WifiConfigurationUtil: Validate UTF-8 ssid length correctly

Validate the number of bytes in UTF-8 encoded SSID's. The previous
check was only validating the number of characters which could end up
violating the SSID length specification in the standard.

Also, added an extra validation in NativeUtil.decodeSsid() to ensure the
string is UTF-8 encoded.

Bug: 78483295
Test: Unit tests
Test: Able to add/update wifi network configs.
Change-Id: I46076ba6b309af006c10f6a9d4ab1d9bc40be428

2 files changed, 26 insertions, 0 deletions

diff --git a/tests/wifitests/src/com/android/server/wifi/WifiConfigurationUtilTest.java b/tests/wifitests/src/com/android/server/wifi/WifiConfigurationUtilTest.java
index eb498e9d6..7bb24371a 100644
--- a/tests/wifitests/src/com/android/server/wifi/WifiConfigurationUtilTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/WifiConfigurationUtilTest.java
@@ -265,6 +265,20 @@ public class WifiConfigurationUtilTest {
     }
 
     /**
+     * Verify that the validate method fails to validate WifiConfiguration with bad ssid length.
+     */
+    @Test
+    public void testValidateNegativeCases_BadUtf8SsidLength() {
+        WifiConfiguration config = WifiConfigurationTestUtil.createOpenNetwork();
+        assertTrue(WifiConfigurationUtil.validate(config, WifiConfigurationUtil.VALIDATE_FOR_ADD));
+
+        config.SSID = "\"가하아너너ㅓ저저ㅓ어아아다자저ㅓ더타아어어러두어\"";
+        assertFalse(WifiConfigurationUtil.validate(config, WifiConfigurationUtil.VALIDATE_FOR_ADD));
+        config.SSID = "\"\"";
+        assertFalse(WifiConfigurationUtil.validate(config, WifiConfigurationUtil.VALIDATE_FOR_ADD));
+    }
+
+    /**
      * Verify that the validate method fails to validate WifiConfiguration with malformed ssid
      * string.
      */
diff --git a/tests/wifitests/src/com/android/server/wifi/util/NativeUtilTest.java b/tests/wifitests/src/com/android/server/wifi/util/NativeUtilTest.java
index 367e6b34a..05b719cd2 100644
--- a/tests/wifitests/src/com/android/server/wifi/util/NativeUtilTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/util/NativeUtilTest.java
@@ -113,6 +113,18 @@ public class NativeUtilTest {
     }
 
     /**
+     * Test that conversion of non utf-8 SSID string to bytes fail.
+     */
+    @Test
+    public void testNonUtf8SsidDecodeFails() throws Exception {
+        try {
+            NativeUtil.decodeSsid("\"\ud800\"");
+            fail("Expected ssid decode to fail");
+        } catch (IllegalArgumentException e) {
+        }
+    }
+
+    /**
      * Test that conversion of ssid bytes to hex string ssid works.
      */
     @Test