Author: Jason A. Donenfeld <Jason@zx2c4.com>
auth: lua string comparisons are time invariant By default, strings are compared by hash, so we can remove this comment. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
filters/simple-authentication.lua | 4 ++--
diff --git a/filters/simple-authentication.lua b/filters/simple-authentication.lua index 5935d080f87e0388a2dfdcf9b8b1586f93c186d5..5c4f074b8b1a6d84572aeeac3eb507f88aa2eca3 100644 --- a/filters/simple-authentication.lua +++ b/filters/simple-authentication.lua @@ -45,7 +45,7 @@ end redirect_to(redirect) - -- TODO: Implement time invariant string comparison function to mitigate timing attack. + -- Lua hashes strings, so these comparisons are time invariant. if password == nil or password ~= post["password"] then set_cookie("cgitauth", "") else @@ -222,7 +222,7 @@ if hmac == nil or hmac:len() == 0 then return nil end - -- TODO: implement time invariant comparison to prevent against timing attack. + -- Lua hashes strings, so these comparisons are time invariant. if hmac ~= crypto.hmac.digest("sha1", value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then return nil end