-- 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")
--
--
--
+-- 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 = "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"
}
-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"
--
--
--
--
--- Sets HTTP cookie headers based on post
+-- Sets HTTP cookie headers based on post and sets up redirection.
function authenticate_post()
- 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")
+ 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", "")
else
- construct_cookie(post["username"], "cgitauth")
+ -- One week expiration time
+ local username = secure_value("username", post["username"], os.time() + 604800)
+ set_cookie("cgitauth", username)
end
+
+ html("\n")
return 0
end
return 1
end
- local username = validate_cookie(get_cookie(http["cookie"], "cgitauth"))
- if username == nil or not accepted_users[username] then
+ local username = validate_value("username", get_cookie(http["cookie"], "cgitauth"))
+ if username == nil or not accepted_users[username:lower()] then
return 0
else
return 1
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>")
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 follows below, exposing the http table, the cgit table, and the post table to the above functions.
+-- Wrapper around filter API, exposing the http table, the cgit table, and the post table to the above functions.
--
--
cgit["repo"] = select(9, ...)
cgit["page"] = select(10, ...)
cgit["url"] = select(11, ...)
-
- cgit["login"] = ""
- for _ in cgit["url"]:gfind("/") do
- cgit["login"] = cgit["login"] .. "../"
- end
- cgit["login"] = cgit["login"] .. "?p=login"
+ cgit["login"] = select(12, ...)
end
--
--
--- Utility functions follow below, based on keplerproject/wsapi.
+-- Utility functions based on keplerproject/wsapi.
--
--
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
cookies = string.gsub(";" .. cookies .. ";", "%s*;%s*", ";")
return url_decode(string.match(cookies, ";" .. name .. "=(.-);"))
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." .. 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)
+ local i = 0
+ local value = ""
+ local field = ""
+ local expiration = 0
+ local salt = ""
+ local hmac = ""
+
+ 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
+ hmac = component
+ else
+ break
+ end
+ i = i + 1
+ end
+
+ if hmac == nil or hmac: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, get_secret()) 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 = crypto.hex(crypto.rand.bytes(16))
+ value = url_encode(value)
+ field = url_encode(field)
+ authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
+ authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, get_secret())
+ 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
projects / ps-cgit / blobdiff