Bug 1841348 - Avoid an exception when S/MIME certificates cannot be downloaded from LDAP. r=leftmostcat

Differential Revision: https://phabricator.services.mozilla.com/D182870

--HG--
extra : rebase_source : a306d170f15c97e8130d352622096b4a545d623d
extra : amend_source : 22621704ee02b3cf6890b0caad7a141ae32124b9

mailnews/extensions/smime/certFetchingStatus.js

@@ -223,12 +223,21 @@ class LDAPMessageListener {
     }
 
     if (Ci.nsILDAPMessage.RES_SEARCH_ENTRY == message.type) {
-      let outBinValues = message.getBinaryValues(USER_CERT_ATTRIBUTE);
+      let outBinValues = null;
+      try {
+        // This call may throw if the result message is empty or doesn't
+        // contain this attribute.
+        // It's an allowed condition that the attribute is missing on
+        // the server, so we silently ignore a failure to obtain it.
+        outBinValues = message.getBinaryValues(USER_CERT_ATTRIBUTE);
+      } catch (ex) {}
+      if (outBinValues) {
         for (let i = 0; i < outBinValues.length; ++i) {
           importCert(outBinValues[i]);
         }
       }
     }
+  }
 
   /**
    * @param {nsresult} status