[PATCH storage 3/7] iscsi: validate target names with a dedicated format

[Dietmar Maurer <dietmar@proxmox.com>]

The target property accepted any string, so typos or pasted portal
addresses were only caught later when iscsiadm fails. Validate against
the iSCSI name grammar from RFC 7143 (iqn, eui and naa types, 223 byte
limit). Accept uppercase letters even where the grammar only permits
lowercase, because such admin-typed names exist in the wild and work,
and rejecting them would break existing setups on upgrade.

This also covers the iSCSI direct and ZFS over iSCSI plugins, which
share the property.

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>
---
 src/PVE/Storage/ISCSIPlugin.pm | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/PVE/Storage/ISCSIPlugin.pm b/src/PVE/Storage/ISCSIPlugin.pm
index 9944806..0165a58 100644
--- a/src/PVE/Storage/ISCSIPlugin.pm
+++ b/src/PVE/Storage/ISCSIPlugin.pm
@@ -334,6 +334,27 @@ sub iscsi_device_list {
 
 # Configuration
 
+# Name grammar from RFC 7143 section 6.1: iqn, eui and naa types with a
+# 223 byte limit. The IQN grammar only permits lowercase, but accept any
+# case because admin-typed names with uppercase letters exist and work.
+sub verify_iscsi_target {
+    my ($target, $noerr) = @_;
+
+    if (
+        length($target) > 223
+        || $target !~ m/^(?:
+            iqn\.\d{4}-\d{2}(?:\.[a-z0-9-]+)+(?::[a-z0-9.:-]+)?
+            |eui\.[0-9a-f]{16}
+            |naa\.(?:[0-9a-f]{16}|[0-9a-f]{32})
+        )$/xi
+    ) {
+        return undef if $noerr;
+        die "value does not look like a valid iSCSI target name\n";
+    }
+    return $target;
+}
+PVE::JSONSchema::register_format('pve-storage-iscsi-target', \&verify_iscsi_target);
+
 sub type {
     return 'iscsi';
 }
@@ -351,6 +372,7 @@ sub properties {
         target => {
             description => "iSCSI target.",
             type => 'string',
+            format => 'pve-storage-iscsi-target',
         },
         portal => {
             description => "iSCSI portal (IP or DNS name with optional port).",
-- 
2.47.3