280882 - subjectAltName in presented ceritficate from secure site confuses Firefox

Status: RESOLVED EXPIRED

(Firefox :: General, defect)

Description

[Øyvind Grønnesby]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20050110 Firefox/1.0 (Debian package 1.0+dfsg.1-2)
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20050110 Firefox/1.0 (Debian package 1.0+dfsg.1-2)

When Firefox encounters a webserver that presents a SSL certificate that has
multiple identities with subjectAltName it will get confused, or at least give a
confusing message.

If you have a certificate with CN=hostname-1 and subjectAltName=dnsName:host-2,
and you go open a hostname-1 URL in the browser Firefox will not look in the CN
field for identification, only the subjectAltName extension field.

I don't know if the above is according to spec or standard, but it also presents
a bad error message.  The error message is as follows:

  You have attempted to establish a connection with "hostname-1".  However
  the security certificate presented belongs to "hostname-1".  It is possible,
  though unlikely, that someone may be trying to intercept your communication
  with this web site.

  If you suspect the certificate does not belong to "hostname-1", please
  cancel the connection and notify the site administrator.

Now if you click the `view certificate' button presented on the same screen, you
will see a certificate that belongs to `hostname-1'.

Reproducible: Always

Steps to Reproduce:

Comment 1

[Alexandra Kossovsky]

http://www.faqs.org/rfcs/rfc2818.html:
   If a subjectAltName extension of type dNSName is present, that MUST
   be used as the identity. Otherwise, the (most specific) Common Name
   field in the Subject field of the certificate MUST be used. Although
   the use of the Common Name is existing practice, it is deprecated and
   Certification Authorities are encouraged to use the dNSName instead.
Mozilla behaviour is correct in general, but error message is wrong and confusing. 

Comment 2

[jdnurmi+bugzilla]

I can confirm the same bug in thunderbird 1.0 (20050207) for ssl enabled ldap
servers

Comment 3

[Gervase Markham [:gerv]]

This is an automated message, with ID "auto-resolve01".

This bug has had no comments for a long time. Statistically, we have found that
bug reports that have not been confirmed by a second user after three months are
highly unlikely to be the source of a fix to the code.

While your input is very important to us, our resources are limited and so we
are asking for your help in focussing our efforts. If you can still reproduce
this problem in the latest version of the product (see below for how to obtain a
copy) or, for feature requests, if it's not present in the latest version and
you still believe we should implement it, please visit the URL of this bug
(given at the top of this mail) and add a comment to that effect, giving more
reproduction information if you have it.

If it is not a problem any longer, you need take no action. If this bug is not
changed in any way in the next two weeks, it will be automatically resolved.
Thank you for your help in this matter.

The latest beta releases can be obtained from:
Firefox:     http://www.mozilla.org/projects/firefox/
Thunderbird: http://www.mozilla.org/products/thunderbird/releases/1.5beta1.html
Seamonkey:   http://www.mozilla.org/projects/seamonkey/

Comment 4

[Gervase Markham [:gerv]]

This bug has been automatically resolved after a period of inactivity (see above
comment). If anyone thinks this is incorrect, they should feel free to reopen it.