carrier-wifi: support encrypted identity for V1.6

Encrypted identity for V1.6 requires to encrypt permanent_identity@NAIRealm
while the encrypted identity for V1.0 requires to encrypt permanent_identity
only.

Define additional sequence flag to specify the sequence that it sends
anonymous identity and then permanent identity for v1.6

Bug: 130569681
Test: unit test
Change-Id: Ia0d263ed2704fe2c83fe1501092a5ffe454ec0c3
Signed-off-by: Ecco Park <eccopark@google.com>

5 files changed, 109 insertions, 30 deletions

diff --git a/service/java/com/android/server/wifi/CarrierNetworkConfig.java b/service/java/com/android/server/wifi/CarrierNetworkConfig.java
index 56e7c261b..1814eecf4 100644
--- a/service/java/com/android/server/wifi/CarrierNetworkConfig.java
+++ b/service/java/com/android/server/wifi/CarrierNetworkConfig.java
@@ -61,7 +61,7 @@ public class CarrierNetworkConfig {
     private final Map<String, NetworkInfo> mCarrierNetworkMap;
     private boolean mIsCarrierImsiEncryptionInfoAvailable = false;
     private int mBase64EncodingMethod = Base64.DEFAULT;
-    private int mEapIdentitySequence = IDENTITY_SEQUENCE_IMSI;
+    private int mEapIdentitySequence = IDENTITY_SEQUENCE_IMSI_V1_0;
     private ImsiEncryptionInfo mLastImsiEncryptionInfo = null; // used for dumpsys only
 
     // RFC2045: adds Line Feed at each 76 chars and encode it.
@@ -70,8 +70,20 @@ public class CarrierNetworkConfig {
     // RFC4648: encodes whole data into one string.
     public static final int ENCODING_METHOD_RFC_4648 = 4648;
 
-    public static final int IDENTITY_SEQUENCE_IMSI = 1;
-    public static final int IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI = 2;
+    // Send encrypted IMSI with the format of V1.0
+    // V1.0 format: "\0"|<encrypted IMSI>|@NAIRealm
+    // <encrypted IMSI>: Base64{RSA Public Key Encryption{<permanent ID>}}
+    // <permanent ID>: One char ("0" for AKA, "1" for SIM, "6" for AKA')|IMSI
+    public static final int IDENTITY_SEQUENCE_IMSI_V1_0 = 1;
+
+    // Send anonymous identity and encrypted IMSI identity with the format of V1.0
+    public static final int IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_0 = 2;
+
+    // Send anonymous identity and encrypted IMSI identity with the format of V1.6
+    // V1.6 format: "\0"|<encrypted identity>
+    // <encrypted identity>: Base64{RSA Public Key Encryption{<permanent ID>}}.
+    // <permanent ID>: One char ("0" for AKA, "1" for SIM, "6" for AKA')|IMSI|@NAIRealm
+    public static final int IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_6 = 3;
 
     /**
      * Enable/disable verbose logging.
@@ -144,6 +156,15 @@ public class CarrierNetworkConfig {
     }
 
     /**
+     * @return {@code true} if current carrier wifi network supports anonymous identity, {@code
+     * false} otherwise.
+     */
+    public boolean isSupportAnonymousIdentity() {
+        return mEapIdentitySequence == IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_0
+                || mEapIdentitySequence == IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_6;
+    }
+
+    /**
      * @return True if carrier IMSI encryption info is available, False otherwise.
      */
     public boolean isCarrierEncryptionInfoAvailable() {
@@ -268,9 +289,10 @@ public class CarrierNetworkConfig {
         }
 
         int sequence = carrierConfig.getInt(CarrierConfigManager.KEY_EAP_IDENTITY_SEQUENCE_INT,
-                IDENTITY_SEQUENCE_IMSI);
-        if (sequence != IDENTITY_SEQUENCE_IMSI
-                && sequence != IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI) {
+                IDENTITY_SEQUENCE_IMSI_V1_0);
+        if (sequence != IDENTITY_SEQUENCE_IMSI_V1_0
+                && sequence != IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_0
+                && sequence != IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_6) {
             Log.e(TAG, "Invalid eap identity sequence: " + sequence);
             return;
         }
diff --git a/service/java/com/android/server/wifi/CarrierNetworkEvaluator.java b/service/java/com/android/server/wifi/CarrierNetworkEvaluator.java
index fd143529b..3b19eaff8 100644
--- a/service/java/com/android/server/wifi/CarrierNetworkEvaluator.java
+++ b/service/java/com/android/server/wifi/CarrierNetworkEvaluator.java
@@ -161,8 +161,7 @@ public class CarrierNetworkEvaluator implements NetworkEvaluator {
 
                 // In case of a carrier supporting anonymous identity, we need
                 // to send anonymous@realm as EAP-IDENTITY response.
-                if (mCarrierNetworkConfig.getEapIdentitySequence()
-                        == CarrierNetworkConfig.IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI) {
+                if (mCarrierNetworkConfig.isSupportAnonymousIdentity()) {
                     config.enterpriseConfig.setAnonymousIdentity(
                             TelephonyUtil.getAnonymousIdentityWith3GppRealm(getTelephonyManager()));
                 }
diff --git a/service/java/com/android/server/wifi/ClientModeImpl.java b/service/java/com/android/server/wifi/ClientModeImpl.java
index 0bdd37b1a..2ae6b4ed5 100644
--- a/service/java/com/android/server/wifi/ClientModeImpl.java
+++ b/service/java/com/android/server/wifi/ClientModeImpl.java
@@ -23,8 +23,6 @@ import static android.net.wifi.WifiManager.WIFI_STATE_ENABLED;
 import static android.net.wifi.WifiManager.WIFI_STATE_ENABLING;
 import static android.net.wifi.WifiManager.WIFI_STATE_UNKNOWN;
 
-import static com.android.server.wifi.CarrierNetworkConfig.IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI;
-
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.app.ActivityManager;
@@ -4434,9 +4432,8 @@ public class ClientModeImpl extends StateMachine {
                             } else {
                                 CarrierNetworkConfig carrierNetworkConfig =
                                         mWifiInjector.getCarrierNetworkConfig();
-                                if (carrierNetworkConfig.isCarrierEncryptionInfoAvailable() && (
-                                        carrierNetworkConfig.getEapIdentitySequence()
-                                                == IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI)) {
+                                if (carrierNetworkConfig.isCarrierEncryptionInfoAvailable()
+                                        && carrierNetworkConfig.isSupportAnonymousIdentity()) {
                                     // In case of a carrier supporting encrypted IMSI and
                                     // anonymous identity, we need to send anonymous@realm as
                                     // EAP-IDENTITY response.
diff --git a/service/java/com/android/server/wifi/hotspot2/PasspointNetworkEvaluator.java b/service/java/com/android/server/wifi/hotspot2/PasspointNetworkEvaluator.java
index 9f76a2782..58c51486d 100644
--- a/service/java/com/android/server/wifi/hotspot2/PasspointNetworkEvaluator.java
+++ b/service/java/com/android/server/wifi/hotspot2/PasspointNetworkEvaluator.java
@@ -188,8 +188,7 @@ public class PasspointNetworkEvaluator implements WifiNetworkSelector.NetworkEva
         WifiConfiguration config = networkInfo.mProvider.getWifiConfig();
         if (TelephonyUtil.isSimEapMethod(config.enterpriseConfig.getEapMethod())
                 && mCarrierNetworkConfig.isCarrierEncryptionInfoAvailable()
-                && (mCarrierNetworkConfig.getEapIdentitySequence()
-                == CarrierNetworkConfig.IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI)) {
+                && mCarrierNetworkConfig.isSupportAnonymousIdentity()) {
             // In case of a carrier supporting encrypted IMSI and anonymous identity, we need
             // to send anonymous@realm as EAP-IDENTITY response.
             config.enterpriseConfig.setAnonymousIdentity(
diff --git a/service/java/com/android/server/wifi/util/TelephonyUtil.java b/service/java/com/android/server/wifi/util/TelephonyUtil.java
index 873fda528..80cadc0af 100644
--- a/service/java/com/android/server/wifi/util/TelephonyUtil.java
+++ b/service/java/com/android/server/wifi/util/TelephonyUtil.java
@@ -16,6 +16,10 @@
 
 package com.android.server.wifi.util;
 
+import static com.android.server.wifi.CarrierNetworkConfig.IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_0;
+import static com.android.server.wifi.CarrierNetworkConfig.IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_6;
+import static com.android.server.wifi.CarrierNetworkConfig.IDENTITY_SEQUENCE_IMSI_V1_0;
+
 import android.annotation.NonNull;
 import android.net.wifi.WifiConfiguration;
 import android.net.wifi.WifiEnterpriseConfig;
@@ -102,6 +106,12 @@ public class TelephonyUtil {
             mccMnc = tm.getSimOperator();
         }
 
+        String identity = buildIdentity(getSimMethodForConfig(config), imsi, mccMnc, false);
+        if (identity == null) {
+            Log.e(TAG, "Failed to build the identity");
+            return null;
+        }
+
         ImsiEncryptionInfo imsiEncryptionInfo;
         try {
             imsiEncryptionInfo = tm.getCarrierInfoForImsiEncryption(TelephonyManager.KEY_TYPE_WLAN);
@@ -109,21 +119,30 @@ public class TelephonyUtil {
             Log.e(TAG, "Failed to get imsi encryption info: " + e.getMessage());
             return null;
         }
-
-        String identity = buildIdentity(getSimMethodForConfig(config), imsi, mccMnc, false);
-        if (identity == null) {
-            Log.e(TAG, "Failed to build the identity");
-            return null;
+        if (imsiEncryptionInfo == null) {
+            // Does not support encrypted identity.
+            return Pair.create(identity, "");
         }
 
         int base64EncodingFlag = carrierNetworkConfig.getBase64EncodingFlag();
 
-        String encryptedIdentity = buildEncryptedIdentity(telephonyUtil,
-                getSimMethodForConfig(config), imsi, mccMnc, imsiEncryptionInfo,
-                base64EncodingFlag);
-
-        // In case of failure for encryption, set empty string
-        if (encryptedIdentity == null) encryptedIdentity = "";
+        String encryptedIdentity = null;
+        int eapSequence = carrierNetworkConfig.getEapIdentitySequence();
+        if (eapSequence == IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_6) {
+            encryptedIdentity = buildEncryptedIdentityV1_6(telephonyUtil, identity,
+                    imsiEncryptionInfo, base64EncodingFlag);
+        } else if (eapSequence == IDENTITY_SEQUENCE_IMSI_V1_0
+                || eapSequence == IDENTITY_SEQUENCE_ANONYMOUS_THEN_IMSI_V1_0) {
+            encryptedIdentity = buildEncryptedIdentityV1_0(telephonyUtil,
+                    getSimMethodForConfig(config), imsi, mccMnc, imsiEncryptionInfo,
+                    base64EncodingFlag);
+        }
+
+        // In case of failure for encryption, abort current EAP authentication.
+        if (encryptedIdentity == null) {
+            Log.e(TAG, "failed to encrypt the identity, eapIdentitySequence: " + eapSequence);
+            return null;
+        }
         return Pair.create(identity, encryptedIdentity);
     }
 
@@ -179,19 +198,21 @@ public class TelephonyUtil {
     }
 
     /**
-     * Create the encrypted IMSI.
-     *  Prefix value:
+     * Create the encrypted identity for V1.0.
+     *
+     * Prefix value:
      * "0" - EAP-AKA Identity
      * "1" - EAP-SIM Identity
      * "6" - EAP-AKA' Identity
-     *
+     * Encrypted Identity format for V1.0: prefix|IMSI
      * @param eapMethod EAP authentication method: EAP-SIM, EAP-AKA, EAP-AKA'
      * @param imsi The IMSI retrieved from the SIM
      * @param mccMnc The MCC MNC identifier retrieved from the SIM
      * @param imsiEncryptionInfo The IMSI encryption info retrieved from the SIM
      * @param base64EncodingFlag base64 encoding flag
+     * @return "\0" + encryptedIdentity@<NAIRealm> + "{, Key Identifier AVP}"
      */
-    private static String buildEncryptedIdentity(TelephonyUtil telephonyUtil, int eapMethod,
+    private static String buildEncryptedIdentityV1_0(TelephonyUtil telephonyUtil, int eapMethod,
             String imsi, String mccMnc,
             ImsiEncryptionInfo imsiEncryptionInfo, int base64EncodingFlag) {
         if (imsiEncryptionInfo == null) {
@@ -220,6 +241,47 @@ public class TelephonyUtil {
     }
 
     /**
+     * Create the encrypted identity for V1.6.
+     *
+     * Prefix value:
+     * "0" - EAP-AKA Identity
+     * "1" - EAP-SIM Identity
+     * "6" - EAP-AKA' Identity
+     * Encrypted identity format for V1.6: prefix|IMSI@<NAIRealm>
+     * @param telephonyUtil      TelephonyUtil instance
+     * @param identity           permanent identity with format based on section 4.1.1.6 of RFC 4187
+     *                           and 4.2.1.6 of RFC 4186.
+     * @param imsiEncryptionInfo The IMSI encryption info retrieved from the SIM
+     * @param base64EncodingFlag base64 encoding flag
+     * @return "\0" + encryptedIdentity + "{, Key Identifier AVP}"
+     */
+    private static String buildEncryptedIdentityV1_6(TelephonyUtil telephonyUtil, String identity,
+            ImsiEncryptionInfo imsiEncryptionInfo, int base64EncodingFlag) {
+        if (imsiEncryptionInfo == null) {
+            Log.e(TAG, "imsiEncryptionInfo is not valid");
+            return null;
+        }
+        if (identity == null) {
+            Log.e(TAG, "identity is not valid");
+            return null;
+        }
+
+        // Build and return the encrypted identity.
+        String encryptedIdentity = telephonyUtil.encryptDataUsingPublicKey(
+                imsiEncryptionInfo.getPublicKey(), identity.getBytes(), base64EncodingFlag);
+        if (encryptedIdentity == null) {
+            Log.e(TAG, "Failed to encrypt IMSI");
+            return null;
+        }
+        encryptedIdentity = DEFAULT_EAP_PREFIX + encryptedIdentity;
+        if (imsiEncryptionInfo.getKeyIdentifier() != null) {
+            // Include key identifier AVP (Attribute Value Pair).
+            encryptedIdentity = encryptedIdentity + "," + imsiEncryptionInfo.getKeyIdentifier();
+        }
+        return encryptedIdentity;
+    }
+
+    /**
      * Create an identity used for SIM-based EAP authentication. The identity will be based on
      * the info retrieved from the SIM card, such as IMSI and IMSI encryption info. The IMSI
      * contained in the identity will be encrypted if IMSI encryption info is provided.