From: Maximiliano Sandoval <m.sandoval@proxmox.com>
To: pve-devel@lists.proxmox.com
Cc: Wolfgang Bumiller <w.bumiller@proxmox.com>
Subject: [pve-devel] [PATCH qemu-server] config: add system and service credentials support
Date: Wed, 2 Apr 2025 16:36:20 +0200 [thread overview]
Message-ID: <20250402143620.440158-1-m.sandoval@proxmox.com> (raw)
Allows to pass system and service credentials to a VM. See [1] for a
description of credentials. This can be potentially used to provision a
VM as per [2]. Values can be passed either as plain text or as a base64
encoded string when the base64 flag is set.
A VM configuration file which, for example, contains:
systemd-cred0: name=foo,value=bar
systemd-cred1: name=encoded-foo,value=YmFy,base64=1
will have the following arguments added to its kvm command:
-smbios 'type=11,value=io.systemd.credential:foo=bar' \
-smbios 'type=11,value=io.systemd.credential.binary:encoded-foo=YmFy'
On the guest these credentials can be read via:
dmidecode -t 11
via:
systemd-creds --system list
systemd-creds --system cat $CREDENTIAL_NAME
or at:
/run/credentials/@system/$CREDENTIAL_NAME
[1] https://systemd.io/CREDENTIALS/
[2] https://www.freedesktop.org/software/systemd/man/latest/systemd.system-credentials.html
Suggested-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
Differences from RFC:
- Fixed multiple points from the feedback in the RFC
- Uses "systemd-cred$i" instead of "systemd-credential.$name" as a name
- The snipped support was dropped
- More strict format required on credential names and values
PVE/QemuServer.pm | 72 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index ffd5d56b..1f902b8b 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -150,6 +150,31 @@ my $watchdog_fmt = {
};
PVE::JSONSchema::register_format('pve-qm-watchdog', $watchdog_fmt);
+my $MAX_CREDENTIALS = 16;
+
+my $systemd_cred_fmt = {
+ value => {
+ description => 'The credential\'s value. This is a Base64 encoded string.'
+ .' If the value should contain arbitrary binary data,'
+ .' then the value can be a Base64 encoded string and the base64=1 flag should be set.',
+ type => 'string',
+ pattern => '[A-Za-z0-9+\/]+={0,2}',
+ typetext => '<string>',
+ },
+ name => {
+ description => 'The credential\'s name. This is a short ASCII string suitable as filename in the filesystem',
+ type => 'string',
+ pattern => '[A-Za-z0-9\-\._]+',
+ typetext => '<string>',
+ },
+ base64 => {
+ description => 'Whether the credential\'s value is base64 encoded.',
+ type => 'boolean',
+ optional => 1,
+ default => 0,
+ },
+};
+
my $agent_fmt = {
enabled => {
description => "Enable/disable communication with a QEMU Guest Agent (QGA) running in the VM.",
@@ -946,6 +971,13 @@ my $netdesc = {
description => "Specify network devices.",
};
+my $systemd_cred_desc = {
+ optional => 1,
+ type => 'string',
+ format => $systemd_cred_fmt,
+ description => 'Specify system and service credentials.',
+};
+
PVE::JSONSchema::register_standard_option("pve-qm-net", $netdesc);
my $ipconfig_fmt = {
@@ -1007,6 +1039,10 @@ for (my $i = 0; $i < $MAX_NETS; $i++) {
$confdesc_cloudinit->{"ipconfig$i"} = $ipconfigdesc;
}
+for (my $i = 0; $i < $MAX_CREDENTIALS; $i++) {
+ $confdesc->{"systemd-cred$i"} = $systemd_cred_desc;
+}
+
foreach my $key (keys %$confdesc_cloudinit) {
$confdesc->{$key} = $confdesc_cloudinit->{$key};
}
@@ -1955,6 +1991,16 @@ sub parse_guest_agent {
return $res;
}
+sub parse_systemd_credential {
+ my ($value) = @_;
+
+ return {} if !$value;
+
+ my $res = eval { parse_property_string($systemd_cred_fmt, $value) };
+ warn $@ if $@;
+ return $res;
+}
+
sub get_qga_key {
my ($conf, $key) = @_;
return undef if !defined($conf->{agent});
@@ -3383,6 +3429,17 @@ my sub get_vga_properties {
return ($vga, $qxlnum);
}
+sub smbios_11_cred_arg {
+ my ($name, $value, $is_encoded) = @_;
+
+ if ($is_encoded) {
+ die "value $value is not base64 encoded\n" if $value !~ /^[A-Za-z0-9+\/]+={0,2}$/;
+ return ('-smbios', "type=11,value=io.systemd.credential.binary:$name=$value");
+ } else {
+ return ('-smbios', "type=11,value=io.systemd.credential:$name=$value");
+ }
+}
+
sub config_to_command {
my ($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu,
$live_restore_backing) = @_;
@@ -4015,6 +4072,21 @@ sub config_to_command {
push @$cmd, '-snapshot';
}
+ for (my $i = 0; $i < $MAX_CREDENTIALS; $i++) {
+ my $cred_name = "systemd-cred$i";
+
+ next if !$conf->{$cred_name};
+
+ my $opts = parse_systemd_credential($conf->{$cred_name});
+ my $name = $opts->{'name'};
+ my $is_encoded = $opts->{'base64'};
+ my $value = $opts->{'value'};
+
+ if ($value && $name) {
+ push @$cmd, smbios_11_cred_arg($name, $value, $is_encoded);
+ }
+ }
+
# add custom args
if ($conf->{args}) {
my $aa = PVE::Tools::split_args($conf->{args});
--
2.39.5
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next reply other threads:[~2025-04-02 14:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-02 14:36 Maximiliano Sandoval [this message]
2025-04-03 7:49 ` Thomas Lamprecht
2025-04-03 7:56 ` Thomas Lamprecht
2025-04-03 8:48 ` Maximiliano Sandoval
2025-04-03 8:34 ` Maximiliano Sandoval
2025-04-03 9:04 ` Thomas Lamprecht
2025-04-03 9:42 ` Lukas Wagner
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