Re: [PING] PoC for JDK-4347142: Need method to set Password protection to Zip entries

[Yasumasa Suenaga]

I've uploaded testcase here:

  http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.04/Test.java


Yasumasa


On 2016/02/10 23:34, Yasumasa Suenaga wrote:

Hi Sherman,

I've refactored a patch for this enhancement:

   http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.04/

   1. I changed ZipCryption and implementation class to package private.
   2. Encryption / Decryption key is allowed passphrase string.
   3. I added passphrase and validation methods to ZipEntry.

I would like to hear your comment.


Thanks,

Yasumasa


On 2016/02/01 18:23, KUBOTA Yuji wrote:

Hi Sherman and all,

Could you please let know your thought and the past case about AES?

Thanks,
Yuji


2016-01-08 0:01 GMT+09:00 KUBOTA Yuji <kubota.y...@gmail.com>:

Hi Sherman,

Thank you for sharing!

2016-01-07 4:04 GMT+09:00 Xueming Shen <xueming.s...@oracle.com>:

The reason that I'm not convinced that we really need a public interface of
ZipCryption here
is I don't know how useful/helpful/likely it would be going forward that
someone might really
use this interface to implement other encryption(s), especially the pkware
proprietary one,
I doubt it might be not that straightforward.

In this proposal, we aim to support "traditional" because most people need it
in secure environment. BTW, could you please share the reason why you did
not support WinZip AES? Do you have a plan to support in the future?

If you can share the reason, we want to decide the way of implementation with
consideration for your information. I think we can implement by two
way as below.

1. Implementing by reference to
http://cr.openjdk.java.net/~sherman/zipmisc/ZipFile.java
This is good simply API. If we need to implement other encryption(s),
try to refactor it.

2. Implementing with a package private interface of ZipCryption for next step.
This has two problems as your advice.

We agree with that the "encryption" and "compression" should be
separated logically.
However, current implementation compress the encrypted data, and buffering it.
It is too tightly-coupled, so we need refactoring to separate the
managing buffer
processing and the stream processing of InflaterInputStream /
DeflaterOutputStream.

About "push back the bytes belong to next entry", we think
InflaterInputStream.originBuf
of our PoC do not required the needed info. Do this implements have problem?

http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.00/src/java.base/share/classes/java/util/zip/InflaterInputStream.java.cdiff.html

Thanks,
Yuji

In fact I did have a draft implementation that supports WinZip AES about 5-6
years ago :-)
(which also supports compression methods bzip and lzma, btw)  Here is the
top class, It appears
a general interface might not be that helpful and it might be ideal to
simply implement it inside
the JDK, as what is proposed here, when it's really desired.

http://cr.openjdk.java.net/~sherman/zipmisc/ZipFile.java

It is a ZipFile based implementation, so it does not have the headache that
ZipInputStream has,
such as to push back the bytes belong to next entry, since the loc might not
have the needed
info regarding the size/csize in stream mode.

 From abstract point of view. The "encryption" and "compression" are
different layers, it would
be ideal to have them in separate classes logically, instead of mixing the
encryption into
compression. Sure, it might be convenient and probably may have better
performance to mix
them in certain use scenario, but the "encryption" should never appear in
the public interface
of those compression classes. Package private interface should be fine, if
have to.

-Sherman

2016-01-06 7:10 GMT+09:00 Xueming Shen <xueming.s...@oracle.com>:

it appears that instead of adding "password" specific method to these
classes directly, it might be more appropriate to extend the ZipEntry
class
for such "password" functionality. For example, with a pair of new
methods

boolean ZipEntry.isTraditionalEncryption().
void ZipEntry.setTraditionalEncryption(String password);

Thanks advice, I agree. We should re-design the API to extend the
ZipEntry class.

The encryption support should/can be added naturally/smoothly with
ZipFile.getInputStream(e), ZipInputstream and
ZipOutputStream.putNextEntry(e),
with no extra new method in these two classes. The implementation checks
the flag (bit0, no bit 6) first and then verifies the password, as an
implementation details.

Agree. For this proposal, we aim to support only traditional
encryption. So I think we should also check bit 6.

For ZipFile and ZipInputStream, we can add note to the api doc to force
the
invoker to check if the returned ZipEntry indicates it's an encrypted
entry.
If yes, it must to set the appropriate password to the returned ZipEntry
via
ZipEntry.setTraditionalEncryption(password); before reading any byte from
the input stream.

Yes, we have to add note the flow of codes to the JavaDoc.

Again, we should not have any "encryption" related public field/method in
DeflaterOutputStream/InflaterInputStream. Ideally these two classes
really
should not be aware of "encryption" at all.

Agree, but I think we might be faced technical difficulty about a
processing between zlib and the internal buffer of InflaterInputStream
/ DeflaterOutputStream. Please give us time to implement.

-Sherman

Thanks,
Yuji

On 01/04/2016 06:26 AM, KUBOTA Yuji wrote:

Hi Sherman and all,

Happy new year to everyone!

Please let know your feedback about this proposal. :-)

Thanks,
Yuji

2015-12-21 22:38 GMT+09:00 KUBOTA Yuji<kubota.y...@gmail.com>:

Hi Sherman,

2015-12-20 16:35 GMT+09:00 Xueming Shen<xueming.s...@oracle.com>:

It is no longer necessary to touch the native code (zip_util.c/h)
after
the
native ZipFile implementation has been moved up to the java level.
Those
native code are for vm access only now, which I dont think care about
the
password support at all.

Thanks for your information. We do not take care the native.

I discussed with Yasumasa, and our thought is as below.

(1) what's the benefit of exposing the public interface ZipCryption?
the
real
question is whether or not this interface is good enough for other
encryption
implementation to plugin their implementation to support the
ZipFile/Input/
OutputStream to their encryption spec.

We aimed that the public interface ZipCryption supports the
extensibillity for other encrypt engine. The JDK core libs developers
have to implementation ZipyCryption only. If not provide, the JDK
developers must implement ZipStream/Entry by JDK API to design the
data structure of entry.
If you want to use binary key data such as PKI, you can implement new
encrypt/decrypt engine by ZipCryption interface.
So we think we should provide this interface to be clearly how to
implement a new engine, e.g., cipher algorithm, cipher strength and
converting the header, etc.

(2) it seems like it might be possible to hide most of the
implementation
and only expose the "String password" (instead of the ZipCryption) as
the
public interface to support the "traditional" encryption. This depends
on the
result of (1) though.

Thanks for your clues. We think the string password at first. However,
we should also create a new binary interface given we support PKI in
the future.

(3) I'm concerned of pushing ZipCryption into
InflaterInputStream/DeflaterOutputStream.
It might be worth considering to replace the ZipCryption
implementation
with
a pair of FilterOutput/InputStream. It would be easy and reasonable to
use
the FilterOutputStream for the ZipOutputStream and the
FilterInputStream
for the
ZipFile. The PushbackInputStream in ZipInputStream might be an issue
...

Thanks for your clues, too. Honestly speaking, we think the current
zip implementation may break the data when used PushbackInputStream
for the following reasons.

* PushbackInputStream uses an unique internal buffer for re-read
operation.
* But, InflaterInputStream provide date to Inflater per reads and
buffer by JNI (zlib).
* So we think PushbackInputStream is poor compatibility with
InflaterInputStream.

We generally use InputStream through ZipEntry#getInputStream(). We do
not touch FileInputStream for reading ZIP data. If we call unread()
when we use PushbackInputStream as reading ZIP archive, we guess that
it will break the reading data.
So, our approach do not affect the PushbackInputStream.
What do you think about this?

(4) It seems the ZipOutputStream only supports the "stream based"
password, while
the ZipInputStream  supports the "entry based" password. Do we really
need
"entry based" support here?

As your suggestion, we should support "entry based". We will start to
implement "entry based" after this discussion is closed.

Thanks,
Yuji

On 12/17/15, 9:45 PM, Yasumasa Suenaga wrote:

Hi Jason,

Thank you for your comment.
I've fixed it in new webrev:
     http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.03/


Thanks,

Yasumasa


On 2015/12/17 0:33, Jason Mehrens wrote:

The null check of 'entry' at line 351 of ZipFile.getInputStream  is
in
conflict with line 350 and 348.

________________________________________
From: core-libs-dev<core-libs-dev-boun...@openjdk.java.net>  on
behalf
of
Yasumasa Suenaga<yasue...@gmail.com>
Sent: Wednesday, December 16, 2015 8:47 AM
To: Sergey Bylokhov; Xueming Shen
Cc: core-libs-dev@openjdk.java.net
Subject: Re: [PING] PoC for JDK-4347142: Need method to set Password
protection to Zip entries

Hi Sergey,

Thank you for your comment.

I added that description in new webrev:
       http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.02/


Thanks,

Yasumasa


On 2015/12/16 22:19, Sergey Bylokhov wrote:

Should the new methods describe how they will work in case of null
params?

On 16/12/15 16:04, Yasumasa Suenaga wrote:

I adapted this enhancement after JDK-8145260:
       http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.01/

Could you review it?


Thanks,

Yasumasa


On 2015/12/12 21:23, Yasumasa Suenaga wrote:

Hi Sherman,

Our proposal is affected by JDK-8142508.
We have to change ZipFile.java and and ZipFile.c .
Thus we will create a new webrev for current (after 8142508)
jdk9/dev
repos.

Do you have any comments about current webrev?
       http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.00/

If you have comments, we will fix them in new webrev.


Thanks,

Yasumasa


On 2015/12/03 16:51, KUBOTA Yuji wrote:

Hi Sherman,

Thanks for your quick response :)

I aimed to implement the "traditional" at this proposal by the
below
reasons.

      * We want to prepare API for encrypted zip files at first.
        * Many people use the "traditional" in problem-free scope
like a
temporary file.
      * We do not know which implementation of the "stronger" is
best
for
openjdk.
        * PKWare claims that they have patents about the
"stronger"
on
Zip[1].
        * OTOH, WinZip have the alternative implementation of the
"stronger" [2][3].
      * Instead, we prepared the extensibility by ZipCryption
interface
to
implement other encrypt engine, such as the AES based.

Thus, I think this PoC should support the "traditional" only.
In the future, anyone who want to implement the "stronger" can
easily
add their code by virtue of this proposal.

[1]
https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.3.TXT
         (1.4 Permitted Use&  7.0 Strong Encryption
Specification)

[2]



https://en.wikipedia.org/wiki/Zip_(file_format)#Strong_encryption_controversy

[3] http://www.winzip.com/aes_info.htm

Thanks,
Yuji

2015-12-03 12:29 GMT+09:00 Xueming
Shen<xueming.s...@oracle.com>:

Hi Yuji,

I will take a look at your PoC.  Might need some time and even
bring
in the
security guy
to evaluate the proposal. It seems like you are only interested
in
the
"traditional PKWare
decryption", which is, based on the wiki, "known to be
seriously
flawed, and
in particular
is vulnerable to known-plaintext attacks":-) Any request to
support
"stronger" encryption
mechanism, such as the AES based?

Regards,
Sherman


On 12/2/15 6:48 PM, KUBOTA Yuji wrote:

Hi all,

We need reviewer(s) for this PoC.
Could you please review this proposal and PoC ?

Thanks,
Yuji

2015-11-26 13:22 GMT+09:00 KUBOTA Yuji<kubota.y...@gmail.com>:

Hi all,

* Sorry for my mistake. I re-post this mail because I sent
before
get
a response of subscription confirmation of core-libs-dev.

Our customers have to handle password-protected zip files.
However,
Java SE does not provide the APIs to handle it yet, so we
must
use
third party library so far.

Recently, we found JDK-4347142: "Need method to set Password
protection to Zip entries", and we tried to implement it.

The current zlib in JDK is completely unaffected by this
proposal.
The
traditional zip encryption encrypts a data after it is has
been
compressed by zlib.[1] So we do NOT need to change existing
zlib
implementation.

We've created PoC and uploaded it as webrev:


http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.00/

          Test code is as below. This code will let you know
how
this
PoC
works.




http://cr.openjdk.java.net/~ysuenaga/JDK-4347142/webrev.00/Test.java

In NTT, a Japanese telecommunications company. We are
providing
many
enterprise systems to customers. Some of them, we need to
implement to
handle password-protected zip file. I guess that this
proposal
is
desired for many developers and users.

I'm working together with Yasumasa Suenaga, jdk9 committer
(ysuenaga).
We want to implement it if this proposal accepted.

[1]:
https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.3.TXT
(6.0  Traditional PKWARE Encryption)

Thanks,
Yuji