Reorganise the tree into vendor/ and custom/

1 file changed, 0 insertions, 556 deletions

diff --git a/extensions/auth-file.lua b/extensions/auth-file.luadeleted file mode 100644index 5415ca7..0000000--- a/extensions/auth-file.lua+++ /dev/null@@ -1,556 +0,0 @@--- cgit auth-filter that gates repositories behind a login form and a signed--- session cookie.------ This is the FILE-BACKED variant. The user accounts, the groups, and the--- per-repository access lists are read from files on disk, whose paths are set--- in the CONFIGURATION block below. Edit those files without touching this--- script. This suits larger or externally managed user sets.------ The companion auth-inline.lua behaves identically but keeps its accounts and--- access lists inline in the script itself, which suits a small fixed set of--- users.------ Enable it in cgitrc with---     auth-filter=lua:/path/to/auth-file.lua------ SUPPORTED LUA------ Lua 5.1, 5.2, 5.3, 5.4 and LuaJIT. Lua 5.5 is not supported, because luaossl--- has no 5.5 build. Match the runtime to the Lua that cgit is built against.------ HTTPS IS RECOMMENDED------ Serve cgit over HTTPS. Terminate TLS at the web server in front of cgit. The--- session cookie is marked Secure by default, so a browser only sends it back--- over HTTPS. If you genuinely run cgit over plain HTTP with no TLS anywhere,--- set cookie_insecure below, otherwise the cookie is never returned and login--- appears to loop.------ DEPENDENCIES------     luaossl    OpenSSL binding, provides openssl.rand and openssl.hmac---                <https://github.com/wahern/luaossl>---     luaposix   POSIX binding, provides posix.sys.stat and posix.unistd---                <https://github.com/luaposix/luaposix>------ The reliable cross-platform install is LuaRocks, matched to your Lua--- version. luaossl also needs the OpenSSL development headers present.------     # Debian and Ubuntu---     sudo apt install luarocks libssl-dev---     sudo luarocks --lua-version 5.1 install luaossl---     sudo luarocks --lua-version 5.1 install luaposix------     # Fedora---     sudo dnf install luarocks openssl-devel---     sudo luarocks --lua-version 5.1 install luaossl luaposix------     # Alpine---     sudo apk add luarocks openssl-dev---     sudo luarocks-5.1 install luaossl luaposix------     # macOS with Homebrew---     brew install luarocks openssl---     luarocks install luaossl OPENSSL_DIR="$(brew --prefix openssl)"---     luarocks install luaposix------ Some distributions also package these, for example lua-luaossl and lua-posix--- on Debian. If you use a distribution package, make sure it is built for the--- same Lua version as cgit.------ SECURITY NOTES------ The cookie carries only a username with no server-side session store, so--- deleting an account does not revoke a cookie already issued until it--- expires, and instances that share a secret file accept each other's cookies.--- The login form carries no CSRF token. Both are acceptable for gating read--- access to a git browser. Weigh them before guarding anything more sensitive.--local sysstat = require("posix.sys.stat")-local unistd = require("posix.unistd")-local rand = require("openssl.rand")-local hmac = require("openssl.hmac")------- ========================= CONFIGURATION =========================--- Edit the values in this block. Nothing below it needs changing for--- ordinary use.------- Accounts, one per line, as username:hash. Generate a hash with---     mkpasswd -m sha-512 -R 300000--- This file should not be world-readable.-local users_filename = "/etc/cgit-auth/users"---- Group membership, one per line, as groupname:user1,user2,user3,...-local groups_filename = "/etc/cgit-auth/groups"---- Per-repository access, one per line, as reponame:group1,group2,...--- A repository listed here is protected. One not listed is public.-local repos_filename = "/etc/cgit-auth/repos"---- Where the cookie-signing secret is stored. It is created on first use. It--- must be persistent and writable by cgit. Prefer a path OUTSIDE the cache--- root, because pruning the cache would delete a secret kept inside it and--- invalidate every live session. This file should not be world-readable.-local secret_filename = "/var/cache/cgit/auth-secret"---- How long a login stays valid, in seconds. Default one week.-local session_seconds = 7 * 24 * 60 * 60---- Name of the session cookie.-local cookie_name = "cgitauth"---- Path the cookie is scoped to. "/" covers the whole host. Set it to the cgit--- root to scope the cookie more tightly.-local cookie_path = "/"---- Leave false so the cookie is marked Secure and only travels over HTTPS. Set--- it true ONLY if cgit is served over plain HTTP with no TLS anywhere, see the--- HTTPS note in the header.-local cookie_insecure = false------- =================================================================------- A throwaway hash of the documented shape, used only to spend the same work--- on a missing account as on a present one, so a failed login does not reveal--- by timing whether the username exists.-local dummy_hash = "$6$rounds=300000$0000000000000000$"---- Module state shared across the open, write and close calls of one request.-local action, http, cgit, post---------- Account and access-list storage. This is the ONLY part that differs from--- auth-inline.lua. Swap these two functions to change where accounts live.--------local function trim(s)-	return (string.gsub(s, "^%s*(.-)%s*$", "%1"))-end---- Return the stored password hash for a user, or nil. Reads the users file--- fresh each call. A missing or unreadable file, and any unparsable line, are--- skipped rather than fatal.-function account_hash(user)-	if user == nil then-		return nil-	end-	local wanted = user:lower()-	local f = io.open(users_filename, "r")-	if f == nil then-		return nil-	end-	for line in f:lines() do-		local u, h = string.match(line, "(.-):(.+)")-		if u ~= nil and trim(u):lower() == wanted then-			f:close()-			return h-		end-	end-	f:close()-	return nil-end---- Return the set of users allowed to access a repository, keyed by lowercased--- username, or nil if the repository is not protected. A protected repository--- whose groups resolve to no users returns an EMPTY table, which denies--- everyone rather than falling through to public.-function repo_userset(repo)-	if repo == nil then-		return nil-	end-	local groups = nil-	local f = io.open(repos_filename, "r")-	if f ~= nil then-		for line in f:lines() do-			local r, g = string.match(line, "(.-):(.+)")-			if r ~= nil and trim(r) == repo then-				groups = {}-				for group in string.gmatch(g, "([^,]+)") do-					groups[trim(group):lower()] = true-				end-				break-			end-		end-		f:close()-	end-	if groups == nil then-		return nil-	end-	local users = {}-	local gf = io.open(groups_filename, "r")-	if gf ~= nil then-		for line in gf:lines() do-			local g, u = string.match(line, "(.-):(.+)")-			if g ~= nil and groups[trim(g):lower()] then-				for user in string.gmatch(u, "([^,]+)") do-					users[trim(user):lower()] = true-				end-			end-		end-		gf:close()-	end-	return users-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---- Parse an application/x-www-form-urlencoded body. A value may itself contain--- '=', for example a base64 password, so the value runs to the next '&'.-function parse_qs(qs)-	local tab = {}-	for key, val in string.gmatch(qs or "", "([^&=]+)=([^&]*)") do-		tab[url_decode(key)] = url_decode(val)-	end-	return tab-end---- Return the value of the named cookie, or nil. The stored token was already--- url-encoded by secure_value, so it is returned verbatim, which keeps the--- write path (set_cookie) and the read path symmetric. Decoding it here would--- break the signature check for any value carrying a percent escape.-function get_cookie(cookies, name)-	cookies = string.gsub(";" .. (cookies or "") .. ";", "%s*;%s*", ";")-	return string.match(cookies, ";" .. name .. "=(.-);")-end--function tohex(b)-	local x = ""-	for i = 1, #b do-		x = x .. string.format("%.2x", string.byte(b, i))-	end-	return x-end---------- Cookie construction and validation helpers.--------local secret = nil---- Load the cookie-signing secret, creating it on first use. Failures raise,--- which cgit turns into a request error, so a broken secret denies rather than--- signs with nothing.-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." .. tohex(rand.bytes(16))-		local temporary_file = io.open(temporary_filename, "w")-		if temporary_file == nil then-			sysstat.umask(old_umask)-			error("cgit auth: cannot create secret file " .. secret_filename)-		end-		local wrote = temporary_file:write(tohex(rand.bytes(32)))-		local closed = temporary_file:close()-		if not wrote or not closed then-			os.remove(temporary_filename)-			sysstat.umask(old_umask)-			error("cgit auth: failed writing secret file " .. secret_filename)-		end-		unistd.link(temporary_filename, secret_filename) -- Intentionally fails if another worker won the race.-		unistd.unlink(temporary_filename)-		sysstat.umask(old_umask)-		secret_file = io.open(secret_filename, "r")-	end-	if secret_file == nil then-		error("cgit auth: cannot read secret file " .. secret_filename)-	end-	secret = secret_file:read("*l")-	secret_file:close()-	if secret == nil or secret:len() ~= 64 then-		secret = nil-		error("cgit auth: secret file " .. secret_filename .. " is malformed, expected 64 hex characters")-	end-	return secret-end---- A redirect target is unsafe if a browser would read it as another origin.--- The only such form cgit can be tricked into signing is a scheme-relative--- "//host" or "/\host". Everything else stays on this host.-function is_safe_redirect(url)-	if type(url) ~= "string" then-		return false-	end-	local head = url:sub(1, 2)-	if head == "//" or head == "/\\" then-		return false-	end-	return true-end---- Return the value carried by a signed cookie, or nil if it does not verify.-function validate_value(expected_field, cookie)-	local i = 0-	local value = ""-	local field = ""-	local expiration = 0-	local salt = ""-	local chmac = ""--	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-			-- The expiration must be a plain integer. Rejecting other forms-			-- keeps the signed bytes canonical, since tonumber and tostring of-			-- "1e9" or "100.0" differ across Lua versions.-			if not string.match(component, "^%d+$") then-				return nil-			end-			expiration = tonumber(component)-		elseif i == 3 then-			salt = component-		elseif i == 4 then-			chmac = component-		else-			break-		end-		i = i + 1-	end--	if chmac == nil or chmac:len() == 0 then-		return nil-	end--	-- Compare the HMAC without short-circuiting on the first mismatch.-	if not constant_equals(chmac, tohex(hmac.new(get_secret(), "sha256"):final(field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt))) then-		return nil-	end--	-- An expiration of 0 never expires and is used for the redirect token.-	if expiration ~= 0 and expiration <= os.time() then-		return nil-	end--	if url_decode(field) ~= expected_field then-		return nil-	end--	local decoded = url_decode(value)-	-- Reject values carrying control characters so a signed value cannot-	-- smuggle CR or LF into a response header.-	if decoded:find("%c") then-		return nil-	end-	return decoded-end--function secure_value(field, value, expiration)-	if value == nil or value:len() <= 0 then-		return ""-	end--	local salt = tohex(rand.bytes(16))-	value = url_encode(value)-	field = url_encode(field)-	local authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt-	authstr = authstr .. "|" .. tohex(hmac.new(get_secret(), "sha256"):final(authstr))-	return authstr-end---- Strip control characters that could split an HTTP response header.-function strip_ctl(s)-	return (string.gsub(s or "", "%c", ""))-end---- Compare two strings in time that does not depend on how many leading bytes--- match, so a mismatch position is not revealed by timing.-function constant_equals(a, b)-	if type(a) ~= "string" or type(b) ~= "string" or #a ~= #b then-		return false-	end-	local diff = 0-	for i = 1, #a do-		local d = a:byte(i) - b:byte(i)-		diff = diff + d * d-	end-	return diff == 0-end--function set_cookie(cookie, value)-	local attrs = "; HttpOnly; SameSite=Lax; Path=" .. cookie_path-	if not cookie_insecure then-		attrs = attrs .. "; Secure"-	end-	if value == "" then-		attrs = attrs .. "; Max-Age=0"-	elseif session_seconds > 0 then-		attrs = attrs .. "; Max-Age=" .. tostring(session_seconds)-	end-	html("Set-Cookie: " .. cookie .. "=" .. strip_ctl(value) .. attrs .. "\n")-end--function redirect_to(url)-	html("Status: 302 Redirect\n")-	html("Cache-Control: no-cache, no-store\n")-	html("Location: " .. strip_ctl(url) .. "\n")-end--function not_found()-	html("Status: 404 Not Found\n")-	html("Cache-Control: no-cache, no-store\n\n")-end---------- Authentication actions. Identical to auth-inline.lua from here down.---------- Sets HTTP cookie headers based on post and sets up redirection.-function authenticate_post()-	local redirect = validate_value("redirect", post["redirect"])--	if redirect == nil or not is_safe_redirect(redirect) then-		not_found()-		return 0-	end--	redirect_to(redirect)--	local username = post["username"]-	local password = post["password"]-	local ok = false-	if username ~= nil and password ~= nil then-		local hash = account_hash(username)-		if hash == nil then-			-- Spend the work anyway, see dummy_hash.-			unistd.crypt(password, dummy_hash)-		elseif constant_equals(hash, unistd.crypt(password, hash)) then-			ok = true-		end-	end--	if ok then-		set_cookie(cookie_name, secure_value("username", username, os.time() + session_seconds))-	else-		set_cookie(cookie_name, "")-	end--	html("\n")-	return 0-end---- Returns 1 if the cookie is valid and 0 if it is not.-function authenticate_cookie()-	local accepted_users = repo_userset(cgit["repo"])-	if accepted_users == nil then-		-- The repository is not protected.-		return 1-	end--	local username = validate_value("username", get_cookie(http["cookie"], cookie_name))-	if username == nil or not accepted_users[username:lower()] then-		return 0-	end-	return 1-end---- Prints the html for the login form.-function body()-	local target = cgit["url"]-	if not is_safe_redirect(target) then-		target = cgit["login"]-	end--	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", target, 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 the filter API, exposing the http, cgit and post tables to--- the functions above.--------local actions = {}-actions["authenticate-post"] = authenticate_post-actions["authenticate-cookie"] = authenticate_cookie-actions["body"] = body--function filter_open(...)-	action = actions[select(1, ...)]--	post = {}--	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()-	if action == nil then-		-- Unknown action, deny rather than raise.-		return 0-	end-	return action()-end--function filter_write(str)-	post = parse_qs(str)-end
diff --git a/extensions/auth-file.lua b/extensions/auth-file.lua
deleted file mode 100644
index 5415ca7..0000000
--- a/extensions/auth-file.lua
+++ /dev/null
@@ -1,556 +0,0 @@
--- cgit auth-filter that gates repositories behind a login form and a signed
--- session cookie.
---
--- This is the FILE-BACKED variant. The user accounts, the groups, and the
--- per-repository access lists are read from files on disk, whose paths are set
--- in the CONFIGURATION block below. Edit those files without touching this
--- script. This suits larger or externally managed user sets.
---
--- The companion auth-inline.lua behaves identically but keeps its accounts and
--- access lists inline in the script itself, which suits a small fixed set of
--- users.
---
--- Enable it in cgitrc with
---     auth-filter=lua:/path/to/auth-file.lua
---
--- SUPPORTED LUA
---
--- Lua 5.1, 5.2, 5.3, 5.4 and LuaJIT. Lua 5.5 is not supported, because luaossl
--- has no 5.5 build. Match the runtime to the Lua that cgit is built against.
---
--- HTTPS IS RECOMMENDED
---
--- Serve cgit over HTTPS. Terminate TLS at the web server in front of cgit. The
--- session cookie is marked Secure by default, so a browser only sends it back
--- over HTTPS. If you genuinely run cgit over plain HTTP with no TLS anywhere,
--- set cookie_insecure below, otherwise the cookie is never returned and login
--- appears to loop.
---
--- DEPENDENCIES
---
---     luaossl    OpenSSL binding, provides openssl.rand and openssl.hmac
---                <https://github.com/wahern/luaossl>
---     luaposix   POSIX binding, provides posix.sys.stat and posix.unistd
---                <https://github.com/luaposix/luaposix>
---
--- The reliable cross-platform install is LuaRocks, matched to your Lua
--- version. luaossl also needs the OpenSSL development headers present.
---
---     # Debian and Ubuntu
---     sudo apt install luarocks libssl-dev
---     sudo luarocks --lua-version 5.1 install luaossl
---     sudo luarocks --lua-version 5.1 install luaposix
---
---     # Fedora
---     sudo dnf install luarocks openssl-devel
---     sudo luarocks --lua-version 5.1 install luaossl luaposix
---
---     # Alpine
---     sudo apk add luarocks openssl-dev
---     sudo luarocks-5.1 install luaossl luaposix
---
---     # macOS with Homebrew
---     brew install luarocks openssl
---     luarocks install luaossl OPENSSL_DIR="$(brew --prefix openssl)"
---     luarocks install luaposix
---
--- Some distributions also package these, for example lua-luaossl and lua-posix
--- on Debian. If you use a distribution package, make sure it is built for the
--- same Lua version as cgit.
---
--- SECURITY NOTES
---
--- The cookie carries only a username with no server-side session store, so
--- deleting an account does not revoke a cookie already issued until it
--- expires, and instances that share a secret file accept each other's cookies.
--- The login form carries no CSRF token. Both are acceptable for gating read
--- access to a git browser. Weigh them before guarding anything more sensitive.
-
-local sysstat = require("posix.sys.stat")
-local unistd = require("posix.unistd")
-local rand = require("openssl.rand")
-local hmac = require("openssl.hmac")
-
---
--- ========================= CONFIGURATION =========================
--- Edit the values in this block. Nothing below it needs changing for
--- ordinary use.
---
-
--- Accounts, one per line, as username:hash. Generate a hash with
---     mkpasswd -m sha-512 -R 300000
--- This file should not be world-readable.
-local users_filename = "/etc/cgit-auth/users"
-
--- Group membership, one per line, as groupname:user1,user2,user3,...
-local groups_filename = "/etc/cgit-auth/groups"
-
--- Per-repository access, one per line, as reponame:group1,group2,...
--- A repository listed here is protected. One not listed is public.
-local repos_filename = "/etc/cgit-auth/repos"
-
--- Where the cookie-signing secret is stored. It is created on first use. It
--- must be persistent and writable by cgit. Prefer a path OUTSIDE the cache
--- root, because pruning the cache would delete a secret kept inside it and
--- invalidate every live session. This file should not be world-readable.
-local secret_filename = "/var/cache/cgit/auth-secret"
-
--- How long a login stays valid, in seconds. Default one week.
-local session_seconds = 7 * 24 * 60 * 60
-
--- Name of the session cookie.
-local cookie_name = "cgitauth"
-
--- Path the cookie is scoped to. "/" covers the whole host. Set it to the cgit
--- root to scope the cookie more tightly.
-local cookie_path = "/"
-
--- Leave false so the cookie is marked Secure and only travels over HTTPS. Set
--- it true ONLY if cgit is served over plain HTTP with no TLS anywhere, see the
--- HTTPS note in the header.
-local cookie_insecure = false
-
---
--- =================================================================
---
-
--- A throwaway hash of the documented shape, used only to spend the same work
--- on a missing account as on a present one, so a failed login does not reveal
--- by timing whether the username exists.
-local dummy_hash = "$6$rounds=300000$0000000000000000$"
-
--- Module state shared across the open, write and close calls of one request.
-local action, http, cgit, post
-
---
---
--- Account and access-list storage. This is the ONLY part that differs from
--- auth-inline.lua. Swap these two functions to change where accounts live.
---
---
-
-local function trim(s)
-	return (string.gsub(s, "^%s*(.-)%s*$", "%1"))
-end
-
--- Return the stored password hash for a user, or nil. Reads the users file
--- fresh each call. A missing or unreadable file, and any unparsable line, are
--- skipped rather than fatal.
-function account_hash(user)
-	if user == nil then
-		return nil
-	end
-	local wanted = user:lower()
-	local f = io.open(users_filename, "r")
-	if f == nil then
-		return nil
-	end
-	for line in f:lines() do
-		local u, h = string.match(line, "(.-):(.+)")
-		if u ~= nil and trim(u):lower() == wanted then
-			f:close()
-			return h
-		end
-	end
-	f:close()
-	return nil
-end
-
--- Return the set of users allowed to access a repository, keyed by lowercased
--- username, or nil if the repository is not protected. A protected repository
--- whose groups resolve to no users returns an EMPTY table, which denies
--- everyone rather than falling through to public.
-function repo_userset(repo)
-	if repo == nil then
-		return nil
-	end
-	local groups = nil
-	local f = io.open(repos_filename, "r")
-	if f ~= nil then
-		for line in f:lines() do
-			local r, g = string.match(line, "(.-):(.+)")
-			if r ~= nil and trim(r) == repo then
-				groups = {}
-				for group in string.gmatch(g, "([^,]+)") do
-					groups[trim(group):lower()] = true
-				end
-				break
-			end
-		end
-		f:close()
-	end
-	if groups == nil then
-		return nil
-	end
-	local users = {}
-	local gf = io.open(groups_filename, "r")
-	if gf ~= nil then
-		for line in gf:lines() do
-			local g, u = string.match(line, "(.-):(.+)")
-			if g ~= nil and groups[trim(g):lower()] then
-				for user in string.gmatch(u, "([^,]+)") do
-					users[trim(user):lower()] = true
-				end
-			end
-		end
-		gf:close()
-	end
-	return users
-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
-
--- Parse an application/x-www-form-urlencoded body. A value may itself contain
--- '=', for example a base64 password, so the value runs to the next '&'.
-function parse_qs(qs)
-	local tab = {}
-	for key, val in string.gmatch(qs or "", "([^&=]+)=([^&]*)") do
-		tab[url_decode(key)] = url_decode(val)
-	end
-	return tab
-end
-
--- Return the value of the named cookie, or nil. The stored token was already
--- url-encoded by secure_value, so it is returned verbatim, which keeps the
--- write path (set_cookie) and the read path symmetric. Decoding it here would
--- break the signature check for any value carrying a percent escape.
-function get_cookie(cookies, name)
-	cookies = string.gsub(";" .. (cookies or "") .. ";", "%s*;%s*", ";")
-	return string.match(cookies, ";" .. name .. "=(.-);")
-end
-
-function tohex(b)
-	local x = ""
-	for i = 1, #b do
-		x = x .. string.format("%.2x", string.byte(b, i))
-	end
-	return x
-end
-
---
---
--- Cookie construction and validation helpers.
---
---
-
-local secret = nil
-
--- Load the cookie-signing secret, creating it on first use. Failures raise,
--- which cgit turns into a request error, so a broken secret denies rather than
--- signs with nothing.
-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." .. tohex(rand.bytes(16))
-		local temporary_file = io.open(temporary_filename, "w")
-		if temporary_file == nil then
-			sysstat.umask(old_umask)
-			error("cgit auth: cannot create secret file " .. secret_filename)
-		end
-		local wrote = temporary_file:write(tohex(rand.bytes(32)))
-		local closed = temporary_file:close()
-		if not wrote or not closed then
-			os.remove(temporary_filename)
-			sysstat.umask(old_umask)
-			error("cgit auth: failed writing secret file " .. secret_filename)
-		end
-		unistd.link(temporary_filename, secret_filename) -- Intentionally fails if another worker won the race.
-		unistd.unlink(temporary_filename)
-		sysstat.umask(old_umask)
-		secret_file = io.open(secret_filename, "r")
-	end
-	if secret_file == nil then
-		error("cgit auth: cannot read secret file " .. secret_filename)
-	end
-	secret = secret_file:read("*l")
-	secret_file:close()
-	if secret == nil or secret:len() ~= 64 then
-		secret = nil
-		error("cgit auth: secret file " .. secret_filename .. " is malformed, expected 64 hex characters")
-	end
-	return secret
-end
-
--- A redirect target is unsafe if a browser would read it as another origin.
--- The only such form cgit can be tricked into signing is a scheme-relative
--- "//host" or "/\host". Everything else stays on this host.
-function is_safe_redirect(url)
-	if type(url) ~= "string" then
-		return false
-	end
-	local head = url:sub(1, 2)
-	if head == "//" or head == "/\\" then
-		return false
-	end
-	return true
-end
-
--- Return the value carried by a signed cookie, or nil if it does not verify.
-function validate_value(expected_field, cookie)
-	local i = 0
-	local value = ""
-	local field = ""
-	local expiration = 0
-	local salt = ""
-	local chmac = ""
-
-	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
-			-- The expiration must be a plain integer. Rejecting other forms
-			-- keeps the signed bytes canonical, since tonumber and tostring of
-			-- "1e9" or "100.0" differ across Lua versions.
-			if not string.match(component, "^%d+$") then
-				return nil
-			end
-			expiration = tonumber(component)
-		elseif i == 3 then
-			salt = component
-		elseif i == 4 then
-			chmac = component
-		else
-			break
-		end
-		i = i + 1
-	end
-
-	if chmac == nil or chmac:len() == 0 then
-		return nil
-	end
-
-	-- Compare the HMAC without short-circuiting on the first mismatch.
-	if not constant_equals(chmac, tohex(hmac.new(get_secret(), "sha256"):final(field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt))) then
-		return nil
-	end
-
-	-- An expiration of 0 never expires and is used for the redirect token.
-	if expiration ~= 0 and expiration <= os.time() then
-		return nil
-	end
-
-	if url_decode(field) ~= expected_field then
-		return nil
-	end
-
-	local decoded = url_decode(value)
-	-- Reject values carrying control characters so a signed value cannot
-	-- smuggle CR or LF into a response header.
-	if decoded:find("%c") then
-		return nil
-	end
-	return decoded
-end
-
-function secure_value(field, value, expiration)
-	if value == nil or value:len() <= 0 then
-		return ""
-	end
-
-	local salt = tohex(rand.bytes(16))
-	value = url_encode(value)
-	field = url_encode(field)
-	local authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
-	authstr = authstr .. "|" .. tohex(hmac.new(get_secret(), "sha256"):final(authstr))
-	return authstr
-end
-
--- Strip control characters that could split an HTTP response header.
-function strip_ctl(s)
-	return (string.gsub(s or "", "%c", ""))
-end
-
--- Compare two strings in time that does not depend on how many leading bytes
--- match, so a mismatch position is not revealed by timing.
-function constant_equals(a, b)
-	if type(a) ~= "string" or type(b) ~= "string" or #a ~= #b then
-		return false
-	end
-	local diff = 0
-	for i = 1, #a do
-		local d = a:byte(i) - b:byte(i)
-		diff = diff + d * d
-	end
-	return diff == 0
-end
-
-function set_cookie(cookie, value)
-	local attrs = "; HttpOnly; SameSite=Lax; Path=" .. cookie_path
-	if not cookie_insecure then
-		attrs = attrs .. "; Secure"
-	end
-	if value == "" then
-		attrs = attrs .. "; Max-Age=0"
-	elseif session_seconds > 0 then
-		attrs = attrs .. "; Max-Age=" .. tostring(session_seconds)
-	end
-	html("Set-Cookie: " .. cookie .. "=" .. strip_ctl(value) .. attrs .. "\n")
-end
-
-function redirect_to(url)
-	html("Status: 302 Redirect\n")
-	html("Cache-Control: no-cache, no-store\n")
-	html("Location: " .. strip_ctl(url) .. "\n")
-end
-
-function not_found()
-	html("Status: 404 Not Found\n")
-	html("Cache-Control: no-cache, no-store\n\n")
-end
-
---
---
--- Authentication actions. Identical to auth-inline.lua from here down.
---
---
-
--- Sets HTTP cookie headers based on post and sets up redirection.
-function authenticate_post()
-	local redirect = validate_value("redirect", post["redirect"])
-
-	if redirect == nil or not is_safe_redirect(redirect) then
-		not_found()
-		return 0
-	end
-
-	redirect_to(redirect)
-
-	local username = post["username"]
-	local password = post["password"]
-	local ok = false
-	if username ~= nil and password ~= nil then
-		local hash = account_hash(username)
-		if hash == nil then
-			-- Spend the work anyway, see dummy_hash.
-			unistd.crypt(password, dummy_hash)
-		elseif constant_equals(hash, unistd.crypt(password, hash)) then
-			ok = true
-		end
-	end
-
-	if ok then
-		set_cookie(cookie_name, secure_value("username", username, os.time() + session_seconds))
-	else
-		set_cookie(cookie_name, "")
-	end
-
-	html("\n")
-	return 0
-end
-
--- Returns 1 if the cookie is valid and 0 if it is not.
-function authenticate_cookie()
-	local accepted_users = repo_userset(cgit["repo"])
-	if accepted_users == nil then
-		-- The repository is not protected.
-		return 1
-	end
-
-	local username = validate_value("username", get_cookie(http["cookie"], cookie_name))
-	if username == nil or not accepted_users[username:lower()] then
-		return 0
-	end
-	return 1
-end
-
--- Prints the html for the login form.
-function body()
-	local target = cgit["url"]
-	if not is_safe_redirect(target) then
-		target = cgit["login"]
-	end
-
-	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", target, 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 the filter API, exposing the http, cgit and post tables to
--- the functions above.
---
---
-
-local actions = {}
-actions["authenticate-post"] = authenticate_post
-actions["authenticate-cookie"] = authenticate_cookie
-actions["body"] = body
-
-function filter_open(...)
-	action = actions[select(1, ...)]
-
-	post = {}
-
-	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()
-	if action == nil then
-		-- Unknown action, deny rather than raise.
-		return 0
-	end
-	return action()
-end
-
-function filter_write(str)
-	post = parse_qs(str)
-end