apparmor: Fix regression in mount mediation

commit 2db154b3ea8e ("vfs: syscall: Add move_mount(2) to move mounts around")

introduced a new move_mount(2) system call and a corresponding new LSM
security_move_mount hook but did not implement this hook for any
existing LSM. This creates a regression for AppArmor mediation of
mount. This patch provides a base mapping of the move_mount syscall to
the existing mount mediation. In the future we may introduce
additional mediations around the new mount calls.

Fixes: 2db154b3ea8e ("vfs: syscall: Add move_mount(2) to move mounts around")
CC: stable@vger.kernel.org
Reported-by: Andreas Steinmetz <anstein99@googlemail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

apparmor: pass cred through to audit info.

The cred is needed to properly audit some messages, and will be needed
in the future for uid conditional mediation. So pass it through to
where the apparmor_audit_data struct gets defined.

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

apparmor: add mount mediation

Add basic mount mediation. That allows controlling based on basic
mount parameters. It does not include special mount parameters for
apparmor, super block labeling, or any triggers for apparmor namespace
parameter modifications on pivot root.

default userspace policy rules have the form of
MOUNT RULE = ( MOUNT | REMOUNT | UMOUNT )

MOUNT = [ QUALIFIERS ] 'mount' [ MOUNT CONDITIONS ] [ SOURCE FILEGLOB ]
[ '->' MOUNTPOINT FILEGLOB ]

REMOUNT = [ QUALIFIERS ] 'remount' [ MOUNT CONDITIONS ]
MOUNTPOINT FILEGLOB

UMOUNT = [ QUALIFIERS ] 'umount' [ MOUNT CONDITIONS ] MOUNTPOINT FILEGLOB

MOUNT CONDITIONS = [ ( 'fstype' | 'vfstype' ) ( '=' | 'in' )
MOUNT FSTYPE EXPRESSION ]
[ 'options' ( '=' | 'in' ) MOUNT FLAGS EXPRESSION ]

MOUNT FSTYPE EXPRESSION = ( MOUNT FSTYPE LIST | MOUNT EXPRESSION )

MOUNT FSTYPE LIST = Comma separated list of valid filesystem and
virtual filesystem types (eg ext4, debugfs, etc)

MOUNT FLAGS EXPRESSION = ( MOUNT FLAGS LIST | MOUNT EXPRESSION )

MOUNT FLAGS LIST = Comma separated list of MOUNT FLAGS.

MOUNT FLAGS = ( 'ro' | 'rw' | 'nosuid' | 'suid' | 'nodev' | 'dev' |
'noexec' | 'exec' | 'sync' | 'async' | 'remount' |
'mand' | 'nomand' | 'dirsync' | 'noatime' | 'atime' |
'nodiratime' | 'diratime' | 'bind' | 'rbind' | 'move' |
'verbose' | 'silent' | 'loud' | 'acl' | 'noacl' |
'unbindable' | 'runbindable' | 'private' | 'rprivate' |
'slave' | 'rslave' | 'shared' | 'rshared' |
'relatime' | 'norelatime' | 'iversion' | 'noiversion' |
'strictatime' | 'nouser' | 'user' )

MOUNT EXPRESSION = ( ALPHANUMERIC | AARE ) ...

PIVOT ROOT RULE = [ QUALIFIERS ] pivot_root [ oldroot=OLD PUT FILEGLOB ]
[ NEW ROOT FILEGLOB ]

SOURCE FILEGLOB = FILEGLOB

MOUNTPOINT FILEGLOB = FILEGLOB

eg.
mount,
mount /dev/foo,
mount options=ro /dev/foo -> /mnt/,
mount options in (ro,atime) /dev/foo -> /mnt/,
mount options=ro options=atime,

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>