e6520ef815
Fix sendmail improper close-on-exec flag handling. [SA-14:11] Fix ktrace memory disclosure. [SA-14:12] Fix incorrect error handling in PAM policy parser. [SA-14:13] Fix triple-fault when executing from a threaded process. [EN-14:06]
144 lines
5.6 KiB
Text
144 lines
5.6 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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=============================================================================
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FreeBSD-SA-14:12.ktrace Security Advisory
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The FreeBSD Project
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Topic: ktrace kernel memory disclosure
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Category: core
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Module: kern
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Announced: 2014-06-03
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Credits: Jilles Tjoelker
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Affects: FreeBSD 8.4, FreeBSD 9.1 and FreeBSD 9.2
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Corrected: 2014-06-03 19:02:33 UTC (stable/9, 9.3-BETA1)
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2014-06-03 19:02:33 UTC (stable/9, 9.3-BETA1-p1)
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2014-06-03 19:03:11 UTC (releng/9.2, 9.2-RELEASE-p7)
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2014-06-03 19:03:11 UTC (releng/9.1, 9.1-RELEASE-p14)
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2014-06-03 19:02:42 UTC (stable/8, 8.4-STABLE)
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2014-06-03 19:03:23 UTC (releng/8.4, 8.4-RELEASE-p11)
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CVE Name: CVE-2014-3873
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For general information regarding FreeBSD Security Advisories,
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including descriptions of the fields above, security branches, and the
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following sections, please visit <URL:http://security.FreeBSD.org/>.
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I. Background
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The ktrace utility enables kernel trace logging for the specified processes,
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commonly used for diagnostic or debugging purposes. The kernel operations
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that are traced include system calls, namei translations, signal processing,
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and I/O as well as data associated with these operations.
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The utility may be used only with a kernel that has been built with the
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``KTRACE'' option in the kernel configuration file, which is enabled by
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default.
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II. Problem Description
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Due to an overlooked merge to -STABLE branches, the size for page fault
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kernel trace entries was set incorrectly.
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III. Impact
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A user who can enable kernel process tracing could end up reading the
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contents of kernel memory.
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Such memory might contain sensitive information, such as portions of the
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file cache or terminal buffers. This information might be directly
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useful, or it might be leveraged to obtain elevated privileges in some
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way; for example, a terminal buffer might include a user-entered
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password.
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IV. Workaround
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The system administrator may set sysctl security.bsd.unprivileged_proc_debug
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to 0 to prevent non-privileged users from using all process debugging
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facilities provided by the kernel, that includes ktrace functionality.
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Please note that this flag have broad effect and may break applications,
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as some of them may rely on certain debugging facilities to function.
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V. Solution
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Perform one of the following:
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1) Upgrade your vulnerable system to a supported FreeBSD stable or
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release / security branch (releng) dated after the correction date.
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2) To update your vulnerable system via a source code patch:
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The following patches have been verified to apply to the applicable
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FreeBSD release branches.
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a) Download the relevant patch from the location below, and verify the
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detached PGP signature using your PGP utility.
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# fetch http://security.FreeBSD.org/patches/SA-14:12/ktrace.patch
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# fetch http://security.FreeBSD.org/patches/SA-14:12/ktrace.patch.asc
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# gpg --verify ktrace.patch.asc
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b) Apply the patch. Execute the following commands as root:
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# cd /usr/src
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# patch < /path/to/patch
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c) Recompile your kernel as described in
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<URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
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system.
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3) To update your vulnerable system via a binary patch:
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Systems running a RELEASE version of FreeBSD on the i386 or amd64
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platforms can be updated via the freebsd-update(8) utility:
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# freebsd-update fetch
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# freebsd-update install
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VI. Correction details
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The following list contains the correction revision numbers for each
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affected branch.
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Branch/path Revision
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- -------------------------------------------------------------------------
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stable/8/ r267016
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releng/8.4/ r267019
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stable/9/ r267015
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releng/9.1/ r267018
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releng/9.2/ r267018
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- -------------------------------------------------------------------------
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To see which files were modified by a particular revision, run the
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following command, replacing NNNNNN with the revision number, on a
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machine with Subversion installed:
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# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base
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Or visit the following URL, replacing NNNNNN with the revision number:
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<URL:http://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>
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VII. References
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<URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3873>
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The latest revision of this advisory is available at
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<URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-14:12.ktrace.asc>
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