RFR: 8031572: jarsigner -verify exits with 0 when a jar file is not properly signed

Wang Weijun weijun.wang at oracle.com
Wed Jan 22 17:57:27 PST 2014

More explanations:

JarVerifier works in 2 stages: parsing signatures and verifying entries. There are 2 ways to enter the 2nd stage: 1) Someone else call JarEntry::doneWithMeta() directly, 2) JarVerfier itself sees an incoming JarEntry and decides to enter. Before JDK-8021788 (that triggers the regression as described in 8031572), we have:

- JarVerifier: when incoming JarEntry is not in META-INF, automatically enters the 2nd stage

- JarFile: feed JarVerifier with all META-INF entries when initializing verifier, and then force JarVerifier into 2nd stage

- JarInputStream: feed JarVerifier in natural order

So JarFile and JarVerifier are a perfect match, but when using JarInputStream and there are files in META-INF but not signature-related, JarVerifier cannot enter 2nd stage and these entries are treated as unsigned.

After JDK-8021788, there is one change:

- JarVerifier: when incoming JarEntry is not in signature-related, automatically enters the 2nd stage

This fixes the JarInputStream issue (of course, we still need signature files at the beginning). But if a non-signature META-INF file appears before a signature, during the JarFile’s initializing process it could make JarVerifier entering the 2nd stage prematurely and thus ignore later coming signature files.

This fix change JarFile behavior:

- JarFile: feed JarVerifier with all signature-related META-INF entries when initializing verifier, and then force JarVerifier into 2nd stage

so JarFile and JarVerifier work fine together again.

As you can see, the 2 ways JarVerifier entering the 2nd stage should have been used by JarFile and JarInputStream separately, so when opened with JarFile it need not enter itself. I would like to make some enhancement in JDK 9 to make the logic more simple and intuitive.

Please note that when using a JarFile, the initializing process is before the first getInpuStream(JarEntry) is returned. Therefore you can getJarEntry() on anything (including those non-signatures in META-INF) and call getInputStream() on it and it will be verified.


On Jan 22, 2014, at 15:01, Wang Weijun <weijun.wang at oracle.com> wrote:

> Hi All
> Please take a look at the webrev at
>   http://cr.openjdk.java.net/~weijun/8031572/8/webrev.00/
> JarVerifier has a flag that separates parsing signatures and verifying other entries. The fix makes sure only signature-related files are processed in the beginning so JarVerifier does not enter the second stage prematurely. Please note that JarInputStream always feeds JarVerifier by natural order so once a non-signatued-related file is processed it goes into verification stage and will not parse a signature anymore.
> Maybe a smarter solution is to be *always on alert*, which means at anytime an incoming entry can be anything, so that even if signature-related files appear at the middle of a file, at least those come after them can be treated as signed when opening with a JarInputStream. This will be a huge change to the JarVerifier class and IMHO does not really help much. Also I don’t want to consider it at this final time of JDK 8.
> You can also find webrevs for jdk9 and jdk7u at
>   http://cr.openjdk.java.net/~weijun/8031572/webrev.00/
> and
>   http://cr.openjdk.java.net/~weijun/8031572/7/webrev.00/
> There are some tiny differences. For 9, the JarVerifier fix needs to be rebased on a language style changeset.  For 7u, there are some differences in the test because of class name change, implicit final, and default method.
> Thanks
> Max

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