[pve-devel] [PATCH container v3 1/2] add deny-write option for device passthrough

[Filip Schauer]

Add the deny-write options for device passthrough, to restrict container
access to devices.

Signed-off-by: Filip Schauer <f.schauer at proxmox.com>
---
 src/PVE/LXC.pm        | 7 ++++++-
 src/PVE/LXC/Config.pm | 6 ++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
index 65d0fa8..cb24f2d 100644
--- a/src/PVE/LXC.pm
+++ b/src/PVE/LXC.pm
@@ -651,7 +651,12 @@ sub update_lxc_config {
 	my $major = PVE::Tools::dev_t_major($rdev);
 	my $minor = PVE::Tools::dev_t_minor($rdev);
 	my $device_type_char = S_ISBLK($mode) ? 'b' : 'c';
-	$raw .= "lxc.cgroup2.devices.allow = $device_type_char $major:$minor rw\n";
+	my $allow_perms = "r" . $device->{'deny-write'} ? "" : "w";
+	$raw .= "lxc.cgroup2.devices.allow = $device_type_char $major:$minor $allow_perms\n";
+
+	if ($device->{'deny-write'}) {
+	    $raw .= "lxc.cgroup2.devices.deny = $device_type_char $major:$minor w\n";
+	}
     });
 
     # WARNING: DO NOT REMOVE this without making sure that loop device nodes
diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
index 1664a35..ce64c4c 100644
--- a/src/PVE/LXC/Config.pm
+++ b/src/PVE/LXC/Config.pm
@@ -962,6 +962,12 @@ my $dev_desc = {
 	minimum => 0,
 	description => 'Group ID to be assigned to the device node',
     },
+    'deny-write' => {
+	optional => 1,
+	type => 'boolean',
+	description => 'Deny the container to write to the device',
+	default => 0,
+    },
 };
 
 for (my $i = 0; $i < $MAX_DEVICES; $i++) {
-- 
2.39.2