* [pve-devel] [PATCH container 1/2] config: add `lxc.init.uid`/`gid`/`groups` keys
2025-12-15 17:41 [pve-devel] [PATCH container 0/2] oci create: honor `User` from OCI image config Filip Schauer
@ 2025-12-15 17:41 ` Filip Schauer
2025-12-15 17:41 ` [pve-devel] [PATCH container 2/2] oci create: honor `User` from OCI image config Filip Schauer
2025-12-16 12:03 ` [pve-devel] [PATCH container 0/2] " Maximiliano Sandoval
2 siblings, 0 replies; 5+ messages in thread
From: Filip Schauer @ 2025-12-15 17:41 UTC (permalink / raw)
To: pve-devel
These config keys allow one to specify the uid, gid and groups of the
init process. This is useful for application containers.
Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
---
src/PVE/LXC/Config.pm | 3 +++
1 file changed, 3 insertions(+)
diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
index 6445528..6f54e9f 100644
--- a/src/PVE/LXC/Config.pm
+++ b/src/PVE/LXC/Config.pm
@@ -711,6 +711,9 @@ my $valid_lxc_conf_keys = {
'lxc.signal.stop' => 1,
'lxc.init.cmd' => 1,
'lxc.init.cwd' => 1,
+ 'lxc.init.uid' => 1,
+ 'lxc.init.gid' => 1,
+ 'lxc.init.groups' => 1,
'lxc.pty.max' => 1,
'lxc.console.logfile' => 1,
'lxc.console.path' => 1,
--
2.47.3
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^ permalink raw reply [flat|nested] 5+ messages in thread* [pve-devel] [PATCH container 2/2] oci create: honor `User` from OCI image config
2025-12-15 17:41 [pve-devel] [PATCH container 0/2] oci create: honor `User` from OCI image config Filip Schauer
2025-12-15 17:41 ` [pve-devel] [PATCH container 1/2] config: add `lxc.init.uid`/`gid`/`groups` keys Filip Schauer
@ 2025-12-15 17:41 ` Filip Schauer
2025-12-16 12:03 ` [pve-devel] [PATCH container 0/2] " Maximiliano Sandoval
2 siblings, 0 replies; 5+ messages in thread
From: Filip Schauer @ 2025-12-15 17:41 UTC (permalink / raw)
To: pve-devel
Honor a custom user and group specified for the entrypoint via the OCI
image config `User` field instead of ignoring it.
User and group name lookups, including supplementary groups, are
resolved from /etc/passwd and /etc/group in the container file system.
This behaviour matches the OCI image spec. [0]
[0] https://specs.opencontainers.org/image-spec/config/?v=v1.1.1#properties
Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
---
This requires the following patch for LXC in order to work properly:
https://github.com/lxc/lxc/pull/4626
src/PVE/LXC/Create.pm | 59 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)
diff --git a/src/PVE/LXC/Create.pm b/src/PVE/LXC/Create.pm
index 9956cf9..08e0386 100644
--- a/src/PVE/LXC/Create.pm
+++ b/src/PVE/LXC/Create.pm
@@ -768,6 +768,65 @@ sub restore_oci_archive {
}
}
+ if (my $usercfg = $oci_config_get_checked_scalar->('User')) {
+ my ($user, $group) = $usercfg =~ /^([^:]+)(?::([^:]+))?$/
+ or die "OCI config value for 'User' has an invalid format\n";
+
+ my $etc_passwd = "$rootdir/etc/passwd";
+ my $etc_group = "$rootdir/etc/group";
+
+ # Scan file, match column $match_index against $match_val, return value at $ret_index
+ my $lookup_field = sub {
+ my ($file, $match_index, $match_val, $ret_index) = @_;
+
+ open(my $fh, '<', $file) or return undef;
+ while (my $line = <$fh>) {
+ my @fields = split(/:/, $line);
+ if (defined($fields[$match_index]) && $fields[$match_index] eq $match_val) {
+ return $fields[$ret_index];
+ }
+ }
+ return undef;
+ };
+
+ my $get_supplementary_groups = sub {
+ my ($username) = @_;
+
+ my @groups;
+ open(my $fh, '<', $etc_group) or return undef;
+ while (defined(my $line = <$fh>)) {
+ push @groups, $1
+ if ($line =~ m/^[^:]*:[^:]*:([^:]*):(?:[^,]*,)*$username(?:,|$)/);
+ }
+ return join(',', @groups);
+ };
+
+ my ($uid, $username, $gid, $groups);
+
+ if ($user =~ /^\d+$/) {
+ $uid = $user;
+ $username = $lookup_field->($etc_passwd, 2, $uid, 0);
+ } else {
+ $username = $user;
+ $uid = $lookup_field->($etc_passwd, 0, $username, 2);
+ }
+
+ if (defined($group)) {
+ if ($group =~ /^\d+$/) {
+ $gid = $group;
+ } else {
+ $gid = $lookup_field->($etc_group, 0, $group, 2);
+ }
+ } else {
+ $gid = $lookup_field->($etc_passwd, 2, $uid, 3) if defined($uid);
+ $groups = $get_supplementary_groups->($username) if defined($username);
+ }
+
+ push $conf->{lxc}->@*, ['lxc.init.uid', $uid] if defined($uid);
+ push $conf->{lxc}->@*, ['lxc.init.gid', $gid] if defined($gid);
+ push $conf->{lxc}->@*, ['lxc.init.groups', $groups] if defined($groups);
+ }
+
if (my $working_dir = $oci_config_get_checked_scalar->('WorkingDir')) {
push $conf->{lxc}->@*, ['lxc.init.cwd', $working_dir];
}
--
2.47.3
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^ permalink raw reply [flat|nested] 5+ messages in thread