# Fixes installation of those addons which don't have ID on IceCat ("Cannot find id for addon" error).

--- a/toolkit/mozapps/extensions/internal/XPIInstall.jsm

+++ b/toolkit/mozapps/extensions/internal/XPIInstall.jsm

@@ -627,8 +627,30 @@

         throw new Error(`Extension is signed with an invalid id (${addon.id})`);

       }

     }

-    if (!addon.id && aLocation.isTemporary) {

-      addon.id = generateTemporaryInstallID(aPackage.file);

+    if (!addon.id) {

+      if (aInstallLocation.name == KEY_APP_TEMPORARY) {

+        addon.id = generateTemporaryInstallID(aZipReader.file);

+      } else {

+        try {

+          let sigInput = aZipReader.getInputStream("META-INF/cose.sig");

+          let sigBinary = Cc['@mozilla.org/binaryinputstream;1']

+            .createInstance(Ci.nsIBinaryInputStream);

+          sigBinary.setInputStream(sigInput);

+          var sig = ''

+          var sigCount;

+          while ((sigCount = sigBinary.available()) > 0) {

+            sig += sigBinary.readBytes(sigCount);

+          }

+          let sigMatch = sig.match(/\{\w{8}-\w{4}-\w{4}-\w{4}-\w{12}\}/g)

+          if (sigMatch && sigMatch.length == 1) {

+            addon.id = sigMatch[0]

+          } else {

+            logger.warn("Failed to find addon id");

+          }

+        } catch (e) {

+          logger.warn("Failed to process META-INF/cose.sig");

+        }

+      }

     }

   }