UBUNTU: SAUCE: apparmor: fix replacement race in reading rawdata

UBUNTU: SAUCE: apparmor: fix replacement race in reading rawdata

The reading of rawdata is subject to a replacement race when the
rawdata is read in chunks smaller than the data size.

For each read the profile proxy is rechecked for the newest profile;
Which means if a profile is replaced between reads later chunks will
contain data from the new version of the profile while the earlier
reads will contain data from the previous version. This can result in
data that is inconsistent and corrupt.

Instead of rechecking for the current profile at each read. Get the
current profile at the time of the open and use the rawdata of the
profile for the lifetime that the file handle is open.

BugLink: http://bugs.launchpad.net/bugs/1638996
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>