-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-14:05.nfsserver Security Advisory The FreeBSD Project Topic: Deadlock in the NFS server Category: core Module: nfsserver Announced: 2014-04-08 Credits: Rick Macklem Affects: All supported versions of FreeBSD. Corrected: 2014-04-08 18:27:39 UTC (stable/10, 10.0-STABLE) 2014-04-08 18:27:46 UTC (releng/10.0, 10.0-RELEASE-p1) 2014-04-08 23:16:19 UTC (stable/9, 9.2-STABLE) 2014-04-08 23:16:05 UTC (releng/9.2, 9.2-RELEASE-p4) 2014-04-08 23:16:05 UTC (releng/9.1, 9.1-RELEASE-p11) 2014-04-08 23:16:19 UTC (stable/8, 8.4-STABLE) 2014-04-08 23:16:05 UTC (releng/8.4, 8.4-RELEASE-p8) 2014-04-08 23:16:05 UTC (releng/8.3, 8.3-RELEASE-p15) CVE Name: CVE-2014-1453 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:http://security.FreeBSD.org/>. I. Background The Network File System (NFS) allows a host to export some or all of its file systems so that other hosts can access them over the network and mount them as if they were on local disks. FreeBSD includes both server and client implementations of NFS. II. Problem Description The kernel holds a lock over the source directory vnode while trying to convert the target directory file handle to a vnode, which needs to be returned with the lock held, too. This order may be in violation of normal lock order, which in conjunction with other threads that grab locks in the right order, constitutes a deadlock condition because no thread can proceed. III. Impact An attacker on a trusted client could cause the NFS server become deadlocked, resulting in a denial of service. IV. Workaround Systems that do not provide NFS services are not vulnerable. Neither are systems that do but use the old NFS implementation, which is the default in FreeBSD 8.x. To determine which implementation an NFS server is running, run the following command: # kldstat -v | grep -cw nfsd This will print 1 if the system is running the new NFS implementation, and 0 otherwise. To switch to the old NFS implementation: 1) Append the following lines to /etc/rc.conf: nfsv4_server_enable="no" oldnfs_server_enable="yes" 2) If the NFS server is compiled into the kernel (which is the case for the stock GENERIC kernel), replace the NFSD option with the NFSSERVER option, then recompile your kernel as described in <URL:http://www.FreeBSD.org/handbook/kernelconfig.html>. If the NFS server is not compiled into the kernel, the correct module will be loaded at boot time. 3) Finally, reboot the system. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. 2) To update your vulnerable system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch http://security.FreeBSD.org/patches/SA-14:05/nfsserver.patch # fetch http://security.FreeBSD.org/patches/SA-14:05/nfsserver.patch.asc # gpg --verify nfsserver.patch.asc b) Apply the patch. # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in <URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the system. 3) To update your vulnerable system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/8/ r264285 releng/8.3/ r264284 releng/8.4/ r264284 stable/9/ r264285 releng/9.1/ r264284 releng/9.2/ r264284 stable/10/ r264266 releng/10.0/ r264267 - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: <URL:http://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-1453> The latest revision of this advisory is available at <URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-14:05.nfsserver.asc> -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iQIcBAEBCgAGBQJTRISyAAoJEO1n7NZdz2rnOvoQAJoxWjKV1UACccAi4Z/ChESU rSi2NrW6ZixCmSzbPxAcz9Qv7vaQVSywfG5Zy1JddNh1aVy4ExUsd/FZcRr92Cz2 ujprve/JBMc0YOsND7KIna9Rk7Ryj0IchRXquN5SyDhZbvWwnDNatQWID5awzgYM aX+48WUFk/oFX009JCR2LO3u3GqOZN6fJhLSQs+Yj+CuxQO9XlQSSUK+lTDO/2ig snT7j52eCJhsMNn1QcdMGx1Y+NdfIEDfinioAPKLUfWCXWwNRAhTD5scasHDQWV4 60kVXZzl/CNOD7awOXwIrx3GRPQSwsg2YUqGP+jXlEdIA+MNE5+vUijDcLI/cTBj WSApShrdybIyOyPzczDKmLae9NUeKspUoZTwwwSJ6p8Zr6m0/dBzKbk7TB+XFn17 Q1FVDkpq7pJUzPQxNfB9Z6wwRXeZgaJBEck/P0DvHZwJDq1mZLbcPFap91I4p471 iBVhSHHP466pj0EUuCjNrld7BgVj/iCrCO7LZr4L9t/7sDAIE+CYqv5eR7byUIOO WoMs3zplSR1XgTk5c9p6XQifv3dtRGyJicfjtKdNFxYjeokIhXxdAjWjQmwC2XoG PK7enzV2MHWg3nCpdCztD+4ZjHqdwOq/o2g0rVrum7SfOeZXyqr+YB58rpd6uR11 8z8hxDfKCzc/Lo1/T+EO =xBcd -----END PGP SIGNATURE----- _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-security To unsubscribe, send any mail to "[email protected]"