[prev in list] [next in list] [prev in thread] [next in thread] 

List:       oss-security
Subject:    [oss-security] CVE-2014-0022 insecure install of rpm packages via yum cron
From:       "Vincent Danen" <vdanen () redhat ! com>
Date:       2014-01-23 23:46:54
Message-ID: 966D5BC4-E4E8-45FE-89B9-C4A92B11A648 () redhat ! com
[Download RAW message or body]

Just wanted to give a heads up of a flaw that was reported to our bugzilla.  Our primary bug on \
this is here:

https://bugzilla.redhat.com/show_bug.cgi?id=1057377

I'm just going to cut-n-paste what I wrote in the bug.  Obviously no CVE needs to be assigned; \
this is for others who may be shipping yum.

Gabriel VLASIU reported [1] that yum-cron would install unsigned RPM packages that yum itself \
would refuse to install.  The yum-cron code is based on that in yum-updatesd.py.  This is due \
to  the installUpdates() function (processPkgs() in yum-updatesd.py) failing to fully check the \
return code of the called sigCheckPkg() function.  sigCheckPkg() is described thus:

    def sigCheckPkg(self, po):
        """Verify the GPG signature of the given package object.

        :param po: the package object to verify the signature of
        :return: (result, error_string)
           where result is::

              0 = GPG signature verifies ok or verification is not required.
              1 = GPG verification failed but installation of the right GPG key
                    might help.
              2 = Fatal GPG verification error, give up.
        """

However, the processPkgs() and installUpdates() calling function do not account for return code \
2:

    def processPkgs(self, dlpkgs):
...
        for po in dlpkgs:
            result, err = self.updd.sigCheckPkg(po)
            if result == 0:
                continue
            elif result == 1:
                try:
                    self.updd.getKeyForPackage(po)
                except yum.Errors.YumBaseError, errmsg:
                    self.failed([str(errmsg)])

and:

    def installUpdates(self, emit):
...
        for po in dlpkgs:
            result, err = self.sigCheckPkg(po)
            if result == 0:
                continue
            elif result == 1:
                try:
                    self.getKeyForPackage(po)
                except yum.Errors.YumBaseError, errmsg:
                    self.emitUpdateFailed(errmsg)
                    return False

yum-cron.py replaced yum-cron.sh in Fedora 19 (3.4.3-47); earlier versions of Fedora use \
yum-updatesd.

This has been corrected upstream [2] and in Fedora via yum-3.4.3-132.fc19 and \
yum-3.4.3-130.fc20.

This does not affect Red Hat Enterprise Linux 6 as it used neither yum-updatesd nor yum-cron; \
it used a shellscript that called yum itself to do updates.


[1] https://bugzilla.redhat.com/show_bug.cgi?id=1052440
[2] http://yum.baseurl.org/gitweb?p=yum.git;a=commitdiff;h=9df69e579496ccb6df5c3f5b5b7bab8d648b06b4


-- 
Vincent Danen / Red Hat Security Response Team


["signature.asc" (signature.asc)]

-----BEGIN PGP SIGNATURE-----
Version: GnuPG/MacGPG2 v2.0.22 (Darwin)
Comment: GPGTools - http://gpgtools.org

iQGcBAEBAgAGBQJS4anuAAoJEJS+gzzouGyr7wcMAJwexmW7jUD/eTxarrMAa03P
s5fGf7nB+4OMmUUAxIjtN50gSOD6je9MewSbZOWv7yfJo1QHpJ/HalNtMS86M5wE
8FrC8D/yMq3g6WSsf9iSnVJkzlZcS22zoy6gc3NJ/9bHrLgNJbkb+WbgU4lohn2Z
yE1MJ8sSL8UZ/ej822Sd/uZvlqKd9CM34ojepCITggLWjwiNa2hAgWcQ2sedp3k6
/kzAOIi7cHvtFelzTjc/+PRWo0JqA6iSAclzs6eC8cjz/4Dym01YE9mRfFMxu+id
fXT0xKsDCHa2LYiveMUlnXrivTnF6hHOY45zkaz2Zm1snTcz2A8DkjSUp40V0FfC
R8Mr+oNYCghFb6Wddn5IAYScGsCB1TlabMhTR9H7/sA0++Tslyhx5CSBivG1P6LC
xxdfK98pQYRB+xItd2yXO9a90wFhyyyErJgzINQt+GdMvdxH0CD/UuiCuD5pqq+r
0IPyLO/rYUynTIKqs9hPxOGNAmivmnJMbUbuNwIMng==
=vXfK
-----END PGP SIGNATURE-----


[prev in list] [next in list] [prev in thread] [next in thread]