Ignore spurious RTM_NEWLINK wireless messages from rtnetlink.

Netlink will send out spurious RTM_NEWLINK messages. These messages
should not be used to update online_links_. Filter these RTM_NEWLINK
messages if ifi_change is zero and IFLA_WIRELESS.

R=pauljensen@chromium.org,wzhong@chromium.org,icoolidge@chromium.org
BUG=501982

Review URL: https://codereview.chromium.org/1192713003

Cr-Commit-Position: refs/heads/master@{#335425}

2 files changed, 58 insertions, 0 deletions

diff --git a/net/base/address_tracker_linux.cc b/net/base/address_tracker_linux.cc
index 9d41387..58a122f 100644
--- a/net/base/address_tracker_linux.cc
+++ b/net/base/address_tracker_linux.cc
@@ -20,6 +20,20 @@ namespace internal {
 
 namespace {
 
+// Some kernel functions such as wireless_send_event and rtnetlink_ifinfo_prep
+// may send spurious messages over rtnetlink. RTM_NEWLINK messages where
+// ifi_change == 0 and rta_type == IFLA_WIRELESS should be ignored.
+bool IgnoreWirelessChange(const struct nlmsghdr* header,
+                          const struct ifinfomsg* msg) {
+  size_t length = IFLA_PAYLOAD(header);
+  for (const struct rtattr* attr = IFLA_RTA(msg); RTA_OK(attr, length);
+       attr = RTA_NEXT(attr, length)) {
+    if (attr->rta_type == IFLA_WIRELESS && msg->ifi_change == 0)
+      return true;
+  }
+  return false;
+}
+
 // Retrieves address from NETLINK address message.
 // Sets |really_deprecated| for IPv6 addresses with preferred lifetimes of 0.
 bool GetAddress(const struct nlmsghdr* header,
@@ -355,6 +369,10 @@ void AddressTrackerLinux::HandleMessage(char* buffer,
             reinterpret_cast<struct ifinfomsg*>(NLMSG_DATA(header));
         if (IsInterfaceIgnored(msg->ifi_index))
           break;
+        if (IgnoreWirelessChange(header, msg)) {
+          VLOG(2) << "Ignoring RTM_NEWLINK message";
+          break;
+        }
         if (!(msg->ifi_flags & IFF_LOOPBACK) && (msg->ifi_flags & IFF_UP) &&
             (msg->ifi_flags & IFF_LOWER_UP) && (msg->ifi_flags & IFF_RUNNING)) {
           AddressTrackerAutoLock lock(*this, online_links_lock_);
diff --git a/net/base/address_tracker_linux_unittest.cc b/net/base/address_tracker_linux_unittest.cc
index ad81517..694c091 100644
--- a/net/base/address_tracker_linux_unittest.cc
+++ b/net/base/address_tracker_linux_unittest.cc
@@ -21,6 +21,7 @@ namespace internal {
 namespace {
 
 const int kTestInterfaceEth = 1;
+const int kTestInterfaceWifi = 2;
 const int kTestInterfaceTun = 123;
 const int kTestInterfaceAp = 456;
 
@@ -212,6 +213,24 @@ void MakeLinkMessage(uint16_t type,
   nlmsg.AppendTo(output);
 }
 
+// Creates a netlink message generated by wireless_send_event. These events
+// should be ignored.
+void MakeWirelessLinkMessage(uint16_t type,
+                             uint32_t flags,
+                             uint32_t index,
+                             Buffer* output) {
+  NetlinkMessage nlmsg(type);
+  struct ifinfomsg msg = {};
+  msg.ifi_index = index;
+  msg.ifi_flags = flags;
+  msg.ifi_change = 0;
+  nlmsg.AddPayload(&msg, sizeof(msg));
+  char data[8] = {0};
+  nlmsg.AddAttribute(IFLA_WIRELESS, data, sizeof(data));
+  output->clear();
+  nlmsg.AppendTo(output);
+}
+
 const unsigned char kAddress0[] = { 127, 0, 0, 1 };
 const unsigned char kAddress1[] = { 10, 0, 0, 1 };
 const unsigned char kAddress2[] = { 192, 168, 0, 1 };
@@ -469,6 +488,13 @@ TEST_F(AddressTrackerLinuxTest, AddInterface) {
   EXPECT_EQ(1u, GetOnlineLinks().count(kTestInterfaceEth));
   EXPECT_EQ(1u, GetOnlineLinks().size());
 
+  // Ignores messages from wireless_send_event.
+  MakeWirelessLinkMessage(RTM_NEWLINK, IFF_UP | IFF_LOWER_UP | IFF_RUNNING,
+                          kTestInterfaceWifi, &buffer);
+  EXPECT_FALSE(HandleLinkMessage(buffer));
+  EXPECT_EQ(0u, GetOnlineLinks().count(kTestInterfaceWifi));
+  EXPECT_EQ(1u, GetOnlineLinks().size());
+
   // Verify adding another online device (e.g. VPN) is considered a change.
   MakeLinkMessage(RTM_NEWLINK, IFF_UP | IFF_LOWER_UP | IFF_RUNNING, 2, &buffer);
   EXPECT_TRUE(HandleLinkMessage(buffer));
@@ -513,6 +539,20 @@ TEST_F(AddressTrackerLinuxTest, RemoveInterface) {
                   kTestInterfaceEth, &buffer);
   EXPECT_TRUE(HandleLinkMessage(buffer));
   EXPECT_TRUE(GetOnlineLinks().empty());
+
+  // Ignores messages from wireless_send_event.
+  MakeLinkMessage(RTM_NEWLINK, IFF_UP | IFF_LOWER_UP | IFF_RUNNING,
+                  kTestInterfaceWifi, &buffer);
+  EXPECT_TRUE(HandleLinkMessage(buffer));
+  EXPECT_FALSE(GetOnlineLinks().empty());
+  MakeWirelessLinkMessage(RTM_NEWLINK, IFF_UP | IFF_LOWER_UP,
+                          kTestInterfaceWifi, &buffer);
+  EXPECT_FALSE(HandleLinkMessage(buffer));
+  EXPECT_FALSE(GetOnlineLinks().empty());
+  MakeLinkMessage(RTM_NEWLINK, IFF_UP | IFF_RUNNING, kTestInterfaceWifi,
+                  &buffer);
+  EXPECT_TRUE(HandleLinkMessage(buffer));
+  EXPECT_TRUE(GetOnlineLinks().empty());
 }
 
 TEST_F(AddressTrackerLinuxTest, IgnoreInterface) {