src: fix intermittent SIGSEGV in resolveTxt

evanlucas · Evan Lucas · commit e435a0114d97 · 2015-02-25T22:45:35.000-06:00
Fixes a SIGSEGV by making sure `txt_chunk` is not empty before setting it on `txt_records` PR-URL: #960 Reviewed-By: Rod Vagg <rod@vagg.org>
diff --git a/src/cares_wrap.cc b/src/cares_wrap.cc
@@ -611,8 +611,9 @@ 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);
+});

Original file line number	Diff line number	Diff line change
`@@ -611,8 +611,9 @@ class QueryTxtWrap: public QueryWrap {`
`611`	`611`	`}`
`612`	`612`	`txt_chunk->Set(j++, txt);`
`613`	`613`	`}`
`614`		`- // Push last chunk`
`615`		`- txt_records->Set(i, txt_chunk);`
	`614`	`+ // Push last chunk if it isn't empty`
	`615`	`+ if (!txt_chunk.IsEmpty())`
	`616`	`+ txt_records->Set(i, txt_chunk);`
`616`	`617`
`617`	`618`	`ares_free_data(txt_out);`
`618`	`619`