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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
-
-<!ENTITY % aptent SYSTEM "apt.ent">
-%aptent;
-
-<!ENTITY % aptverbatiment SYSTEM "apt-verbatim.ent">
-%aptverbatiment;
-
+<!ENTITY % aptent SYSTEM "apt.ent"> %aptent;
+<!ENTITY % aptverbatiment SYSTEM "apt-verbatim.ent"> %aptverbatiment;
+<!ENTITY % aptvendor SYSTEM "apt-vendor.ent"> %aptvendor;
]>
<refentry>
&apt-email;
&apt-product;
<!-- The last update date -->
- <date>2012-06-09T00:00:00Z</date>
+ <date>2016-08-06T00:00:00Z</date>
</refentryinfo>
<refmeta>
<refsect1><title>Description</title>
<para>
- Starting with version 0.6, <command>apt</command> contains code
- that does signature checking of the Release file for all
- archives. This ensures that packages in the archive can't be
- modified by people who have no access to the Release file signing
- key.
+ Starting with version 0.6, <command>APT</command> contains code that does
+ signature checking of the Release file for all repositories. This ensures
+ that data like packages in the archive can't be modified by people who
+ have no access to the Release file signing key. Starting with version 1.1
+ <command>APT</command> requires repositories to provide recent authentication
+ information for unimpeded usage of the repository.
+ </para>
+
+ <para>
+ If an archive has an unsigned Release file or no Release file at all
+ current APT versions will refuse to download data from them by default
+ in <command>update</command> operations and even if forced to download
+ front-ends like &apt-get; will require explicit confirmation if an
+ installation request includes a package from such an unauthenticated
+ archive.
+ </para>
+
+ <para>
+ As a temporary exception &apt-get; (not &apt;!) raises warnings only if it
+ encounters unauthenticated archives to give a slightly longer grace period
+ on this backward compatibility effecting change. This exception will be removed
+ in future releases and you can opt-out of this grace period by setting the
+ configuration option <option>Binary::apt-get::Acquire::AllowInsecureRepositories</option>
+ to <literal>false</literal> or <option>--no-allow-insecure-repositories</option>
+ on the command line.
+ </para>
+
+ <para>
+ You can force all APT clients to raise only warnings by setting the
+ configuration option <option>Acquire::AllowInsecureRepositories</option> to
+ <literal>true</literal>. Individual repositories can also be allowed to be insecure
+ via the &sources-list; option <literal>allow-insecure=yes</literal>.
+ Note that insecure repositories are strongly discouraged and all options
+ to force apt to continue supporting them will eventually be removed.
+ Users also have the <option>Trusted</option> option available to disable
+ even the warnings, but be sure to understand the implications as detailed in
+ &sources-list;.
</para>
<para>
- If a package comes from a archive without a signature, or with a
- signature that apt does not have a key for, that package is
- considered untrusted, and installing it will result in a big
- warning. <command>apt-get</command> will currently only warn
- for unsigned archives; future releases might force all sources
- to be verified before downloading packages from them.
+ A repository which previously was authentication but would loose this state in
+ an <command>update</command> operation raises an error in all APT clients
+ irrespective of the option to allow or forbid usage of insecure repositories.
+ The error can be overcome by additionally setting
+ <option>Acquire::AllowDowngradeToInsecureRepositories</option>
+ to <literal>true</literal> or for Individual repositories with the &sources-list;
+ option <literal>allow-downgrade-to-insecure=yes</literal>.
</para>
<para>
- The package frontends &apt-get;, &aptitude; and &synaptic; support this new
- authentication feature.
+ Note: All APT-based package management front-ends like &apt-get;, &aptitude;
+ and &synaptic; support this authentication feature, so this manpage uses
+ <literal>APT</literal> to refer to them all for simplicity only.
</para>
</refsect1>
- <refsect1><title>Trusted archives</title>
+ <refsect1><title>Trusted Repositories</title>
- <para>
- The chain of trust from an apt archive to the end user is made up of
+ <para>
+ The chain of trust from an APT archive to the end user is made up of
several steps. <command>apt-secure</command> is the last step in
this chain; trusting an archive does not mean that you trust its
packages not to contain malicious code, but means that you
devscripts packages respectively).</para>
<para>
- The chain of trust in Debian starts when a maintainer uploads a new
+ The chain of trust in Debian starts (e.g.) when a maintainer uploads a new
package or a new version of a package to the Debian archive. In
order to become effective, this upload needs to be signed by a key
- contained in the Debian Maintainers keyring (available in
+ contained in one of the Debian package maintainer keyrings (available in
the debian-keyring package). Maintainers' keys are signed by
other maintainers following pre-established procedures to
- ensure the identity of the key holder.
+ ensure the identity of the key holder. Similar procedures exist in all
+ Debian-based distributions.
</para>
<para>
the maintainer signature is stripped off, and checksums of the package
are computed and put in the Packages file. The checksums of all of the
Packages files are then computed and put into the Release file. The
- Release file is then signed by the archive key for this Debian release,
+ Release file is then signed by the archive key for this &keyring-distro; release,
and distributed alongside the packages and the Packages files on
- Debian mirrors. The keys are in the Debian archive keyring available in
- the <package>debian-archive-keyring</package> package.
+ &keyring-distro; mirrors. The keys are in the &keyring-distro; archive keyring
+ available in the &keyring-package; package.
</para>
<para>
</itemizedlist>
<para>However, it does not defend against a compromise of the
- Debian master server itself (which signs the packages) or against a
+ master server itself (which signs the packages) or against a
compromise of the key used to sign the Release files. In any case,
this mechanism can complement a per-package signature.</para>
</refsect1>
- <refsect1><title>User configuration</title>
- <para>
- <command>apt-key</command> is the program that manages the list
- of keys used by apt. It can be used to add or remove keys, although
- an installation of this release will automatically contain the
- default Debian archive signing keys used in the Debian package
- repositories.
- </para>
+ <refsect1><title>User Configuration</title>
<para>
+ <command>apt-key</command> is the program that manages the list of keys used
+ by APT to trust repositories. It can be used to add or remove keys as well
+ as list the trusted keys. Limiting which key(s) are able to sign which archive
+ is possible via the <option>Signed-By</option> in &sources-list;.
+ </para><para>
+ Note that a default installation already contains all keys to securely
+ acquire packages from the default repositories, so fiddling with
+ <command>apt-key</command> is only needed if third-party repositories are
+ added.
+ </para><para>
In order to add a new key you need to first download it
(you should make sure you are using a trusted communication channel
when retrieving it), add it with <command>apt-key</command> and
</para>
</refsect1>
-<refsect1><title>Archive configuration</title>
+<refsect1><title>Archive Configuration</title>
<para>
If you want to provide archive signatures in an archive under your
maintenance you have to:
<command>gpg --clearsign -o InRelease Release</command> and
<command>gpg -abs -o Release.gpg Release</command>.</para></listitem>
- <listitem><para><emphasis>Publish the key fingerprint</emphasis>,
- that way your users will know what key they need to import in
- order to authenticate the files in the
- archive.</para></listitem>
+ <listitem><para>
+ <emphasis>Publish the key fingerprint</emphasis>, so that your users
+ will know what key they need to import in order to authenticate the files
+ in the archive. It is best to ship your key in its own keyring package
+ like &keyring-distro; does with &keyring-package; to be able to
+ distribute updates and key transitions automatically later.
+ </para></listitem>
+
+ <listitem><para>
+ <emphasis>Provide instructions on how to add your archive and key</emphasis>.
+ If your users can't acquire your key securely the chain of trust described above is broken.
+ How you can help users add your key depends on your archive and target audience ranging
+ from having your keyring package included in another archive users already have configured
+ (like the default repositories of their distribution) to leveraging the web of trust.
+ </para></listitem>
</itemizedlist>
<refsect1><title>See Also</title>
<para>
&apt-conf;, &apt-get;, &sources-list;, &apt-key;, &apt-ftparchive;,
-&debsign; &debsig-verify;, &gpg;
+&debsign;, &debsig-verify;, &gpg;
</para>
<para>For more background information you might want to review the
<ulink
-url="http://www.debian.org/doc/manuals/securing-debian-howto/ch7">Debian
+url="https://www.debian.org/doc/manuals/securing-debian-howto/ch7">Debian
Security Infrastructure</ulink> chapter of the Securing Debian Manual
-(available also in the harden-doc package) and the
+(also available in the harden-doc package) and the
<ulink url="http://www.cryptnet.net/fdp/crypto/strong_distro.html"
>Strong Distribution HOWTO</ulink> by V. Alex Brennen. </para>
</refentry>
-
projects / apt.git / blobdiff