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Diffstat (limited to 'filters/simple-authentication.lua')
| -rw-r--r-- | filters/simple-authentication.lua | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/filters/simple-authentication.lua b/filters/simple-authentication.lua new file mode 100644 index 0000000..4cd4983 --- /dev/null +++ b/filters/simple-authentication.lua @@ -0,0 +1,225 @@ +-- 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/> +-- + + +-- +-- +-- Configure these variables for your settings. +-- +-- + +local protected_repos = { + glouglou = { laurent = true, jason = true }, + qt = { jason = true, bob = true } +} + +local users = { + jason = "secretpassword", + laurent = "s3cr3t", + bob = "ilikelua" +} + +local secret = "BE SURE TO CUSTOMIZE THIS STRING TO SOMETHING BIG AND RANDOM" + + + +-- +-- +-- Authentication functions follow below. Swap these out if you want different authentication semantics. +-- +-- + +-- Sets HTTP cookie headers based on post +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") + else + construct_cookie(post["username"], "cgitauth") + end + return 0 +end + + +-- Returns 1 if the cookie is valid and 0 if it is not. +function authenticate_cookie() + accepted_users = protected_repos[cgit["repo"]] + if accepted_users == nil then + -- We return as valid if the repo is not protected. + return 1 + end + + local username = validate_cookie(get_cookie(http["cookie"], "cgitauth")) + if username == nil or not accepted_users[username] 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("<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 + + +-- +-- +-- 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. +-- +-- + +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"] = "" + for _ in cgit["url"]:gfind("/") do + cgit["login"] = cgit["login"] .. "../" + end + cgit["login"] = cgit["login"] .. "?p=login" + +end + +function filter_close() + return action() +end + +function filter_write(str) + post = parse_qs(str) +end + + +-- +-- +-- Utility functions follow below, 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 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 |