mirror of https://git.zx2c4.com/cgit/
auth: add basic authentication filter framework
This leverages the new lua support. See filters/simple-authentication.lua for explaination of how this works. There is also additional documentation in cgitrc.5.txt. Though this is a cookie-based approach, cgit's caching mechanism is preserved for authenticated pages. Very plugable and extendable depending on user needs. The sample script uses an HMAC-SHA1 based cookie to store the currently logged in user, with an expiration date. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>jk/collapsible-sections
Jason A. Donenfeld
10 years ago
parent
3741254a69
commit
d6e9200cc3
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-- This script may be used with the auth-filter. Be sure to configure it as you wish.
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--
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-- Requirements:
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-- luacrypto >= 0.3
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-- <http://mkottman.github.io/luacrypto/>
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--
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--
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--
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-- Configure these variables for your settings.
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--
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--
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local protected_repos = {
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glouglou = { laurent = true, jason = true },
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qt = { jason = true, bob = true }
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}
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local users = {
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jason = "secretpassword",
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laurent = "s3cr3t",
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bob = "ilikelua"
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}
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local secret = "BE SURE TO CUSTOMIZE THIS STRING TO SOMETHING BIG AND RANDOM"
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--
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--
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-- Authentication functions follow below. Swap these out if you want different authentication semantics.
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--
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--
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-- Sets HTTP cookie headers based on post
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function authenticate_post()
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local password = users[post["username"]]
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-- TODO: Implement time invariant string comparison function to mitigate against timing attack.
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if password == nil or password ~= post["password"] then
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construct_cookie("", "cgitauth")
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else
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construct_cookie(post["username"], "cgitauth")
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end
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return 0
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end
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-- Returns 1 if the cookie is valid and 0 if it is not.
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function authenticate_cookie()
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accepted_users = protected_repos[cgit["repo"]]
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if accepted_users == nil then
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-- We return as valid if the repo is not protected.
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return 1
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end
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local username = validate_cookie(get_cookie(http["cookie"], "cgitauth"))
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if username == nil or not accepted_users[username] then
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return 0
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else
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return 1
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end
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end
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-- Prints the html for the login form.
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function body()
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html("<h2>Authentication Required</h2>")
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html("<form method='post' action='")
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html_attr(cgit["login"])
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html("'>")
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html("<table>")
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html("<tr><td><label for='username'>Username:</label></td><td><input id='username' name='username' autofocus /></td></tr>")
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html("<tr><td><label for='password'>Password:</label></td><td><input id='password' name='password' type='password' /></td></tr>")
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html("<tr><td colspan='2'><input value='Login' type='submit' /></td></tr>")
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html("</table></form>")
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return 0
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end
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--
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--
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-- Cookie construction and validation helpers.
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--
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--
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local crypto = require("crypto")
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-- Returns username of cookie if cookie is valid. Otherwise returns nil.
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function validate_cookie(cookie)
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local i = 0
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local username = ""
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local expiration = 0
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local salt = ""
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local hmac = ""
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if cookie:len() < 3 or cookie:sub(1, 1) == "|" then
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return nil
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end
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for component in string.gmatch(cookie, "[^|]+") do
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if i == 0 then
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username = component
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elseif i == 1 then
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expiration = tonumber(component)
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if expiration == nil then
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expiration = 0
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end
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elseif i == 2 then
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salt = component
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elseif i == 3 then
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hmac = component
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else
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break
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end
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i = i + 1
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end
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if hmac == nil or hmac:len() == 0 then
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return nil
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end
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-- TODO: implement time invariant comparison to prevent against timing attack.
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if hmac ~= crypto.hmac.digest("sha1", username .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
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return nil
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end
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if expiration <= os.time() then
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return nil
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end
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return username:lower()
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end
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function construct_cookie(username, cookie)
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local authstr = ""
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if username:len() > 0 then
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-- One week expiration time
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local expiration = os.time() + 604800
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local salt = crypto.hex(crypto.rand.bytes(16))
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authstr = username .. "|" .. tostring(expiration) .. "|" .. salt
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authstr = authstr .. "|" .. crypto.hmac.digest("sha1", authstr, secret)
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end
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html("Set-Cookie: " .. cookie .. "=" .. authstr .. "; HttpOnly")
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if http["https"] == "yes" or http["https"] == "on" or http["https"] == "1" then
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html("; secure")
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end
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html("\n")
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end
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--
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--
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-- Wrapper around filter API follows below, exposing the http table, the cgit table, and the post table to the above functions.
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--
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--
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local actions = {}
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actions["authenticate-post"] = authenticate_post
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actions["authenticate-cookie"] = authenticate_cookie
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actions["body"] = body
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function filter_open(...)
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action = actions[select(1, ...)]
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http = {}
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http["cookie"] = select(2, ...)
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http["method"] = select(3, ...)
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http["query"] = select(4, ...)
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http["referer"] = select(5, ...)
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http["path"] = select(6, ...)
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http["host"] = select(7, ...)
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http["https"] = select(8, ...)
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cgit = {}
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cgit["repo"] = select(9, ...)
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cgit["page"] = select(10, ...)
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cgit["url"] = select(11, ...)
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cgit["login"] = ""
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for _ in cgit["url"]:gfind("/") do
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cgit["login"] = cgit["login"] .. "../"
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end
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cgit["login"] = cgit["login"] .. "?p=login"
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end
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function filter_close()
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return action()
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end
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function filter_write(str)
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post = parse_qs(str)
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end
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--
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--
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-- Utility functions follow below, based on keplerproject/wsapi.
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--
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--
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function url_decode(str)
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if not str then
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return ""
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end
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str = string.gsub(str, "+", " ")
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str = string.gsub(str, "%%(%x%x)", function(h) return string.char(tonumber(h, 16)) end)
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str = string.gsub(str, "\r\n", "\n")
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return str
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end
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function parse_qs(qs)
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local tab = {}
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for key, val in string.gmatch(qs, "([^&=]+)=([^&=]*)&?") do
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tab[url_decode(key)] = url_decode(val)
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end
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return tab
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end
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function get_cookie(cookies, name)
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cookies = string.gsub(";" .. cookies .. ";", "%s*;%s*", ";")
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return url_decode(string.match(cookies, ";" .. name .. "=(.-);"))
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end
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