-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-14:12.ktrace Security Advisory The FreeBSD Project Topic: ktrace kernel memory disclosure Category: core Module: kern Announced: 2014-06-03 Credits: Jilles Tjoelker Affects: FreeBSD 8.4, FreeBSD 9.1 and FreeBSD 9.2 Corrected: 2014-06-03 19:02:33 UTC (stable/9, 9.3-BETA1) 2014-06-03 19:02:33 UTC (stable/9, 9.3-BETA1-p1) 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) 2014-06-03 19:02:42 UTC (stable/8, 8.4-STABLE) 2014-06-03 19:03:23 UTC (releng/8.4, 8.4-RELEASE-p11) CVE Name: CVE-2014-3873 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 ktrace utility enables kernel trace logging for the specified processes, commonly used for diagnostic or debugging purposes. The kernel operations that are traced include system calls, namei translations, signal processing, and I/O as well as data associated with these operations. The utility may be used only with a kernel that has been built with the ``KTRACE'' option in the kernel configuration file, which is enabled by default. II. Problem Description Due to an overlooked merge to -STABLE branches, the size for page fault kernel trace entries was set incorrectly. III. Impact A user who can enable kernel process tracing could end up reading the contents of kernel memory. Such memory might contain sensitive information, such as portions of the file cache or terminal buffers. This information might be directly useful, or it might be leveraged to obtain elevated privileges in some way; for example, a terminal buffer might include a user-entered password. IV. Workaround The system administrator may set sysctl security.bsd.unprivileged_proc_debug to 0 to prevent non-privileged users from using all process debugging facilities provided by the kernel, that includes ktrace functionality. Please note that this flag have broad effect and may break applications, as some of them may rely on certain debugging facilities to function. 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-14:12/ktrace.patch # fetch http://security.FreeBSD.org/patches/SA-14:12/ktrace.patch.asc # gpg --verify ktrace.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 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/ r267016 releng/8.4/ r267019 stable/9/ r267015 releng/9.1/ r267018 releng/9.2/ r267018 - ------------------------------------------------------------------------- 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-2014-3873> The latest revision of this advisory is available at <URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-14:12.ktrace.asc> -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iQIcBAEBCgAGBQJTjiDaAAoJEO1n7NZdz2rnIfQP/0kHBNvnNUiZ+1OWo5fMDg3N Oe7UdrvnfyeXlgw5bP4t0qwbTpn0kVYL2dfr3bxhkT1w7oF/xQjbcosx/DbzPZZs VtlAGQYh0CvOXcUZmh+COuRfcy2wkr1kKFlc2bGQVTq1uzKS+vceqA3619IWMnJO b6ClzFnn+0hk6BrUd8xdvoiYIF2RG+zcw7CxuoBQrzPYA9iO/S4ACmxzfTIgRcAD ZLGXfUEw3wlftfg605H1iV9xKm4FDUGr9qoL4W0UmYmmTmU4Z71yXSzX3A53qlRg Xd1Grw2K+zhaKaV6xL+mqox0nzSKiYuNf/ZguB5+x9ZA14ck7NtCYg6up1fgh7Ms pznVb8/GCc+IPdWJGXpSz6yFhl/MJc6mTOi+L0gOGvNKp0raNHelCpxlqavGt/tv 9Niv791FK32S8ynlP0yKRvd8Hzq4b185ehWuGWbQO8bEHljqhOyZDhysBYYWdgFi 0KG16lJopCbMPPPBVb4zfsFBvokr31m2w+/xsDD+hmaXa6C9bHIvHpuyJep4q02E 4NOoVr1x8dO5s7yVk7bNZx0WFCDYZ/DLMycLjEftHog7iq4nw29HW/Mt/rPgJWOf NiO0GEJ1XucJ1ShV/OC0B+69mFx9OsOI8kDNLE4l9oqGu2UqcZ/W0Dsa9PPl+ec+ njyksdL+yqvx9kF8fnJ0 =46Yf -----END PGP SIGNATURE----- _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-security To unsubscribe, send any mail to "[email protected]"