Improve IKEv2/IPsec VPN by proposing more IPsec algorithms

This commit allows IKEv2/IPsec VPN to propose more algorithms that
newly added in IpSecAlgorithm. Those new algorithms have stronger
security guarantees and better performances.

This commit also removes algorithm name validation because all
algorithms are URL encoded to ensure no special characters create
problems due to their use by VpnProfile for list or field delimiting
(e.g. rfc7539esp(chacha20,poly1305))

Bug: 185265778
Test: atest FrameworksNetTests, CtsNetTestCases
Test: All new algorithms are manually verified
Change-Id: I1de322c95aacc8924e95bcdbcfdbd1ec441de99c

2 files changed, 56 insertions, 31 deletions

diff --git a/core/java/android/net/Ikev2VpnProfile.java b/core/java/android/net/Ikev2VpnProfile.java
index cc1312bac180..b18e9be28eb5 100644
--- a/core/java/android/net/Ikev2VpnProfile.java
+++ b/core/java/android/net/Ikev2VpnProfile.java
@@ -16,6 +16,16 @@
 
 package android.net;
 
+import static android.net.IpSecAlgorithm.AUTH_AES_CMAC;
+import static android.net.IpSecAlgorithm.AUTH_AES_XCBC;
+import static android.net.IpSecAlgorithm.AUTH_CRYPT_AES_GCM;
+import static android.net.IpSecAlgorithm.AUTH_CRYPT_CHACHA20_POLY1305;
+import static android.net.IpSecAlgorithm.AUTH_HMAC_SHA256;
+import static android.net.IpSecAlgorithm.AUTH_HMAC_SHA384;
+import static android.net.IpSecAlgorithm.AUTH_HMAC_SHA512;
+import static android.net.IpSecAlgorithm.CRYPT_AES_CBC;
+import static android.net.IpSecAlgorithm.CRYPT_AES_CTR;
+
 import static com.android.internal.annotations.VisibleForTesting.Visibility;
 import static com.android.internal.util.Preconditions.checkStringNotEmpty;
 import static com.android.net.module.util.NetworkStackConstants.IPV6_MIN_MTU;
@@ -70,13 +80,28 @@ public final class Ikev2VpnProfile extends PlatformVpnProfile {
     private static final String EMPTY_CERT = "";
 
     /** @hide */
-    public static final List<String> DEFAULT_ALGORITHMS =
-            Collections.unmodifiableList(Arrays.asList(
-                    IpSecAlgorithm.CRYPT_AES_CBC,
-                    IpSecAlgorithm.AUTH_HMAC_SHA256,
-                    IpSecAlgorithm.AUTH_HMAC_SHA384,
-                    IpSecAlgorithm.AUTH_HMAC_SHA512,
-                    IpSecAlgorithm.AUTH_CRYPT_AES_GCM));
+    public static final List<String> DEFAULT_ALGORITHMS;
+
+    private static void addAlgorithmIfSupported(List<String> algorithms, String ipSecAlgoName) {
+        if (IpSecAlgorithm.getSupportedAlgorithms().contains(ipSecAlgoName)) {
+            algorithms.add(ipSecAlgoName);
+        }
+    }
+
+    static {
+        final List<String> algorithms = new ArrayList<>();
+        addAlgorithmIfSupported(algorithms, CRYPT_AES_CBC);
+        addAlgorithmIfSupported(algorithms, CRYPT_AES_CTR);
+        addAlgorithmIfSupported(algorithms, AUTH_HMAC_SHA256);
+        addAlgorithmIfSupported(algorithms, AUTH_HMAC_SHA384);
+        addAlgorithmIfSupported(algorithms, AUTH_HMAC_SHA512);
+        addAlgorithmIfSupported(algorithms, AUTH_AES_XCBC);
+        addAlgorithmIfSupported(algorithms, AUTH_AES_CMAC);
+        addAlgorithmIfSupported(algorithms, AUTH_CRYPT_AES_GCM);
+        addAlgorithmIfSupported(algorithms, AUTH_CRYPT_CHACHA20_POLY1305);
+
+        DEFAULT_ALGORITHMS = Collections.unmodifiableList(algorithms);
+    }
 
     @NonNull private final String mServerAddr;
     @NonNull private final String mUserIdentity;
@@ -195,8 +220,6 @@ public final class Ikev2VpnProfile extends PlatformVpnProfile {
      * @param allowedAlgorithms The list to be validated
      */
     private static void validateAllowedAlgorithms(@NonNull List<String> algorithmNames) {
-        VpnProfile.validateAllowedAlgorithms(algorithmNames);
-
         // First, make sure no insecure algorithms were proposed.
         if (algorithmNames.contains(IpSecAlgorithm.AUTH_HMAC_MD5)
                 || algorithmNames.contains(IpSecAlgorithm.AUTH_HMAC_SHA1)) {
diff --git a/core/java/com/android/internal/net/VpnProfile.java b/core/java/com/android/internal/net/VpnProfile.java
index b7170d857da9..6e1d3ce9a297 100644
--- a/core/java/com/android/internal/net/VpnProfile.java
+++ b/core/java/com/android/internal/net/VpnProfile.java
@@ -30,7 +30,10 @@ import android.text.TextUtils;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.net.module.util.ProxyUtils;
 
+import java.io.UnsupportedEncodingException;
 import java.net.InetAddress;
+import java.net.URLDecoder;
+import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -74,6 +77,9 @@ public final class VpnProfile implements Cloneable, Parcelable {
 
     private static final String ENCODED_NULL_PROXY_INFO = "\0\0\0\0";
 
+    /** Default URL encoding. */
+    private static final String DEFAULT_ENCODING = StandardCharsets.UTF_8.name();
+
     // Entity fields.
     @UnsupportedAppUsage
     public final String key;                                   // -1
@@ -129,9 +135,6 @@ public final class VpnProfile implements Cloneable, Parcelable {
 
     /**
      * The list of allowable algorithms.
-     *
-     * <p>This list is validated in the setter to ensure that encoding characters (list, value
-     * delimiters) are not present in the algorithm names. See {@link #validateAllowedAlgorithms()}
      */
     private List<String> mAllowedAlgorithms = new ArrayList<>(); // 19
     public boolean isBypassable = false;                         // 20
@@ -196,11 +199,8 @@ public final class VpnProfile implements Cloneable, Parcelable {
      *
      * @param allowedAlgorithms the list of allowable algorithms, as listed in {@link
      *     IpSecAlgorithm}.
-     * @throws IllegalArgumentException if any delimiters are used in algorithm names. See {@link
-     *     #VALUE_DELIMITER} and {@link LIST_DELIMITER}.
      */
     public void setAllowedAlgorithms(List<String> allowedAlgorithms) {
-        validateAllowedAlgorithms(allowedAlgorithms);
         mAllowedAlgorithms = allowedAlgorithms;
     }
 
@@ -297,7 +297,11 @@ public final class VpnProfile implements Cloneable, Parcelable {
 
             // Either all must be present, or none must be.
             if (values.length >= 24) {
-                profile.mAllowedAlgorithms = Arrays.asList(values[19].split(LIST_DELIMITER));
+                profile.mAllowedAlgorithms = new ArrayList<>();
+                for (String algo : Arrays.asList(values[19].split(LIST_DELIMITER))) {
+                    profile.mAllowedAlgorithms.add(URLDecoder.decode(algo, DEFAULT_ENCODING));
+                }
+
                 profile.isBypassable = Boolean.parseBoolean(values[20]);
                 profile.isMetered = Boolean.parseBoolean(values[21]);
                 profile.maxMtu = Integer.parseInt(values[22]);
@@ -348,7 +352,19 @@ public final class VpnProfile implements Cloneable, Parcelable {
             builder.append(ENCODED_NULL_PROXY_INFO);
         }
 
-        builder.append(VALUE_DELIMITER).append(String.join(LIST_DELIMITER, mAllowedAlgorithms));
+        final List<String> encodedAlgoNames = new ArrayList<>();
+
+        try {
+            for (String algo : mAllowedAlgorithms) {
+                encodedAlgoNames.add(URLEncoder.encode(algo, DEFAULT_ENCODING));
+            }
+        } catch (UnsupportedEncodingException e) {
+            // Unexpected error
+            throw new IllegalStateException("Failed to encode algorithms.", e);
+        }
+
+        builder.append(VALUE_DELIMITER).append(String.join(LIST_DELIMITER, encodedAlgoNames));
+
         builder.append(VALUE_DELIMITER).append(isBypassable);
         builder.append(VALUE_DELIMITER).append(isMetered);
         builder.append(VALUE_DELIMITER).append(maxMtu);
@@ -425,20 +441,6 @@ public final class VpnProfile implements Cloneable, Parcelable {
         return true;
     }
 
-    /**
-     * Validates that the provided list of algorithms does not contain illegal characters.
-     *
-     * @param allowedAlgorithms The list to be validated
-     */
-    public static void validateAllowedAlgorithms(List<String> allowedAlgorithms) {
-        for (final String alg : allowedAlgorithms) {
-            if (alg.contains(VALUE_DELIMITER) || alg.contains(LIST_DELIMITER)) {
-                throw new IllegalArgumentException(
-                        "Algorithm contained illegal ('\0' or ',') character");
-            }
-        }
-    }
-
     /** Generates a hashcode over the VpnProfile. */
     @Override
     public int hashCode() {