-----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 . 0. Revision History v1.0 2014-06-03 Initial release. v1.1 2014-06-03 Corrected some technical details for the advisory. v1.1 2014-06-04 Corrected a typo. I. Background The execve(2) and fexecve(2) system calls transforms the calling process into a new process, constructed from an ordinary 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 does not share its address space with another process (for instance, via rfork(2) with RFMEM) and when the new minimum/maximum 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, may be destroyed if the old address space is not suitable for the new image execution. The destruction happens before other threads in the current process are terminated. If the address space is destroyed, such threads still reference old address space and corresponding mapping structures, and an attempt to switch to them to gracefully terminate the remaining threads cause a triple fault and machine reset. III. Impact The system will reboot without any log or panic message 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 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: VII. References 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) iQIcBAEBCgAGBQJTj1v/AAoJEO1n7NZdz2rnh2IQALLdJp0DmXZfFxhDctIyb8Ma 9mwBzVRnyfWwhq0q6GwnSKd1hZh0qQ8SCRuaq4+SwO5conlw4NUx+ADyEBo2cx5B w6uYNZF75QAVh0eFATuYaj5TH5XC7NlqJU8YDKY2mOS1C7Ghbk4jo6fo1EFLwnt8 lMG/H1H1RBSNsvboqCCpW7kkJPjz1npg12gAO0k4jDKGw/jusC5Beq57HeJE53Wz iisYQCwLUB+3H/AZLnbj4FBBvD2tOzvuKhnk3GCmVTUHRTecZWAEmWWJ3Jxc/6gB vu+oIadMHlouLmTBJPZ1sosrhENmM4TG5IfJPRAXCZ8uaaPHR0zY8qgWxvOCLvO+ zImMhru3DVpJmY1A8KJy/c6R8q/W3meEqv0WhB9B2cgxcgXE8/btmMHy4tss1tN8 LBv5SlMDm/5xjbM4ApE8cJjQm3JowuCIN1ZAkyHRz8+dDaPBcfZED2MEODE1J3xR nUJzQzFvUk95vobbUXf2IQXGiVbWX5clS8VFkt8Jo5tgGmoq2lsgEIkNVQTd5eZA jtG+4HvcGLQP5csBf+SeIEBL4HBYaMpu/grH4bDsqSAVLNC3F/UcsKX1eyv0c3gA wFPTs2hrkd5LdgplzpLFetdpP0d48msLDBI494skz5eI0/LlBoU0sbtKCwrkYbpO RUGJumiUhHycxEdXwSgd =mTIM -----END PGP SIGNATURE-----