index : cgit

-- Unit checks for the two auth filters, run under a standalone Lua by
-- t0505-auth.sh with the script path as the first argument, the variant,
-- inline or file, as the second and a directory of the run's own as the
-- third, which takes the fixtures and the signing secret. The scripts need
-- luaossl and luaposix, which the harness meets with deterministic
-- stand-ins, so the checks are about the script's own logic, the cookie
-- layout, the expiry and field rules, the redirect vetting and the action
-- flows, rather than about OpenSSL. Given a fourth argument, a hash the
-- system's crypt(3) makes of the password below, the same checks run
-- against the real libraries instead, which is where a misuse of their
-- interfaces would show. The accounts and access lists are filled through
-- each variant's own channel, its commented-out examples switched on for
-- the inline script and fixture files reached through a redirected io.open
-- for the file one. Both variants carry the same data so the flow checks
-- read identically for the two.

local test_directory = arg[0]:match("^(.*)/") or "."
local h = dofile(test_directory .. "/harness.lua")

local script = arg[1]
local variant = arg[2]
local directory = assert(arg[3], "test-auth.lua needs a directory for its fixtures")
local real_hash = arg[4]

if real_hash == nil then
	h.stub_auth_modules()
end

-- The password behind every test account. With the stand-ins it is stored
-- as what their crypt returns for it, so a login with it verifies and any
-- other fails.
local password = "open sesame"
local stored_hash = real_hash or "$6$rounds=300000$testsalt$" .. password
-- carol never logs in, and her hash only has to differ from Alice's, so a
-- session bound to one account's hash cannot pass for another's.
local carol_hash = "$6$rounds=5000$carolsalt$carols-password"

if variant == "file" then
	local users_file = io.open(directory .. "/auth-users", "w")
	users_file:write("Alice:" .. stored_hash .. "\r\n")
	users_file:write("not a parsable line\n")
	users_file:write("carol:" .. carol_hash .. "\n")
	users_file:close()
	local groups_file = io.open(directory .. "/auth-groups", "w")
	groups_file:write("DEVS:Alice, bob\n")
	groups_file:write("others:carol, alice\n")
	groups_file:close()
	local repos_file = io.open(directory .. "/auth-repos", "w")
	repos_file:write("secret-repo:Devs\n")
	repos_file:write("both-repo:devs,others\n")
	repos_file:write("empty-repo:ghosts\n")
	repos_file:write("bare-repo:\n")
	repos_file:close()
	h.redirect_file("/etc/cgit-auth/users", directory .. "/auth-users")
	h.redirect_file("/etc/cgit-auth/groups", directory .. "/auth-groups")
	h.redirect_file("/etc/cgit-auth/repos", directory .. "/auth-repos")
end

-- The inline script carries its lists in the code, so its commented-out
-- examples are switched on with the same data the fixture files hold.
local inline_config = {
	{ "local protected_repos = {\n", "local protected_repos = {\n" ..
		"\t[\"secret-repo\"] = { alice = true, Bob = true },\n" ..
		"\t[\"both-repo\"] = { alice = true, bob = true, carol = true },\n" ..
		"\t[\"empty-repo\"] = {},\n" },
	{ "local users = {\n", "local users = {\n" ..
		"\tAlice = \"" .. stored_hash .. "\",\n" ..
		"\tcarol = \"" .. carol_hash .. "\",\n" },
}

-- Every load keeps its signing secret in the run's directory, at the path
-- given or else at one shared by all of them.
local function load_script(changes, secret_path)
	local all = {
		{ "local secret_filename = \"/var/lib/cgit/auth-secret\"",
			"local secret_filename = " .. string.format("%q", secret_path or directory .. "/auth-secret") },
	}
	if variant == "inline" then
		for _, change in ipairs(inline_config) do
			all[#all + 1] = change
		end
	end
	for _, change in ipairs(changes or {}) do
		all[#all + 1] = change
	end
	h.load_with(script, all)
end

load_script()

-- Served over https at the root, the session cookie takes the __Host- name.
local session_name = "__Host-cgitauth"

-- crypt is watched through the module the script requires, so a check can
-- see whether a login spent it and on which hash. With crypt_unchecked set
-- it answers nil, as crypt(3) does for a kind of hash the system does not
-- check.
local unistd = require("posix.unistd")
local real_crypt = unistd.crypt
local crypt_settings = {}
local crypt_unchecked = false
unistd.crypt = function(trypass, setting)
	crypt_settings[#crypt_settings + 1] = setting
	if crypt_unchecked then
		return nil
	end
	return real_crypt(trypass, setting)
end

local function read_file(path)
	local file = io.open(path, "rb")
	if file == nil then
		return nil
	end
	local text = file:read("*a")
	file:close()
	return text
end

local function write_file(path, text)
	local file = assert(io.open(path, "wb"))
	file:write(text)
	file:close()
end

-- The secret is made on first use, so the masks it is made under and the
-- temporary files it is linked from are watched the same way. A secret set
-- in race_winner is written just ahead of the link, the way another request
-- making the file at the same moment would.
local sysstat = require("posix.sys.stat")
local real_umask = sysstat.umask
local umasks = {}
sysstat.umask = function(mask)
	local old = real_umask(mask)
	umasks[#umasks + 1] = { mask = mask, old = old }
	return old
end
local real_link = unistd.link
local linked = {}
local race_winner = nil
unistd.link = function(from, to)
	linked[#linked + 1] = from
	if race_winner then
		write_file(to, race_winner)
	end
	return real_link(from, to)
end

local _, made = pcall(get_secret)
h.check("a new secret is 64 hex characters",
	type(made) == "string" and #made == 64 and not made:find("%X"), tostring(made))
h.equals("and is what its file holds", read_file(directory .. "/auth-secret"), made)
if real_hash then
	local stat = sysstat.stat(directory .. "/auth-secret")
	h.equals("which only its owner can read", stat and stat.st_mode % 512, 384)
end
h.equals("it is written under a mask that keeps everyone else out", umasks[1] and umasks[1].mask, 63)
h.check("and the mask before it goes back after",
	#umasks == 2 and umasks[2].mask == umasks[1].old)
h.equals("it reaches its name through one link", #linked, 1)
h.equals("and the temporary file it was linked from is removed", linked[1] and read_file(linked[1]), nil)
load_script()
h.equals("a later load takes the same secret from the file", select(2, pcall(get_secret)), made)
h.equals("without making another", #linked, 1)

-- The request that made the secret first keeps it, since it may have
-- signed sessions with it already.
race_winner = string.rep("9", 64)
load_script(nil, directory .. "/raced-secret")
h.equals("a secret made meanwhile by another request wins", select(2, pcall(get_secret)), race_winner)
h.equals("and is left as it was", read_file(directory .. "/raced-secret"), race_winner)
h.equals("while the temporary file is still removed", read_file(linked[#linked]), nil)
race_winner = nil

-- A secret made by hand is read as its first line, so one saved with a
-- newline still serves, while one of the wrong length is refused.
write_file(directory .. "/typed-secret", made .. "\n")
load_script(nil, directory .. "/typed-secret")
h.equals("a secret ending in a newline is read without it", select(2, pcall(get_secret)), made)
write_file(directory .. "/short-secret", "0123456789\n")
load_script(nil, directory .. "/short-secret")
local short_ok, short_err = pcall(get_secret)
h.check("a secret of the wrong length is refused", not short_ok)
h.contains("as malformed", tostring(short_err), "is malformed, expected 64 hex characters")
load_script()

-- The lookups themselves, which are the part the two variants do not share.

local hash = account_hash("ALICE")
h.equals("an account is found whatever its case", hash, stored_hash)
h.equals("an unknown account is not", account_hash("nobody"), nil)
local _, stand_in = account_hash("nobody")
h.check("it brings another account's hash to spend instead",
	stand_in == stored_hash or stand_in == carol_hash, tostring(stand_in))

local userset = repo_userset("secret-repo")
h.check("a protected repository lists its users",
	userset ~= nil and userset.alice and userset.bob)
h.equals("an unlisted repository is public", repo_userset("unlisted"), nil)
h.equals("the repository name matches case exactly", repo_userset("Secret-Repo"), nil)
local empty = repo_userset("empty-repo")
h.check("a protected repository with no members denies as an empty set",
	empty ~= nil and next(empty) == nil)
local both = repo_userset("both-repo")
h.check("a repository of two groups lets in the members of each",
	both ~= nil and both.alice and both.bob and both.carol)
if variant == "file" then
	local bare = repo_userset("bare-repo")
	h.check("a protected repository with no groups at all denies too",
		bare ~= nil and next(bare) == nil)
end

if variant == "file" then
	h.redirect_file("/etc/cgit-auth/users", directory .. "/auth-users-missing")
	h.equals("a missing users file turns every login down", account_hash("alice"), nil)
	h.redirect_file("/etc/cgit-auth/users", directory .. "/auth-users")
	-- Without the repos file nothing tells a protected repository from a
	-- public one, so every page is refused, the index too, which cgit asks
	-- about with an empty repository name.
	h.redirect_file("/etc/cgit-auth/repos", directory .. "/auth-repos-missing")
	h.reset()
	local refused = repo_userset("unlisted")
	h.check("a missing repos file refuses every repository",
		refused ~= nil and next(refused) == nil)
	h.contains("and says so in the error log", h.error_log(), "[cgit] Unable to read the auth repos file: ")
	local index = repo_userset("")
	h.check("and the index as well", index ~= nil and next(index) == nil)
	h.redirect_file("/etc/cgit-auth/repos", directory .. "/auth-repos")
	-- Without the groups file nobody is a member, which has to deny rather
	-- than make the repository public.
	h.redirect_file("/etc/cgit-auth/groups", directory .. "/auth-groups-missing")
	local memberless = repo_userset("secret-repo")
	h.check("a missing groups file leaves a protected repository with nobody let in",
		memberless ~= nil and next(memberless) == nil)
	h.redirect_file("/etc/cgit-auth/groups", directory .. "/auth-groups")
end

-- The url and cookie helpers.

h.equals("decode handles escapes and plus", url_decode("%41+b"), "A b")
h.equals("encode escapes what is not a word", url_encode("a b|c"), "a+b%7Cc")
local tricky = "x&=?|"
h.equals("decode inverts encode", url_decode(url_encode(tricky)), tricky)

local params = parse_query("u=a&p=b=c&x=%41")
h.equals("a query splits on ampersands", params.u, "a")
h.equals("a value keeps its own equals signs", params.p, "b=c")
h.equals("a value is decoded", params.x, "A")

h.equals("a cookie is found among others",
	get_cookie("foo=1; cgitauth=abc; bar=2", "cgitauth"), "abc")
h.equals("a lone cookie is found", get_cookie("cgitauth=abc", "cgitauth"), "abc")
h.equals("no header yields no cookie", get_cookie(nil, "cgitauth"), nil)
h.equals("a longer name does not match", get_cookie("xcgitauth=z", "cgitauth"), nil)
h.equals("a magic character in the name is taken literally", get_cookie("a-b=z", "a-b"), "z")
h.equals("spaces around a pair are ignored", get_cookie(" foo=1 ;  cgitauth=abc ", "cgitauth"), "abc")
h.equals("a cookie value keeps its own equals signs", get_cookie("cgitauth=a=b", "cgitauth"), "a=b")

-- The Cookie header is the visitor's to write, so a run of spaces in it
-- must not cost the square of its length. At this length a linear trim
-- takes about a millisecond and the square about fifteen seconds.
local spaces = string.rep(" ", 100000)
local started = os.clock()
get_cookie("a=" .. spaces .. "b", "cgitauth")
h.check("a long run of spaces inside a cookie is read within half a second", os.clock() - started < 0.5)
started = os.clock()
local found = get_cookie(spaces .. "cgitauth=abc", "cgitauth")
h.check("and one ahead of it as well", os.clock() - started < 0.5)
h.equals("without losing the cookie behind it", found, "abc")

h.check("equal strings compare equal", constant_equals("abc", "abc"))
h.check("differing strings do not", not constant_equals("abc", "abd"))
h.check("nor do strings whose byte differences cancel out",
	not constant_equals("ab", "ba") and not constant_equals("ac", "bb"))
h.check("differing lengths do not", not constant_equals("a", "ab"))
h.check("non strings do not", not constant_equals(nil, "a"))

h.check("a local path is a safe redirect", is_safe_redirect("/x"))
h.check("and so is the root", is_safe_redirect("/"))
h.check("a scheme relative target is not", not is_safe_redirect("//evil"))
h.check("a backslash variant is not", not is_safe_redirect("/\\evil"))
h.check("nor one of backslashes alone", not is_safe_redirect("\\\\evil"))
h.check("nor an absolute url", not is_safe_redirect("https://evil.example/"))
h.check("nor any other scheme", not is_safe_redirect("javascript:x"))
h.check("nor a relative path", not is_safe_redirect("x/y"))
h.check("nor an empty target", not is_safe_redirect(""))
h.check("a missing target is not", not is_safe_redirect(nil))

-- Signing and verification.

local now = os.time()

local cookie = secure_value("username", "alice", now + 3600)
h.equals("a signed value verifies and comes back", validate_value("username", cookie), "alice")
local signature = cookie:match("|(%x+)$")
h.equals("its signature is a whole SHA-256 in hex", signature and #signature, 64)
h.equals("each byte becomes two hex digits", tohex("\0\15\255"), "000fff")

cookie = secure_value("username", "a|b", now + 3600)
h.equals("a value holding the separator survives the round trip", validate_value("username", cookie), "a|b")

cookie = secure_value("username", "a\nb", now + 3600)
h.equals("a signed control character is still rejected on the way out",
	validate_value("username", cookie), nil)

cookie = secure_value("redirect", "/repo/?a=b", 0)
h.equals("an expiration of zero never expires", validate_value("redirect", cookie), "/repo/?a=b")

cookie = secure_value("username", "alice", now - 10)
h.equals("an expired value is rejected", validate_value("username", cookie), nil)

-- The expiry second itself is already too late, which only a clock held
-- still can show.
local real_time = os.time
os.time = function()
	return now
end
h.equals("a value is rejected at its expiry second",
	validate_value("username", secure_value("username", "alice", now)), nil)
h.equals("and accepted the second before",
	validate_value("username", secure_value("username", "alice", now + 1)), "alice")
os.time = real_time

cookie = secure_value("username", "alice", now + 3600)
local flipped = cookie:sub(1, -2) .. (cookie:sub(-1) == "0" and "1" or "0")
h.equals("a tampered signature is rejected", validate_value("username", flipped), nil)

h.equals("a value signed for one field does not serve another", validate_value("redirect", cookie), nil)

-- The signature covers every field beside it, so none can be changed under
-- it. A later expiry would let a captured session run for ever.
local function with_field(token, index, replacement)
	local fields = {}
	for part in token:gmatch("[^|]+") do
		fields[#fields + 1] = part
	end
	fields[index] = replacement
	return table.concat(fields, "|")
end
h.equals("a cookie rebuilt unchanged still verifies",
	validate_value("username", with_field(cookie, 1, "username")), "alice")
h.equals("a later expiry under the same signature does not",
	validate_value("username", with_field(cookie, 3, tostring(now + 7200))), nil)
h.equals("nor does another salt", validate_value("username", with_field(cookie, 4, string.rep("0", 32))), nil)
h.equals("nor another name", validate_value("username", with_field(cookie, 2, "mallory")), nil)
local way_out = secure_value("redirect", "/repo/", 0)
h.equals("nor a way back pointed at another page",
	validate_value("redirect", with_field(way_out, 2, url_encode("/other/"))), nil)

h.equals("no cookie does not verify", validate_value("username", nil), nil)
h.equals("a tiny cookie does not verify", validate_value("username", "ab"), nil)
h.equals("a leading separator does not verify", validate_value("username", "|" .. cookie), nil)
h.equals("a trailing field does not verify", validate_value("username", cookie .. "|x"), nil)
h.equals("an unsigned cookie does not verify",
	validate_value("username", "username|alice|123|salt"), nil)
h.equals("an exponent spelling of the expiry does not verify, even signed",
	validate_value("username", secure_value("username", "alice", "1e10")), nil)
h.equals("an empty value signs to nothing", secure_value("username", "", 1), "")

-- The headers the filter writes itself.

h.reset()
set_cookie("cgitauth", "value")
local out = h.output()
h.contains("a session cookie carries the hardening attributes", out,
	"Set-Cookie: cgitauth=value; HttpOnly; SameSite=Lax; Path=/; Secure; " ..
	"Max-Age=604800\n")

h.reset()
set_cookie("cgitauth", "")
h.contains("an empty value clears the cookie instead", h.output(),
	"Set-Cookie: cgitauth=; HttpOnly; SameSite=Lax; Path=/; Secure; " ..
	"Max-Age=0\n")

h.reset()
redirect_to("/x\r\nX-Evil: 1")
out = h.output()
h.contains("a newline cannot split the location header", out,
	"Location: /xX-Evil: 1\n")
h.excludes("no carriage return slips through", out, "\r")

-- The three actions, driven the way cgit drives them, an open carrying the
-- request, a write only for the posted form and the answer read off the
-- close.

local function run_action(action, opts)
	opts = opts or {}
	h.reset()
	filter_open(action, opts.cookie or "", opts.method or "GET", "", "",
		"/", "example.org", opts.https or "on", opts.repo or "", "summary",
		opts.url or "/repo/", "/?p=login")
	if opts.body then
		filter_write(opts.body)
	end
	local ret = filter_close()
	return h.output(), ret
end

-- A login posts the form, and a visit asks about a repository, with a
-- session cookie when it is given one, and comes back with the answer.
local function login(user, pass, redirect)
	local body = "username=" .. url_encode(user) .. "&password=" .. url_encode(pass)
	if redirect then
		body = body .. "&redirect=" .. url_encode(redirect)
	end
	return run_action("authenticate-post", { method = "POST", body = body })
end

local function visit(repo, token)
	local _, ret = run_action("authenticate-cookie",
		{ repo = repo, cookie = token and session_name .. "=" .. token })
	return ret
end

-- Where the signed way back in a login form leads.
local function way_back_in(form)
	local token = form:match("name='redirect' value='([^']*)'")
	return token and validate_value("redirect", token)
end

h.equals("a public repository needs no cookie", visit("unlisted"), 1)
h.equals("a protected repository turns a bare request away", visit("secret-repo"), 0)

local session = secure_value("username", "Alice", now + 3600, stored_hash)
h.equals("a signed session for a member is let through", visit("secret-repo", session), 1)

-- A session is signed with its account's hash, so a new password or a
-- removed account ends it.
local stale = secure_value("username", "Alice", now + 3600, "$6$rounds=300000$old$hash")
h.equals("a session from before a password change is turned away", visit("secret-repo", stale), 0)

local orphan = secure_value("username", "bob", now + 3600, stored_hash)
h.equals("a session for a member with no account is turned away", visit("secret-repo", orphan), 0)

local unbound = secure_value("username", "Alice", now + 3600)
h.equals("a session signed without its binding does not verify",
	validate_value("username", unbound, account_hash), nil)

h.equals("a memberless repository denies even a valid session", visit("empty-repo", session), 0)
h.equals("a repository of two groups lets in a member of the first", visit("both-repo", session), 1)
if variant == "file" then
	h.redirect_file("/etc/cgit-auth/groups", directory .. "/auth-groups-missing")
	h.equals("as does one whose groups file is missing", visit("secret-repo", session), 0)
	h.redirect_file("/etc/cgit-auth/groups", directory .. "/auth-groups")
end

local outsider = secure_value("username", "carol", now + 3600, carol_hash)
h.equals("a signed session for an outsider is turned away", visit("secret-repo", outsider), 0)
h.equals("while one in the second group lets them in", visit("both-repo", outsider), 1)

local forged = session:sub(1, -2) .. (session:sub(-1) == "0" and "1" or "0")
h.equals("a forged session is turned away", visit("secret-repo", forged), 0)

local expired = secure_value("username", "Alice", now - 10, stored_hash)
h.equals("an expired session is turned away", visit("secret-repo", expired), 0)

-- Only the __Host- name is safe from a cookie a sibling subdomain planted.
local _, planted = run_action("authenticate-cookie", { repo = "secret-repo", cookie = "cgitauth=" .. session })
h.equals("a session under the plain cookie name is turned away", planted, 0)

-- Only the secret keeps a visitor from signing a session of their own, so
-- one signed under any other secret is worthless.
local real_get_secret = get_secret
get_secret = function()
	return string.rep("fedcba9876543210", 4)
end
h.equals("a session signed under another secret does not verify",
	validate_value("username", session, account_hash), nil)
h.equals("and lets nobody in", visit("secret-repo", session), 0)
get_secret = real_get_secret
h.equals("while under its own secret it still does", visit("secret-repo", session), 1)

local _, ret = run_action("no-such-action", {})
h.equals("an unknown action denies rather than raising", ret, 0)

out = run_action("body", { url = "/repo/log/?q=x" })
h.contains("the login form posts to the login url", out, "<form class='login' method='post' action='/?p=login'>")
h.contains("and its table is read as layout, not data", out, "<table role='presentation'>")
-- login() posts the fields under names of its own, so nothing else holds
-- the form to the names a login reads.
h.contains("the form names its fields as a login reads them", out, "<input id='username' name='username'")
h.contains("the password among them", out, "<input id='password' name='password'")
h.equals("a first visit says nothing failed", out:find("login-error", 1, true), nil)
h.equals("the form carries a signed way back", way_back_in(out), "/repo/log/?q=x")

out = run_action("body", { cookie = session_name .. "=" .. outsider })
h.contains("a visitor signed in without access is told so", out,
	"<p class='login-error' role='alert'>You are signed in but have no access to this repository.</p>")
h.check("and can still sign in as someone else", way_back_in(out) ~= nil)
out = run_action("body", { cookie = session_name .. "=" .. forged })
h.contains("a visitor with a forged session is still shown the form", out, "<form class='login'")
h.excludes("a forged session is not taken for a signed-in visitor", out, "signed in")

-- The session cookie is Secure, so a form served over plain http would only
-- come round again after every login.
out = run_action("body", { https = "" })
h.contains("over plain http the form says logging in needs https", out,
	"<p class='login-error' role='alert'>Logging in only works over https.</p>")
h.check("and is still there to fill in", way_back_in(out) ~= nil)
out = run_action("body", {})
h.contains("over https the form is shown", out, "<form class='login'")
h.excludes("over https it says nothing of the kind", out, "only works over https")

out = run_action("body", { url = "//evil.example/x" })
h.equals("an unsafe destination is swapped for the login page", way_back_in(out), "/?p=login")
h.equals("and is not taken for a failed login", out:find("login-error", 1, true), nil)
out = run_action("body", { url = "https://evil.example/x" })
h.equals("and so is one with a scheme", way_back_in(out), "/?p=login")

out = run_action("body", { url = "/repo/log/?q=x&login=failed" })
h.contains("a failed login says so", out,
	"<p class='login-error' role='alert'>Wrong username or password.</p>")
h.equals("and leaves the flag out of the way back", way_back_in(out), "/repo/log/?q=x")
-- A page with no query of its own comes back flagged after a question mark.
out = run_action("body", { url = "/repo/?login=failed" })
h.contains("a flag after a question mark says so too", out,
	"<p class='login-error' role='alert'>Wrong username or password.</p>")
h.equals("and leaves the flag and its mark out of the way back", way_back_in(out), "/repo/")

-- The real get_secret, pointed at a directory nobody made, cannot sign the
-- way back, so the page says so whole rather than breaking off in the form.
load_script(nil, directory .. "/no-such-directory/auth-secret")
out = run_action("body", {})
h.contains("a secret that cannot be made leaves a page saying so", out,
	"<p class='login-error' role='alert'>Logins are unavailable. The server's error log says why.</p>")
h.excludes("with no form to fill in", out, "<form")
h.contains("and the error log names the directory", h.error_log(),
	"as " .. directory .. "/no-such-directory is missing or not writable by cgit\n")
load_script()

local way_back = secure_value("redirect", "/repo/", 0)

-- A session's expiry is signed into it, apart from the Max-Age the browser
-- is told, and is what still counts once a visitor keeps the cookie longer.
local function session_expiry(token)
	return tonumber(token and token:match("^[^|]+|[^|]+|(%d+)|"))
end

local before = os.time()
out = login("Alice", password, way_back)
h.contains("a good login redirects back", out, "Status: 302")
h.contains("to where the form said", out, "Location: /repo/\n")
local granted = out:match("Set%-Cookie: __Host%-cgitauth=([^;]*);")
h.equals("and grants a session that verifies", granted and validate_value("username", granted, account_hash), "Alice")
local expires = session_expiry(granted)
h.check("which expires a week after the login",
	expires and expires >= before + 604800 and expires <= os.time() + 604800, tostring(expires))

-- A plain == at either comparison would leave every check above passing
-- while timing told a visitor how much of a guess was right.
local real_constant_equals = constant_equals
local compared = {}
constant_equals = function(a, b)
	compared[#compared + 1] = { a, b }
	return real_constant_equals(a, b)
end
local function was_compared(value)
	for _, pair in ipairs(compared) do
		if pair[1] == value or pair[2] == value then
			return true
		end
	end
	return false
end
visit("secret-repo", session)
h.check("a visit compares the signature in constant time", was_compared(session:match("[^|]+$")))
compared = {}
login("Alice", password, way_back)
h.check("and a login the password's hash", was_compared(stored_hash))
constant_equals = real_constant_equals
h.equals("and logs nothing", h.error_log(), "")

out = login("Alice", "wrong", way_back)
local wrong_password = out
h.contains("a bad password redirects the same way", out, "Status: 302")
h.contains("back to the page with the failure flagged", out, "Location: /repo/?login=failed\n")
h.contains("but clears the session cookie", out, "Set-Cookie: " .. session_name .. "=; ")
crypt_unchecked = true
local answered, answer = pcall(login, "Alice", password, way_back)
crypt_unchecked = false
h.check("a hash the system cannot check turns a login down without an error", answered, tostring(answer))
h.equals("as a wrong password does", answer, wrong_password)
h.contains("and is logged with the name and the page", h.error_log(),
	"[cgit] Failed login as Alice for /repo/\n")
h.excludes("but never with the password", h.error_log(), "wrong")
login("eve\r\n[cgit] Forged", "x", way_back)
h.contains("a name cannot forge a log line of its own", h.error_log(),
	"[cgit] Failed login as eve[cgit] Forged for /repo/\n")

-- A failed login for a name with no account spends crypt on a configured
-- hash, the same work a real check costs, so timing tells nothing.
crypt_settings = {}
out = login("nobody", "unknown secret", way_back)
h.equals("an unknown user is told nothing different", out, wrong_password)
h.check("a missing account spends crypt on a configured hash",
	crypt_settings[1] == stored_hash or crypt_settings[1] == carol_hash, tostring(crypt_settings[1]))
h.contains("and is logged by name", h.error_log(), "[cgit] Failed login as nobody for /repo/\n")
h.excludes("but never with the password", h.error_log(), "unknown secret")

-- A post missing a field, or with a field that has no value, is a failed
-- login like any other rather than an error.
local back = url_encode(way_back)
for _, case in ipairs({
	{ "with no name", "password=hunter2&redirect=" .. back, "" },
	{ "with no password", "username=Alice&redirect=" .. back, "Alice" },
	{ "with neither", "redirect=" .. back, "" },
	{ "with a field that has no value", "hunter2&redirect=" .. back, "" },
}) do
	local answered, answer = pcall(run_action, "authenticate-post", { method = "POST", body = case[2] })
	h.check("a login " .. case[1] .. " is answered without an error", answered, tostring(answer))
	h.contains("a login " .. case[1] .. " clears the session cookie", tostring(answer),
		"Set-Cookie: " .. session_name .. "=; ")
	h.contains("a login " .. case[1] .. " lands on the flagged page", tostring(answer),
		"Location: /repo/?login=failed\n")
	h.contains("a login " .. case[1] .. " is logged", h.error_log(),
		"[cgit] Failed login as " .. case[3] .. " for /repo/\n")
	h.excludes("a login " .. case[1] .. " never logs a password", h.error_log(), "hunter2")
end

if variant == "file" then
	h.redirect_file("/etc/cgit-auth/users", directory .. "/auth-users-missing")
	crypt_settings = {}
	login("nobody", "x", way_back)
	h.equals("with no accounts at all nothing is spent", #crypt_settings, 0)
	write_file(directory .. "/auth-users-unparsable", "not a parsable line\nnor this one\n")
	h.redirect_file("/etc/cgit-auth/users", directory .. "/auth-users-unparsable")
	crypt_settings = {}
	out = login("Alice", password, way_back)
	h.contains("a users file with no line that parses turns a login down", out,
		"Location: /repo/?login=failed\n")
	h.equals("and spends nothing either", #crypt_settings, 0)
	h.redirect_file("/etc/cgit-auth/users", directory .. "/auth-users")
end

-- crypt's work grows with the password, so one past the cap is turned down
-- before crypt sees it.
crypt_settings = {}
out = login("Alice", string.rep("a", 257), way_back)
h.contains("an overlong password is turned down", out, "Set-Cookie: " .. session_name .. "=; ")
h.equals("without spending crypt on it", #crypt_settings, 0)
h.contains("and is logged like any failed login", h.error_log(), "[cgit] Failed login as Alice for /repo/\n")
h.excludes("without the password", h.error_log(), string.rep("a", 257))
login("Alice", string.rep("a", 256), way_back)
h.equals("a password at the cap is still checked", #crypt_settings, 1)

out = login("Alice", password)
h.contains("a post without the signed token is not served", out, "Status: 404")

out = login("Alice", password, secure_value("redirect", "//evil.example/", 0))
h.contains("even a signed unsafe destination is not followed", out, "Status: 404")
out = login("Alice", password, secure_value("redirect", "https://evil.example/", 0))
h.contains("nor a signed one with a scheme", out, "Status: 404")

-- Over plain http the cookie cannot be Secure, and so loses the __Host- name.
load_script({ { "local cookie_insecure = false", "local cookie_insecure = true" } })
out = login("Alice", password, way_back)
h.contains("an insecure session cookie keeps its plain name", out, "Set-Cookie: cgitauth=")
h.excludes("and is not marked Secure", out, "; Secure")
out = run_action("body", { https = "" })
h.contains("so its form is shown over plain http", out, "<form class='login'")
h.excludes("without asking for https", out, "only works over https")
load_script()

-- A browser takes a __Host- cookie only for the whole host, so one scoped
-- below the root keeps the plain name, though it stays Secure.
load_script({ { "local cookie_path = \"/\"", "local cookie_path = \"/cgit/\"" } })
out = login("Alice", password, way_back)
h.check("a cookie scoped below the root keeps its plain name and stays Secure",
	out:find("\nSet%-Cookie: cgitauth=[^;]+; HttpOnly; SameSite=Lax; Path=/cgit/; Secure; Max%-Age=604800\n") ~= nil, out)
h.excludes("rather than the __Host- one", out, "__Host-")
load_script()

-- A cookie carries whole seconds, while on Lua 5.3 and later a session length
-- worked out with a fraction is a float, which tostring writes with a ".0".
load_script({ { "local session_seconds = 7 * 24 * 60 * 60",
	"local session_seconds = 1.5 * 24 * 60 * 60" } })
before = os.time()
out = login("Alice", password, way_back)
granted = out:match("Set%-Cookie: __Host%-cgitauth=([^;]*);")
h.equals("a session a day and a half long still verifies",
	granted and validate_value("username", granted, account_hash), "Alice")
expires = session_expiry(granted)
h.check("and expires as long after the login",
	expires and expires >= before + 129600 and expires <= os.time() + 129600, tostring(expires))
h.contains("and its cookie lasts as many whole seconds", out, "; Max-Age=129600\n")
load_script()

local libraries = { "openssl.rand", "openssl.hmac", "posix.sys.stat", "posix.unistd" }

local function without(name)
	package.loaded[name] = nil
	h.preload_failure(name)
end

-- Before the secret is made a login needs every library, so with any one of
-- them gone the form gives way to a page saying logins are unavailable,
-- while a session or a posted login fails closed, and each says which.
for _, name in ipairs(libraries) do
	local loaded, loader = package.loaded[name], package.preload[name]
	without(name)
	load_script(nil, directory .. "/unmade-secret")
	out = run_action("body", {})
	h.contains("without " .. name .. " the login page says logins are unavailable", out,
		"Logins are unavailable.")
	h.excludes("without " .. name .. " it has no form", out, "<form")
	h.contains("without " .. name .. " the error log names it", h.error_log(), name)
	local visited, visit_err = pcall(visit, "secret-repo", session)
	h.check("without " .. name .. " a session fails closed", not visited)
	h.contains("without " .. name .. " its error names it", tostring(visit_err), name)
	local posted, post_err = pcall(login, "Alice", password, way_back)
	h.check("without " .. name .. " a login fails closed", not posted)
	h.contains("without " .. name .. " the login's error names it", tostring(post_err), name)
	package.loaded[name], package.preload[name] = loaded, loader
end

-- Once the secret exists a login still needs crypt.
load_script()
local loaded, loader = package.loaded["posix.unistd"], package.preload["posix.unistd"]
without("posix.unistd")
local posted, post_err = pcall(login, "Alice", password, way_back)
h.check("without posix.unistd a login with a made secret fails closed", not posted)
h.contains("naming posix.unistd", tostring(post_err), "posix.unistd")
package.loaded["posix.unistd"], package.preload["posix.unistd"] = loaded, loader

-- The libraries load only once a request needs one, so with every one of
-- them gone the script still loads and a public repository is served,
-- while a protected one fails closed instead of reaching its content.
for _, name in ipairs(libraries) do
	without(name)
end
load_script()
h.equals("without the libraries a public repository is served", visit("unlisted"), 1)
local visited, visit_err = pcall(visit, "secret-repo", session)
h.check("while a protected one fails closed", not visited)
h.contains("with an error naming the library it needed", tostring(visit_err), "openssl.hmac")
out = run_action("body", {})
h.contains("and its login page says logins are unavailable", out, "Logins are unavailable.")
h.excludes("and no form to fill in", out, "<form")
h.contains("while the error log names the missing library", h.error_log(), "openssl.rand")

h.finish()