From f3dbd0fbc8841ccbf357b8053d2cbd0d3e5f8f67 Mon Sep 17 00:00:00 2001
From: "Visal .In" <invisal@gmail.com>
Date: Sat, 22 Aug 2020 14:27:28 +0700
Subject: [PATCH] Support importKey certificate file

---
 src/rsa/import_key.ts            | 39 ++++++++++++++++++++++++--------
 tests/rsa/rsa.import_key.test.ts | 29 ++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/src/rsa/import_key.ts b/src/rsa/import_key.ts
index 36503a9..2881137 100644
--- a/src/rsa/import_key.ts
+++ b/src/rsa/import_key.ts
@@ -6,6 +6,9 @@ import { os2ip } from "./primitives.ts";
 
 type RSAImportKeyFormat = "auto" | "jwk" | "pem";
 type RSAPublicKeyFormat = [[string, null], [[bigint, bigint]]];
+type RSACertKeyFormat = [
+  [number, string, null, null, null, RSAPublicKeyFormat],
+];
 
 /**
  * Automatically detect the key format
@@ -47,6 +50,25 @@ function rsa_import_jwk(key: JSONWebKey): RSAKey {
   };
 }
 
+/**
+ * 
+ * https://tools.ietf.org/html/rfc5280#section-4.1
+ * 
+ * @param key 
+ */
+function rsa_import_pem_cert(key: string): RSAKey {
+  const trimmedKey = key.substr(27, key.length - 52);
+  const parseKey = ber_simple(
+    ber_decode(base64_to_binary(trimmedKey)),
+  ) as RSACertKeyFormat;
+
+  return {
+    length: get_key_size(parseKey[0][5][1][0][0]),
+    n: parseKey[0][5][1][0][0],
+    e: parseKey[0][5][1][0][1],
+  };
+}
+
 /**
  * Import private key from Privacy-Enhanced Mail (PEM) format
  * https://tools.ietf.org/html/rfc5208
@@ -100,15 +122,14 @@ function rsa_import_pem_public(key: string): RSAKey {
 function rsa_import_pem(key: string): RSAKey {
   if (typeof key !== "string") throw new TypeError("PEM key must be string");
 
-  if (
-    key.indexOf("-----BEGIN RSA PRIVATE KEY-----") === 0
-  ) {
-    return rsa_import_pem_private(key);
-  }
-  if (
-    key.indexOf("-----BEGIN PUBLIC KEY-----") === 0
-  ) {
-    return rsa_import_pem_public(key);
+  const maps: [string, (key: string) => RSAKey][] = [
+    ["-----BEGIN RSA PRIVATE KEY-----", rsa_import_pem_private],
+    ["-----BEGIN PUBLIC KEY-----", rsa_import_pem_public],
+    ["-----BEGIN CERTIFICATE-----", rsa_import_pem_cert],
+  ];
+
+  for (const [prefix, func] of maps) {
+    if (key.indexOf(prefix) === 0) return func(key);
   }
 
   throw new TypeError("Unsupported key format");
diff --git a/tests/rsa/rsa.import_key.test.ts b/tests/rsa/rsa.import_key.test.ts
index 603a19f..7478c08 100644
--- a/tests/rsa/rsa.import_key.test.ts
+++ b/tests/rsa/rsa.import_key.test.ts
@@ -22,3 +22,32 @@ Deno.test("RSA - Import JWK Public Key", () => {
   assertEquals(key.e, 65537n);
   assertEquals(key.length, 256);
 });
+
+Deno.test("RSA - Import Certificate PEM", () => {
+  const cert = `-----BEGIN CERTIFICATE-----
+  MIIC8DCCAdgCAQMwDQYJKoZIhvcNAQELBQAwPDE6MDgGA1UEAwwxTXlTUUxfU2Vy
+  dmVyXzUuNy4xN19BdXRvX0dlbmVyYXRlZF9DQV9DZXJ0aWZpY2F0ZTAeFw0yMDA2
+  MDMwNzExMjBaFw0zMDA2MDEwNzExMjBaMEAxPjA8BgNVBAMMNU15U1FMX1NlcnZl
+  cl81LjcuMTdfQXV0b19HZW5lcmF0ZWRfQ2xpZW50X0NlcnRpZmljYXRlMIIBIjAN
+  BgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtupn4nzv5elNq6+L8MzuSuUYmwCt
+  EojEZ9vtv83DTQI24brXVk1/1ccOGe5hGGu4aTTpXU5LOb1V6v4robe0Vt3BuPsw
+  GHZRt1LE/BQcuuZ0f/TCBafdEdLLpUP5TBUCVomKvZFxu+5P44bJW1d4iWsXUkyZ
+  gO5TtF7x7PQvRVtsblaD4a8Et1qs58PNWN5AbOQw8GYokaSbkXDnP24ZTZbdNwu6
+  W521oJuG9HFvIM6trGjoZR7N2NxJCUtq8OjTtmUqa5BVyTBJegp+pgLZEn/YDLag
+  ll2Gx8xBOp0axxpzbc7P0JODCz21sh4ttyhyMMVjNPbn/vitgKpn0sdctQIDAQAB
+  MA0GCSqGSIb3DQEBCwUAA4IBAQBbMXuLz2qZYqgZc/2CuD4w8E+sF4n1fWpdb9EP
+  GWsHiyevEOF15YNkGlqQ8r4+h87TfL+SR4gw3PqfXEXuCkM3FuWvCulPTp/cFb7z
+  T+EcNgGKuLbLpRdi0XpvyLtG9B5yi3nvhl8XHh31xFZ0WiTgwvdwUw/bQ+fKR6xQ
+  8e0oj3SBjhcXmH5pmakFFeBjChIEPDkte5ImB6JwtwAlfvP/yTJEJxb9fUHEkR4A
+  Q258orSdJ6gNn0XC7grCTpPYpMv2foIE0lPR1BryDD+M0QeBsLENlVNFEtnNLTcI
+  UWFGFt5RctaF1ApP+inoTYapAQoDjTrOWcWYBJMkgKDk65Tg
+  -----END CERTIFICATE-----`;
+
+  const key = RSA.importKey(cert);
+  assertEquals(key.e, 65537n);
+  assertEquals(
+    key.n,
+    23090961311737573793101890708283924695433283000385054150823173852612673758230706931831331316346585281948637691806795052569468114184708524749728610979168598273283877538163829031755269185449374762314082288398270538054993384545276491531066649969558630423935152857250299602221281913410774031127740158653973996811337367884788028635132184093457045502358896056164012639638637637694971273993250785116955454220202034598919946428438516582026303702956399809398972276905876470428715345135826409789537975085486698172979761097583691702126455811212002371429452274581681294432992139097164326433615550289131259416635196384643694156981n,
+  );
+  assertEquals(key.length, 256);
+});