From 8048b53d183f3e225c85f4ca06e54ebc0b07e058 Mon Sep 17 00:00:00 2001 From: Matthew Wild Date: Thu, 13 May 2021 14:13:07 +0100 Subject: util.jwt: Use constant-time comparison with expected signature --- util/jwt.lua | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'util/jwt.lua') diff --git a/util/jwt.lua b/util/jwt.lua index 2b172d38..bf106dfa 100644 --- a/util/jwt.lua +++ b/util/jwt.lua @@ -3,6 +3,7 @@ local json = require "util.json"; local hashes = require "util.hashes"; local base64_encode = require "util.encodings".base64.encode; local base64_decode = require "util.encodings".base64.decode; +local secure_equals = require "util.hashes".equals; local b64url_rep = { ["+"] = "-", ["/"] = "_", ["="] = "", ["-"] = "+", ["_"] = "/" }; local function b64url(data) @@ -33,7 +34,7 @@ local function verify(key, blob) elseif header.alg ~= "HS256" then return nil, "unsupported-algorithm"; end - if b64url(hashes.hmac_sha256(key, signed)) ~= signature then + if not secure_equals(b64url(hashes.hmac_sha256(key, signed)), signature) then return false, "signature-mismatch"; end local payload, err = json.decode(unb64url(bpayload)); -- cgit v1.2.3