FreeBSD Errata Notices
2014-Jun-03 19:34 UTC
[FreeBSD-Announce] FreeBSD Errata Notice FreeBSD-EN-14:06.exec
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================FreeBSD-EN-14:06.exec Errata Notice The FreeBSD Project Topic: triple-fault when executing from a threaded process Category: core Module: kern Announced: 2014-06-03 Credits: Ivo De Decker and Debian GNU/kFreeBSD porters Affects: All supported versions of FreeBSD. Corrected: 2014-05-23 09:29:04 UTC (stable/10, 10.0-STABLE) 2014-06-03 19:02:52 UTC (releng/10.0, 10.0-RELEASE-p4) 2014-05-23 11:56:32 UTC (stable/9, 9.2-STABLE) 2014-06-03 19:03:11 UTC (releng/9.2, 9.2-RELEASE-p7) 2014-06-03 19:03:11 UTC (releng/9.1, 9.1-RELEASE-p14) 2014-05-23 09:48:42 UTC (stable/8, 8.4-STABLE) 2014-06-03 19:03:23 UTC (releng/8.4, 8.4-RELEASE-p11) CVE Name: CVE-2014-3880 For general information regarding FreeBSD Errata Notices and Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:http://security.freebsd.org/>. I. Background The execve and fexecve system calls transforms the calling process into a new process, constructed from an ordinarty file. When executing a new process, the FreeBSD virtual memory subsystem tries to optimize the process by avoiding destroying the old virtual memory address space when the calling process do not share its address space with another process (for instance, via rfork(2) with RFMEM) and when the new min/max address limit stays the same. In the optimized scenario, the virtual memory subsystem only removes usermode mappings from the existing virtual memory address space instead of destroying and recreating it. II. Problem Description When the virtual memory address space is recreated for the calling process, the old virtual memory address space as well as its associated mappings are destroyed before thread_single(9) boundary, where threads were allowed to run to safely terminate. If such threads were on other CPUs, the old page table pointer may still be referenced. III. Impact The system will crash when this happens due to a triple-fault triggered by dereferencing an invalid page table pointer. IV. Workaround No workaround is available, but systems that do not run binaries that are of different bit-ness (e.g. 32-bit and 64-bit binaries) are not affected. V. Solution Perform one of the following: 1) Upgrade your system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. 2) To update your present 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. [FreeBSD 8.4] # fetch http://security.FreeBSD.org/patches/EN-14:06/exec-8.4.patch # fetch http://security.FreeBSD.org/patches/EN-14:06/exec-8.4.patch.asc # gpg --verify exec-8.4.patch.asc [FreeBSD 9.1] # fetch http://security.FreeBSD.org/patches/EN-14:06/exec-9.1.patch # fetch http://security.FreeBSD.org/patches/EN-14:06/exec-9.1.patch.asc # gpg --verify exec-9.1.patch.asc [FreeBSD 9.2] # fetch http://security.FreeBSD.org/patches/EN-14:06/exec-9.2.patch # fetch http://security.FreeBSD.org/patches/EN-14:06/exec-9.2.patch.asc # gpg --verify exec-9.2.patch.asc [FreeBSD 10.0] # fetch http://security.FreeBSD.org/patches/EN-14:06/exec-10.0.patch # fetch http://security.FreeBSD.org/patches/EN-14:06/exec-10.0.patch.asc # gpg --verify exec-10.0.patch.asc b) Apply the patch. Execute the following commands as root: # 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 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 revision numbers of each file that was corrected in FreeBSD. Branch/path Revision - ------------------------------------------------------------------------- stable/8/ r266583 releng/8.4/ r267019 stable/9/ r266585 releng/9.1/ r267018 releng/9.2/ r267018 stable/10/ r266582 releng/10.0/ r267017 - ------------------------------------------------------------------------- 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://bugs.debian.org/743141> <URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3880> The latest revision of this Errata Notice is available at http://security.FreeBSD.org/advisories/FreeBSD-EN-14:06.exec.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iQIcBAEBCgAGBQJTjiDaAAoJEO1n7NZdz2rnNcIQANX2RW/Yeuso43ziviT10iH9 IBd0Ibazfq4HIVANEGfBF9pkL7vQ4VZzzWJBZEA6r/0qDMVO0mMoFA2/SDAB3oCO Wjc2TF/FLNPlrYamO1Comb1lKG8nmXj3C+AEEOyzlxDBLIH4cEuCX6yBbjZgjeuz eYTmFWqiMBwjOctZSFzmaZjaG0EtUIig8ELkPePXBP+zGZiBlBRpLuXWTUuRTT1T I8YbhEhlvw7rZmtK7rq5uRFfFclmFCC1cYRxKb9o+9tXUL9Qq6q0740hAG/I1HJU s7M3gvQZNhFa6B8fC2XbBwe1g51pfcxRkU8ZZ0kIU4064r9CP9In9InmcFKrfZTo xNYNiV9/8rY2lHts6cXZgfrJQLfEWzYghlKVBBZpd8syVjt8ozA08YAD4RAzGAsb s1cwI9ZCpc9ak6kd9xvDV/ZUmJLE3XS8HkogUd/RBYiu0GTn6MsCIc/pnOpAL1Cq BWLmWS8vDT4rcuC828L2VmdfLjrdWcr9DHreiW7xxCX4O+/ktOT43PrgQtjd/mf+ i0k9OAJRwdoh92ylLkEJqm3kugoDGxOITKHvo2dx+g2ySukIzTv0BCNT9EAJ0kX+ i4G0eyGNTsIycZcokil1rUzk2giNLa5yqKOZNzPZ3EA7U/knuXDN1rdN0OzrqncY WZlllko53SvpSDli15vp =A9nK -----END PGP SIGNATURE-----