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nixpkgs: allow packages to be marked insecure

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If a package's meta has `knownVulnerabilities`, like so:

    stdenv.mkDerivation {
      name = "foobar-1.2.3";

      ...

      meta.knownVulnerabilities = [
        "CVE-0000-00000: remote code execution"
        "CVE-0000-00001: local privilege escalation"
      ];
    }

and a user attempts to install the package, they will be greeted with
a warning indicating that maybe they don't want to install it:

    error: Package ‘foobar-1.2.3’ in ‘...default.nix:20’ is marked as insecure, refusing to evaluate.

    Known issues:

     - CVE-0000-00000: remote code execution
     - CVE-0000-00001: local privilege escalation

    You can install it anyway by whitelisting this package, using the
    following methods:

    a) for `nixos-rebuild` you can add ‘foobar-1.2.3’ to
       `nixpkgs.config.permittedInsecurePackages` in the configuration.nix,
       like so:

         {
           nixpkgs.config.permittedInsecurePackages = [
             "foobar-1.2.3"
           ];
         }

    b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
    ‘foobar-1.2.3’ to `permittedInsecurePackages` in
    ~/.config/nixpkgs/config.nix, like so:

         {
           permittedInsecurePackages = [
             "foobar-1.2.3"
           ];
         }

Adding either of these configurations will permit this specific
version to be installed. A third option also exists:

  NIXPKGS_ALLOW_INSECURE=1 nix-build ...

though I specifically avoided having a global file-based toggle to
disable this check. This way, users don't disable it once in order to
get a single package, and then don't realize future packages are
insecure.
This commit is contained in:
Graham Christensen
2017-02-16 21:02:13 -05:00
parent d36b1ccc13
commit a9c875fc2e
3 changed files with 245 additions and 59 deletions
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224
doc/configuration.xml
View File

@@ -4,83 +4,213 @@
<title>Global configuration</title>
<para>Nix packages can be configured to allow or deny certain options.</para>
<para>Nix comes with certain defaults about what packages can and
cannot be installed, based on a package's metadata. By default, Nix
will prevent installation if any of the following criteria are
true:</para>
<para>To apply the configuration edit
<filename>~/.config/nixpkgs/config.nix</filename> and set it like
<itemizedlist>
<listitem><para>The packages is thought to be broken, and has had
its <literal>meta.broken</literal> set to
<literal>true</literal>.</para></listitem>
<listitem><para>The package's <literal>meta.license</literal> is set
to a license which is considered to be unfree.</para></listitem>
<listitem><para>The package has known security vulnerabilities but
has not or can not be updated for some reason, and a list of issues
has been entered in to the package's
<literal>meta.knownVulnerabilities</literal>.</para></listitem>
</itemizedlist>
<para>Each of these criteria can be altering the nixpkgs
configuration.</para>
<para>The nixpkgs configuration for a NixOS system is set in the
<literal>configuration.nix</literal>, as in the following example:
<programlisting>
{
nixpkgs.config = {
allowUnfree = true;
};
}
</programlisting>
However, this does not allow unfree software for individual users.
Their configurations are managed separately.</para>
<para>A user's of nixpkgs configuration is stored in a user-specific
configuration file located at
<filename>~/.config/nixpkgs/config.nix</filename>. For example:
<programlisting>
{
allowUnfree = true;
}
</programlisting>
</para>
and will allow the Nix package manager to install unfree licensed packages.</para>
<section xml:id="sec-allow-broken">
<title>Installing broken packages</title>
<para>The configuration as listed also applies to NixOS under
<option>nixpkgs.config</option> set.</para>
<itemizedlist>
<para>There are two ways to try compiling a package which has been
marked as broken.</para>
<listitem>
<para>Allow installing of packages that are distributed under
unfree license by setting <programlisting>allowUnfree =
true;</programlisting> or deny them by setting it to
<literal>false</literal>.</para>
<itemizedlist>
<listitem><para>
For allowing the build of a broken package once, you can use an
environment variable for a single invocation of the nix tools:
<para>Same can be achieved by setting the environment variable:
<programlisting>$ export NIXPKGS_ALLOW_BROKEN=1</programlisting>
</para></listitem>
<listitem><para>
For permanently allowing broken packages to be built, you may
add <literal>allowBroken = true;</literal> to your user's
configuration file, like this:
<programlisting>
{
allowBroken = true;
}</programlisting>
</para></listitem>
</itemizedlist>
</section>
<section xml:id="sec-allow-unfree">
<title>Installing unfree packages</title>
<para>There are several ways to tweak how Nix handles a package
which has been marked as unfree.</para>
<itemizedlist>
<listitem><para>
To temporarily allow all unfree packages, you can use an
environment variable for a single invocation of the nix tools:
<programlisting>$ export NIXPKGS_ALLOW_UNFREE=1</programlisting>
</para></listitem>
<listitem><para>
It is possible to permanently allow individual unfree packages,
while still blocking unfree packages by default using the
<literal>allowUnfreePredicate</literal> configuration
option in the user configuration file.</para>
<para>This option is a function which accepts a package as a
parameter, and returns a boolean. The following example
configuration accepts a package and always returns false:
<programlisting>
{
allowUnfreePredicate = (pkg: false);
}
</programlisting>
</para>
<para>A more useful example, the following configuration allows
only allows flash player and visual studio code:
<programlisting>
$ export NIXPKGS_ALLOW_UNFREE=1
{
allowUnfreePredicate = (pkg: elem (builtins.parseDrvName pkg.name).name [ "flashplayer" "vscode" ]);
}
</programlisting>
</para></listitem>
</para>
</listitem>
<listitem>
<para>It is also possible to whitelist and blacklist licenses
that are specifically acceptable or not acceptable, using
<literal>whitelistedLicenses</literal> and
<literal>blacklistedLicenses</literal>, respectively.
</para>
<listitem>
<para>Whenever unfree packages are not allowed, single packages
can still be allowed by a predicate function that accepts package
as an argument and should return a boolean:
<para>The following example configuration whitelists the
licenses <literal>amd</literal> and <literal>wtfpl</literal>:
<programlisting>
allowUnfreePredicate = (pkg: ...);
{
whitelistedLicenses = with stdenv.lib.licenses; [ amd wtfpl ];
}
</programlisting>
</para>
Example to allow flash player and visual studio code only:
<para>The following example configuration blacklists the
<literal>gpl3</literal> and <literal>agpl3</literal> licenses:
<programlisting>
allowUnfreePredicate = with builtins; (pkg: elem (parseDrvName pkg.name).name [ "flashplayer" "vscode" ]);
{
blacklistedLicenses = with stdenv.lib.licenses; [ agpl3 gpl3 ];
}
</programlisting>
</para>
</listitem>
</itemizedlist>
</para>
</listitem>
<para>A complete list of licenses can be found in the file
<filename>lib/licenses.nix</filename> of the nixpkgs tree.</para>
</section>
<listitem>
<para>Whenever unfree packages are not allowed, packages can still
be whitelisted by their license:
<section xml:id="sec-allow-insecure">
<title>
Installing insecure packages
</title>
<para>There are several ways to tweak how Nix handles a package
which has been marked as unfree.</para>
<itemizedlist>
<listitem><para>
To temporarily allow all insecure packages, you can use an
environment variable for a single invocation of the nix tools:
<programlisting>$ export NIXPKGS_ALLOW_INSECURE=1</programlisting>
</para></listitem>
<listitem><para>
It is possible to permanently allow individual insecure
packages, while still blocking other insecure packages by
default using the <literal>permittedInsecurePackages</literal>
configuration option in the user configuration file.</para>
<para>The following example configuration permits the
installation of the hypothetically insecure package
<literal>hello</literal>, version <literal>1.2.3</literal>:
<programlisting>
{
permittedInsecurePackages = [
"hello-1.2.3"
];
}
</programlisting>
</para>
</listitem>
<listitem><para>
It is also possible to create a custom policy around which
insecure packages to allow and deny, by overriding the
<literal>allowInsecurePredicate</literal> configuration
option.</para>
<para>The <literal>allowInsecurePredicate</literal> option is a
function which accepts a package and returns a boolean, much
like <literal>allowUnfreePredicate</literal>.</para>
<para>The following configuration example only allows insecure
packages with very short names:
<programlisting>
whitelistedLicenses = with stdenv.lib.licenses; [ amd wtfpl ];
{
allowInsecurePredicate = (pkg: (builtins.stringLength (builtins.parseDrvName pkg.name).name) &lt;= 5);
}
</programlisting>
</para>
</listitem>
<listitem>
<para>In addition to whitelisting licenses which are denied by the
<literal>allowUnfree</literal> setting, you can also explicitely
deny installation of packages which have a certain license:
<programlisting>
blacklistedLicenses = with stdenv.lib.licenses; [ agpl3 gpl3 ];
</programlisting>
</para>
</listitem>
</itemizedlist>
<para>A complete list of licenses can be found in the file
<filename>lib/licenses.nix</filename> of the nix package tree.</para>
</para>
<para>Note that <literal>permittedInsecurePackages</literal> is
only checked if <literal>allowInsecurePredicate</literal> is not
specified.
</para></listitem>
</itemizedlist>
</section>
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