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-rw-r--r--filters/simple-authentication.lua69
1 files changed, 48 insertions, 21 deletions
diff --git a/filters/simple-authentication.lua b/filters/simple-authentication.lua
index de34d09..77d1fd0 100644
--- a/filters/simple-authentication.lua
+++ b/filters/simple-authentication.lua
@@ -3,7 +3,12 @@
-- Requirements:
-- luacrypto >= 0.3
-- <http://mkottman.github.io/luacrypto/>
+-- luaposix
+-- <https://github.com/luaposix/luaposix>
--
+local sysstat = require("posix.sys.stat")
+local unistd = require("posix.unistd")
+local crypto = require("crypto")
--
@@ -18,24 +23,16 @@ local protected_repos = {
qt = { jason = true, bob = true }
}
--- Please note that, in production, you'll want to replace this simple lookup
--- table with either a table of salted and hashed passwords (using something
--- smart like scrypt), or replace this table lookup with an external support,
--- such as consulting your system's pam / shadow system, or an external
--- database, or an external validating web service. For testing, or for
--- extremely low-security usage, you may be able, however, to get away with
--- compromising on hardcoding the passwords in cleartext, as we have done here.
+-- A list of users and hashes, generated with `mkpasswd -m sha-512 -R 300000`.
local users = {
- jason = "secretpassword",
- laurent = "s3cr3t",
- bob = "ilikelua"
+ 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"
}
--- 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"
--
--
@@ -45,7 +42,7 @@ local secret = "BE SURE TO CUSTOMIZE THIS STRING TO SOMETHING BIG AND RANDOM"
-- Sets HTTP cookie headers based on post and sets up redirection.
function authenticate_post()
- local password = users[post["username"]]
+ local hash = users[post["username"]]
local redirect = validate_value("redirect", post["redirect"])
if redirect == nil then
@@ -55,8 +52,7 @@ function authenticate_post()
redirect_to(redirect)
- -- Lua hashes strings, so these comparisons are time invariant.
- if password == nil or password ~= post["password"] then
+ if hash == nil or hash ~= unistd.crypt(post["password"], hash) then
set_cookie("cgitauth", "")
else
-- One week expiration time
@@ -191,7 +187,38 @@ 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." .. crypto.hex(crypto.rand.bytes(16))
+ local temporary_file = io.open(temporary_filename, "w")
+ if temporary_file == nil then
+ os.exit(177)
+ end
+ temporary_file:write(crypto.hex(crypto.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)
@@ -231,7 +258,7 @@ function validate_value(expected_field, cookie)
end
-- Lua hashes strings, so these comparisons are time invariant.
- if hmac ~= crypto.hmac.digest("sha1", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
+ if hmac ~= crypto.hmac.digest("sha256", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, get_secret()) then
return nil
end
@@ -256,7 +283,7 @@ function secure_value(field, value, expiration)
value = url_encode(value)
field = url_encode(field)
authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
- authstr = authstr .. "|" .. crypto.hmac.digest("sha1", authstr, secret)
+ authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, get_secret())
return authstr
end