[gnutls-dev] Variant of Bleichenbacher's crypto 06 rump session attack

[Andreas Metzler]

On 2006-09-08 Simon Josefsson <jas at extundo.com> wrote:
[...]
> The patch that fixes this is for lib/x509/verify.c, see below.

[...]
> --- /cvs/gnutls/gnutls/lib/x509/verify.c	2005/11/07 23:28:02	1.52
> +++ /cvs/gnutls/gnutls/lib/x509/verify.c	2006/09/08 13:38:55	1.52.2.1
>  <at>  <at>  -1,5 +1,5  <at>  <at> 
>  /*
> - * Copyright (C) 2003, 2004, 2005 Free Software Foundation
> + * Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation
>   *
>   * Author: Nikos Mavroyanopoulos
>   *
>  <at>  <at>  -505,6 +505,15  <at>  <at> 
>        return GNUTLS_E_UNKNOWN_HASH_ALGORITHM;
>      }

> +  len = sizeof (str) - 1;
> +  result = asn1_read_value (dinfo, "digestAlgorithm.parameters", NULL, &len);
> +  if (result != ASN1_ELEMENT_NOT_FOUND)
> +    {
> +      gnutls_assert ();
> +      asn1_delete_structure (&dinfo);
> +      return _gnutls_asn2err (result);
> +    }
> +
>    result = asn1_read_value (dinfo, "digest", digest, digest_size);
>    if (result != ASN1_SUCCESS)
>      {

Hello,
This seems to cause breakage with mutt, muttng and OpenLDAP.
http://bugs.debian.org/386643
http://bugs.debian.org/386680

The asn1_read_value() segfaults under certain conditions (libtasn1-3
0.3.5).

I have been able to reproduce the segfault using mutt 1.5.13 and
gnutls 1.0.16 + the patch quoted above on imaps:m26s25.vlinux.de, but
have been unable to find the reason.

cu andreas
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