Bug 603574 (CVE-2016-9594) – <net-misc/curl-7.52.1: uninitialized random

• Product: Gentoo Security
• Status: RESOLVED FIXED

[Description Thomas Deutschmann (RETIRED) 2016-12-23 12:11:31 UTC]

uninitialized random
====================

Project curl Security Advisory, December 23, 2016 -
[Permalink](https://curl.haxx.se/docs/adv_20161223.html)

VULNERABILITY
-------------

libcurl's (new) internal function that returns a good 32bit random value was
implemented poorly and overwrote the pointer instead of writing the value into
the buffer the pointer pointed to.

This random value is used to generate nonces for Digest and NTLM
authentication, for generating boundary strings in HTTP formposts and
more. Having a weak or virtually non-existent random there makes these
operations vulnerable.

This function is brand new in 7.52.0 and is the result of an overhaul to make
sure libcurl uses strong random as much as possible - provided by the backend
TLS crypto libraries when present. The faulty function was introduced in [this
commit](https://github.com/curl/curl/commit/f682156a4fc6c43fb).

We are not aware of any exploit of this flaw.

INFO
----

This mistake managed to slip in because:

  1. It wasn't detected by manual code reviews

  2. When libcurl is built debug-enabled (which is often the case when libcurl
     developers build it), the bug doesn't trigger.

  3. When built without -g, the test suite's "valgrind output parser" wrongly
     ignored the valgrind output and with libcurl's standard build it is
     typically built without -g. Thus hiding this problem to most users.

The Common Vulnerabilities and Exposures (CVE) project has assigned the name
CVE-2016-9594 to this issue.

AFFECTED VERSIONS
-----------------

This flaw exists in the following libcurl versions.

- Affected versions: libcurl 7.52.0 only
- Not affected versions: libcurl < 7.52.0 and libcurl >= 7.52.1

libcurl is used by many applications, but not always advertised as such!

THE SOLUTION
------------

In version 7.52.1, we fixed the function and we fixed the valgrind parser in
the test suite.

A [patch for CVE-2016-9594](https://curl.haxx.se/CVE-2016-9594.patch) is
available.

RECOMMENDATIONS
---------------

We suggest you take one of the following actions immediately, in order of
preference:

  A - Upgrade curl and libcurl to version 7.52.1

  B - Apply the patch to 7.52.0 and rebuild

TIME LINE
---------

It was first reported to the curl project on December 21 by Kamil Dudka.

We contacted distros@openwall on December 21.

curl 7.52.1 was released on December 23 2016, coordinated with the publication
of this advisory.

CREDITS
-------

Reported and patched by Kamil Dudka.

[Comment 1 Thomas Deutschmann (RETIRED) 2016-12-23 14:47:31 UTC]

@ Maintainer(s): Thank you for the bump!


@ Arches,

please test and mark stable: =net-misc/curl-7.52.1

Some arches still have to re-keyword curl itself _and_ =net-dns/libidn2-0.11 (including stabilization).

[Comment 2 Aaron Bauman (RETIRED) 2016-12-24 02:31:26 UTC]

=net-dns/libidn2-0.11 is already stable on all stable arches.

[Comment 3 Aaron Bauman (RETIRED) 2016-12-24 06:57:22 UTC]

amd64 stable

[Comment 4 Thomas Deutschmann (RETIRED) 2016-12-25 13:31:43 UTC]

(In reply to Aaron Bauman from comment #2)
> =net-dns/libidn2-0.11 is already stable on all stable arches.

No, this bug also covers re-keywording of net-misc/curl. I.e. alpha, ia64 and sparc still have to re-keyword net-misc/curl (keywords were dropped when new =net-dns/libidn2 dependency was introduced), including net-dns/libidn2. See depending bug and large blocking history.

[Comment 5 Thomas Deutschmann (RETIRED) 2016-12-25 13:40:37 UTC]

x86 stable

[Comment 6 Thomas Deutschmann (RETIRED) 2016-12-30 01:19:07 UTC]

Stopping stabilization due to upstream issue https://github.com/curl/curl/issues/1174

We will continue shortly after the rev bump including the patch landed in Gentoo repository.

[Comment 7 Anthony Basile 2016-12-30 01:49:03 UTC]

(In reply to Thomas Deutschmann from comment #6)
> Stopping stabilization due to upstream issue
> https://github.com/curl/curl/issues/1174
> 
> We will continue shortly after the rev bump including the patch landed in
> Gentoo repository.

Okay let's restart with curl-7.52.1-r1.ebuild.  It fixes bug #604104.

[Comment 8 Thomas Deutschmann (RETIRED) 2016-12-30 01:53:43 UTC]

@ Arches,

please test and mark stable: =net-misc/curl-7.52.1-r1

Some arches still have to re-keyword curl itself _and_ =net-dns/libidn2-0.11 (including stabilization).

[Comment 9 Agostino Sarubbo 2016-12-30 17:15:45 UTC]

amd64 stable

[Comment 10 Agostino Sarubbo 2016-12-30 17:16:17 UTC]

x86 stable

[Comment 11 Jeroen Roovers (RETIRED) 2016-12-31 11:56:46 UTC]

Stable for HPPA PPC64.

[Comment 12 Tobias Klausmann (RETIRED) 2017-01-05 12:36:36 UTC]

Stable on alpha.

[Comment 13 Markus Meier 2017-01-08 18:36:03 UTC]

arm stable

[Comment 14 Agostino Sarubbo 2017-01-15 16:05:01 UTC]

ppc stable

[Comment 15 Agostino Sarubbo 2017-01-18 09:46:08 UTC]

ia64 stable

[Comment 16 Agostino Sarubbo 2017-01-18 09:51:30 UTC]

sparc stable.

Maintainer(s), please cleanup.
Security, please vote.

[Comment 17 Thomas Deutschmann (RETIRED) 2017-01-19 19:58:42 UTC]

This issue was resolved and addressed in
 GLSA 201701-47 at https://security.gentoo.org/glsa/201701-47
by GLSA coordinator Thomas Deutschmann (whissi).



@ Maintainer(s): Please cleanup and drop <net-misc/curl-7.52.1!

[Comment 18 Aaron Bauman (RETIRED) 2017-01-24 04:37:41 UTC]

https://github.com/gentoo/gentoo/pull/3614

[Comment 19 Anthony Basile 2017-02-01 14:40:04 UTC]

I removed the vulnerable versions.