From 16c8fd1166bf7c02a8ddd7d468d94e66b44ef079 Mon Sep 17 00:00:00 2001
From: Chuwei He <chuweih@google.com>
Date: Tue, 8 Jul 2025 16:20:18 +0900
Subject: [PATCH] Ignore RtNetlinkMessage with null or empty interface names

This patch checks if interface name is null or empty for
RtNetlinkMessage and ignores the message if it is.

Bug: 429497348
Test: build
Flag: EXEMPT bugfix
Change-Id: I6000f5442f341f152b7fbd235affded0fa56fe50
---
 .../util/netlink/RtNetlinkLinkMessage.java    |  7 +++++-
 .../netlink/RtNetlinkLinkMessageTest.java     | 22 +++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkLinkMessage.java b/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkLinkMessage.java
index 8c36ed8344..4600e697c2 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkLinkMessage.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkLinkMessage.java
@@ -26,6 +26,7 @@ import static com.android.net.module.util.netlink.StructNlMsgHdr.NLM_F_REQUEST_A
 
 import android.net.MacAddress;
 import android.system.OsConstants;
+import android.text.TextUtils;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -122,7 +123,7 @@ public class RtNetlinkLinkMessage extends NetlinkMessage {
         return mHardwareAddress;
     }
 
-    @Nullable
+    @NonNull
     public String getInterfaceName() {
         return mInterfaceName;
     }
@@ -165,6 +166,10 @@ public class RtNetlinkLinkMessage extends NetlinkMessage {
         if (nlAttr != null) {
             interfaceName = nlAttr.getValueAsString();
         }
+        // Theoretically this should not happen, added a check just for safety.
+        if (TextUtils.isEmpty(interfaceName)) {
+            return null;
+        }
 
         return new RtNetlinkLinkMessage(header, ifinfoMsg, mtu, hardwareAddress, interfaceName);
     }
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkLinkMessageTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkLinkMessageTest.java
index dca47eec60..9c60354ae1 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkLinkMessageTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkLinkMessageTest.java
@@ -336,4 +336,26 @@ public class RtNetlinkLinkMessageTest {
                 + "}";
         assertEquals(expected, linkMsg.toString());
     }
+
+    @Test
+    public void testParseRtNetlinkMessageWithNullInterfaceName() {
+        // Invalid NetlinkMessage bytes without IFLA_IFNAME attribute.
+        final String msgBytes = "34000000100000000000000000000000000001001E0000000210000000000000"
+                + "08000400DC0500000A00010092C3E3C9374E0000";
+        final ByteBuffer byteBuffer = toByteBuffer(msgBytes);
+        byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
+        final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
+        assertNull(msg);
+    }
+
+    @Test
+    public void testParseRtNetlinkMessageWithEmptyInterfaceName() {
+        // Invalid NetlinkMessage bytes with empty IFLA_IFNAME attribute.
+        final String msgBytes = "3C000000100000000000000000000000000001001E0000000210000000000000"
+                + "08000400DC0500000A00010092C3E3C9374E00000500030000000000";
+        final ByteBuffer byteBuffer = toByteBuffer(msgBytes);
+        byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
+        final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
+        assertNull(msg);
+    }
 }