[pve-devel] [PATCH container] api: config: permission checks: fix check for 'nesting' feature

[Fiona Ebner]

As reported in the community forum [0], remote migration for a container
with 'features: nesting=0' would fail with a confusing error message

> changing feature flags (except nesting) is only allowed for root at pam

This is because of a faulty check during container creation that would
only detect 'nesting=1', but not 'nesting=0'. Fix it by properly
checking if only the 'nesting' property is affected via an 'exists'
check for the hash key.

The check for deleting the feature is also broken, so fix it too.

The check for modifying the feature already works correctly.

[0]: https://forum.proxmox.com/threads/161432/

Fixes: 88ef170 ("allow nesting to be changed for VM.Allocate on unprivileged containers")
Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
---
 src/PVE/LXC.pm | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
index 4d20645..64f8564 100644
--- a/src/PVE/LXC.pm
+++ b/src/PVE/LXC.pm
@@ -1474,7 +1474,7 @@ sub check_ct_modify_config_perm {
 		    }
 		} else {
 		    # new container or no features defined
-		    if (scalar(keys %$features) == 1 && $features->{nesting}) {
+		    if (scalar(keys %$features) == 1 && exists($features->{nesting})) {
 			$nesting_changed = 1;
 		    } elsif (scalar(keys %$features) > 0) {
 			$other_changed = 1;
@@ -1482,7 +1482,7 @@ sub check_ct_modify_config_perm {
 		}
 	    } else {
 		my $features = PVE::LXC::Config->parse_features($oldconf->{$opt});
-		if (scalar(keys %$features) == 1 && $features->{nesting}) {
+		if (scalar(keys %$features) == 1 && exists($features->{nesting})) {
 		    $nesting_changed = 1;
 		} elsif (scalar(keys %$features) > 0) {
 		    $other_changed = 1;
-- 
2.39.5