[GH-ISSUE #5577] Snap install: AppArmor blocks SetDefaultRoute/SetDNSOverTLS/SetDomains on systemd-resolved Link object (snapd bug) #10804

New Issue

saavagebueno · 2026-08-05T01:27:20-04:00

saavagebueno commented

2026-08-05 01:27:20 -04:00

Originally created by @jean147 on GitHub (Mar 11, 2026).
Original GitHub issue: https://github.com/netbirdio/netbird/issues/5577

Summary

The NetBird snap's DNS configuration via systemd-resolved is broken due to an incomplete AppArmor fix in snapd. This prevents search domains from being set on the WireGuard interface, breaking short hostname resolution (e.g. go → go.company.internal).

Root cause

snapd's network-control interface has D-Bus rules for org.freedesktop.resolve1. The Manager-level rules allow all SetLink* methods:

member="SetLink{DefaultRoute,DNSOverTLS,DNS,DNSEx,DNSSEC,DNSSECNegativeTrustAnchors,MulticastDNS,Domains,LLMNR}"

But the Link object rules (added in snapd 2.67.1 via canonical/snapd#14751) are missing DefaultRoute, DNSOverTLS, and DNSEx:

member="Set{DNS,DNSSEC,DNSSECNegativeTrustAnchors,MulticastDNS,Domains,LLMNR}"

NetBird uses GetLink then calls methods on the Link object directly (systemd_linux.go). So:

SetDNS ✅ allowed
SetDNSSEC ✅ allowed
SetDNSOverTLS ❌ blocked by AppArmor (warning, continues)
SetDefaultRoute ❌ blocked by AppArmor (returns hard error)
SetDomains ⏭️ never reached (function already returned)

Result: DNS server is set on wt0, but no search/match domains are configured. resolvectl domain wt0 shows nothing.

AppArmor denial

AppArmor policy prevents this sender from sending this message to this recipient;
type="method_call", sender=":1.2681" (uid=0 pid=220931
  comm="/snap/netbird/197/bin/netbird service run --log-le"
  label="snap.netbird.service-run (enforce)")
interface="org.freedesktop.resolve1.Link" member="SetDefaultRoute"
destination="org.freedesktop.resolve1" (uid=101 pid=1076
  comm="/usr/lib/systemd/systemd-resolved" label="unconfined")

Who is affected

All NetBird snap users on Ubuntu with snapd >= 2.65 (where the AppArmor tightening was introduced). The incomplete fix in snapd 2.67.1 restored GetLink, SetDNS, SetDNSSEC, SetDomains, and SetLLMNR on the Link object, but missed SetDefaultRoute and SetDNSOverTLS. Since SetDefaultRoute returns a hard error in applyDNSConfig, SetDomains is never called.

Apt/deb installs are not affected (no snap confinement).

Workaround

Manually patch the AppArmor profile (needs to be redone after each snap refresh netbird):

sudo sed -i 's/member="Set{DNS,DNSSEC,DNSSECNegativeTrustAnchors,MulticastDNS,Domains,LLMNR}"/member="Set{DefaultRoute,DNS,DNSEx,DNSSEC,DNSSECNegativeTrustAnchors,DNSOverTLS,Domains,LLMNR,MulticastDNS}"/' \
  /var/lib/snapd/apparmor/profiles/snap.netbird.service-run
sudo apparmor_parser -r /var/lib/snapd/apparmor/profiles/snap.netbird.service-run
sudo systemctl restart snap.netbird.service-run.service

Upstream fix needed

A bug has been filed against snapd to add the missing members to the Link object rules in interfaces/builtin/network_control.go and network_manager.go: https://bugs.launchpad.net/snapd/+bug/2143934
Related: LP #2086203.

Secondary note

In systemd_linux.go, when setDomainsForInterface fails, the error is only logged and not returned. This means that even if SetDefaultRoute were fixed, a SetDomains failure would be silently swallowed. Consider returning the error so DNS misconfigurations are visible to the user.

Environment

Ubuntu 24.04, kernel 6.17.0-14-generic
snapd 2.73+ubuntu24.04
NetBird snap 0.66.1

Originally created by @jean147 on GitHub (Mar 11, 2026). Original GitHub issue: https://github.com/netbirdio/netbird/issues/5577 ## Summary The NetBird snap's DNS configuration via systemd-resolved is broken due to an incomplete AppArmor fix in snapd. This prevents search domains from being set on the WireGuard interface, breaking short hostname resolution (e.g. `go` → `go.company.internal`). ## Root cause snapd's `network-control` interface has D-Bus rules for `org.freedesktop.resolve1`. The Manager-level rules allow all `SetLink*` methods: ``` member="SetLink{DefaultRoute,DNSOverTLS,DNS,DNSEx,DNSSEC,DNSSECNegativeTrustAnchors,MulticastDNS,Domains,LLMNR}" ``` But the Link object rules (added in snapd 2.67.1 via [canonical/snapd#14751](https://github.com/canonical/snapd/pull/14751)) are missing `DefaultRoute`, `DNSOverTLS`, and `DNSEx`: ``` member="Set{DNS,DNSSEC,DNSSECNegativeTrustAnchors,MulticastDNS,Domains,LLMNR}" ``` NetBird uses `GetLink` then calls methods on the Link object directly (`systemd_linux.go`). So: 1. `SetDNS` ✅ allowed 2. `SetDNSSEC` ✅ allowed 3. `SetDNSOverTLS` ❌ **blocked by AppArmor** (warning, continues) 4. `SetDefaultRoute` ❌ **blocked by AppArmor** (returns hard error) 5. `SetDomains` ⏭️ **never reached** (function already returned) Result: DNS server is set on `wt0`, but no search/match domains are configured. `resolvectl domain wt0` shows nothing. ## AppArmor denial ``` AppArmor policy prevents this sender from sending this message to this recipient; type="method_call", sender=":1.2681" (uid=0 pid=220931 comm="/snap/netbird/197/bin/netbird service run --log-le" label="snap.netbird.service-run (enforce)") interface="org.freedesktop.resolve1.Link" member="SetDefaultRoute" destination="org.freedesktop.resolve1" (uid=101 pid=1076 comm="/usr/lib/systemd/systemd-resolved" label="unconfined") ``` ## Who is affected All NetBird snap users on Ubuntu with snapd >= 2.65 (where the AppArmor tightening was introduced). The incomplete fix in snapd 2.67.1 restored `GetLink`, `SetDNS`, `SetDNSSEC`, `SetDomains`, and `SetLLMNR` on the Link object, but missed `SetDefaultRoute` and `SetDNSOverTLS`. Since `SetDefaultRoute` returns a hard error in `applyDNSConfig`, `SetDomains` is never called. Apt/deb installs are not affected (no snap confinement). ## Workaround Manually patch the AppArmor profile (needs to be redone after each `snap refresh netbird`): ```bash sudo sed -i 's/member="Set{DNS,DNSSEC,DNSSECNegativeTrustAnchors,MulticastDNS,Domains,LLMNR}"/member="Set{DefaultRoute,DNS,DNSEx,DNSSEC,DNSSECNegativeTrustAnchors,DNSOverTLS,Domains,LLMNR,MulticastDNS}"/' \ /var/lib/snapd/apparmor/profiles/snap.netbird.service-run sudo apparmor_parser -r /var/lib/snapd/apparmor/profiles/snap.netbird.service-run sudo systemctl restart snap.netbird.service-run.service ``` ## Upstream fix needed A bug has been filed against snapd to add the missing members to the Link object rules in `interfaces/builtin/network_control.go` and `network_manager.go`: https://bugs.launchpad.net/snapd/+bug/2143934 Related: [LP #2086203](https://bugs.launchpad.net/snapd/+bug/2086203). ## Secondary note In `systemd_linux.go`, when `setDomainsForInterface` fails, the error is only logged and not returned. This means that even if `SetDefaultRoute` were fixed, a `SetDomains` failure would be silently swallowed. Consider returning the error so DNS misconfigurations are visible to the user. ## Environment - Ubuntu 24.04, kernel 6.17.0-14-generic - snapd 2.73+ubuntu24.04 - NetBird snap 0.66.1

saavagebueno commented

2026-08-05 01:27:20 -04:00

@jean147 commented on GitHub (Mar 11, 2026):

The upstream snapd bug has been filed: https://bugs.launchpad.net/snapd/+bug/2143934

@jean147 commented on GitHub (Mar 11, 2026): The upstream snapd bug has been filed: https://bugs.launchpad.net/snapd/+bug/2143934

Sign in to join this conversation.

Branches Tags

main

claude/agent-network-test-cases-p743vw

android/gui-integration

revert/component-types

feat-post_quantum_ml_kem

ice-stun-wg-demux

dependabot/npm_and_yarn/proxy/web/npm_and_yarn-b39864987c

agent-network-setup-poc

dependabot/go_modules/aws-sdk-8f849ebaed

dependabot/github_actions/actions-a940c7c866

dependabot/go_modules/otel-e34c790afd

dependabot/go_modules/testcontainers-de325c0dd6

dependabot/go_modules/wireguard-dbd6b95108

dependabot/go_modules/pion-5f703e1eca

dependabot/go_modules/gorm-2271c8195b

fix-login-needed-check

dependabot/go_modules/google.golang.org/grpc-1.82.1

fix/ui-gtk3-support

enterprise-traefik-and-migration-fixes

disambiguate_p2p_metrics

revert/component-types-hookup

embedded-vnc

feature/ios-ssh

docs/agent-network-docs-update

dependabot/go_modules/github.com/aws/aws-sdk-go-v2/service/s3-1.106.3

dependabot/go_modules/github.com/pion/stun/v3-3.1.5

fix-ssh-authorized-users-multi-rule

peer-acl-multi-source

reverse-proxy-crowdsec-appsec

reverse-proxy-allow-match-or

client-local-metrics

lazy-conn-per-peer

lazy-conn-rosenpass

dependabot/go_modules/github.com/gopacket/gopacket-1.7.0

dependabot/go_modules/goauthentik.io/api/v3-3.2026050.6

dependabot/go_modules/github.com/pires/go-proxyproto-0.15.0

dependabot/go_modules/github.com/jackc/pgx/v5-5.10.0

dependabot/go_modules/github.com/oapi-codegen/runtime-1.6.0

dependabot/go_modules/github.com/eko/gocache/lib/v4-4.2.4

dependabot/go_modules/github.com/pkg/sftp-1.13.11

dependabot/go_modules/github.com/coreos/go-oidc/v3-3.20.0

ssh-windows-privilege-check

fix/explicit-cors-handling

fix/remove-math-rand

test/gui-memory-leak-fix

fix/ui-status-dispatch

install-script-ui-dependencies

fix/grpc-get-network-map

fix/subscribe-status-coalesce

fix/tray-menu-item-leak

fix/windows-tray-race

feature/changeset

worktree-dns-route-qtype-fallthrough

mdm_integration

mlsmaycon-patch-2

feat/agent-network-ollama

proxy-tunnel-cache-ttl-env

coderabbitai/utg/1e5b0a5

grpc-acl

test/battery-drain

components-impl-drop-indexes-use-xids-no-resource-policy-map

fix/nmap-relevant-groups

e2e-guardrail-blocks-unselected-model

fix/lazyconn-cold-start-allowed-ips

vertex-guardrails-model-access-e2e

add-atomic-cache-ops

refactor/relay-foreign-cache

ci/trigger-release-tests

feature/kimi-3-agent-networks-dns-warmup

feature/dns-lazy-conn-warmup

daemon-ipc-acl

feature/ui-translation-key-parity-check

refactor/relay-foreign-cache-tests

fix/lazyconn-idle-keep-wg-peer

dmitri-propagate-auth-grant-types-on-combined

0.74.7-branch

diagnose-empty-vs-corrupt-state

windows-sleep-detector

fix/cli-up-wait-for-daemon

rp_key_persistency

feature/native-grpc

0.74.6-branch

0.74.6-branch-sync

0.74.5-branch-sync

0.74.4-branch

fix/remove-stale-peers-removal

fix/remove-stale-proxy-logic

fix/nsis-preserve-autostart-on-upgrade

refactor/peer-event-bus

dependabot/go_modules/goauthentik.io/api/v3-3.2026050.3

dependabot/go_modules/github.com/pkg/sftp-1.13.10

components-impl-drop-indexes

fix-reset-aggregation-window-flake

dependabot/go_modules/github.com/pion/dtls/v3-3.1.5

0.74.x

fix/relay-states-lock

update-process-pkg

update-gopsutil-v4

fix/relay_states_lock

increase-sysinfo-timeout

dependabot/go_modules/github.com/Azure/go-ntlmssp-0.1.1

dependabot/go_modules/github.com/eko/gocache/store/redis/v4-4.2.6

dependabot/go_modules/github.com/eko/gocache/lib/v4-4.2.3

fix/fail-to-create-upnp-port-mapping-on-opnsense-firewall

0.74.3-branch

fix/routeselector-atomic-exit-node

netmap_progressive_alignment

nmap/components-impl

dependabot/go_modules/github.com/jackc/pgx/v5-5.9.2

dependabot/go_modules/github.com/oapi-codegen/runtime-1.4.2

dependabot/go_modules/github.com/gopacket/gopacket-1.6.1

dependabot/go_modules/github.com/coreos/go-oidc/v3-3.19.0

dependabot/go_modules/github.com/pires/go-proxyproto-0.12.0

fix/signal-watchdog-sync-stop

docs/agent-network

test/affected-logic

fix/revert-ice-filter

refactor/simplify-affected-peers

pascal-filter-policies-by-direction

claude/lock-contention-peer-connect-g8t6au

dmitri-filter-policies-by-direction

refactor/migrate-profiles-to-go

profile-bindings-ios

fix/skip-restart-unchanged-route

fix/mgmt-cache-async-resolve

refactor/wails-update-105

client_lifetime_serialization_refactor

fix/browser-ssh-2

fix/ipv6-and-netstack-accept-loop

fix/browser-ssh

profile-id-name-test

refactor/mgmt-bootstrap

feat/getting-started-unified-wizard

socket-grpc-permissions

fix/mysql-index-migration

windows-dns-firewall

tests/enable-race-on-tests

ui-refactor-gtk3

feature/affected-peers-grpc

profile-id

lazyconn-first-packet-fix-v2

claude/focused-gates-VMTgb

ui-tray-linux-leftclick

fix/ctx-enrichment

daemon-owner

feature/android-client-ssh

worktree-accept-ra-forwarding

nmap/combined-deploy

task/align_protobuff_toolset

feature/session-extend

add-json-yaml-flags

refactor/ephemeral-cleanup

claude/webtransport-relay-wasm-mUjY9

claude/vnc-udp-feasibility-6KB1U

fix/wgport-config

e2e-windows-dns-combined

fix/login-cmd-root-flags

feat/reseller-openapi-spec

github-issue-resolver

add-steamos-support

fix-darwin-uninstaller

flutter-test

ci/freebsd-pkg-bootstrap

cached-serial-check-on-sync

fix-mgmt-cache-bypass-overlay

revert-easyjson-5938

revert-ice-5820

revert-firewalld-5928

refactor/permissions-manager

revert-dns-5935-systemd-resolved

revert-dns-5935-5945

revert-dns-5945-mgmt-cache

feature/log-most-busy-peers

prototype/ui-wails

coderabbitai/utg/8ae8f20

feature/use-peer-fqdn-on-https

release/0.68.3

add-slack-channel

claude/rdp-token-passthrough-eNcqW

transparent-proxy

fix/macos-stale-route-eexist

crowdsec-selfhosted

fix/remove-otel-units

entire/checkpoints/v1

fix/getting-started

feat/static-connectors-combined-server

feature/use-local-keys-embedded

feature/fleetdm

set-env-only-if-not-fork

feature/expose-has-channel

fix/connection-status-race

fix/filter-cgnat-cni-ice-candidates

feature/check-cert-locker-before-acme

test/proxy-fixes

test/proxy-mtu

prototype/ui-tauri

test/proxy-speed

fix-reused-ports

feat/migrate-to-embedded-idp

feature/add-serial-to-proxy-merged

deploy/proxy-serial

test/connection

feature/disable-legacy-port

feature/flag-to-disable-legacy-port

test/perftest

fix/http-redirect

poc-token-command

dn-reverse-proxy

prototype/reverse-proxy-rename

prototype/reverse-proxy-logs-pagination

feature/client-metrics

prototype/reverse-proxy-clusters

debug-dns-route

fix/win-dns-batch

add-extra-route-logs

job-stream-notify-disconnection-eof

deploy/secrets-manager

trigger-proxy-update

bug/update-ios-client-code-build-tags

sync-client-netmap-serial

log/conn-disconn

nmap/compaction-deploy

ci-win-test

feature/disk-encryption-check

wasm-debug

swap-dns-prio

fix/dex-config

feature/migrate-auto-groups-to-table

nmap/compaction

dex-nocgo-stub

feature/exclude-terraform-from-rate-limiting

test-freebsd

retries-refactor

coderabbitai/docstrings/b7e98ac

feat/integrate-zitadel

bug/ios-hanging-reconection

zitadel-idp

feat/network-map-serial

refactor/get-account-no-users

feat/auto-upgrade

feature/report-high-pat-id

feature/temporary-access-for-resource

fix/nmap-fwrules

dont-restart-dns

prototype/ui

update-gomobile

go-dns-for-ice

wasm-ldflags

test-ldflags

wasmbuild-test

feature/networks-s2s

vk/compare-nmaps

dbg/bothmaps

reorder-dns-shutdown

fix/relay-reconnection-race

fix/nmap-exitnodes

vk/debug/nmap-both

move-licensed-code

feat/better-daemon-connection-lost-message

feat/auto-update-2

test/timings

refactor/getaccount-raw

tests/nmap-getaccount

refactor/nmap

refactor/nmap-limit-buffer

feature/detect-mac-wakeup

feature/extract-modules

quick-setings

feat/sync-limiter

feature/store-cache-impl

fix-install-version

feature/store-metrics

feature/metrics-on-store

feature/use-gorm-cache

loadtest-signal

unsymmetrical-squash

refactor/reducate-signaling

test/update-reduce

feature/store-cache

feature/remote-debug

cli-ws-proxy-backend-addr

feat/mgmt-map-serial

snyk-fix-d9d0081a4c7f9137bdb59d0d50a141a2

snyk-fix-7415cea5a11acd66753540ca2c598c63

job-yml-update

feature/android-allow-selecting-routes

fix/up-sequence

fix/dns-hash-update

snyk-fix-967adae9863f17f108ce8948d9117b8d

log/getaccount-by-peer

signal-suppressor

dns-exit-node

feature/auto-updates

feature/cache-srv-key

merged-fixes

fix/missed-offers-and-debug

debug-and-fixes

poc-wasm-clean-backend-s2s

test/remote-debug

debug-api

fix/remove-gpo-if-empty

fix/test-freebsd

fix/mysql-setup

fix/remove-logout-btn

handle-existing-domain-user

chore/unify-domain-validation

snyk-fix-c5fafc8a50ce1f29046e25a1fc346185

feat/profile-edit-btn

snyk-fix-a54966211e18d4cf67e5a2757cc006d1

log-short-id

feat/logout-ephemeral

log-checks

batch-wg-ops

nb-interface-default

feat/aws-integration

add/race-test

feature/relay-feature-versioning

fix/systemd-service-logs

poc/preprocessed-map

add-account-onboarding

bind-ipv6

fix/merge-main

logs/peerlogs-addpeer

feature/net-297-network-migration

feature/support-skip-auto-apply-exit-node-routes

set-cmd

set-command-with-cursor

feature/limit-update-channel

stop-using-locking-share

feature/poc-lazy-detection

feature/net-248-removal-of-sync-mutex-locks

test/multiple-peer-logging

preresolve

add-ns-punnycode-support

apply-routes-early

windows-search-domains

fix/connecting-route-filter

feature/management/rest-client/impersonate

debug-local-records

resource-fields-snake-case

test/grpc-rate-limit

traffic-correlation-policy

feature/rest-client-options

feat/events-metrics

feature/buf-cli

test/add-ratelimiter

test/remove-write-lock-on-add-peer

fix/add-peer-semaphore

feature/users-roles-endpoint

mlsmaycon-patch-1

debug-user-role

chore/primary-key-on-networks

feature/update-account-peers-buffer-startup

remove-ubuntu2004-runners

refactor/permissions-no-pat-allowed

ref/logrus-factory

use-conntrack-zone

deploy/permissions-account

feature/lazy-connection-idle

ref/improve-test-cov

restore-pr-3440

test/increase-grpc-timeouts

feat/buffer-account-peers-update

test/networkmapgeneration-changes

feature/base-manager

feature/flow-receiver

chore/benchmark-with-large-runner

refactor/handshake-initiator

client/ui-update-systray-icons

userspace-router

wgwatcher-test

output-if-key-already-exists

fix/relay-reconnection

feature/port-forwarding-client-codecleaning

detached2

test/callbacks-nil-iceconninfo

refactor/optimize-peer-expiration

enable-udp-port-for-docker-template

fix/relay-update

feature/apply-posture-netmap

fix/group-update-existing-resource

conntrack-stats

upgrade-okta-sdk

multi-price

test/conn-stat

set-min-parallel-tests-for-management

dns-interceptor

debug-dns

router-dns

add-static-system-info

debug-0.29.4

debug-0.33.0

account-refactoring

relay/2800_quic

route-get-account-refactoring

test/seed-random-routes

feature/get-account-refactoring

test/reconnect-race-condition

refactor/get-account-usage

feature/add-session-id-to-update-channel

improve-ipv4conn

fix/async-pion-event-handling

debug

add-offload

feature/validate-group-association-debug

fix/limit-conn-for-sqlite

test/engine-iface

test/transaction-for-jwt-sync

fix/engine-stop-in-foreground

feature/add-mysql-support

test-migration

refactor/header-size-values

relay/eliminate-gob

test/signal-dispatcher-with-relay

relay/debug

validate-icon

feature/ipv6-support

use-pre-expanded-peers-map

feature/use-signal-dispatcher

validate/peer-status

add-read-write-times

fix/sync-peer-race

feature/relay-status

netmap

evaluate/network-map-hash

fix/lower-dns-resolve-interval-on-fail

feature/relay

fix/go-mod-version

upgrade-nftables

synology-userspace-mode

fix/use-ip-for-default-routes-on-darwin

fix/proxy_close

enable-release-workflow-on-pr

deploy/peer-performance

feature/permanent-turn

feature/permanent-turn-proxy

deploy/posture-check-sqlite

feature/optimize_sqlite_save

debug-ios-behavior

fix/delete-route-only-after-adding

tshoot/windows-logger

remove-new-routing

refactor/eliminate-repo-dependency

add-arm-to-ci

refactor-demo-account-object

test/abc2

test/abc

send-ssh-rosenpass-config-meta

refactor-demo

ensure-schedule-never-runs-non-positive

feature/peer-validator-groupmgm

feature/peer-validator-fix

fix/include-active-dashboard-users

fix/handle-canceling-schedule

fix/geo-download

debug-google-workspace

yury/resolve-ip-to-location

feature/extend-sysinfo

sqlite-async-peer-status

yury/add-postgresql-store

fix/route

test-build

posture-checks-poc

debug-keycloak-idp

poc/netstack

for-pascal-tmp

peer-logout-management

manual-peer-logout

detached

chore/refactor-management

test/dns-bind

fix/enforce-acl-for-containers

yury/use-sync-map-in-updatechannel

fix/events-key-handling

filter-cache-on-load-account

fix/user-expiration

handle-user-context-cancellation

nb-client-k8s-statefulset

fake-addr

fix/iptables_in_docker

ebpf-debug

update-getting-started-flow-use-postgres

fix/peer_list_notification

feature/device-authentication-with-client-secret

feature/keep_alive

feat-groups-from-jwt

separate_proxy_from_wgconfig

fix/wg_conn

wg_conn_fix

wg_bind_parallel_processing

fix-rollback-get-acls

proxy_cfg_cleanup

performance-improvement-rego

update-lock-log-level

feat-client-side-acl

refactor/move_grpcserver_logic_to_account_manager

feature/event-storage

feature/update-idp-redeeming-invite

feature/api-peer-info

return-groupminimum-setupkey

feature/interface-bind

documentation_enhancement

fix-peer-registration

ssh

users_cache

pass-client-caller

client_caller_type

revert-283-feat-fix-windows-installer

periodic-peer-updates

ebpf

braginini/wasm

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: DYNR/netbird#10804