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Clear passphrase bytes after use #609

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merged 1 commit into from
Jul 1, 2020
Merged

Clear passphrase bytes after use #609

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3 changes: 3 additions & 0 deletions src/main/java/com/hierynomus/sshj/userauth/keyprovider/OpenSSHKeyV1KeyFile.java
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Original file line number Diff line number Diff line change
Expand Up @@ -143,9 +143,12 @@ private void initializeCipher(String kdfName, byte[] kdfOptions, Cipher cipher)
CharBuffer charBuffer = CharBuffer.wrap(pwdf.reqPassword(null));
ByteBuffer byteBuffer = Charset.forName("UTF-8").encode(charBuffer);
passphrase = Arrays.copyOfRange(byteBuffer.array(), byteBuffer.position(), byteBuffer.limit());
Arrays.fill(charBuffer.array(), '\u0000');
Arrays.fill(byteBuffer.array(), (byte) 0);
}
byte[] keyiv = new byte[48];
new BCrypt().pbkdf(passphrase, opts.readBytes(), opts.readUInt32AsInt(), keyiv);
Arrays.fill(passphrase, (byte) 0);
byte[] key = Arrays.copyOfRange(keyiv, 0, 32);
byte[] iv = Arrays.copyOfRange(keyiv, 32, 48);
cipher.init(Cipher.Mode.Decrypt, key, iv);
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65 changes: 42 additions & 23 deletions src/test/java/net/schmizz/sshj/keyprovider/OpenSSHKeyFileTest.java
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Expand Up @@ -47,10 +47,7 @@
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.Map;
import java.util.Scanner;
import java.util.*;

import static org.hamcrest.CoreMatchers.containsString;
import static org.hamcrest.CoreMatchers.equalTo;
Expand All @@ -70,6 +67,44 @@ public class OpenSSHKeyFileTest {
final char[] correctPassphrase = "test_passphrase".toCharArray();
final char[] incorrectPassphrase = new char[]{' '};

private static class WipeTrackingPasswordFinder implements PasswordFinder {
private int reqCounter = 0;

final private String password;
final private boolean withRetry;
final private ArrayList<char[]> toWipe = new ArrayList<>();

WipeTrackingPasswordFinder(String password, Boolean withRetry) {
this.password = password;
this.withRetry = withRetry;
}

@Override
public char[] reqPassword(Resource<?> resource) {
char[] passwordChars;
if (withRetry && reqCounter < 3) {
reqCounter++;
// Return an incorrect password three times before returning the correct one.
passwordChars = (password + "incorrect").toCharArray();
} else {
passwordChars = password.toCharArray();
}
toWipe.add(passwordChars);
return passwordChars;
}

@Override
public boolean shouldRetry(Resource<?> resource) {
return withRetry && reqCounter <= 3;
}

public void assertWiped() {
for (char[] passwordChars : toWipe) {
assertArrayEquals(new char[passwordChars.length], passwordChars);
}
}
};

final PasswordFinder onlyGivesWhenReady = new PasswordFinder() {
@Override
public char[] reqPassword(Resource resource) {
Expand Down Expand Up @@ -249,27 +284,11 @@ public void shouldLoadECDSAPrivateKeyAsOpenSSHV1() throws IOException {

private void checkOpenSSHKeyV1(String key, final String password, boolean withRetry) throws IOException {
OpenSSHKeyV1KeyFile keyFile = new OpenSSHKeyV1KeyFile();
keyFile.init(new File(key), new PasswordFinder() {
private int reqCounter = 0;

@Override
public char[] reqPassword(Resource<?> resource) {
if (withRetry && reqCounter < 3) {
reqCounter++;
// Return an incorrect password three times before returning the correct one.
return (password + "incorrect").toCharArray();
} else {
return password.toCharArray();
}
}

@Override
public boolean shouldRetry(Resource<?> resource) {
return withRetry && reqCounter <= 3;
}
});
WipeTrackingPasswordFinder pwf = new WipeTrackingPasswordFinder(password, withRetry);
keyFile.init(new File(key), pwf);
PrivateKey aPrivate = keyFile.getPrivate();
assertThat(aPrivate.getAlgorithm(), equalTo("EdDSA"));
pwf.assertWiped();
}

@Test
Expand Down