[Help-gnutls] GnuTLS 2.6.1 - Security release [GNUTLS-SA-2008-3]

Simon Josefsson simon at josefsson.org
Mon Nov 10 11:48:33 CET 2008

We are proud to announce a new stable GnuTLS release: Version 2.6.1.

GnuTLS is a modern C library that implement the standard network
security protocol Transport Layer Security (TLS), for use by network
applications.  GnuTLS is developed for GNU/Linux, but works on many
Unix-like systems and comes with a binary installer for Windows.

The GnuTLS library is distributed under the terms of the GNU Lesser
General Public License version 2.1 (or later).  The "extra" GnuTLS
library (which contains TLS/IA support, LZO compression and Libgcrypt
FIPS-mode handler), the OpenSSL compatibility library, the self tests
and the command line tools are all distributed under the GNU General
Public License version 3.0 (or later).  The manual is distributed under
the GNU Free Documentation License version 1.2 (or later).

The project page of the library is available at:

What's New

Version 2.6.1 is a maintainance and security release on our stable

** libgnutls: Fix X.509 certificate chain validation error. [GNUTLS-SA-2008-3]
The flaw makes it possible for man in the middle attackers (i.e.,
active attackers) to assume any name and trick GNU TLS clients into
trusting that name.  Thanks for report and analysis from Martin von
Gagern <Martin.vGagern at gmx.net>.  [CVE-2008-4989]

Any updates with more details about this vulnerability will be added
to <http://www.gnu.org/software/gnutls/security.html>

** libgnutls: Add missing prototype for gnutls_srp_set_prime_bits.
Reported by Kevin Quick <quick at sparq.org> in

** libgnutls-extra: Protect internal symbols with static.
Fixes problem when linking certtool statically.  Tiny patch from Aaron
Ucko <ucko at ncbi.nlm.nih.gov>.

** libgnutls-openssl: Fix patch against X509_get_issuer_name.
It incorrectly returned the subject DN instead of issuer DN in v2.6.0.
Thanks to Thomas Viehmann <tv at beamnet.de> for report.

** certtool: Print a PKCS #8 key even if it is not encrypted.

** tests: Make tests compile when using internal libtasn1.
Patch by ludo at gnu.org (Ludovic Courtès).

** API and ABI modifications:
No changes since last version.

Getting the Software

GnuTLS may be downloaded from one of the mirror sites or direct from
<ftp://ftp.gnu.org/gnu/gnutls/>.  The list of mirrors can be found at

Here are the BZIP2 compressed sources (4.9MB):


Here are OpenPGP detached signatures signed using key 0xB565716F:


Note, that we don't distribute gzip compressed tarballs.

In order to check that the version of GnuTLS which you are going to
install is an original and unmodified one, you should verify the OpenPGP
signature.  You can use the command

     gpg --verify gnutls-2.6.1.tar.bz2.sig

This checks whether the signature file matches the source file.  You
should see a message indicating that the signature is good and made by
that signing key.  Make sure that you have the right key, either by
checking the fingerprint of that key with other sources or by checking
that the key has been signed by a trustworthy other key.  The signing
key can be identified with the following information:

pub   1280R/B565716F 2002-05-05 [expires: 2009-04-21]
      Key fingerprint = 0424 D4EE 81A0 E3D1 19C6  F835 EDA2 1E94 B565 716F
uid                  Simon Josefsson <simon at josefsson.org>
uid                  Simon Josefsson <jas at extundo.com>
sub   1280R/4D5D40AE 2002-05-05 [expires: 2009-04-21]

The key is available from:

Alternatively, after successfully verifying the OpenPGP signature of
this announcement, you could verify that the files match the following
checksum values.  The values are for SHA-1 and SHA-224 respectively:

a445e84176bf772794db9d8c71d5515dedb14bcc  gnutls-2.6.1.tar.bz2

f3882745a290cc2a091dc50d9fb8bc7b4b999c29ecebe9730fe3bafd  gnutls-2.6.1.tar.bz2


The manual is available online at:


In particular the following formats are available:

 HTML: http://www.gnu.org/software/gnutls/manual/html_node/index.html
 PDF: http://www.gnu.org/software/gnutls/manual/gnutls.pdf

For developers there is a GnuTLS API reference manual formatted using
the GTK-DOC tools:



If you need help to use GnuTLS, or want to help others, you are invited
to join our help-gnutls mailing list, see:


If you wish to participate in the development of GnuTLS, you are invited
to join our gnutls-dev mailing list, see:


Windows installer

GnuTLS has been ported to the Windows operating system, and a binary
installer is available.  The installer contains DLLs for application
development, manuals, examples, and source code.  The installer uses
libgpg-error v1.6, libgcrypt v1.4.3, libtasn1 v1.5, and GnuTLS v2.6.1.

For more information about GnuTLS for Windows:

The Windows binary installer and PGP signature:
  http://josefsson.org/gnutls4win/gnutls-2.6.1.exe (14MB)

The checksum values for SHA-1 and SHA-224 are:

7efc24d79a258927d803b7fb25f798d82f9d1ac0  gnutls-2.6.1.exe

20054cf34bf6bf5dafda13b6956c2de02c1f91ed63858c5bf8e0268c  gnutls-2.6.1.exe

Thanks to Enrico Tassi, we also have mingw32 *.deb's available:

The checksum values for SHA-1 and SHA-224 are:

e4f70a2348dce9c1dec9de6f05e2e40872f2551c  mingw32-gnutls_2.6.1-1_all.deb

8483af5489daa10086ef8f2db288e632184744c9bc0fc278a2dd7db2  mingw32-gnutls_2.6.1-1_all.deb


GnuTLS messages have been translated into Dutch, French, German,
Malay, Polish, Swedish, and Vietnamese.  We welcome the addition of
more translations.


Improving GnuTLS is costly, but you can help!  We are looking for
organizations that find GnuTLS useful and wish to contribute back.
You can contribute by reporting bugs, improve the software, or donate
money or equipment.

Commercial support contracts for GnuTLS are available, and they help
finance continued maintenance.  Simon Josefsson Datakonsult, a
Stockholm based privately held company, is currently funding GnuTLS
maintenance.  We are always looking for interesting development
projects.  See http://josefsson.org/ for more details.

The GnuTLS service directory is available at:


Security Patch

The following patch can be used if you use releases older than v2.6.0,
or if you don't want to upgrade from v2.6.0 to v2.6.1.  It fixes the
GNUTLS-SA-2008-3 aka CVE-2008-4989 vulnerability.  The patch was
created against v2.6.0.

--- lib/x509/verify.c.orig	2008-11-10 10:58:33.000000000 +0100
+++ lib/x509/verify.c	2008-11-10 10:58:41.000000000 +0100
@@ -374,6 +374,17 @@
   int i = 0, ret;
   unsigned int status = 0, output;
+  /* Check if the last certificate in the path is self signed.
+   * In that case ignore it (a certificate is trusted only if it
+   * leads to a trusted party by us, not the server's).
+   */
+  if (gnutls_x509_crt_check_issuer (certificate_list[clist_size - 1],
+				    certificate_list[clist_size - 1]) > 0
+      && clist_size > 0)
+    {
+      clist_size--;
+    }
   /* Verify the last certificate in the certificate path
    * against the trusted CA certificate list.
@@ -412,17 +423,6 @@
-  /* Check if the last certificate in the path is self signed.
-   * In that case ignore it (a certificate is trusted only if it
-   * leads to a trusted party by us, not the server's).
-   */
-  if (gnutls_x509_crt_check_issuer (certificate_list[clist_size - 1],
-				    certificate_list[clist_size - 1]) > 0
-      && clist_size > 0)
-    {
-      clist_size--;
-    }
   /* Verify the certificate path (chain) 
   for (i = clist_size - 1; i > 0; i--)

Happy Hacking,
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