Line data    Source code

       1             : // Copyright (C) 2009 The Android Open Source Project
       2             : //
       3             : // Licensed under the Apache License, Version 2.0 (the "License");
       4             : // you may not use this file except in compliance with the License.
       5             : // You may obtain a copy of the License at
       6             : //
       7             : // http://www.apache.org/licenses/LICENSE-2.0
       8             : //
       9             : // Unless required by applicable law or agreed to in writing, software
      10             : // distributed under the License is distributed on an "AS IS" BASIS,
      11             : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             : // See the License for the specific language governing permissions and
      13             : // limitations under the License.
      14             : 
      15             : package com.google.gerrit.server.mime;
      16             : 
      17             : import static java.util.Comparator.comparing;
      18             : 
      19             : import com.google.common.flogger.FluentLogger;
      20             : import com.google.gerrit.server.config.GerritServerConfig;
      21             : import com.google.inject.Inject;
      22             : import com.google.inject.Singleton;
      23             : import eu.medsea.mimeutil.MimeException;
      24             : import eu.medsea.mimeutil.MimeType;
      25             : import eu.medsea.mimeutil.MimeUtil2;
      26             : import java.io.InputStream;
      27             : import java.util.Collection;
      28             : import java.util.Collections;
      29             : import java.util.HashSet;
      30             : import java.util.Set;
      31             : import org.eclipse.jgit.lib.Config;
      32             : 
      33             : @Singleton
      34             : public class MimeUtilFileTypeRegistry implements FileTypeRegistry {
      35         145 :   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
      36             : 
      37             :   private static final String KEY_SAFE = "safe";
      38             :   private static final String SECTION_MIMETYPE = "mimetype";
      39             : 
      40             :   private final Config cfg;
      41             :   private final MimeUtil2 mimeUtil;
      42             : 
      43             :   @Inject
      44         145 :   MimeUtilFileTypeRegistry(@GerritServerConfig Config gsc, MimeUtil2 mu2) {
      45         145 :     cfg = gsc;
      46         145 :     mimeUtil = mu2;
      47         145 :   }
      48             : 
      49             :   /**
      50             :    * Get specificity of mime types with generic types forced to low values
      51             :    *
      52             :    * <p>"application/octet-stream" is forced to -1. "text/plain" is forced to 0. All other mime
      53             :    * types return the specificity reported by mimeType itself.
      54             :    *
      55             :    * @param mimeType The mimeType to get the corrected specificity for.
      56             :    * @return The corrected specificity.
      57             :    */
      58             :   private int getCorrectedMimeSpecificity(MimeType mimeType) {
      59             :     // Although the documentation of MimeType's getSpecificity claims that for
      60             :     // example "application/octet-stream" always has a specificity of 0, it
      61             :     // effectively returns 1 for us. This causes problems when trying to get
      62             :     // the correct mime type via sorting. For example in
      63             :     // [application/octet-stream, image/x-icon] both mime types come with
      64             :     // specificity 1 for us. Hence, getMimeType below may end up using
      65             :     // application/octet-stream instead of the more specific image/x-icon.
      66             :     // Therefore, we have to force the specificity of generic types below the
      67             :     // default of 1.
      68             :     //
      69          22 :     final String mimeTypeStr = mimeType.toString();
      70          22 :     if (mimeTypeStr.equals("application/octet-stream")) {
      71          22 :       return -1;
      72             :     }
      73          22 :     if (mimeTypeStr.equals("text/plain")) {
      74          20 :       return 0;
      75             :     }
      76           6 :     return mimeType.getSpecificity();
      77             :   }
      78             : 
      79             :   @Override
      80             :   @SuppressWarnings("unchecked")
      81             :   public MimeType getMimeType(String path, byte[] content) {
      82          24 :     Set<MimeType> mimeTypes = new HashSet<>();
      83          24 :     if (content != null && content.length > 0) {
      84             :       try {
      85          24 :         mimeTypes.addAll(mimeUtil.getMimeTypes(content));
      86           0 :       } catch (MimeException e) {
      87           0 :         logger.atWarning().withCause(e).log("Unable to determine MIME type from content");
      88          24 :       }
      89             :     }
      90          24 :     return getMimeType(mimeTypes, path);
      91             :   }
      92             : 
      93             :   @Override
      94             :   @SuppressWarnings("unchecked")
      95             :   public MimeType getMimeType(String path, InputStream is) {
      96           0 :     Set<MimeType> mimeTypes = new HashSet<>();
      97             :     try {
      98           0 :       mimeTypes.addAll(mimeUtil.getMimeTypes(is));
      99           0 :     } catch (MimeException e) {
     100           0 :       logger.atWarning().withCause(e).log("Unable to determine MIME type from content");
     101           0 :     }
     102           0 :     return getMimeType(mimeTypes, path);
     103             :   }
     104             : 
     105             :   @SuppressWarnings("unchecked")
     106             :   private MimeType getMimeType(Set<MimeType> mimeTypes, String path) {
     107             :     try {
     108          24 :       mimeTypes.addAll(mimeUtil.getMimeTypes(path));
     109           0 :     } catch (MimeException e) {
     110           0 :       logger.atWarning().withCause(e).log("Unable to determine MIME type from path");
     111          24 :     }
     112             : 
     113          24 :     if (isUnknownType(mimeTypes)) {
     114           6 :       return MimeUtil2.UNKNOWN_MIME_TYPE;
     115             :     }
     116             : 
     117          22 :     return Collections.max(mimeTypes, comparing(this::getCorrectedMimeSpecificity));
     118             :   }
     119             : 
     120             :   @Override
     121             :   public boolean isSafeInline(MimeType type) {
     122           1 :     if (MimeUtil2.UNKNOWN_MIME_TYPE.equals(type)) {
     123             :       // Most browsers perform content type sniffing when they get told
     124             :       // a generic content type. This is bad, so assume we cannot send
     125             :       // the file inline.
     126             :       //
     127           0 :       return false;
     128             :     }
     129             : 
     130           1 :     final boolean any = isSafe(cfg, "*/*", false);
     131           1 :     final boolean genericMedia = isSafe(cfg, type.getMediaType() + "/*", any);
     132           1 :     return isSafe(cfg, type.toString(), genericMedia);
     133             :   }
     134             : 
     135             :   private static boolean isSafe(Config cfg, String type, boolean def) {
     136           1 :     return cfg.getBoolean(SECTION_MIMETYPE, type, KEY_SAFE, def);
     137             :   }
     138             : 
     139             :   private static boolean isUnknownType(Collection<MimeType> mimeTypes) {
     140          24 :     if (mimeTypes.isEmpty()) {
     141           0 :       return true;
     142             :     }
     143          24 :     return mimeTypes.size() == 1 && mimeTypes.contains(MimeUtil2.UNKNOWN_MIME_TYPE);
     144             :   }
     145             : }