[pve-devel] [PATCH qemu-server v2 8/9] allow non-root users to set /dev/u?random as an RNG source

[Filip Schauer]

Allow non-root users with the VM.Config.HWType privilege to configure
/dev/urandom & /dev/random as an entropy source for a VirtIO RNG device.
/dev/hwrng remains restricted to the root user.

Signed-off-by: Filip Schauer <f.scha...@proxmox.com>
---
 PVE/API2/Qemu.pm  | 42 ++++++++++++++++++++++++++++++++++++++++++
 PVE/QemuServer.pm | 13 +++++++++++--
 2 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
index db356b7e..8262c9d4 100644
--- a/PVE/API2/Qemu.pm
+++ b/PVE/API2/Qemu.pm
@@ -670,6 +670,7 @@ my $hwtypeoptions = {
     'vga' => 1,
     'watchdog' => 1,
     'audio0' => 1,
+    'rng0' => 1,
 };
 
 my $generaloptions = {
@@ -798,6 +799,36 @@ my sub check_vm_create_hostpci_perm {
     return 1;
 };
 
+my sub check_rng_perm {
+    my ($rpcenv, $authuser, $vmid, $pool, $opt, $value) = @_;
+
+    return 1 if $authuser eq 'root@pam';
+
+    $rpcenv->check_vm_perm($authuser, $vmid, $pool, ['VM.Config.HWType']);
+
+    my $device = PVE::JSONSchema::parse_property_string('pve-qm-rng', $value);
+    if ($device->{source}) {
+       if ($device->{source} eq '/dev/hwrng') {
+           die "only root can set '$opt' config for a non-mapped Hardware RNG 
device\n";
+       }
+    }
+
+    return 1;
+}
+
+my sub check_vm_create_rng_perm {
+    my ($rpcenv, $authuser, $vmid, $pool, $param) = @_;
+
+    return 1 if $authuser eq 'root@pam';
+
+    foreach my $opt (keys %{$param}) {
+       next if $opt !~ m/^rng\d+$/;
+       check_rng_perm($rpcenv, $authuser, $vmid, $pool, $opt, $param->{$opt});
+    }
+
+    return 1;
+};
+
 my $check_vm_modify_config_perm = sub {
     my ($rpcenv, $authuser, $vmid, $pool, $key_list) = @_;
 
@@ -1111,6 +1142,7 @@ __PACKAGE__->register_method({
            &$check_vm_create_serial_perm($rpcenv, $authuser, $vmid, $pool, 
$param);
            check_vm_create_usb_perm($rpcenv, $authuser, $vmid, $pool, $param);
            check_vm_create_hostpci_perm($rpcenv, $authuser, $vmid, $pool, 
$param);
+           check_vm_create_rng_perm($rpcenv, $authuser, $vmid, $pool, $param);
 
            PVE::QemuServer::check_bridge_access($rpcenv, $authuser, $param);
            &$check_cpu_model_access($rpcenv, $authuser, $param);
@@ -2008,6 +2040,10 @@ my $update_vm_api  = sub {
                    check_hostpci_perm($rpcenv, $authuser, $vmid, undef, $opt, 
$val);
                    PVE::QemuConfig->add_to_pending_delete($conf, $opt, $force);
                    PVE::QemuConfig->write_config($vmid, $conf);
+               } elsif ($opt eq m/^rng\d+$/) {
+                   check_rng_perm($rpcenv, $authuser, $vmid, undef, $opt, 
$val);
+                   PVE::QemuConfig->add_to_pending_delete($conf, $opt, $force);
+                   PVE::QemuConfig->write_config($vmid, $conf);
                } elsif ($opt eq 'tags') {
                    assert_tag_permissions($vmid, $val, '', $rpcenv, $authuser);
                    delete $conf->{$opt};
@@ -2098,6 +2134,12 @@ my $update_vm_api  = sub {
                    }
                    check_hostpci_perm($rpcenv, $authuser, $vmid, undef, $opt, 
$param->{$opt});
                    $conf->{pending}->{$opt} = $param->{$opt};
+               } elsif ($opt =~ m/^rng\d+$/) {
+                   if (my $oldvalue = $conf->{$opt}) {
+                       check_rng_perm($rpcenv, $authuser, $vmid, undef, $opt, 
$oldvalue);
+                   }
+                   check_rng_perm($rpcenv, $authuser, $vmid, undef, $opt, 
$param->{$opt});
+                   $conf->{pending}->{$opt} = $param->{$opt};
                } elsif ($opt eq 'tags') {
                    assert_tag_permissions($vmid, $conf->{$opt}, 
$param->{$opt}, $rpcenv, $authuser);
                    $conf->{pending}->{$opt} = 
PVE::GuestHelpers::get_unique_tags($param->{$opt});
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 93e65825..606f51fa 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -6602,8 +6602,17 @@ sub check_mapping_access {
            } else {
                die "either 'host' or 'mapping' must be set.\n";
            }
-       }
-   }
+       } elsif ($opt =~ m/^rng\d+$/) {
+           my $device = PVE::JSONSchema::parse_property_string('pve-qm-rng', 
$conf->{$opt});
+
+           if ($device->{source}) {
+               if ($device->{source} eq '/dev/hwrng') {
+                   die "only root can set '$opt' config for a non-mapped 
Hardware RNG device\n"
+                       if $user ne 'root@pam';
+               }
+           }
+       }
+    }
 };
 
 sub check_restore_permissions {
-- 
2.39.5



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