libsoup fails to validate certain Verisign certificates

[Marc Deslauriers]

[Impact]
Some SSL certificates which can legitimately be verified using known CAs will fail to verify due to wrong root certificates bundled with them over the wire.

[Test Case]
- run the reproducer script from comment #1
*or*
- purchase something inside software-center that uses the "3dsecure" system to authenticate the credit card

Verisign shipped G1 PCA Roots with md2 signatures on them. At some point, they
resigned those same roots using SHA1.

[Regression potential]
Minimal; the code path only changes behavior if the self-signed check fails, falling back to checking against certificates in the local database.

See discussion here:
https://groups.google.com/forum/?fromgroups#!msg/mozilla.dev.security.policy/I6bUbW3WkBU/lRxqGv6vYHYJ

In Ubuntu, the Verisign md2 certs do not ship in the system CA certs bundle, as
the sha1 certs are being shipped instead. SSL libraries are supposed to verify
certs with the sha1 G1 PCA Root just fine, even if the web site sends the md2
G1 PCA Root as part of the cert bundle.

You can test this by using the following command:

gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt --print-cert -p 443
secure-test.streamline-esolutions.com

In older versions of libsoup, such as 2.36.1, this worked fine. Since libsoup
2.37.1, this is no longer working correctly. It seems glib-networking
gtlsfiledatabase-gnutls.c:g_tls_file_database_gnutls_lookup_assertion() is
attempting to validate the whole DER, which wouldn't properly accept the sha1
cert for validation.

Attached is a reproducer. It will first attempt to validate the web site cert
using the old md2 Root, and then will attempt with the sha1 Root. Both should
succeed. With libsoup > 2.37, the sha1 Root fails verification.

[Howard Chan (smartboyhw)]

I confirmed this.

Status: Undecided -> Confirmed,

[Michael Vogt (mvo)]

It seems like one way we could fix this would be to make g_tls_file_database_gnutls_lookup_assert() looks into the self->priv->issuers hashtable instead of the "complete" hashtable that contains the full DER representation of the cert. I will write a proof-of-concept patch for review tomorrow morning.

[Launchpad Janitor (janitor)]

This bug was fixed in the package glib-networking - 2.33.8-0ubuntu3

---------------
glib-networking (2.33.8-0ubuntu3) quantal; urgency=low

  * debian/patches/gnutls-Try-to-find-root-certificates-locally-if-no.patch:
    - If a server erroneously sends us a root certificate, and it
      is not anchored, then try to lookup a certificate for the same
      issuer in the database (LP: #1033516)
      Thanks to Stef Walter
 -- Michael Vogt <email address hidden> Fri, 10 Aug 2012 13:07:24 +0200

[Michael Vogt (mvo)]

I tested the versions build with the debdiff against both precise/quantal and 3dsecure works fine there.

[Michael Vogt (mvo)]

This patch is also commited to upstream git now:
http://git.gnome.org/browse/glib-networking/commit/?id=acec8a8d9098341c58cbc73c1f8c25a01dd0b8b8

[Michael Vogt (mvo)]

Hello SRU team, is there anything I can do to help getting this update published to precise-proposed?

[Steve Langasek (vorlon)]

Hello Marc, or anyone else affected,

Accepted glib-networking into precise-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/glib-networking/2.32.1-1ubuntu2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please change the bug tag from verification-needed to verification-done. If it does not, change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Peter Mahnke (peterm-ubuntu)]

 hi,

just to confirm this but.

I was just trying to buy something in the software center... got to review order... hit go and http://screencloud.net/v/Bzmp

thought I would mention it

Peter

[Peter Mahnke (peterm-ubuntu)]

Hi

I can also confirm that the proposed fix: https://bugs.launchpad.net/ubuntu/+source/glib-networking/+bug/1033516/comments/10 worked for me.

Peter

[Michael Vogt (mvo)]

Setting to verification done based on the feedback from Peter.

[Colin Watson (cjwatson)]

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package glib-networking - 2.32.1-1ubuntu2

---------------
glib-networking (2.32.1-1ubuntu2) precise-proposed; urgency=low

  * debian/patches/gnutls-Try-to-find-root-certificates-locally-if-no.patch:
    - If a server erroneously sends us a root certificate, and it
      is not anchored, then try to lookup a certificate for the same
      issuer in the database (LP: #1033516)
      Thanks to Stef Walter
 -- Michael Vogt <email address hidden> Fri, 10 Aug 2012 12:55:58 +0200

[Charles Lease (mellowchuck-y)]

Still doesn't work for US dollars have to choose EUR for work-around.