[Bug 1987842] Re: wireguard: netdev file can leak private key

Thu Jul 4 19:48:24 UTC 2024

This bug was fixed in the package netplan.io - 1.0.1-1ubuntu1

---------------
netplan.io (1.0.1-1ubuntu1) oracular; urgency=medium

  * Merge from Debian unstable.  Remaining changes:
    - d/p/0003-Revert-wait-online-disabled-wait-online-for-stable-1.patch:
      Fix wait-online via s-n-wait-online.service.d/10-netplan.
    - d/libnetplan1.symbols: Update for new (private) symbol

netplan.io (1.0.1-1) unstable; urgency=medium

  * New upstream release: 1.0.1:
    - sriov: accept setting the eswitch mode without VFs (LP: #2020409)
    - cli/sriov: refactoring
    - tests: use proper 0o600 file permissions in more places
    - doc:  Adding missing 'watchfiles' dependency for Sphinx
    - doc: Minor fixes in lang. and mark-up in YAML reference
    - doc: Tutorial reorg & lang. + formatting improvements
    - networkd: add wait-online enumeration utils
    - generate: enable systemd-networkd-wait-online for non-optional interfaces
    - CLI:utils: Do not ask for daemon-reload password interactively
    - CLI:generate: call daemon-reload after (re-)generating services
    - wait-online: Do not block on loopback interface
    - generate: Do not touch wait-online, if we don't have any networkd NetDefs
    - wait-online: wait for existing interfaces only and downgrade operational
      state for interfaces without IP configuration
    - wait-online: account for DHCPv4/v6 addresses
    - wait-online: do not require virtual devices to be created already
    - wait-online: recognize that bridge/bond members will never gain
      link-local addresses
    - networkd:apply: Drop handling of legacy wpa@ instance units
    - wait-online: disabled wait-online for stable 1.0
    - test:integration: Try to improve test flakyness
    - autopkgtest: More fixes for flaky 'ethernets' test
    -  Increase some test timeouts to account for slow (riscv64) buildds
    SECURITY UPDATE:
    - libnetplan: use more restrictive file permissions
      (Closes: #1072789, LP: #2065738, LP: #1987842)
    - CVE-2022-4968
    - libnetplan: escape control characters
    - backends: escape file paths
    - backends: escape semicolons in service units (LP: #2066258)
    Bug fixes:
    - cli: Fix logging setup when python-rich is not present
    - CI: fix DebCI case for no-change rebuilds
    - CI: adopt autopkgtest for 1.0-1 on 22.04
    - doc: Update README, move CODE_OF_CONDUCT
    - doc: fix en_GB spelling
    - CI: adopt snapd.patch for autopkgtest SRU (LP: #2051939)
    - parse-nm: add a workaround for the DoT DNS option  (LP: #2055148)
    - CI: Install netplan-ci PPA
    - parse: don't remove datalist items during iteration
    - ATTN: parse/bonds: handle same primary in multiple bonds
    - parse/bonds: don't fail on primary reassignment
    - cli/sriov: set eswitch regardless of pcidev.vfs
    - doc: Fix wrong bonds.parameters.mode syntax in example
    - parse: fix redefinition of gateway(4|6)
    - doc:tutorial: fix whitespace formatting
    - util: fix potential NULL pointer assert
    - python: elements of __all__ must be strings
    - tests: fix diff test with iproute2 6.8
    - cli/generate: skip daemon_reload with --mapping
    - test: cleanup after wait_online test to fix DebCI
    - CI: fork spread to get !179 fixes
    - doc: Fix netplan-generate.md formatting !483
    - emitter: allow unicode characters in the emitter (LP: #2071652)
    - parse: do not escape all non-ascii bytes
  * d/t/control: 'diff' autopkgtest is not flaky anymore
  * d/patches: Drop patches, applied upstream
  * d/p/0003: Update 'udevadm trigger' patch, using MOVE action (LP: #2071363)
  * debian/netplan-generator.postinst: Add a postinst maintainer script to call
    the generator, so the file permissions fixes will be applied automatically.
  * d/libnetplan1.symbols: Update for new internal wait-online symbol
  * d/copyright: Update for 2024

 -- Lukas Märdian <slyon at ubuntu.com>  Thu, 04 Jul 2024 16:00:36 +0200

** Changed in: netplan.io (Ubuntu Oracular)
       Status: New => Fix Released

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https://bugs.launchpad.net/bugs/1987842

Title:
  wireguard: netdev file can leak private key

Status in Netplan:
  Fix Released
Status in netplan.io package in Ubuntu:
  Fix Released
Status in netplan.io source package in Focal:
  Fix Released
Status in netplan.io source package in Jammy:
  Fix Released
Status in netplan.io source package in Mantic:
  Fix Released
Status in netplan.io source package in Noble:
  Fix Released
Status in netplan.io source package in Oracular:
  Fix Released

Bug description:
  When using netplan with wireguard, netplan will render the
  /run/systemd/network/10-netplan-${name}.netdev file with 0644
  permissions.

  That file contains the wireguard private key, which, if specified literally (instead of using a file), will leak that key to all local users of the system. This may not be desirable.

  For example, I have this yaml in /etc/netplan/home0.yaml:
  network:
    version: 2
    tunnels:
      home0:
        mode: wireguard
        key: <base64 private key contents>
        port: 51000
        addresses: [10.10.11.2/24]
        peers:
          - keys:
              public: <base64 public key contents>
            endpoint: 10.48.132.39:51000
            allowed-ips: [10.10.11.0/24,10.10.10.0/24]
        routes:
          - to: 10.10.10.0/24
            from: 10.10.11.2
            scope: link

  When that is rendered and applied with `netplan apply`, this error is logged in /var/log/syslog:
  Aug 26 14:23:30 laptop-coffee-shop systemd-networkd[537]: /run/systemd/network/10-netplan-home0.netdev has 0644 mode that is too permissive, please adjust the ownership and access mode.

  And indeed, that file contains the same literal private key, as expected:

  # cat /run/systemd/network/10-netplan-home0.netdev
  [NetDev]
  Name=home0
  Kind=wireguard

  [WireGuard]
  PrivateKey=<base64 private key contents>
  ListenPort=51000

  [WireGuardPeer]
  PublicKey=<base64 public key contents>
  AllowedIPs=10.10.11.0/24,10.10.10.0/24
  Endpoint=10.48.132.39:51000

  Its permissions should probably be 0640 root:systemd-networkd.

  This is not an issue if the private key is specified via a file, in
  which case systemd-networkd won't even issue that warning.

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