From 17a06bef180e74dc6d32472acee6efa622499d13 Mon Sep 17 00:00:00 2001
From: AJ ONeal <coolaj86@gmail.com>
Date: Sun, 18 Nov 2018 04:12:56 -0700
Subject: [PATCH] WIP uasn1

---
 lib/ecdsacsr.js | 75 +++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 66 insertions(+), 9 deletions(-)

diff --git a/lib/ecdsacsr.js b/lib/ecdsacsr.js
index b4fe82d..729854d 100644
--- a/lib/ecdsacsr.js
+++ b/lib/ecdsacsr.js
@@ -6,6 +6,55 @@ var crypto = require('crypto');
 // prime256v1 (ANSI X9.62 named elliptic curve)
 var OBJ_ID_EC  = '06 08 2A8648CE3D030107'.replace(/\s+/g, '').toLowerCase();
 
+function ANY() {
+  var args = Array.prototype.slice.call(arguments);
+  var typ = args.shift();
+  var str = args.join('').replace(/\s+/g, '');
+  console.log('typ:', typ, 'str:', str);
+  var len = (str.length/2);
+  var len2 = len;
+  var lenlen = 1;
+  var hex = typ;
+  // high-order bit means multiple bytes
+  if (len2 !== Math.round(len2)) {
+    throw new Error("invalid hex");
+  }
+  console.log(len);
+  if (0x80 & len) {
+    while (len2 > 127) { lenlen += 1; len2 = len2 >> 8; }
+    hex += numToHex(0x80 + lenlen);
+  }
+  return hex + numToHex(len) + str;
+}
+
+function UINT() {
+  var str = Array.prototype.slice.call(arguments).join('');
+  var first = parseInt(str.slice(0, 2), 16);
+  // high-order bit means signed, negative
+  // we want positive, so we pad with a leading '00'
+  if (0x80 & first) { str = '00' + str; }
+  return ANY('02', str);
+}
+
+function BITSTR() {
+  var str = Array.prototype.slice.call(arguments).join('');
+  var first = parseInt(str.slice(0, 2), 16);
+  // '00' is a mask of how many bits of the next byte to ignore
+  return ANY('03', '00' + str);
+}
+function SEQ() {
+  return ANY('30', Array.prototype.slice.call(arguments).join(''));
+}
+function SET() {
+  return ANY('31', Array.prototype.slice.call(arguments).join(''));
+}
+function OBJID() {
+  return ANY('06', Array.prototype.slice.call(arguments).join(''));
+}
+function NULL() {
+  return '0500';
+}
+
 function fromBase64(b64) {
   var buf;
   var ab;
@@ -144,16 +193,22 @@ function toBase64(der) {
 // (those segments will be content, signature header, and signature)
 var csrHead = '30 82 {0seq0len}'.replace(/\s+/g, '');
 // The tail specifies the ES256 signature header (and is followed by the signature
-var csrEcFoot =
-  ( '30 0A'
+
+function csrEcSig(r, s) {
+  return [
+    SEQ(
       // 1.2.840.10045.4.3.2 ecdsaWithSHA256
       // (ANSI X9.62 ECDSA algorithm with SHA256)
-    + '06 08 2A 86 48 CE 3D 04 03 02'
-  + '03 {len} 00' // bit stream (why??)
-    + '30 {rslen}'  // sequence
-      + '02 {rlen} {r}' // integer r
-      + '02 {slen} {s}' // integer s
-  ).replace(/\s+/g, '');
+      OBJID('2A 86 48 CE 3D 04 03 02')
+    )
+  , BITSTR(
+      SEQ(
+        UINT(toHex(r))
+      , UINT(toHex(s))
+      )
+    )
+  ].join('');
+}
 var csrDomains = '82 {dlen} {domain.tld}';  // 2+n bytes (type 82?)
 
 function strToHex(str) {
@@ -329,7 +384,8 @@ function createEcCsr(domains, keypem, ecpub) {
   if (0x80 & new Uint8Array(sig.r)[0]) { rc = '00'; rLen += 1; }
   if (0x80 & new Uint8Array(sig.s)[0]) { sc = '00'; sLen += 1; }
 
-  var csrSig = csrEcFoot
+  var csrSig = csrEcSig(sig.r, sig.s);
+  /*
     .replace(/{len}/, numToHex(1 + 2 + 2 + 2 + rLen + sLen))
     .replace(/{rslen}/, numToHex(2 + 2 + rLen + sLen))
     .replace(/{rlen}/, numToHex(rLen))
@@ -337,6 +393,7 @@ function createEcCsr(domains, keypem, ecpub) {
     .replace(/{slen}/, numToHex(sLen))
     .replace(/{s}/, sc + toHex(sig.s))
   ;
+  */
 
   // Note: If we supported P-521 a number of the lengths would change
   // by one byte and that would be... annoying to update