Merge branch 'dnssec'

The DNSSEC notes in CHANGELOG.md belong under Unreleased; git had put
them into the 0.1.0 section, which didn't exist when the branch was made.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/systemd/jarl-backup.service

@@ -1,4 +1,5 @@
-# Jarl: one database backup, run daily by jarl-backup.timer.
+# Jarl: one database backup (with the DNSSEC keys), run daily by
+# jarl-backup.timer.
 # Installed as /etc/systemd/system/jarl-backup.service (see
 # docs/operations.md#backups). What to keep, and where, is in the backup:
 # section of /etc/jarl/jarl.yaml; when it runs is in jarl-backup.timer.
@@ -28,8 +29,12 @@ PrivateTmp=yes
 PrivateDevices=yes
 PrivateNetwork=yes
 NoNewPrivileges=yes
-CapabilityBoundingSet=
-AmbientCapabilities=
+# Read access to every file, and nothing else: named's DNSSEC private keys
+# (under /var/lib/bind/jarl/dnssec-keys) are readable only by named's user,
+# and the backup includes them. Everything outside the paths above stays
+# read-only (ProtectSystem=strict).
+CapabilityBoundingSet=CAP_DAC_READ_SEARCH
+AmbientCapabilities=CAP_DAC_READ_SEARCH
 ProtectKernelTunables=yes
 ProtectKernelModules=yes
 ProtectKernelLogs=yes