Bug 1526302 - remove MD2 support from nsICryptoHash, clarifiy hash IDs must be synchronized with NSS hasht.h r=keeler

Differential Revision: https://phabricator.services.mozilla.com/D19150

--HG--
extra : moz-landing-system : lando

security/manager/ssl/nsCryptoHash.cpp

@@ -38,9 +38,6 @@ NS_IMETHODIMP
 nsCryptoHash::Init(uint32_t algorithm) {
   HASH_HashType hashType;
   switch (algorithm) {
-    case nsICryptoHash::MD2:
-      hashType = HASH_AlgMD2;
-      break;
     case nsICryptoHash::MD5:
       hashType = HASH_AlgMD5;
       break;
@@ -85,8 +82,6 @@ nsCryptoHash::Init(uint32_t algorithm) {
 
 NS_IMETHODIMP
 nsCryptoHash::InitWithString(const nsACString &aAlgorithm) {
-  if (aAlgorithm.LowerCaseEqualsLiteral("md2")) return Init(nsICryptoHash::MD2);
-
   if (aAlgorithm.LowerCaseEqualsLiteral("md5")) return Init(nsICryptoHash::MD5);
 
   if (aAlgorithm.LowerCaseEqualsLiteral("sha1"))

security/manager/ssl/nsICryptoHash.idl

@@ -16,10 +16,11 @@ interface nsICryptoHash : nsISupports
     /**
      * Hashing Algorithms.  These values are to be used by the
      * |init| method to indicate which hashing function to
-     * use.  These values map directly onto the values defined
-     * in mozilla/security/nss/lib/cryptohi/hasht.h.
+     * use.  These values must be identical to the values defined
+     * in security/nss/lib/util/hasht.h in type HASH_HashType.
+     * This allows us to use NSS mapping functions like
+     * HASH_GetHashOidTagByHashType with these values.
      */
-    const short MD2    = 1;  /* String value: "md2"    */
     const short MD5    = 2;  /* String value: "md5"    */
     const short SHA1   = 3;  /* String value: "sha1"   */
     const short SHA256 = 4;  /* String value: "sha256" */

security/manager/ssl/tests/unit/test_hash_algorithms.js

@@ -8,18 +8,6 @@ const messages = [
   "",
 ];
 const ALGORITHMS = [
-  {
-    initString: "md2",
-    initConstant: Ci.nsICryptoHash.MD2,
-    hexHashes: [
-      "03d85a0d629d2c442e987525319fc471",
-      "8350e5a3e24c153df2275c9f80692773",
-    ],
-    b64Hashes: [
-      "A9haDWKdLEQumHUlMZ/EcQ==",
-      "g1Dlo+JMFT3yJ1yfgGkncw==",
-    ],
-  },
   {
     initString: "md5",
     initConstant: Ci.nsICryptoHash.MD5,