- Crucial fixes (i.e., changes need to get a source
-package to compile for a released-targeted architecture) can be
-uploaded with <em>no</em> waiting period for the `frozen' distribution.
- -->
- <p>
-However, if you are a porter doing an NMU for `unstable', the above
-guidelines for porting should be followed, with two variations.
-Firstly, the acceptable waiting period — the time between when the
-bug is submitted to the BTS and when it is OK to do an NMU — is seven
-days for porters working on the unstable distribution. This period
-can be shortened if the problem is critical and imposes hardship on
-the porting effort, at the discretion of the porter group. (Remember,
-none of this is Policy, just mutually agreed upon guidelines.)
- <p>
-Secondly, porters doing source NMUs should make sure that the bug they
-submit to the BTS should be of severity `serious' or greater. This
-ensures that a single source package can be used to compile every
-supported Debian architecture by release time. It is very important
-that we have one version of the binary and source package for all
-architecture in order to comply with many licenses.
- <p>
-Porters should try to avoid patches which simply kludge around bugs in
-the current version of the compile environment, kernel, or libc.
-Sometimes such kludges can't be helped. If you have to kludge around
-compilers bugs and the like, make sure you <tt>#ifdef</tt> your work
-properly; also, document your kludge so that people know to remove it
-once the external problems have been fixed.
- <p>
-Porters may also have an unofficial location where they can put the
-results of their work during the waiting period. This helps others
-running the port have the benefit of the porter's work, even during
-the waiting period. Of course, such locations have no official
-blessing or status, so buyer, beware.
+<list>
+ <item>if it is a trivial problem (like insecure temporary files)
+ there is no need to keep the problem a secret and a fix should be
+ made and released.
+
+ <item>if the problem is severe (remotely exploitable, possibility to
+ gain root privileges) it is preferable to share the information with
+ other vendors and coordinate a release. The security team keeps
+ contacts with the various organizations and individuals and can take
+ care of that.
+</list>
+
+<p>
+ In all cases if the person who reports the problem asks to not
+ disclose the information that should be respected, with the obvious
+ exception of informing the security team (make sure you tell the
+ security team that the information can not be disclosed).
+
+<p>
+Please note that if secrecy is needed you can also not upload a fix to
+unstable (or anywhere else), since the changelog and diff information
+for unstable is public.
+
+<p>
+There are two reasons for releasing information even though secrecy is
+requested: the problem has been known for a while, or that the problem
+or exploit has become public.
+
+ <sect2 id="bug-security-advisories">Security Advisories
+ <p>
+Security advisories are only issued for the current, released stable
+distribution, not for testing or unstable. When released, advisories
+are sent to the &email-debian-security-announce;
+mailing list and posted on <url
+id="&url-debian-security-advisories;" name="the security web page">.
+Security advisories are written and posted by the security
+team. However they certainly do not mind if a maintainer can supply
+some of the information for them, or write part of the
+text. Information that should be in an advisory includes:
+
+<list compact>
+ <item>A description of the problem and its scope, including:
+ <list>
+ <item>The type of problem (privilege escalation, denial of
+ service, etc.)
+ <item>How it can be exploited
+ <item>Whether it is remotely or locally exploitable
+ <item>How the problem was fixed
+ </list>
+ <item>Version numbers of affected packages
+ <item>Version numbers of fixed packages
+ <item>Information on where to obtain the updated packages
+ <item>References to upstream advisories, <url
+ id="http://cve.mitre.org" name="CVE"> identifiers, and any other
+ information useful in cross-referencing the vulnerability
+</list>
+
+ <sect2 id="bug-security-building">
+ <heading>Preparing packages to address security issues</heading>
+ <p>
+One way that you can assist the security team in their duties is to
+provide fixed packages suitable for a security advisory for the stable
+Debian release.
+ <p>
+ When an update is made to the stable release, care must be taken to
+ avoid changing system behavior or introducing new bugs. In order to
+ do this, make as few changes as possible to fix the bug. Users and
+ administrators rely on the exact behavior of a release once it is
+ made, so any change that is made might break someone's system.
+ This is especially true of libraries: make sure you never change the
+ API or ABI, no matter how small the change.
+<p>
+This means that moving to a new upstream version is not a good
+solution. Instead, the relevant changes should be back-ported to the
+version present in the current stable Debian release. Generally,
+upstream maintainers are willing to help if needed. If not, the
+Debian security team may be able to help.
+<p>
+In some cases, it is not possible to back-port a security fix, for
+example when large amounts of source code need to be modified or
+rewritten. If this happens, it may be necessary to move to a new
+upstream version. However, you must always coordinate that with the
+security team beforehand.
+<p>
+Related to this is another important guideline: always test your
+changes. If you have an exploit available, try it and see if it
+indeed succeeds on the unpatched package and fails on the fixed
+package. Test other, normal actions as well, as sometimes a security
+fix can break seemingly unrelated features in subtle ways.
+<p>
+Review and test your changes as much as possible. Check the
+differences from the previous version repeatedly
+(<prgn>interdiff</prgn> from the <package>patchutils</package> package
+and <prgn>debdiff</prgn> from <package>devscripts</package> are useful tools for
+this).
+
+When packaging the fix, keep the following points in mind:
+
+<list>
+ <item>Make sure you target the right distribution in your
+ <file>debian/changelog</file>. For stable this is <tt>stable-security</tt> and for
+ testing this is <tt>testing-security</tt>, and for the previous
+ stable release, this is <tt>oldstable-security</tt>. Do not target
+ <var>distribution</var>-proposed-updates!
+
+ <item>Make sure the version number is proper. It must be greater
+ than the current package, but less than package versions in later
+ distributions. If in doubt, test it with <tt>dpkg
+ --compare-versions</tt>. For <em>testing</em>, there must be
+ a higher version in <em>unstable</em>. If there is none yet (for example,
+ if <em>testing</em> and <em>unstable</em> have the same version) you must upload a
+ new version to unstable first.
+
+ <item>Do not make source-only uploads if your package has any
+ binary-all packages (do not use the <tt>-S</tt> option to
+ <prgn>dpkg-buildpackage</prgn>). The <prgn>buildd</prgn> infrastructure will
+ not build those. This point applies to normal package uploads as
+ well.