| // 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.server; |
| |
| import static com.google.gerrit.client.rpc.BaseServiceImplementation.canRead; |
| |
| import com.google.gerrit.client.data.ProjectCache; |
| import com.google.gerrit.client.reviewdb.Account; |
| import com.google.gerrit.client.reviewdb.Change; |
| import com.google.gerrit.client.reviewdb.Patch; |
| import com.google.gerrit.client.reviewdb.PatchSet; |
| import com.google.gerrit.client.reviewdb.Project; |
| import com.google.gerrit.client.reviewdb.ReviewDb; |
| import com.google.gerrit.client.rpc.Common; |
| import com.google.gerrit.git.InvalidRepositoryException; |
| import com.google.gwtjsonrpc.server.XsrfException; |
| import com.google.gwtorm.client.OrmException; |
| |
| import org.spearce.jgit.lib.Constants; |
| import org.spearce.jgit.lib.ObjectId; |
| import org.spearce.jgit.lib.Repository; |
| import org.spearce.jgit.revwalk.RevCommit; |
| import org.spearce.jgit.revwalk.RevWalk; |
| import org.spearce.jgit.treewalk.TreeWalk; |
| import org.spearce.jgit.util.NB; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.io.UnsupportedEncodingException; |
| import java.security.MessageDigest; |
| import java.security.SecureRandom; |
| import java.util.zip.ZipEntry; |
| import java.util.zip.ZipOutputStream; |
| |
| import javax.servlet.ServletConfig; |
| import javax.servlet.ServletException; |
| import javax.servlet.http.HttpServlet; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| |
| /** |
| * 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. |
| */ |
| @SuppressWarnings("serial") |
| public class CatServlet extends HttpServlet { |
| private static final String APPLICATION_OCTET_STREAM = |
| "application/octet-stream"; |
| private GerritServer server; |
| private SecureRandom rng; |
| |
| @Override |
| public void init(final ServletConfig config) throws ServletException { |
| super.init(config); |
| try { |
| server = GerritServer.getInstance(); |
| } catch (OrmException e) { |
| throw new ServletException("Cannot load GerritServer", e); |
| } catch (XsrfException e) { |
| throw new ServletException("Cannot load GerritServer", e); |
| } |
| rng = new SecureRandom(); |
| } |
| |
| @Override |
| protected void doGet(final HttpServletRequest req, |
| final HttpServletResponse rsp) throws IOException { |
| String keyStr = req.getPathInfo(); |
| 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 Account.Id me = new GerritCall(server, req, rsp).getAccountId(); |
| final Change.Id changeId = patchKey.getParentKey().getParentKey(); |
| final Project project; |
| final Change change; |
| final PatchSet patchSet; |
| final Patch patch; |
| try { |
| final ReviewDb db = Common.getSchemaFactory().open(); |
| try { |
| change = db.changes().get(changeId); |
| if (change == null) { |
| rsp.sendError(HttpServletResponse.SC_NOT_FOUND); |
| return; |
| } |
| |
| final ProjectCache.Entry e = |
| Common.getProjectCache().get(change.getDest().getParentKey()); |
| if (e == null || !canRead(me, e)) { |
| rsp.sendError(HttpServletResponse.SC_NOT_FOUND); |
| return; |
| } |
| |
| project = e.getProject(); |
| patchSet = db.patchSets().get(patchKey.getParentKey()); |
| patch = db.patches().get(patchKey); |
| if (patchSet == null || patch == null) { |
| rsp.sendError(HttpServletResponse.SC_NOT_FOUND); |
| return; |
| } |
| } finally { |
| db.close(); |
| } |
| } catch (OrmException e) { |
| getServletContext().log("Cannot query database", e); |
| rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); |
| return; |
| } |
| |
| final Repository repo; |
| try { |
| repo = |
| server.getRepositoryCache() |
| .get(change.getDest().getParentKey().get()); |
| } catch (InvalidRepositoryException e) { |
| getServletContext().log("Cannot open repository", e); |
| rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); |
| return; |
| } |
| |
| final byte[] blobData; |
| final RevCommit fromCommit; |
| final String suffix; |
| final String path = patch.getFileName(); |
| try { |
| final RevWalk rw = new RevWalk(repo); |
| final RevCommit c; |
| final TreeWalk tw; |
| |
| c = rw.parseCommit(ObjectId.fromString(patchSet.getRevision().get())); |
| if (side == 0) { |
| fromCommit = c; |
| suffix = "new"; |
| |
| } else if (1 <= side && side - 1 < c.getParentCount()) { |
| fromCommit = rw.parseCommit(c.getParent(side - 1)); |
| if (c.getParentCount() == 1) { |
| suffix = "old"; |
| } else { |
| suffix = "old" + side; |
| } |
| |
| } else { |
| rsp.sendError(HttpServletResponse.SC_NOT_FOUND); |
| return; |
| } |
| |
| tw = TreeWalk.forPath(repo, path, fromCommit.getTree()); |
| if (tw == null) { |
| rsp.sendError(HttpServletResponse.SC_NOT_FOUND); |
| return; |
| } |
| |
| if (tw.getFileMode(0).getObjectType() == Constants.OBJ_BLOB) { |
| blobData = repo.openBlob(tw.getObjectId(0)).getCachedBytes(); |
| |
| } else { |
| rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); |
| return; |
| } |
| } catch (IOException e) { |
| getServletContext().log("Cannot read repository", e); |
| rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); |
| return; |
| } catch (RuntimeException e) { |
| getServletContext().log("Cannot read repository", e); |
| rsp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); |
| return; |
| } |
| |
| final long when = fromCommit.getCommitTime() * 1000L; |
| String contentType = guessContentType(project, path, blobData); |
| final String fn; |
| final byte[] outData; |
| |
| if (isSafeInline(contentType)) { |
| fn = safeFileName(path, suffix); |
| outData = blobData; |
| |
| } else { |
| // The content may not be safe to transmit inline, as a browser might |
| // interpret it as HTML or JavaScript hosted by this site. Such code |
| // might then run in the site's security domain, and may be able to use |
| // the user's cookies to perform unauthorized actions. |
| // |
| // Usually, wrapping the content into a ZIP file forces the browser to |
| // save the content to the local system instead. |
| // |
| final ByteArrayOutputStream zip = new ByteArrayOutputStream(); |
| final ZipOutputStream zo = new ZipOutputStream(zip); |
| final ZipEntry e = new ZipEntry(safeFileName(path, rand(req, suffix))); |
| e.setComment(fromCommit.name() + ":" + path); |
| e.setSize(blobData.length); |
| e.setTime(when); |
| zo.putNextEntry(e); |
| zo.write(blobData); |
| zo.closeEntry(); |
| zo.close(); |
| |
| outData = zip.toByteArray(); |
| contentType = "application/zip"; |
| fn = safeFileName(path, suffix) + ".zip"; |
| } |
| |
| rsp.setContentType(contentType); |
| rsp.setContentLength(outData.length); |
| rsp.setDateHeader("Last-Modified", when); |
| rsp.setHeader("Content-Disposition", "attachment; filename=\"" + fn + "\""); |
| rsp.setDateHeader("Expires", 0L); |
| rsp.setHeader("Pragma", "no-cache"); |
| rsp.setHeader("Cache-Control", "no-cache, must-revalidate"); |
| rsp.getOutputStream().write(outData); |
| } |
| |
| private String guessContentType(final Project project, final String path, |
| final byte[] content) { |
| // When in doubt, call it a generic binary stream. |
| // |
| return APPLICATION_OCTET_STREAM; |
| } |
| |
| private boolean isSafeInline(final String contentType) { |
| if (APPLICATION_OCTET_STREAM.equals(contentType)) { |
| // Most browsers perform content type sniffing when they get told |
| // a generic content type. This is bad, so assume we cannot send |
| // the file inline. |
| // |
| return false; |
| } |
| |
| // Assume we cannot send the content inline. |
| // |
| return false; |
| } |
| |
| private static String safeFileName(String fileName, final String suffix) { |
| // Convert a file path (e.g. "src/Init.c") to a safe file name with |
| // no meta-characters that might be unsafe on any given platform. |
| // |
| final int slash = fileName.lastIndexOf('/'); |
| if (slash >= 0) { |
| fileName = fileName.substring(slash + 1); |
| } |
| |
| final StringBuilder r = new StringBuilder(fileName.length()); |
| for (int i = 0; i < fileName.length(); i++) { |
| final char c = fileName.charAt(i); |
| if (c == '_' || c == '-' || c == '.' || c == '@') { |
| r.append(c); |
| |
| } else if ('0' <= c && c <= '9') { |
| r.append(c); |
| |
| } else if ('A' <= c && c <= 'Z') { |
| r.append(c); |
| |
| } else if ('a' <= c && c <= 'z') { |
| r.append(c); |
| |
| } else if (c == ' ' || c == '\n' || c == '\r' || c == '\t') { |
| r.append('-'); |
| |
| } else { |
| r.append('_'); |
| } |
| } |
| fileName = r.toString(); |
| |
| final int ext = fileName.lastIndexOf('.'); |
| if (ext <= 0) { |
| return fileName + "_" + suffix; |
| |
| } else { |
| return fileName.substring(0, ext) + "_" + suffix |
| + fileName.substring(ext); |
| } |
| } |
| |
| private String rand(final HttpServletRequest req, final String suffix) |
| throws UnsupportedEncodingException { |
| // Produce a random suffix that is difficult (or nearly impossible) |
| // for an attacker to guess in advance. This reduces the risk that |
| // an attacker could upload a *.class file and have us send a ZIP |
| // that can be invoked through an applet tag in the victim's browser. |
| // |
| final MessageDigest md = Constants.newMessageDigest(); |
| final byte[] buf = new byte[8]; |
| |
| NB.encodeInt32(buf, 0, req.getRemotePort()); |
| md.update(req.getRemoteAddr().getBytes("UTF-8")); |
| md.update(buf, 0, 4); |
| |
| NB.encodeInt64(buf, 0, System.currentTimeMillis()); |
| md.update(buf, 0, 8); |
| |
| rng.nextBytes(buf); |
| md.update(buf, 0, 8); |
| |
| return suffix + "-" + ObjectId.fromRaw(md.digest()).name(); |
| } |
| |
| } |
