Diffstat (limited to 'filters/simple-authentication.lua')
| -rw-r--r-- | filters/simple-authentication.lua | 281 |
1 files changed, 96 insertions, 185 deletions
diff --git a/filters/simple-authentication.lua b/filters/simple-authentication.lua index 23d3457..4cd4983 100644 --- a/filters/simple-authentication.lua +++ b/filters/simple-authentication.lua @@ -1,15 +1,10 @@ -- This script may be used with the auth-filter. Be sure to configure it as you wish. -- -- Requirements: --- luaossl --- <http://25thandclement.com/~william/projects/luaossl.html> --- luaposix --- <https://github.com/luaposix/luaposix> +-- luacrypto >= 0.3 +-- <http://mkottman.github.io/luacrypto/> -- -local sysstat = require("posix.sys.stat") -local unistd = require("posix.unistd") -local rand = require("openssl.rand") -local hmac = require("openssl.hmac") + -- -- @@ -17,22 +12,20 @@ local hmac = require("openssl.hmac") -- -- --- A list of password protected repositories along with the users who can access them. local protected_repos = { glouglou = { laurent = true, jason = true }, qt = { jason = true, bob = true } } --- A list of users and hashes, generated with `mkpasswd -m sha-512 -R 300000`. local users = { - jason = "$6$rounds=300000$YYJct3n/o.ruYK$HhpSeuCuW1fJkpvMZOZzVizeLsBKcGA/aF2UPuV5v60JyH2MVSG6P511UMTj2F3H75.IT2HIlnvXzNb60FcZH1", - laurent = "$6$rounds=300000$dP0KNHwYb3JKigT$pN/LG7rWxQ4HniFtx5wKyJXBJUKP7R01zTNZ0qSK/aivw8ywGAOdfYiIQFqFhZFtVGvr11/7an.nesvm8iJUi.", - bob = "$6$rounds=300000$jCLCCt6LUpTz$PI1vvd1yaVYcCzqH8QAJFcJ60b6W/6sjcOsU7mAkNo7IE8FRGW1vkjF8I/T5jt/auv5ODLb1L4S2s.CAyZyUC" + jason = "secretpassword", + laurent = "s3cr3t", + bob = "ilikelua" } --- 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" +local secret = "BE SURE TO CUSTOMIZE THIS STRING TO SOMETHING BIG AND RANDOM" + + -- -- @@ -40,27 +33,15 @@ local secret_filename = "/var/cache/cgit/auth-secret" -- -- --- Sets HTTP cookie headers based on post and sets up redirection. +-- Sets HTTP cookie headers based on post function authenticate_post() - local hash = users[post["username"]] - local redirect = validate_value("redirect", post["redirect"]) - - if redirect == nil then - not_found() - return 0 - end - - redirect_to(redirect) - - if hash == nil or hash ~= unistd.crypt(post["password"], hash) then - set_cookie("cgitauth", "") + local password = users[post["username"]] + -- TODO: Implement time invariant string comparison function to mitigate against timing attack. + if password == nil or password ~= post["password"] then + construct_cookie("", "cgitauth") else - -- One week expiration time - local username = secure_value("username", post["username"], os.time() + 604800) - set_cookie("cgitauth", username) + construct_cookie(post["username"], "cgitauth") end - - html("\n") return 0 end @@ -73,8 +54,8 @@ function authenticate_cookie() return 1 end - local username = validate_value("username", get_cookie(http["cookie"], "cgitauth")) - if username == nil or not accepted_users[username:lower()] then + local username = validate_cookie(get_cookie(http["cookie"], "cgitauth")) + if username == nil or not accepted_users[username] then return 0 else return 1 @@ -87,9 +68,6 @@ function body() html("<form method='post' action='") html_attr(cgit["login"]) html("'>") - html("<input type='hidden' name='redirect' value='") - html_attr(secure_value("redirect", cgit["url"], 0)) - html("' />") html("<table>") html("<tr><td><label for='username'>Username:</label></td><td><input id='username' name='username' autofocus /></td></tr>") html("<tr><td><label for='password'>Password:</label></td><td><input id='password' name='password' type='password' /></td></tr>") @@ -100,10 +78,81 @@ function body() end +-- +-- +-- Cookie construction and validation helpers. +-- +-- + +local crypto = require("crypto") + +-- Returns username of cookie if cookie is valid. Otherwise returns nil. +function validate_cookie(cookie) + local i = 0 + local username = "" + local expiration = 0 + local salt = "" + local hmac = "" + + if cookie:len() < 3 or cookie:sub(1, 1) == "|" then + return nil + end + + for component in string.gmatch(cookie, "[^|]+") do + if i == 0 then + username = component + elseif i == 1 then + expiration = tonumber(component) + if expiration == nil then + expiration = 0 + end + elseif i == 2 then + salt = component + elseif i == 3 then + hmac = component + else + break + end + i = i + 1 + end + + if hmac == nil or hmac:len() == 0 then + return nil + end + + -- TODO: implement time invariant comparison to prevent against timing attack. + if hmac ~= crypto.hmac.digest("sha1", username .. "|" .. tostring(expiration) .. "|" .. salt, secret) then + return nil + end + + if expiration <= os.time() then + return nil + end + + return username:lower() +end + +function construct_cookie(username, cookie) + local authstr = "" + if username:len() > 0 then + -- One week expiration time + local expiration = os.time() + 604800 + local salt = crypto.hex(crypto.rand.bytes(16)) + + authstr = username .. "|" .. tostring(expiration) .. "|" .. salt + authstr = authstr .. "|" .. crypto.hmac.digest("sha1", authstr, secret) + end + + html("Set-Cookie: " .. cookie .. "=" .. authstr .. "; HttpOnly") + if http["https"] == "yes" or http["https"] == "on" or http["https"] == "1" then + html("; secure") + end + html("\n") +end -- -- --- Wrapper around filter API, exposing the http table, the cgit table, and the post table to the above functions. +-- Wrapper around filter API follows below, exposing the http table, the cgit table, and the post table to the above functions. -- -- @@ -128,7 +177,12 @@ function filter_open(...) cgit["repo"] = select(9, ...) cgit["page"] = select(10, ...) cgit["url"] = select(11, ...) - cgit["login"] = select(12, ...) + + cgit["login"] = "" + for _ in cgit["url"]:gfind("/") do + cgit["login"] = cgit["login"] .. "../" + end + cgit["login"] = cgit["login"] .. "?p=login" end @@ -143,7 +197,7 @@ end -- -- --- Utility functions based on keplerproject/wsapi. +-- Utility functions follow below, based on keplerproject/wsapi. -- -- @@ -157,16 +211,6 @@ function url_decode(str) return str end -function url_encode(str) - if not str then - return "" - end - str = string.gsub(str, "\n", "\r\n") - str = string.gsub(str, "([^%w ])", function(c) return string.format("%%%02X", string.byte(c)) end) - str = string.gsub(str, " ", "+") - return str -end - function parse_qs(qs) local tab = {} for key, val in string.gmatch(qs, "([^&=]+)=([^&=]*)&?") do @@ -179,136 +223,3 @@ function get_cookie(cookies, name) cookies = string.gsub(";" .. cookies .. ";", "%s*;%s*", ";") return url_decode(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 - --- --- --- Cookie construction and validation helpers. --- --- - -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) - local i = 0 - local value = "" - local field = "" - local expiration = 0 - local salt = "" - local chmac = "" - - if cookie == nil or cookie:len() < 3 or cookie:sub(1, 1) == "|" then - return nil - end - - for component in string.gmatch(cookie, "[^|]+") do - if i == 0 then - field = component - elseif i == 1 then - value = component - elseif i == 2 then - expiration = tonumber(component) - if expiration == nil then - expiration = -1 - end - elseif i == 3 then - salt = component - elseif i == 4 then - chmac = component - else - break - end - i = i + 1 - end - - if chmac == nil or chmac:len() == 0 then - return nil - end - - -- Lua hashes strings, so these comparisons are time invariant. - if chmac ~= tohex(hmac.new(get_secret(), "sha256"):final(field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt)) then - return nil - end - - if expiration == -1 or (expiration ~= 0 and expiration <= os.time()) then - return nil - end - - if url_decode(field) ~= expected_field then - return nil - end - - return url_decode(value) -end - -function secure_value(field, value, expiration) - if value == nil or value:len() <= 0 then - return "" - end - - local authstr = "" - local salt = tohex(rand.bytes(16)) - value = url_encode(value) - field = url_encode(field) - authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt - authstr = authstr .. "|" .. tohex(hmac.new(get_secret(), "sha256"):final(authstr)) - return authstr -end - -function set_cookie(cookie, value) - html("Set-Cookie: " .. cookie .. "=" .. value .. "; HttpOnly") - if http["https"] == "yes" or http["https"] == "on" or http["https"] == "1" then - html("; secure") - end - html("\n") -end - -function redirect_to(url) - html("Status: 302 Redirect\n") - html("Cache-Control: no-cache, no-store\n") - html("Location: " .. url .. "\n") -end - -function not_found() - html("Status: 404 Not Found\n") - html("Cache-Control: no-cache, no-store\n\n") -end |