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https://issues.apache.org/jira/browse/HADOOP-11343?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14233673#comment-14233673
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Andrew Wang commented on HADOOP-11343:
--------------------------------------
This makes sense to me too.
Code-wise, it's a little tricky for the compatibility. We can add a new
CipherSuite#AES_CTR_NOPADDING_FIXED (just a suggestion), but it's going to have
the same getName as the original AES_CTR_NOPADDING. This name
("AES/CTR/NoPadding") is currently treated as unique, and used when we're
determining the CipherSuite when creating an EZ, and also when instantiating
the CryptoCodec to read data. We'll need to update these two places in the code
to account for this correctly, FSNamesystem#createEncryptionZone and
CryptoCodec#getInstance respectively.
[~jerrychenhf] does this make sense to you? I'd like to get this in ASAP, so
I'm happy to take your patch and do the above if it helps.
> Overflow is not properly handled in caclulating final iv for AES CTR
> --------------------------------------------------------------------
>
> Key: HADOOP-11343
> URL: https://issues.apache.org/jira/browse/HADOOP-11343
> Project: Hadoop Common
> Issue Type: Bug
> Components: security
> Affects Versions: trunk-win, 2.7.0
> Reporter: Jerry Chen
> Assignee: Jerry Chen
> Priority: Blocker
> Attachments: HADOOP-11343.patch
>
>
> 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);
> }
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