1 files changed, 170 insertions, 0 deletions
diff --git a/java/com/google/gerrit/httpd/raw/CatServlet.java b/java/com/google/gerrit/httpd/raw/CatServlet.java
new file mode 100644
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+++ b/java/com/google/gerrit/httpd/raw/CatServlet.java
@@ -0,0 +1,170 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.httpd.raw;
+
+import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.ResourceConflictException;
+import com.google.gerrit.extensions.restapi.Url;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Patch;
+import com.google.gerrit.reviewdb.client.PatchSet;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.PatchSetUtil;
+import com.google.gerrit.server.edit.ChangeEdit;
+import com.google.gerrit.server.edit.ChangeEditUtil;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import com.google.gerrit.server.permissions.ChangePermission;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.permissions.PermissionBackendException;
+import com.google.gerrit.server.project.NoSuchChangeException;
+import com.google.gerrit.server.project.ProjectCache;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+import java.io.IOException;
+import java.util.Optional;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import org.eclipse.jgit.lib.ObjectId;
+
+/**
+ * Exports a single version of a patch as a normal file download.
+ *
+ * <p>This can be relatively unsafe with Microsoft Internet Explorer 6.0 as the browser will (rather
+ * incorrectly) treat an HTML or JavaScript file its supposed to download as though it was served by
+ * this site, and will execute it with the site's own protection domain. This opens a massive
+ * security hole so we package the content into a zip file.
+ */
+@Singleton
+public class CatServlet extends HttpServlet {
+  private static final long serialVersionUID = 1L;
+
+  private final Provider<ReviewDb> requestDb;
+  private final ChangeEditUtil changeEditUtil;
+  private final PatchSetUtil psUtil;
+  private final ChangeNotes.Factory changeNotesFactory;
+  private final PermissionBackend permissionBackend;
+  private final ProjectCache projectCache;
+
+  @Inject
+  CatServlet(
+      Provider<ReviewDb> sf,
+      ChangeEditUtil ceu,
+      PatchSetUtil psu,
+      ChangeNotes.Factory cnf,
+      PermissionBackend pb,
+      ProjectCache pc) {
+    requestDb = sf;
+    changeEditUtil = ceu;
+    psUtil = psu;
+    changeNotesFactory = cnf;
+    permissionBackend = pb;
+    projectCache = pc;
+  }
+
+  @Override
+  protected void doGet(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
+    String keyStr = req.getPathInfo();
+
+    // We shouldn't have to do this extra decode pass, but somehow we
+    // are now receiving our "^1" suffix as "%5E1", which confuses us
+    // downstream. Other times we get our embedded "," as "%2C", which
+    // is equally bad. And yet when these happen a "%2F" is left as-is,
+    // rather than escaped as "%252F", which makes me feel really really
+    // uncomfortable with a blind decode right here.
+    //
+    keyStr = Url.decode(keyStr);
+
+    if (!keyStr.startsWith("/")) {
+      rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+      return;
+    }
+    keyStr = keyStr.substring(1);
+
+    final Patch.Key patchKey;
+    final int side;
+    {
+      final int c = keyStr.lastIndexOf('^');
+      if (c == 0) {
+        rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+        return;
+      }
+
+      if (c < 0) {
+        side = 0;
+      } else {
+        try {
+          side = Integer.parseInt(keyStr.substring(c + 1));
+          keyStr = keyStr.substring(0, c);
+        } catch (NumberFormatException e) {
+          rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+          return;
+        }
+      }
+
+      try {
+        patchKey = Patch.Key.parse(keyStr);
+      } catch (NumberFormatException e) {
+        rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+        return;
+      }
+    }
+
+    final Change.Id changeId = patchKey.getParentKey().getParentKey();
+    String revision;
+    try {
+      ChangeNotes notes = changeNotesFactory.createChecked(changeId);
+      permissionBackend
+          .currentUser()
+          .change(notes)
+          .database(requestDb)
+          .check(ChangePermission.READ);
+      projectCache.checkedGet(notes.getProjectName()).checkStatePermitsRead();
+      if (patchKey.getParentKey().get() == 0) {
+        // change edit
+        Optional<ChangeEdit> edit = changeEditUtil.byChange(notes);
+        if (edit.isPresent()) {
+          revision = ObjectId.toString(edit.get().getEditCommit());
+        } else {
+          rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+          return;
+        }
+      } else {
+        PatchSet patchSet = psUtil.get(requestDb.get(), notes, patchKey.getParentKey());
+        if (patchSet == null) {
+          rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+          return;
+        }
+        revision = patchSet.getRevision().get();
+      }
+    } catch (ResourceConflictException | NoSuchChangeException | AuthException e) {
+      rsp.sendError(HttpServletResponse.SC_NOT_FOUND);
+      return;
+    } catch (OrmException | PermissionBackendException | IOException e) {
+      getServletContext().log("Cannot query database", e);
+      rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
+      return;
+    }
+
+    String path = patchKey.getFileName();
+    String restUrl =
+        String.format(
+            "%s/changes/%d/revisions/%s/files/%s/download?parent=%d",
+            req.getContextPath(), changeId.get(), revision, Url.encode(path), side);
+    rsp.sendRedirect(restUrl);
+  }
+}