[HADOOP-11343] Overflow is not properly handled in caclulating final iv for AES CTR

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.6.0
• Fix Version/s: 2.6.1, 2.7.0, 3.0.0-alpha1
• Component/s: security
• Labels: 2.6.1-candidate
• Target Version/s: 2.7.0
• Assignee: Haifeng Chen
• Reporter: Haifeng Chen
• Due: 05/Dec/14
• Created: 02/Dec/14 04:57
• Updated: 30/Aug/16 01:31
• Resolved: 06/Dec/14 02:22

Description

In the AesCtrCryptoCodec calculateIV, as the init IV is a random generated 16 bytes,

final byte[] iv = new byte[cc.getCipherSuite().getAlgorithmBlockSize()];
cc.generateSecureRandom(iv);

Then the following calculation of iv and counter on 8 bytes (64bit) space would easily cause overflow and this overflow gets lost. The result would be the 128 bit data block was encrypted with a wrong counter and cannot be decrypted by standard aes-ctr.

/**
   * The IV is produced by adding the initial IV to the counter. IV length 
   * should be the same as {@link #AES_BLOCK_SIZE}
   */
  @Override
  public void calculateIV(byte[] initIV, long counter, byte[] IV) {
    Preconditions.checkArgument(initIV.length == AES_BLOCK_SIZE);
    Preconditions.checkArgument(IV.length == AES_BLOCK_SIZE);
    
    System.arraycopy(initIV, 0, IV, 0, CTR_OFFSET);
    long l = 0;
    for (int i = 0; i < 8; i++) {
      l = ((l << 8) | (initIV[CTR_OFFSET + i] & 0xff));
    }
    l += counter;
    IV[CTR_OFFSET + 0] = (byte) (l >>> 56);
    IV[CTR_OFFSET + 1] = (byte) (l >>> 48);
    IV[CTR_OFFSET + 2] = (byte) (l >>> 40);
    IV[CTR_OFFSET + 3] = (byte) (l >>> 32);
    IV[CTR_OFFSET + 4] = (byte) (l >>> 24);
    IV[CTR_OFFSET + 5] = (byte) (l >>> 16);
    IV[CTR_OFFSET + 6] = (byte) (l >>> 8);
    IV[CTR_OFFSET + 7] = (byte) (l);
  }