[lxc-devel] [lxc/stable-3.0] apparmor: allow various remount, bind options

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From 1cc28d37b7b74c45e5e11a5aa09cc0103a8510b7 Mon Sep 17 00:00:00 2001
From: Wolfgang Bumiller <w.bumiller at proxmox.com>
Date: Thu, 15 Nov 2018 11:51:34 +0100
Subject: [PATCH] apparmor: allow various remount,bind options

RW bind mounts need to be restricted for some paths in
order to avoid MAC restriction bypasses, but read-only bind
mounts shouldn't have that problem.

Additionally, combinations of 'nosuid', 'nodev' and
'noexec' flags shouldn't be a problem either and are
required with newer systemd versions, so let's allow those
as long as they're combined with 'ro,remount,bind'.

Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
(cherry picked from commit e6ec0a9e71aa68c9fd67c691a62aaae87e356cef)
---
 config/apparmor/abstractions/container-base    | 10 ++++++++++
 config/apparmor/abstractions/container-base.in | 11 ++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/config/apparmor/abstractions/container-base b/config/apparmor/abstractions/container-base
index a5e6c35f60..0774765594 100644
--- a/config/apparmor/abstractions/container-base
+++ b/config/apparmor/abstractions/container-base
@@ -120,6 +120,16 @@
   mount options=(rw,bind) /sy[^s]*{,/**},
   mount options=(rw,bind) /sys?*{,/**},
 
+  # allow various ro-bind-*re*-mounts
+  mount options=(ro,remount,bind),
+  mount options=(ro,remount,bind,nosuid),
+  mount options=(ro,remount,bind,noexec),
+  mount options=(ro,remount,bind,nodev),
+  mount options=(ro,remount,bind,nosuid,noexec),
+  mount options=(ro,remount,bind,noexec,nodev),
+  mount options=(ro,remount,bind,nodev,nosuid),
+  mount options=(ro,remount,bind,nosuid,noexec,nodev),
+
   # allow moving mounts except for /proc, /sys and /dev
   mount options=(rw,move) /[^spd]*{,/**},
   mount options=(rw,move) /d[^e]*{,/**},
diff --git a/config/apparmor/abstractions/container-base.in b/config/apparmor/abstractions/container-base.in
index 11ec5c45b9..1a3ead89ad 100644
--- a/config/apparmor/abstractions/container-base.in
+++ b/config/apparmor/abstractions/container-base.in
@@ -119,6 +119,16 @@
   mount options=(rw,bind) /sy[^s]*{,/**},
   mount options=(rw,bind) /sys?*{,/**},
 
+  # allow various ro-bind-*re*-mounts
+  mount options=(ro,remount,bind),
+  mount options=(ro,remount,bind,nosuid),
+  mount options=(ro,remount,bind,noexec),
+  mount options=(ro,remount,bind,nodev),
+  mount options=(ro,remount,bind,nosuid,noexec),
+  mount options=(ro,remount,bind,noexec,nodev),
+  mount options=(ro,remount,bind,nodev,nosuid),
+  mount options=(ro,remount,bind,nosuid,noexec,nodev),
+
   # allow moving mounts except for /proc, /sys and /dev
   mount options=(rw,move) /[^spd]*{,/**},
   mount options=(rw,move) /d[^e]*{,/**},
@@ -136,4 +146,3 @@
   mount options=(rw,move) /s[^y]*{,/**},
   mount options=(rw,move) /sy[^s]*{,/**},
   mount options=(rw,move) /sys?*{,/**},
-