Date: Thu, 23 Jan 2014 16:46:54 -0700 From: "Vincent Danen" <vdanen@...hat.com> To: "OSS Security List" <oss-security@...ts.openwall.com> Subject: CVE-2014-0022 insecure install of rpm packages via yum cron 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  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  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.  https://bugzilla.redhat.com/show_bug.cgi?id=1052440  http://yum.baseurl.org/gitweb?p=yum.git;a=commitdiff;h=9df69e579496ccb6df5c3f5b5b7bab8d648b06b4 -- Vincent Danen / Red Hat Security Response Team Download attachment "signature.asc" of type "application/pgp-signature" (711 bytes)
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