- backport forgotten Valid-Until patch from the obsolete experimental

    branch to prevent replay attacks better, thanks to Thomas Viehmann
    for the initial patch! (Closes: #499897)
* doc/apt.conf.5.xml:
  - document the new Valid-Until related options
* apt-pkg/contrib/strutl.cc:
  - split StrToTime() into HTTP1.1 and FTP date parser methods and
    use strptime() instead of some self-made scanf mangling
  - use the portable timegm shown in his manpage instead of a strange
    looking code copycat from wget
* ftparchive/writer.cc:
  - add ValidTime option to generate a Valid-Until header in Release file

3 files changed, 30 insertions, 1 deletions

diff --git a/doc/apt-ftparchive.1.xml b/doc/apt-ftparchive.1.xml
index a3ac45bd3..549aa6a34 100644
--- a/doc/apt-ftparchive.1.xml
+++ b/doc/apt-ftparchive.1.xml
@@ -122,7 +122,8 @@
      e.g. <literal>APT::FTPArchive::Release::Origin</literal>.  The supported fields
      are: <literal>Origin</literal>, <literal>Label</literal>, <literal>Suite</literal>,
      <literal>Version</literal>, <literal>Codename</literal>, <literal>Date</literal>,
-     <literal>Architectures</literal>, <literal>Components</literal>, <literal>Description</literal>.</para></listitem>
+     <literal>Valid-Until</literal>, <literal>Architectures</literal>,
+     <literal>Components</literal>, <literal>Description</literal>.</para></listitem>
 
      </varlistentry>
 
diff --git a/doc/apt.conf.5.xml b/doc/apt.conf.5.xml
index fe005e0f1..0cf4bb663 100644
--- a/doc/apt.conf.5.xml
+++ b/doc/apt.conf.5.xml
@@ -230,6 +230,30 @@ DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
    and the URI handlers. 
 
    <variablelist>
+     <varlistentry><term>Check-Valid-Until</term>
+	 <listitem><para>Security related option defaulting to true as an
+	 expiring validation for a Release file prevents longtime replay attacks
+	 and can e.g. also help users to identify no longer updated mirrors -
+	 but the feature depends on the correctness of the time on the user system.
+	 Archive maintainers are encouraged to create Release files with the
+	 <literal>Valid-Until</literal> header, but if they don't or a stricter value
+	 is volitional the following <literal>Max-ValidTime</literal> option can be used.
+	 </para></listitem>
+     </varlistentry>
+
+     <varlistentry><term>Max-ValidTime</term>
+	 <listitem><para>Seconds the Release file should be considered valid after
+	 it was created. The default is "for ever" (0) if the Release file of the
+	 archive doesn't include a <literal>Valid-Until</literal> header.
+	 If it does then this date is the default. The date from the Release file or
+	 the date specified by the creation time of the Release file
+	 (<literal>Date</literal> header) plus the seconds specified with this
+	 options are used to check if the validation of a file has expired by using
+	 the earlier date of the two. Archive specific settings can be made by
+	 appending the label of the archive to the option name.
+	 </para></listitem>
+     </varlistentry>
+
      <varlistentry><term>PDiffs</term>
 	 <listitem><para>Try to download deltas called <literal>PDiffs</literal> for
 	 Packages or Sources files instead of downloading whole ones. True
diff --git a/doc/examples/configure-index b/doc/examples/configure-index
index 487c09acb..fdec32c2c 100644
--- a/doc/examples/configure-index
+++ b/doc/examples/configure-index
@@ -176,6 +176,10 @@ Acquire
   PDiffs::SizeLimit "50"; // don't use diffs if size of all patches excess
 			  // 50% of the size of the original file
 
+  Check-Valid-Until "true";
+  Max-ValidTime "864000"; // 10 days
+  Max-ValidTime::Debian-Security "604800"; // 7 days, label specific configuration
+
   // HTTP method configuration
   http 
   {