FreeBSD Security Advisory FreeBSD-SA-17:09.shm
15 November, 2017 by firstname.lastname@example.org | freebsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-17:09.shm Security Advisory The FreeBSD Project Topic: POSIX shm allows jails to access global namespace Category: core Module: shm Announced: 2017-11-15 Credits: Whitewinterwolf Affects: FreeBSD 10.x Corrected: 2017-11-13 23:21:17 UTC (stable/10, 10.4-STABLE) 2017-11-15 22:45:50 UTC (releng/10.4, 10.4-RELEASE-p3) 2017-11-15 22:45:13 UTC (releng/10.3, 10.3-RELEASE-p24) CVE Name: CVE-2017-1087 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>. I. Background POSIX shared memory objects allow realtime inter-process communication by sharing a memory area through the use of a named path (see shm_open(2)). This is used by some multi-process applications to share data between running processes, such as a common cache or to implement a producer-consumer model where several worker processes handle requests pushed by a producer process. II. Problem Description Named paths are globally scoped, meaning a process located in one jail can read and modify the content of POSIX shared memory objects created by a process in another jail or the host system. III. Impact A malicious user that has access to a jailed system is able to abuse shared memory by injecting malicious content in the shared memory region. This memory region might be executed by applications trusting the shared memory, like Squid. This issue could lead to a Denial of Service or local privilege escalation. IV. Workaround No workaround is available, but systems without jails or jails not having local users are not vulnerable. V. Solution 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. Reboot the system for the update to take effect. 2) 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 Reboot the system for the update to take effect. 3) 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. [FreeBSD 10.4, FreeBSD 10-STABLE] # fetch https://security.FreeBSD.org/patches/SA-17:09/shm-10.patch # fetch https://security.FreeBSD.org/patches/SA-17:09/shm-10.patch.asc # gpg --verify shm-10.patch.asc [FreeBSD 10.3] # fetch https://security.FreeBSD.org/patches/SA-17:09/shm-10.3.patch # fetch https://security.FreeBSD.org/patches/SA-17:09/shm-10.3.patch.asc # gpg --verify shm-10.3.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:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/10/ r325783 releng/10.3/ r325873 releng/10.4/ r325874 - ------------------------------------------------------------------------- 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:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-1087> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-17:09.shm.asc> -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEEHPf/b631yp++G4yy7Wfs1l3PaucFAloMxg1fFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldDFD RjdGRjZGQURGNUNBOUZCRTFCOENCMkVENjdFQ0Q2NURDRjZBRTcACgkQ7Wfs1l3P auciExAAhd9IcZrWpAqjKSGQWHrG7wJxrbCyyVVmZeoVQYQCihXJOnp+mhmVoJp5 zvyjIBG23F/dR8ukRO/LnqzM2bhCj7OcijlvZboH3L4os8iIeB2Tc6k9YlnFQeij wYK0CNnQjECf5S4OIBmQ+irpBYATZKk2EEDdmKDltcauSlIhJIzUedGdmMySOFzl jpx3+dHNb+D9v4luOgvF3mVTYPpjYmJ2HIYel3m0XdElW+okM+L4Q5Nt4Krm+DDp L0fUG5tqS+a++53mNIGeGiBhomD0zZMJZ8LXe/FAACHPWA0yUMhCVrZTwzVTHhA7 g5W1prFW3WYui7x1qF2LIA+SnGFTWXRlIhlAA/1n94Jl6shHnV6guZbzLAX0zk/C 6WFydhrYhmPXd3o5uWz+oQQHXQCcHeGrNc+fmPKg/bpkyJvgfLc6YaY2gEQmfIrI 3w/xqhN8mWVVhpHsHK+Wcz44T9uGH4NlYeDYy3TJ1ECri28fbxufAzr8hgbNRDtw B8YTijrPUSjwKBG815oO5JsOmHVCkCkIRx7nW72bHIs8ralXX563HK3RPjlFzr2G tzk9DF2w2TUQlgzS4wbZk9lXmlgvV0vRzsz+7jcJe1K+ZgyweNg+QIVet3BvobIA zeiRFfZuhH3ExNoJKqfZhBtOiePD0JR6JnkhvjEJm1NoHvoDOAQ= =epmQ -----END PGP SIGNATURE----- _______________________________________________ email@example.com mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-announce To unsubscribe, send any mail to "firstname.lastname@example.org"