RFR 8163251 : Hard coded loop limit prevents reading of smart card data greater than 8k

Ivan Gerasimov ivan.gerasimov at oracle.com
Tue Feb 11 20:24:51 UTC 2020


Thank you Roger!

We do have a manual test that performs some sanity verification that a 
transmit call works [1].

I have also received a confirmation from a submitter of the bug that the 
patched JDK now allows to retrieve data larger than 32k, which was not 
possible before the fix.

I'll add a noreg-hard label to the bug.

[1] 
http://hg.openjdk.java.net/jdk/jdk/file/73bcb3e4e596/test/jdk/sun/security/smartcardio/TestTransmit.java

With kind regards,

Ivan


On 2/11/20 6:46 AM, Roger Riggs wrote:
> Hi Ivan,
>
> Raising it to work up to the spec'd limit is a good approach.
>
> Do we have a way to test this?  Aka: There should be a test.
>
> Roger
>
>
> On 2/10/20 8:07 PM, Ivan Gerasimov wrote:
>> Thank you Michael!
>>
>> It's a good point about maximum length.
>>
>> Here's the updated webrev with the new System property dropped and 
>> the increased number of iterations:
>>
>> http://cr.openjdk.java.net/~igerasim/8163251/01/webrev/
>>
>> With kind regards,
>> Ivan
>>
>>
>> On 2/10/20 4:18 PM, Michael StJohns wrote:
>>> On 2/10/2020 6:49 PM, Ivan Gerasimov wrote:
>>>> Hello!
>>>>
>>>> Current implementation of the method 
>>>> javax.smartcardio.CardChannel.transmit() has an internal limitation 
>>>> on the maximum allowed amount of the transmitted data.
>>>>
>>>> This limitation is dictated by the maximum number of iterations to 
>>>> transmit data from a card:  Each iteration can transmit up to 256 
>>>> bytes of data, and we have a hardcoded limit of 32 iterations.
>>>>
>>>> Over time, we've received requests to increase this limit, as there 
>>>> are occasions when the effective limit of 8k is not enough.
>>>>
>>>> Would you please help review a proposal:  First, it is proposed to 
>>>> increase the default limit of iteration to 128 (so that up to 32k 
>>>> of data can be transmitted);  Second, the limit of iterations is 
>>>> made configurable via a System property. This limit can be 
>>>> increased up to 4096 (so that the total amount of transmitted data 
>>>> can be made up to 1m).
>>>>
>>>> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8163251
>>>> WEBREV: http://cr.openjdk.java.net/~igerasim/8163251/00/webrev/
>>>>
>>>> If there is an agreement on the proposal, I'll file a CSR to 
>>>> document a new System property.
>>>>
>>>> Thanks in advance!
>>>>
>>> Given that the maximum length for an extended APDU is 64K (65536) 
>>> (hmm +7 for the header and +2 for LE), and for its return is 64K + 2 
>>> bytes,  I'm not quite sure why you'd up the number to 4096/1M - I'd 
>>> set the default and fixed value to 257 (64K) and leave it at that.
>>>
>>> Mike
>>>
>>>
>>>
>>>
>>>
>
-- 
With kind regards,
Ivan Gerasimov



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