RFR: 8359388: Stricter checking for cipher transformations

[Mikhail Yankelevich]

On Fri, 13 Jun 2025 17:32:12 GMT, Valerie Peng <valeriep at openjdk.org> wrote:

> Based on the javadoc of `javax.crypto.Cipher` class, the cipher transformation should be either "algorithm/mode/padding" or
> "algorithm". When parsing the transformation, space(s) is trimmed off and empty strings are considered as "unspecified". This PR adds checks to ensure that transformations with empty "mode" and/or "padding" value in the "algorithm/mode/padding" form leads to `NoSuchAlgorithmException`. This reverts some changes made in [https://bugs.openjdk.org/browse/JDK-8358159](https://bugs.openjdk.org/browse/JDK-8358159) which allows empty mode and/or padding in the transformations.
> 
> Tier1 - 3 Mach5 job: https://mach5.us.oracle.com/mdash/jobs/vpeng-jdkOh3-20250613-0441-29515109
> JCK javax_crypto and java_security Mach5 job: https://mach5.us.oracle.com/mdash/jobs/vpeng-jdkOh3-20250613-0624-29519811 
> 
> Thanks in advance for the review~

src/java.base/share/classes/javax/crypto/Cipher.java line 348:

> 346:                 transformation.substring(0, endIdx).trim());
> 347:         if (algo.isEmpty()) {
> 348:             throw new NoSuchAlgorithmException("Invalid transformation: " +

I don't think this exception is tested. It could be by adding `test(" ", provider);` in [test/jdk/javax/crypto/Cipher/TestEmptyModePadding.java](https://github.com/openjdk/jdk/pull/25808/files#diff-5442ba4fbe85af64a99ca3c2d2b5795026be4c40e23af8337d52a64cefd6af35) on line 68

test/jdk/javax/crypto/Cipher/TestEmptyModePadding.java line 75:

> 73:         try {
> 74:             Cipher c = Cipher.getInstance(transformation, provider);
> 75:             throw new RuntimeException("Expected NSAE not thrown");

Minor: Do you think it would be a good idea to print out `transformation` and `provider` data for debug? In `System.err` that is. Otherwise afaik the exception is thrown and no trace in system error, just in `System.out.println`, making debugging quite challenging 

Just something like this 
```suggestion 
            System.err.println("Error while testing " + transformation);
            throw new RuntimeException("Expected NSAE not thrown");

or just add it to the `RuntimeException` message

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PR Review Comment: https://git.openjdk.org/jdk/pull/25808#discussion_r2150062308
PR Review Comment: https://git.openjdk.org/jdk/pull/25808#discussion_r2149939460