<?xml version="1.0" encoding="utf-8" standalone="no"?>
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
- "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
+<!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 % aptvendor SYSTEM "apt-vendor.ent">
+%aptvendor;
]>
<refentry>
- &apt-docinfo;
-
+ <refentryinfo>
+ &apt-author.jgunthorpe;
+ &apt-author.team;
+ &apt-email;
+ &apt-product;
+ <!-- The last update date -->
+ <date>2012-06-09T00:00:00Z</date>
+ </refentryinfo>
+
<refmeta>
<refentrytitle>apt-secure</refentrytitle>
<manvolnum>8</manvolnum>
+ <refmiscinfo class="manual">APT</refmiscinfo>
</refmeta>
<!-- NOTE: This manpage has been written based on the
</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
+ 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
+ for unsigned archives; future releases might force all sources
to be verified before downloading packages from them.
</para>
<para>
The chain of trust from an apt archive to the end user is made up of
- different steps. <command>apt-secure</command> is the last step in
- this chain, trusting an archive does not mean that the packages
- that you trust it do not contain malicious code but means that you
- trust the archive maintainer. Its the archive maintainer
- responsibility to ensure that the archive integrity is correct.
+ 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
+ trust the archive maintainer. It's the archive maintainer's
+ responsibility to ensure that the archive's integrity is preserved.
</para>
<para>apt-secure does not review signatures at a
<para>
The chain of trust in Debian starts when a maintainer uploads a new
- package or a new version of a package to the Debian archive. This
- upload in order to become effective needs to be signed by a key of
- a maintainer within the Debian maintainer's keyring (available in
- the debian-keyring package). Maintainer's keys are signed by
+ 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
+ the debian-keyring package). Maintainers' keys are signed by
other maintainers following pre-established procedures to
ensure the identity of the key holder.
</para>
<para>
Once the uploaded package is verified and included in the archive,
- the maintainer signature is stripped off, an MD5 sum of the package
- is computed and put in the Packages file. The MD5 sum 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 (which is created
- once a year and distributed through the FTP server. This key is
- also on the Debian keyring.
+ 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 &keyring-distro; release,
+ and distributed alongside the packages and the Packages files on
+ &keyring-distro; mirrors. The keys are in the &keyring-distro; archive keyring
+ available in the &keyring-package; package.
</para>
<para>
- Any end user can check the signature of the Release file, extract the MD5
- sum of a package from it and compare it with the MD5 sum of the
- package he downloaded. Prior to version 0.6 only the MD5 sum of the
- downloaded Debian package was checked. Now both the MD5 sum and the
- signature of the Release file are checked.
+ End users can check the signature of the Release file, extract a checksum
+ of a package from it and compare it with the checksum of the package
+ they downloaded by hand - or rely on APT doing this automatically.
</para>
<para>Notice that this is distinct from checking signatures on a
<itemizedlist>
<listitem><para><literal>Network "man in the middle"
- attacks</literal>. Without signature checking, a malicious
- agent can introduce himself in the package download process and
+ attacks</literal>. Without signature checking, malicious
+ agents can introduce themselves into the package download process and
provide malicious software either by controlling a network
element (router, switch, etc.) or by redirecting traffic to a
- rogue server (through arp or DNS spoofing
+ rogue server (through ARP or DNS spoofing
attacks).</para></listitem>
<listitem><para><literal>Mirror network compromise</literal>.
Without signature checking, a malicious agent can compromise a
- mirror host and modify the files in it to propage malicious
+ mirror host and modify the files in it to propagate malicious
software to all users downloading packages from that
host.</para></listitem>
</itemizedlist>
<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 provide the
+ 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>
(you should make sure you are using a trusted communication channel
when retrieving it), add it with <command>apt-key</command> and
then run <command>apt-get update</command> so that apt can download
- and verify the <filename>Release.gpg</filename> files from the archives you
- have configured.
+ and verify the <filename>InRelease</filename> or <filename>Release.gpg</filename>
+ files from the archives you have configured.
</para>
</refsect1>
</para>
<itemizedlist>
- <listitem><para><literal>Create a toplevel Release
- file</literal>. if it does not exist already. You can do this
+ <listitem><para><emphasis>Create a toplevel Release
+ file</emphasis>, if it does not exist already. You can do this
by running <command>apt-ftparchive release</command>
- (provided inftp apt-utils).</para></listitem>
+ (provided in apt-utils).</para></listitem>
- <listitem><para><literal>Sign it</literal>. You can do this by running
+ <listitem><para><emphasis>Sign it</emphasis>. You can do this by running
+ <command>gpg --clearsign -o InRelease Release</command> and
<command>gpg -abs -o Release.gpg Release</command>.</para></listitem>
- <listitem><para><literal>Publish the key fingerprint</literal>,
+ <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>
</itemizedlist>
- <para>Whenever the contents of the archive changes (new packages
+ <para>Whenever the contents of the archive change (new packages
are added or removed) the archive maintainer has to follow the
- first two steps previously outlined.</para>
+ first two steps outlined above.</para>
</refsect1>
<refsect1><title>See Also</title>
<para>
-&apt-conf;, &apt-get;, &sources-list;, &apt-key;, &apt-archive;,
-&debsign; &debsig-verify;, &gpg;
+&apt-conf;, &apt-get;, &sources-list;, &apt-key;, &apt-ftparchive;,
+&debsign;, &debsig-verify;, &gpg;
</para>
-<para>For more backgound information you might want to review the
+<para>For more background information you might want to review the
<ulink
-url="http://www.debian.org/doc/manuals/securing-debian-howto/ch7.en.html">Debian
+url="http://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
<ulink url="http://www.cryptnet.net/fdp/crypto/strong_distro.html"
projects / apt.git / blobdiff