Add doPrivilege blocks for socket connect ops in repository-hdfs

[Tim-Brooks]

This is related to #22116. The repository-hdfs plugin opens socket
connections. As SocketPermission is transitioned out of core, hdfs
will require connect permission. This pull request wraps operations
that require this permission in doPrivileged blocks.

[Tim-Brooks]

In hdfs we are calling doPrivileged and explicitly defining the permissions. I was not sure if there was a reason we were doing this differently, so I left it as is and just added new SocketPermission("*", "connect").

[rjernst]

In hdfs we are calling doPrivileged and explicitly defining the permissions

We do this to limit what craziness hdfs can do (and know exactly what it requires).

[rjernst]

LGTM

[s1monw]

I left one comment looks great so far

[s1monw]

can we maybe try to trigger this differently? I mean can we for instance try to call #available() or can we maybe read the first byte on open and wrap in a BufferedInputStream and then do this:

InputStream stream = is.isMarkSupported() ? is : new BufferedInputStream(is);
// do the following in doPrivileged?
stream.mark(1);
stream.skip(1);
stream.reset();
return stream;

[Tim-Brooks]

@s1monw In my testing available() was not doing the trick. So I went with the buffered, mark, skip, reset approach.

[s1monw]

left one more comment we are close I think

[s1monw]

if we run into an exception here we have to close the stream.

we usually do this:

boolean success = false;
try {
 // do something with the stream
  success = true;
  return stream;
} finally {
  if (success == false) {
    IOUtils.closeWhileHandlingException(stream);
  }
}

[Tim-Brooks]

Note to other reviews:

Simon and I talked about this for a while and decided it was safest to return a InputStream implementation that wraps all of the methods.

[s1monw]

LGTM