DNSDomainFromDot: Reject empty labels.

net/base/dns_util_unittest.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/dns_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace net {
 
 class DNSUtilTest : public testing::Test {
@@ skipping 26 matching lines @@
   // Label is too long: invalid
   EXPECT_FALSE(DNSDomainFromDot("123456789a123456789a123456789a123456789a123456789a123456789a1234", &out));
 
   // 253 characters in the name: still valid
   EXPECT_TRUE(DNSDomainFromDot("abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abcdefghi.abc", &out));
   EXPECT_EQ(out, IncludeNUL("\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\011abcdefghi\003abc"));
 
   // 254 characters in the name: invalid
   EXPECT_FALSE(DNSDomainFromDot("123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.123456789.1234", &out));
 
-  // Zero length labels should be dropped.
+  // Zero length labels should fail, except that one trailing dot is allowed
+  // (to disable suffix search):
+  EXPECT_FALSE(DNSDomainFromDot(".google.com", &out));
+  EXPECT_FALSE(DNSDomainFromDot("www..google.com", &out));
+
   EXPECT_TRUE(DNSDomainFromDot("www.google.com.", &out));
   EXPECT_EQ(out, IncludeNUL("\003www\006google\003com"));
-
-  EXPECT_TRUE(DNSDomainFromDot(".google.com", &out));
-  EXPECT_EQ(out, IncludeNUL("\006google\003com"));
-
-  EXPECT_TRUE(DNSDomainFromDot("www..google.com", &out));
-  EXPECT_EQ(out, IncludeNUL("\003www\006google\003com"));
 }
 
 TEST_F(DNSUtilTest, DNSDomainToString) {
   EXPECT_EQ("", DNSDomainToString(IncludeNUL("")));
   EXPECT_EQ("foo", DNSDomainToString(IncludeNUL("\003foo")));
   EXPECT_EQ("foo.bar", DNSDomainToString(IncludeNUL("\003foo\003bar")));
   EXPECT_EQ("foo.bar.uk",
             DNSDomainToString(IncludeNUL("\003foo\003bar\002uk")));
 
   // It should cope with a lack of root label.
   EXPECT_EQ("foo.bar", DNSDomainToString("\003foo\003bar"));
 
   // Invalid inputs should return an empty string.
   EXPECT_EQ("", DNSDomainToString(IncludeNUL("\x80")));
   EXPECT_EQ("", DNSDomainToString("\x06"));
 }
 
 }  // namespace net