src: fix intermittent SIGSEGV in resolveTxt

Fixes a SIGSEGV by making sure `txt_chunk` is not empty before setting it on `txt_records` Fixes: nodejs#9285 PR-URL: nodejs#9300 Reviewed-By: cjihrig - Colin Ihrig <cjihrig@gmail.com> Reviewed-By: jasnell - James M Snell <jasnell@gmail.com>
ibmruntimes · Nov 4, 2016 · 655fbb9 · 655fbb9
1 parent 43ea23a
commit 655fbb9
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Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/src/cares_wrap.cc b/src/cares_wrap.cc
@@ -633,8 +633,9 @@ class QueryTxtWrap: public QueryWrap {
       }
       txt_chunk->Set(j++, txt);
     }
-    // Push last chunk
-    txt_records->Set(i, txt_chunk);
+    // Push last chunk if it isn't empty
+    if (!txt_chunk.IsEmpty())
+      txt_records->Set(i, txt_chunk);
 
     ares_free_data(txt_out);
 

diff --git a/test/internet/test-dns-txt-sigsegv.js b/test/internet/test-dns-txt-sigsegv.js
@@ -0,0 +1,8 @@
+var common = require('../common');
+var assert = require('assert');
+var dns = require('dns');
+
+dns.resolveTxt('www.microsoft.com', function(err, records) {
+  assert.equal(err, null);
+  assert.equal(records.length, 0);
+});