RFR JDK-8066709 Make some JDK system properties read only

[Roger Riggs]

Hi Max,

On 6/4/2018 7:24 PM, Weijun Wang wrote:
> Hi Roger
>
> Thanks for the explanation.
>
> Another question: Before this change, a SecurityException might be thrown when getProperty() is called, does you new code simulate this behavior? Or in these cases this is unnecessary?
Many of the usages were already in doPriv or GetPropertyAction flows so 
no security check was being done.

In a few cases, the existing doPriv is in a different file (e.g. calls 
to SunEntries.getDeviceFile(utl)).
Those would be safer to leave as is, trading off the consistency with 
confidence about the property check
(or add the property access check).

The usage in SocksSocketImpl needs a second look, Alan pointed out a 
difference in behavior.

The use of user.name in MimeTable and MailToURLConnection were missing a 
security check.

> Also, looks like all change is inside java.base, do you have a suggestion we use it in other JDK modules?
Not at this time.

Roger

>
> Thanks
> Max
>
>> On Jun 5, 2018, at 3:54 AM, Roger Riggs <Roger.Riggs at Oracle.com> wrote:
>>
>> Hi Max,
>>
>> On 6/4/2018 11:41 AM, Wang Weijun wrote:
>>> Not a native English speaker, so my feeling might be incorrect.
>>>
>>> Will someone interpret this as that System.getProperty() will return a cached value?
>>>
>> I don't think so, it should be clear that the values are cached at initialization or first use.
>>> I would say “Although getProperty() always returns the last value set by setProperty() (I assume this is the current behavior), it is not uncommon that consumers of a system property may read it once and cache the value it for later use, which means setting the property <strong>may not have the desired effect</strong>”.
>>>
>> The purpose of the change is to clarify the behavior of the java.base module internal access to the properties.
>> How applications handle properties is beyond the intended scope.
>>> I also don’t think it’s worth listing the 4 property names in the spec. Quite some other system properties are also cached. Listing them there could further suggests that calling getProperty() on them will return the cached value.
>>>
>> It seemed worthwhile to highlight the specific properties affected and the release note should be specific.
>> I moved them to an implNote as Alan suggested.
>>
>> Thanks, Roger
>>
>>> Thanks
>>> Max
>>>
>>>
>>>> 在 2018年6月4日，下午9:32，Roger Riggs <Roger.Riggs at oracle.com>
>>>>   写道：
>>>>
>>>> Please review a change to make the values of java.home, user.home, user.dir, and user.name
>>>> effectively read-only for internal use.  The values are cached during initialization and the
>>>> cached values are used.
>>>>
>>>> Webrev:
>>>>    
>>>> http://cr.openjdk.java.net/~rriggs/webrev-static-property-8066709/
>>>>
>>>>
>>>> Issue:
>>>>    
>>>> https://bugs.openjdk.java.net/browse/JDK-8066709
>>>>
>>>>
>>>> CSR:
>>>>    
>>>> https://bugs.openjdk.java.net/browse/JDK-8204235
>>>>
>>>>
>>>> Thanks, Roger
>>>>
>>>>
>>>>