Correctly parse v4 subsecond timestamps

Authored by StefanBruens on Apr 9 2020, 7:54 PM.


Correctly parse v4 subsecond timestamps

All subsecond timestamps are only in the packets if both the
SUBSECOND_TIMES flag and the timestamp flag, e.g. ATTR_ACCESSTIME
are set.

SUBSECOND_TIMES are not very common across server implementations
(e.g. openssh does not include it, nor does libssh's sftpserver
implementation), but this interpretation of the SFTP protocol draft
is used by WinSCP and lftp.

Fixes T219.

Signed-off-by: Stefan BrĂ¼ns <stefan.bruens@rwth-aachen.de>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
(cherry picked from commit 1ff6dda616ecb6327256003d5c0ee7ddd40bc783)