[Devel] [PATCH RHEL COMMIT] ve/security: device_cgroup -- Allow manage devices in @pseudosuper state

[Konstantin Khorenko]

The commit is pushed to "branch-rh9-5.14.vz9.1.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after ark-5.14
------>
commit d6c66265a17a599866e8046ca253aa0e9e67c1d2
Author: Cyrill Gorcunov <gorcunov at virtuozzo.com>
Date:   Wed Sep 22 14:50:56 2021 +0300

    ve/security: device_cgroup -- Allow manage devices in @pseudosuper state
    
    When restoring containers with several disks it's more convenient
    to mount device first and the setup permissions needed. So for this
    sake we allow to escape device permissions testing inside VE only
    if @pseudosuper state enabled.
    
    https://jira.sw.ru/browse/PSBM-48421
    
    CC: Vladimir Davydov <vdavydov at virtuozzo.com>
    CC: Konstantin Khorenko <khorenko at virtuozzo.com>
    CC: Andrey Vagin <avagin at openvz.org>
    Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
    
    (cherry-picked from vz8 commit a3621548b561554887087b281d52c98e039ab593)
    Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
---
 security/device_cgroup.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 04375df52fc9..3591e7144df4 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/rcupdate.h>
 #include <linux/mutex.h>
+#include <linux/ve.h>
 
 #ifdef CONFIG_CGROUP_DEVICE
 
@@ -822,8 +823,24 @@ static int devcgroup_legacy_check_permission(short type, u32 major, u32 minor,
 				     minor, access);
 	rcu_read_unlock();
 
+#ifdef CONFIG_VE
+	/*
+	 * When restoring container allow everything in
+	 * pseudosuper state. We need this for early
+	 * mounting of second ploop device. Still, don't
+	 * change behaviour on the ve0.
+	 */
+	if (!rc) {
+		struct ve_struct *ve = get_exec_env();
+
+		if (!ve_is_super(ve) && ve->is_pseudosuper)
+			return 0;
+		return -EPERM;
+	}
+#else
 	if (!rc)
 		return -EPERM;
+#endif
 
 	return 0;
 }