Unverified Commit 35b146ca authored by Maximilian Bosch's avatar Maximilian Bosch
Browse files

nixos/nextcloud: fixup openssl compat change 

Upon testing the change itself I realized that it doesn't build properly
because

* the `pname` of a php extension is `php-<name>`, not `<name>`.
* calling the extension `openssl-legacy` resulted in PHP trying to compile
  `ext/openssl-legacy` which broke since it doesn't exist:

      source root is php-8.1.12
      setting SOURCE_DATE_EPOCH to timestamp 1666719000 of file php-8.1.12/win32/wsyslog.c
      patching sources
      cdToExtensionRootPhase
      /nix/store/48mnkga4kh84xyiqwzx8v7iv090i7z66-stdenv-linux/setup: line 1399: cd: ext/openssl-legacy: No such file or directory

I didn't encounter that one before because I was mostly interested in
having a sane behavior for everyone not using this "feature" and the
documentation around this. My findings about the behavior with turning
openssl1.1 on/off are still valid because I tested this on `master` with
manually replacing `openssl` by `openssl_1_1` in `php-packages.nix`.

To work around the issue I had to slightly modify the extension
build-system for PHP:

* The attribute `extensionName` is now relevant to determine the output
  paths (e.g. `lib/openssl.so`). This is not a behavioral change for
  existing extensions because then `extensionName==name`.

  However when specifying `extName` in `php-packages.nix` this value is
  overridden and it is made sure that the extension called `extName` NOT
  `name` (i.e. `openssl` vs `openssl-legacy`) is built and installed.

  The `name` still has to be kept to keep the legacy openssl available
  as `php.extensions.openssl-legacy`.

Additionally I implemented a small VM test to check the behavior with
server-side encryption:

* For `stateVersion` below 22.11, OpenSSL 1.1 is used (in `basic.nix`
  it's checked that OpenSSL 3 is used). With that the "default"
  behavior of the module is checked.

* It is ensured that the PHP interpreter for Nextcloud's php-fpm
  actually loads the correct openssl extension.

* It is tested that (encrypted) files remain usable when (temporarily)
  installing OpenSSL3 (of course then they're not decryptable, but on a
  rollback that should still be possible).

Finally, a few more documentation changes:

* I also mentioned the issue in `nextcloud.xml` to make sure the issue
  is at least mentioned in the manual section about Nextcloud. Not too
  much detail here, but the relevant option `enableBrokenCiphersForSSE`
  is referenced.

* I fixed a few minor wording issues to also give the full context
  (we're talking about Nextcloud; we're talking about the PHP extension
  **only**; please check if you really need this even though it's
  enabled by default).

  This is because I felt that sometimes it might be hard to understand
  what's going on when e.g. an eval-warning appears without telling where
  exactly it comes from.
parent 61128cba

nixos/doc/manual/from_md/release-notes/rl-2211.section.xml

+1 −2
Original line number Diff line number Diff line
@@ -610,8 +610,7 @@ 
      <listitem>

        <para>

          The <literal>openssl</literal>-extension for the PHP

          interpreter used by <literal>services.nextcloud</literal> is

          built against OpenSSL 1.1 if

          interpreter used by Nextcloud is built against OpenSSL 1.1 if

          <xref linkend="opt-system.stateVersion" /> is below

          <literal>22.11</literal>. This is to make sure that people

          using

nixos/doc/manual/release-notes/rl-2211.section.md

+1 −1
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ Available as [services.patroni](options.html#opt-services.patroni.enable). 


- The `p4` package now only includes the open-source Perforce Helix Core command-line client and APIs. It no longer installs the unfree Helix Core Server binaries `p4d`, `p4broker`, and `p4p`. To install the Helix Core Server binaries, use the `p4d` package instead.



- The `openssl`-extension for the PHP interpreter used by `services.nextcloud` is built against OpenSSL 1.1 if

- The `openssl`-extension for the PHP interpreter used by Nextcloud is built against OpenSSL 1.1 if

  [](#opt-system.stateVersion) is below `22.11`. This is to make sure that people using [server-side encryption](https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/encryption_configuration.html)

  don't loose access to their files.

nixos/modules/services/web-apps/nextcloud.nix

+18 −13
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ let 
    extensions = { enabled, all }:

      (with all;

        # disable default openssl extension

        (lib.filter (e: e.pname != "openssl") enabled)

        (lib.filter (e: e.pname != "php-openssl") enabled)

        # use OpenSSL 1.1 for RC4 Nextcloud encryption if user

        # has acknowledged the brokeness of the ciphers (RC4).

        # TODO: remove when https://github.com/nextcloud/server/issues/32003 is fixed.
@@ -91,26 +91,29 @@ in { 
      default = versionOlder stateVersion "22.11";

      defaultText = literalExpression "versionOlder system.stateVersion \"22.11\"";

      description = lib.mdDoc ''

        This option uses OpenSSL PHP extension linked against OpenSSL 1.1 rather

        than latest OpenSSL (≥ 3), this is not recommended except if you need

        it.



        Server-side encryption in Nextcloud uses RC4 ciphers, a broken cipher

        since ~2004.

        This option enables using the OpenSSL PHP extension linked against OpenSSL 1.1

        rather than latest OpenSSL (≥ 3), this is not recommended unless you need

        it for server-side encryption (SSE). SSE uses the legacy RC4 cipher which is

        considered broken for several years now. See also [RFC7465](https://datatracker.ietf.org/doc/html/rfc7465).



        This cipher has been disabled in OpenSSL ≥ 3 and requires

        a specific legacy profile to re-enable it.



        If you upgrade to a Nextcloud using OpenSSL ≥ 3 and have

        If you deploy Nextcloud using OpenSSL ≥ 3 for PHP and have

        server-side encryption configured, you will not be able to access

        your files anymore. Enabling this option can restore access to your files.

        Upon testing we didn't encounter any data corruption when turning

        this on and off again, but this cannot be guaranteed for

        each Nextcloud installation.



        Unless you are using external storage,

        it is advised to [disable server-side encryption](https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/encryption_configuration.html#disabling-encryption) as it is unclear

        it provides any amount of security beyond encryption for external storage.

        It is `true` by default for systems with a [](#opt-system.stateVersion) below

        `22.11` to make sure that existing installations won't break on update. On newer

        NixOS systems you have to explicitly enable it on your own.



        Please note that this only provides additional value when using

        external storage such as S3 since it's not an end-to-end encryption.

        If this is not the case,

        it is advised to [disable server-side encryption](https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/encryption_configuration.html#disabling-encryption) and set this to `false`.



        In the future, Nextcloud may move to AES-256-GCM, by then,

        this option will be removed.
@@ -690,12 +693,14 @@ in { 
          This is only necessary if you're using Nextcloud's server-side encryption.

          Please keep in mind that it's using the broken RC4 cipher.



          If you don't use that feature, you can switch to OpenSSL 3 by declaring

          If you don't use that feature, you can switch to OpenSSL 3 and get

          rid of this warning by declaring



            services.nextcloud.enableBrokenCiphersForSSE = false;



          If you need to use server-side encryption you can ignore this waring.

          Otherwise you'd have to disable server-side encryption first in order

          to be able to safely disable this option and get rid of that warning.

          to be able to safely disable this option and get rid of this warning.

          See <https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/encryption_configuration.html#disabling-encryption> on how to achieve this.



          For more context, here is the implementing pull request: https://github.com/NixOS/nixpkgs/pull/198470

nixos/modules/services/web-apps/nextcloud.xml

+14 −0
Original line number Diff line number Diff line
@@ -170,6 +170,20 @@ 
     </listitem>

    </itemizedlist>

   </listitem>

   <listitem>

    <formalpara>

     <title>Server-side encryption</title>

     <para>

      Nextcloud supports <link xlink:href="https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/encryption_configuration.html">server-side encryption (SSE)</link>.

      This is not an end-to-end encryption, but can be used to encrypt files that will be persisted

      to external storage such as S3. Please note that this won't work anymore when using OpenSSL 3

      for PHP's openssl extension because this is implemented using the legacy cipher RC4.

      If <xref linkend="opt-system.stateVersion" /> is <emphasis>above</emphasis> <literal>22.05</literal>,

      this is disabled by default. To turn it on again and for further information please refer to

      <xref linkend="opt-services.nextcloud.enableBrokenCiphersForSSE" />.

     </para>

    </formalpara>

   </listitem>

  </itemizedlist>

 </section>

nixos/tests/nextcloud/basic.nix

+6 −2
Original line number Diff line number Diff line
@@ -37,13 +37,12 @@ in { 
        "d /var/lib/nextcloud-data 0750 nextcloud nginx - -"

      ];



      system.stateVersion = "22.11";

      system.stateVersion = "22.11"; # stateVersion >=21.11 to make sure that we use OpenSSL3



      services.nextcloud = {

        enable = true;

        datadir = "/var/lib/nextcloud-data";

        hostName = "nextcloud";

        enableBrokenCiphersForSSE = args.enableBrokenCiphersForSSE or false;

        config = {

          # Don't inherit adminuser since "root" is supposed to be the default

          adminpassFile = "${pkgs.writeText "adminpass" adminpass}"; # Don't try this at home!
@@ -102,6 +101,10 @@ in { 
    # This is just to ensure the nextcloud-occ program is working

    nextcloud.succeed("nextcloud-occ status")

    nextcloud.succeed("curl -sSf http://nextcloud/login")

    # Ensure that no OpenSSL 1.1 is used.

    nextcloud.succeed(

        "${nodes.nextcloud.services.phpfpm.pools.nextcloud.phpPackage}/bin/php -i | grep 'OpenSSL Library Version' | awk -F'=>' '{ print $2 }' | awk '{ print $2 }' | grep -v 1.1"

    )

    nextcloud.succeed(

        "${withRcloneEnv} ${copySharedFile}"

    )
@@ -111,5 +114,6 @@ in { 
        "${withRcloneEnv} ${diffSharedFile}"

    )

    assert "hi" in client.succeed("cat /mnt/dav/test-shared-file")

    nextcloud.succeed("grep -vE '^HBEGIN:oc_encryption_module' /var/lib/nextcloud-data/data/root/files/test-shared-file")

  '';

})) args