[WFLY-11357] add priv block to FileSystemXAResourceRegistry

[baranowb]

Issues: https://issues.jboss.org/browse/WFLY-11357 , https://issues.jboss.org/browse/WFTC-53
PR master: #61

[jamezp]

This should use the https://issues.jboss.org/browse/WFTC-53 JIRA.

[dmlloyd]

In addition to needing a WFTC JIRA # in the PR and commit summary, this also seems to introduce a privileged block with no corresponding permission check. Can it be shown that this is secure?

[baranowb]

WDYM? mkdir and open require r/w permission.
mkdir(): https://docs.oracle.com/javase/7/docs/api/java/io/File.html#mkdir()
FIleChannel.open(): https://docs.oracle.com/javase/7/docs/api/java/nio/channels/FileChannel.html#open(java.nio.file.Path,%20java.nio.file.OpenOption...)

[dmlloyd]

Yes of course, but any time you add doPrivileged somewhere, you must also add a corresponding permission check to prevent malicious code from subverting it.

See http://word-bits.flurg.com/presentations/security-manager/index.html#/11 for more info.

[baranowb]

You mean to proof it in case JDK classes were tampered with?

[dmlloyd]

No... to prove that no unprivileged caller of XAResourceRegistryFile can take advantage of the added extra privilege in order to perform some malicious action.