == 0 then
                return nil
        end
 
        -- Lua hashes strings, so these comparisons are time invariant.
-       if hmac ~= crypto.hmac.digest("sha256", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
+       if chmac ~= tohex(hmac.new(get_secret(), "sha256"):final(field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt)) then
                return nil
        end
 
@@ -292,11 +332,11 @@ function secure_value(field, value, expiration)
        end
 
        local authstr = ""
-       local salt = crypto.hex(crypto.rand.bytes(16))
+       local salt = tohex(rand.bytes(16))
        value = url_encode(value)
        field = url_encode(field)
        authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
-       authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, secret)
+       authstr = authstr .. "|" .. tohex(hmac.new(get_secret(), "sha256"):final(authstr))
        return authstr
 end