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auth-filters: generate secret securely

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This is much better than having the user generate it themselves.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
master
Jason A. Donenfeld 6 years ago
parent c4d23d02ec
commit b73df8098f
2 changed files with 85 additions and 18 deletions
Show Stats Download Patch File Download Diff File

53
filters/gentoo-ldap-authentication.lua
Unescape Escape View File

@ -5,7 +5,13 @@
-- <http://mkottman.github.io/luacrypto/>
-- lualdap >= 1.2
-- <https://git.zx2c4.com/lualdap/about/>
-- luaposix
-- <https://github.com/luaposix/luaposix>
--
local sysstat = require("posix.sys.stat")
local unistd = require("posix.unistd")
local crypto = require("crypto")
local lualdap = require("lualdap")
--
@ -21,11 +27,9 @@ local protected_repos = {
portage = "dev"
}
-- All cookies will be authenticated based on this secret. Make it something
-- totally random and impossible to guess. It should be large.
local secret = "BE SURE TO CUSTOMIZE THIS STRING TO SOMETHING BIG AND RANDOM"
-- Set this to a path this script can write to for storing a persistent
-- cookie secret, which should be guarded.
local secret_filename = "/var/cache/cgit/auth-secret"
--
@ -102,8 +106,6 @@ end
--
--
local lualdap = require("lualdap")
function gentoo_ldap_user_groups(username, password)
-- Ensure the user is alphanumeric
if username == nil or username:match("%W") then
@ -231,7 +233,38 @@ end
--
--
local crypto = require("crypto")
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)
@ -271,7 +304,7 @@ function validate_value(expected_field, cookie)
end
-- Lua hashes strings, so these comparisons are time invariant.
if hmac ~= crypto.hmac.digest("sha256", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
if hmac ~= crypto.hmac.digest("sha256", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, get_secret()) then
return nil
end
@ -296,7 +329,7 @@ function secure_value(field, value, expiration)
value = url_encode(value)
field = url_encode(field)
authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, secret)
authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, get_secret())
return authstr
end

50
filters/simple-authentication.lua
Unescape Escape View File

@ -3,7 +3,12 @@
-- 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")
--
@ -31,11 +36,9 @@ local users = {
bob = "ilikelua"
}
-- All cookies will be authenticated based on this secret. Make it something
-- totally random and impossible to guess. It should be large.
local secret = "BE SURE TO CUSTOMIZE THIS STRING TO SOMETHING BIG AND RANDOM"
-- Set this to a path this script can write to for storing a persistent
-- cookie secret, which should be guarded.
local secret_filename = "/var/cache/cgit/auth-secret"
--
--
@ -191,7 +194,38 @@ end
--
--
local crypto = require("crypto")
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)
@ -231,7 +265,7 @@ function validate_value(expected_field, cookie)
end
-- Lua hashes strings, so these comparisons are time invariant.
if hmac ~= crypto.hmac.digest("sha256", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
if hmac ~= crypto.hmac.digest("sha256", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, get_secret()) then
return nil
end
@ -256,7 +290,7 @@ function secure_value(field, value, expiration)
value = url_encode(value)
field = url_encode(field)
authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, secret)
authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, get_secret())
return authstr
end

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