Merge pull request video-dev#111 from kanongil/decrypt-fixes

Improve decryption implementation
eutychus · Dec 4, 2015 · 17a1e14 · 17a1e14
2 parents cd5132c + 39bd0c5
commit 17a1e14
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Showing 4 changed files with 29 additions and 18 deletions.
diff --git a/.jshintrc b/.jshintrc
@@ -24,6 +24,7 @@
   "globals"   : {
     "console"     : true,
     "MediaSource" : true,
-    "performance" : true
+    "performance" : true,
+    "crypto"      : true
   }
 }
diff --git a/src/crypt/aes128-decrypter.js b/src/crypt/aes128-decrypter.js
@@ -90,20 +90,20 @@ class AES128Decrypter {
 
     // pull out the words of the IV to ensure we don't modify the
     // passed-in reference and easier access
-    init0 = initVector[0];
-    init1 = initVector[1];
-    init2 = initVector[2];
-    init3 = initVector[3];
+    init0 = ~~initVector[0];
+    init1 = ~~initVector[1];
+    init2 = ~~initVector[2];
+    init3 = ~~initVector[3];
 
     // decrypt four word sequences, applying cipher-block chaining (CBC)
     // to each decrypted block
     for (wordIx = 0; wordIx < encrypted32.length; wordIx += 4) {
       // convert big-endian (network order) words into little-endian
       // (javascript order)
-      encrypted0 = this.ntoh(encrypted32[wordIx]);
-      encrypted1 = this.ntoh(encrypted32[wordIx + 1]);
-      encrypted2 = this.ntoh(encrypted32[wordIx + 2]);
-      encrypted3 = this.ntoh(encrypted32[wordIx + 3]);
+      encrypted0 = ~~this.ntoh(encrypted32[wordIx]);
+      encrypted1 = ~~this.ntoh(encrypted32[wordIx + 1]);
+      encrypted2 = ~~this.ntoh(encrypted32[wordIx + 2]);
+      encrypted3 = ~~this.ntoh(encrypted32[wordIx + 3]);
 
       // decrypt the block
       decipher.decrypt(encrypted0,

diff --git a/src/crypt/decrypter.js b/src/crypt/decrypter.js
@@ -10,7 +10,13 @@ class Decrypter {
 
   constructor(hls) {
     this.hls = hls;
-    this.disableWebCrypto = false;
+    try {
+      const browserCrypto = window ? window.crypto : crypto;
+      this.subtle = browserCrypto.subtle || browserCrypto.webkitSubtle;
+      this.disableWebCrypto = !this.subtle;
+    } catch (e) {
+      this.disableWebCrypto = true;
+    }
   }
 
   destroy() {
@@ -27,17 +33,16 @@ class Decrypter {
   decryptByWebCrypto(data, key, iv, callback) {
     logger.log('decrypting by WebCrypto API');
 
-    var localthis = this;
-    window.crypto.subtle.importKey('raw', key, { name : 'AES-CBC', length : 128 }, false, ['decrypt']).
-      then(function (importedKey) {
-        window.crypto.subtle.decrypt({ name : 'AES-CBC', iv : iv.buffer }, importedKey, data).
+    this.subtle.importKey('raw', key, { name : 'AES-CBC', length : 128 }, false, ['decrypt']).
+      then((importedKey) => {
+        this.subtle.decrypt({ name : 'AES-CBC', iv : iv.buffer }, importedKey, data).
           then(callback).
-          catch (function (err) {
-            localthis.onWebCryptoError(err, data, key, iv, callback);
+          catch ((err) => {
+            this.onWebCryptoError(err, data, key, iv, callback);
           });
       }).
-    catch (function (err) {
-      localthis.onWebCryptoError(err, data, key, iv, callback);
+    catch ((err) => {
+      this.onWebCryptoError(err, data, key, iv, callback);
     });
   }
 

diff --git a/src/demux/demuxer.js b/src/demux/demuxer.js
@@ -34,6 +34,11 @@ class Demuxer {
       this.w = null;
     } else {
       this.demuxer.destroy();
+      this.demuxer = null;
+    }
+    if (this.decrypter) {
+      this.decrypter.destroy();
+      this.decrypter = null;
     }
   }