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      1 /*
      2  * Copyright 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package libcore.java.security;
     18 
     19 import java.io.BufferedReader;
     20 import java.io.FileReader;
     21 import java.io.IOException;
     22 import java.lang.reflect.InvocationTargetException;
     23 import java.lang.reflect.Method;
     24 import java.util.Arrays;
     25 import java.util.List;
     26 import java.util.regex.Matcher;
     27 import java.util.regex.Pattern;
     28 
     29 public class CpuFeatures {
     30     private CpuFeatures() {
     31     }
     32 
     33     public static boolean isAESHardwareAccelerated() {
     34         List<String> features = getListFromCpuinfo("Features");
     35         if (features != null && features.contains("aes")) {
     36             return true;
     37         }
     38 
     39         List<String> flags = getListFromCpuinfo("flags");
     40         if (flags != null && flags.contains("aes")) {
     41             return true;
     42         }
     43 
     44         // If we're in an emulated ABI, Conscrypt's NativeCrypto might bridge to
     45         // a library that has accelerated AES instructions. See if Conscrypt
     46         // detects that condition.
     47         try {
     48             Class<?> nativeCrypto = Class.forName("com.android.org.conscrypt.NativeCrypto");
     49             Method EVP_has_aes_hardware = nativeCrypto.getDeclaredMethod("EVP_has_aes_hardware");
     50             EVP_has_aes_hardware.setAccessible(true);
     51             return ((Integer) EVP_has_aes_hardware.invoke(null)) == 1;
     52         } catch (ClassNotFoundException | NoSuchMethodException | SecurityException
     53                 | IllegalAccessException | IllegalArgumentException ignored) {
     54         } catch (InvocationTargetException e) {
     55             throw new IllegalArgumentException(e);
     56         }
     57 
     58         return false;
     59     }
     60 
     61     private static String getFieldFromCpuinfo(String field) {
     62         try {
     63             BufferedReader br = new BufferedReader(new FileReader("/proc/cpuinfo"));
     64             Pattern p = Pattern.compile(field + "\\s*:\\s*(.*)");
     65 
     66             try {
     67                 String line;
     68                 while ((line = br.readLine()) != null) {
     69                     Matcher m = p.matcher(line);
     70                     if (m.matches()) {
     71                         return m.group(1);
     72                     }
     73                 }
     74             } finally {
     75                 br.close();
     76             }
     77         } catch (IOException ignored) {
     78         }
     79 
     80         return null;
     81     }
     82 
     83     private static List<String> getListFromCpuinfo(String fieldName) {
     84         String features = getFieldFromCpuinfo(fieldName);
     85         if (features == null)
     86             return null;
     87 
     88         return Arrays.asList(features.split("\\s"));
     89     }
     90 }
     91