RFR: JDK-6676643: Improve current C_GetAttributeValue native implementation

[Greg Rubin]

On Tue, 27 Apr 2021 04:28:26 GMT, Greg Rubin <github.com+829871+SalusaSecondus at openjdk.org> wrote:

>> Anyone can help review this somewhat trivial fix? The main change is inside src/jdk.crypto.cryptoki/share/native/libj2pkcs11/p11_objmgmt.c. This is to help better troubleshooting by reporting the type of unavailable attributes in PKCS11 exception message when C_GetAttributeValue(...) call failed. The java file changes are just cleanup for consolidating the CKR_* constants definition into PKCS11Exception class.
>> 
>> Thanks,
>> Valerie
>
> src/jdk.crypto.cryptoki/share/native/libj2pkcs11/p11_objmgmt.c line 262:
> 
>> 260:             temp1 = msg;
>> 261:             temp2 = msg + 80;
>> 262:             for (i = 0; i < ckAttributesLength && temp1 < temp2; i++) {
> 
> I think that this loop will append at most 11 bytes to the string each time (is this correct?), if so, we can make the check `temp1 < temp2 - 12` to count the final null and avoid running off the end with a buffer overflow.

I apologize. This counting code is correct and doesn't have any of the issues I claimed. `snprintf` takes care of everything and I just missed it last night.

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PR: https://git.openjdk.java.net/jdk/pull/3709