Added defense in depth mechanism to host resolver to prevent long hostnames from getting into glibc's getaddrinfo.

BUG=50383
TEST=HostResolverImplTest.LongHost
Review URL: http://codereview.chromium.org/3052044

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55319 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 22 insertions, 0 deletions

diff --git a/net/base/host_resolver_impl_unittest.cc b/net/base/host_resolver_impl_unittest.cc
index 6b33a56..be0e2cb 100644
--- a/net/base/host_resolver_impl_unittest.cc
+++ b/net/base/host_resolver_impl_unittest.cc
@@ -437,6 +437,21 @@ TEST_F(HostResolverImplTest, EmptyHost) {
   EXPECT_EQ(ERR_NAME_NOT_RESOLVED, err);
 }
 
+TEST_F(HostResolverImplTest, LongHost) {
+  scoped_refptr<RuleBasedHostResolverProc> resolver_proc =
+      new RuleBasedHostResolverProc(NULL);
+  resolver_proc->AllowDirectLookup("*");
+
+  scoped_refptr<HostResolver> host_resolver(
+      CreateHostResolverImpl(resolver_proc));
+  AddressList adrlist;
+  const int kPortnum = 5555;
+  std::string hostname(4097, 'a');
+  HostResolver::RequestInfo info(hostname, kPortnum);
+  int err = host_resolver->Resolve(info, &adrlist, NULL, NULL, BoundNetLog());
+  EXPECT_EQ(ERR_NAME_NOT_RESOLVED, err);
+}
+
 // Helper class used by HostResolverImplTest.DeDupeRequests. It receives request
 // completion notifications for all the resolves, so it can tally up and
 // determine when we are done.
diff --git a/net/base/host_resolver_proc.cc b/net/base/host_resolver_proc.cc
index 39d4fc4..9ae4020 100644
--- a/net/base/host_resolver_proc.cc
+++ b/net/base/host_resolver_proc.cc
@@ -83,6 +83,8 @@ int SystemHostResolverProc(const std::string& host,
                            HostResolverFlags host_resolver_flags,
                            AddressList* addrlist,
                            int* os_error) {
+  static const size_t kMaxHostLength = 4096;
+
   if (os_error)
     *os_error = 0;
 
@@ -92,6 +94,11 @@ int SystemHostResolverProc(const std::string& host,
   if (host.empty())
     return ERR_NAME_NOT_RESOLVED;
 
+  // Limit the size of hostnames that will be resolved to combat issues in some
+  // platform's resolvers.
+  if (host.size() > kMaxHostLength)
+    return ERR_NAME_NOT_RESOLVED;
+
   struct addrinfo* ai = NULL;
   struct addrinfo hints = {0};