-
Notifications
You must be signed in to change notification settings - Fork 35
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
12 changed files
with
206 additions
and
62 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
28 changes: 0 additions & 28 deletions
28
src/main/java/org/cryptomator/cryptofs/common/MasterkeyBackupFileHasher.java
This file was deleted.
Oops, something went wrong.
83 changes: 83 additions & 0 deletions
83
src/main/java/org/cryptomator/cryptofs/common/MasterkeyBackupHelper.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,83 @@ | ||
| package org.cryptomator.cryptofs.common; | ||
|
|
||
| import com.google.common.io.BaseEncoding; | ||
| import org.slf4j.Logger; | ||
| import org.slf4j.LoggerFactory; | ||
|
|
||
| import java.io.IOException; | ||
| import java.io.InputStream; | ||
| import java.nio.ByteBuffer; | ||
| import java.nio.channels.FileChannel; | ||
| import java.nio.channels.ReadableByteChannel; | ||
| import java.nio.channels.SeekableByteChannel; | ||
| import java.nio.channels.WritableByteChannel; | ||
| import java.nio.file.AccessDeniedException; | ||
| import java.nio.file.Files; | ||
| import java.nio.file.NoSuchFileException; | ||
| import java.nio.file.Path; | ||
| import java.nio.file.StandardOpenOption; | ||
| import java.security.MessageDigest; | ||
| import java.security.NoSuchAlgorithmException; | ||
| import java.util.Arrays; | ||
|
|
||
| import static java.nio.file.StandardCopyOption.REPLACE_EXISTING; | ||
|
|
||
| /** | ||
| * Utility class for generating a suffix for the backup file to make it unique to its original master key file. | ||
| */ | ||
| public final class MasterkeyBackupHelper { | ||
|
|
||
| private static final Logger LOG = LoggerFactory.getLogger(MasterkeyBackupHelper.class); | ||
|
|
||
| /** | ||
| * Computes the SHA-256 digest of the given byte array and returns a file suffix containing the first 4 bytes in hex string format. | ||
| * | ||
| * @param fileBytes the input byte for which the digest is computed | ||
| * @return "." + first 4 bytes of SHA-256 digest in hex string format | ||
| */ | ||
| public static String generateFileIdSuffix(byte[] fileBytes) { | ||
| try { | ||
| MessageDigest md = MessageDigest.getInstance("SHA-256"); | ||
| byte[] digest = md.digest(fileBytes); | ||
| return "." + BaseEncoding.base16().encode(digest, 0, 4); | ||
| } catch (NoSuchAlgorithmException e) { | ||
| throw new IllegalStateException("Every Java Platform must support the Message Digest algorithm SHA-256", e); | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * Do a best-effort attempt to backup the masterkey at the given path. Fail silently if a valid backup already exists. | ||
| * | ||
| * @param masterKeyPath The masterkey file to backup | ||
| * @throws IOException Any non-recoverable I/O exception that occurs during this attempt | ||
| */ | ||
| public static Path backupMasterKey(Path masterKeyPath) throws IOException { | ||
| byte[] keyFileContents = Files.readAllBytes(masterKeyPath); | ||
| String backupFileName = masterKeyPath.getFileName().toString() + generateFileIdSuffix(keyFileContents) + Constants.MASTERKEY_BACKUP_SUFFIX; | ||
| Path backupFilePath = masterKeyPath.resolveSibling(backupFileName); | ||
| try (WritableByteChannel ch = Files.newByteChannel(backupFilePath, StandardOpenOption.CREATE, StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING)) { | ||
| ch.write(ByteBuffer.wrap(keyFileContents)); | ||
| } catch (AccessDeniedException e) { | ||
| LOG.info("Storage device does not allow writing backup file. Comparing masterkey with backup directly."); | ||
| assertExistingBackupMatchesContent(backupFilePath, ByteBuffer.wrap(keyFileContents)); | ||
| } | ||
| return backupFilePath; | ||
| } | ||
|
|
||
| private static void assertExistingBackupMatchesContent(Path backupFilePath, ByteBuffer expectedContent) throws IOException { | ||
| if (Files.exists(backupFilePath)) { | ||
| // TODO replace by Files.mismatch() when using JDK > 12 | ||
| ByteBuffer buf = ByteBuffer.allocateDirect(expectedContent.remaining() + 1); | ||
| try (ReadableByteChannel ch = Files.newByteChannel(backupFilePath, StandardOpenOption.READ)) { | ||
| ch.read(buf); | ||
| buf.flip(); | ||
| if (buf.compareTo(expectedContent) != 0) { | ||
| throw new IllegalStateException("Corrupt masterkey backup: " + backupFilePath); | ||
| } | ||
| LOG.debug("Verified backup file: {}", backupFilePath); | ||
| } catch (NoSuchFileException e) { | ||
| LOG.warn("Did not find backup file: {}", backupFilePath); | ||
| } | ||
| } | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
59 changes: 59 additions & 0 deletions
59
src/test/java/org/cryptomator/cryptofs/common/MasterkeyBackupHelperTest.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,59 @@ | ||
| package org.cryptomator.cryptofs.common; | ||
|
|
||
| import org.junit.jupiter.api.Assertions; | ||
| import org.junit.jupiter.api.condition.EnabledOnOs; | ||
| import org.junit.jupiter.api.condition.OS; | ||
| import org.junit.jupiter.api.io.TempDir; | ||
| import org.junit.jupiter.params.ParameterizedTest; | ||
| import org.junit.jupiter.params.provider.MethodSource; | ||
|
|
||
| import java.io.IOException; | ||
| import java.nio.file.Files; | ||
| import java.nio.file.Path; | ||
| import java.nio.file.attribute.DosFileAttributeView; | ||
| import java.nio.file.attribute.PosixFilePermissions; | ||
| import java.util.Random; | ||
| import java.util.stream.Stream; | ||
|
|
||
| class MasterkeyBackupHelperTest { | ||
|
|
||
| @EnabledOnOs({OS.LINUX, OS.MAC}) | ||
| @ParameterizedTest | ||
| @MethodSource("createRandomBytes") | ||
| public void testBackupFilePosix(byte[] contents, @TempDir Path tmp) throws IOException { | ||
| Path originalFile = tmp.resolve("original"); | ||
| Files.write(originalFile, contents); | ||
|
|
||
| Path backupFile = MasterkeyBackupHelper.backupMasterKey(originalFile); | ||
| Assertions.assertArrayEquals(contents, Files.readAllBytes(backupFile)); | ||
|
|
||
| Files.setPosixFilePermissions(backupFile, PosixFilePermissions.fromString("r--r--r--")); | ||
| Path backupFile2 = MasterkeyBackupHelper.backupMasterKey(originalFile); | ||
| Assertions.assertEquals(backupFile, backupFile2); | ||
| } | ||
|
|
||
| @EnabledOnOs({OS.WINDOWS}) | ||
| @ParameterizedTest | ||
| @MethodSource("createRandomBytes") | ||
| public void testBackupFileWin(byte[] contents, @TempDir Path tmp) throws IOException { | ||
| Path originalFile = tmp.resolve("original"); | ||
| Files.write(originalFile, contents); | ||
|
|
||
| Path backupFile = MasterkeyBackupHelper.backupMasterKey(originalFile); | ||
| Assertions.assertArrayEquals(contents, Files.readAllBytes(backupFile)); | ||
|
|
||
| Files.getFileAttributeView(backupFile, DosFileAttributeView.class).setReadOnly(true); | ||
| Path backupFile2 = MasterkeyBackupHelper.backupMasterKey(originalFile); | ||
| Assertions.assertEquals(backupFile, backupFile2); | ||
| } | ||
|
|
||
| static Stream<byte[]> createRandomBytes() { | ||
| Random rnd = new Random(42l); | ||
| return Stream.generate(() -> { | ||
| byte[] bytes = new byte[100]; | ||
| rnd.nextBytes(bytes); | ||
| return bytes; | ||
| }).limit(10); | ||
| } | ||
|
|
||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.