--- /dev/null
+-- This script may be used with the auth-filter.
+--
+-- 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")
+
+
+-- This file should contain a series of lines in the form of:
+-- username1:hash1
+-- username2:hash2
+-- username3:hash3
+-- ...
+-- Hashes can be generated using something like `mkpasswd -m sha-512 -R 300000`.
+-- This file should not be world-readable.
+local users_filename = "/etc/cgit-auth/users"
+
+-- This file should contain a series of lines in the form of:
+-- groupname1:username1,username2,username3,...
+-- ...
+local groups_filename = "/etc/cgit-auth/groups"
+
+-- This file should contain a series of lines in the form of:
+-- reponame1:groupname1,groupname2,groupname3,...
+-- ...
+local repos_filename = "/etc/cgit-auth/repos"
+
+-- Set this to a path this script can write to for storing a persistent
+-- cookie secret, which should not be world-readable.
+local secret_filename = "/var/cache/cgit/auth-secret"
+
+--
+--
+-- Authentication functions follow below. Swap these out if you want different authentication semantics.
+--
+--
+
+-- Looks up a hash for a given user.
+function lookup_hash(user)
+ local line
+ for line in io.lines(users_filename) do
+ local u, h = string.match(line, "(.-):(.+)")
+ if u:lower() == user:lower() then
+ return h
+ end
+ end
+ return nil
+end
+
+-- Looks up users for a given repo.
+function lookup_users(repo)
+ local users = nil
+ local groups = nil
+ local line, group, user
+ for line in io.lines(repos_filename) do
+ local r, g = string.match(line, "(.-):(.+)")
+ if r == repo then
+ groups = { }
+ for group in string.gmatch(g, "([^,]+)") do
+ groups[group:lower()] = true
+ end
+ break
+ end
+ end
+ if groups == nil then
+ return nil
+ end
+ for line in io.lines(groups_filename) do
+ local g, u = string.match(line, "(.-):(.+)")
+ if groups[g:lower()] then
+ if users == nil then
+ users = { }
+ end
+ for user in string.gmatch(u, "([^,]+)") do
+ users[user:lower()] = true
+ end
+ end
+ end
+ return users
+end
+
+
+-- Sets HTTP cookie headers based on post and sets up redirection.
+function authenticate_post()
+ local hash = lookup_hash(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
+ -- One week expiration time
+ local username = secure_value("username", post["username"], os.time() + 604800)
+ set_cookie("cgitauth", username)
+ end
+
+ html("\n")
+ return 0
+end
+
+
+-- Returns 1 if the cookie is valid and 0 if it is not.
+function authenticate_cookie()
+ accepted_users = lookup_users(cgit["repo"])
+ if accepted_users == nil then
+ -- We return as valid if the repo is not protected.
+ return 1
+ end
+
+ 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
+ end
+end
+
+-- Prints the html for the login form.
+function body()
+ html("<h2>Authentication Required</h2>")
+ 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>")
+ html("<tr><td colspan='2'><input value='Login' type='submit' /></td></tr>")
+ html("</table></form>")
+
+ return 0
+end
+
+
+
+--
+--
+-- Wrapper around filter API, exposing the http table, the cgit table, and the post table to the above functions.
+--
+--
+
+local actions = {}
+actions["authenticate-post"] = authenticate_post
+actions["authenticate-cookie"] = authenticate_cookie
+actions["body"] = body
+
+function filter_open(...)
+ action = actions[select(1, ...)]
+
+ http = {}
+ http["cookie"] = select(2, ...)
+ http["method"] = select(3, ...)
+ http["query"] = select(4, ...)
+ http["referer"] = select(5, ...)
+ http["path"] = select(6, ...)
+ http["host"] = select(7, ...)
+ http["https"] = select(8, ...)
+
+ cgit = {}
+ cgit["repo"] = select(9, ...)
+ cgit["page"] = select(10, ...)
+ cgit["url"] = select(11, ...)
+ cgit["login"] = select(12, ...)
+
+end
+
+function filter_close()
+ return action()
+end
+
+function filter_write(str)
+ post = parse_qs(str)
+end
+
+
+--
+--
+-- Utility functions based on keplerproject/wsapi.
+--
+--
+
+function url_decode(str)
+ if not str then
+ return ""
+ end
+ str = string.gsub(str, "+", " ")
+ str = string.gsub(str, "%%(%x%x)", function(h) return string.char(tonumber(h, 16)) end)
+ str = string.gsub(str, "\r\n", "\n")
+ 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
+ tab[url_decode(key)] = url_decode(val)
+ end
+ return tab
+end
+
+function get_cookie(cookies, name)
+ 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
git.ckatri.com / cgit.git / commitdiff