Date: Tue, 27 Nov 2018 21:22:22 +0000 (UTC) From: FreeBSD Errata Notices <errata-notices@freebsd.org> To: FreeBSD Errata Notices <errata-notices@freebsd.org> Subject: [FreeBSD-Announce] FreeBSD Errata Notice FreeBSD-EN-18:13.icmp Message-ID: <20181127212222.098161A81F@freefall.freebsd.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-EN-18:13.icmp Errata Notice The FreeBSD Project Topic: ICMP buffer underwrite Category: core Module: kernel Announced: 2018-11-27 Affects: All supported versions of FreeBSD. Corrected: 2018-11-08 21:58:51 UTC (stable/11, 11.2-STABLE) 2018-11-27 19:43:16 UTC (releng/11.2, 11.2-RELEASE-p5) CVE Name: CVE-2018-17156 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:https://security.FreeBSD.org/>. I. Background ICMP messages are control messages used to send error messages and operational information. II. Problem Description The icmp_error routine allocates either an mbuf or a cluster depending on the size of the data to be quoted in the ICMP reply, but the calculation failed to account for additional padding on 64-bit platforms when using a non-default sysctl value for net.inet.icmp.quotelen. III. Impact For systems that set net.inet.icmp.quotelen to a non-default value, a buffer underwrite condition occurs. IV. Workaround Reset net.inet.icmp.quotelen to default value of 8 using sysctl(8): # sysctl net.inet.icmp.quotelen=8 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. Afterwards, reboot the system. 2) 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 Afterwards, reboot the system. 3) To update your 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 11.2] # fetch https://security.FreeBSD.org/patches/EN-18:13/icmp.patch # fetch https://security.FreeBSD.org/patches/EN-18:13/icmp.patch.asc # gpg --verify icmp.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/11/ r340268 releng/11.2/ r341089 - ------------------------------------------------------------------------- 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 <other info on the problem> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-17156> <URL:https://www.reddit.com/r/BSD/comments/9v6xwg/remotely_triggerable_icmp_buffer_underwrite_in/> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-18:13.icmp.asc> -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAlv9n+FfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cKLuRAAqkua0loRn3k5N5OjGl1MFMiCX3Yg7pu7oQ0N/ZifqDOt8B8slp4+qjSO VyH07EFrk5FTz2WKXShqWcdZAL8+dBUHQaMATBI++ORiPBE+lBjYCZ1/+wrw7ie4 bOjJ4F0d/4ijs+qkt/T0hFBPGMVbF8Xafbm29P6H0mjYPNSID64g+TQacVVUQfhN aLXCfkXFXusbOzFT0DRY8vy+SdsV2anqo3979W4G//+ytGvvwxqy6g+8N8CphUSM 3vxCSvNxkd5o0C5EY53QbwueZ3A4nCnQQwGB2AFQnN9fDT1genIPzGjo0fQ8iY36 lQiSeEg9VVSMLRiey8ix7JlLShVCUADt3dNamSMJiNz4Vo4dAjD4tKNPDGFfKhoQ edUEDTSBbqtN8BbW2e/hiHZSu6vQmXwgI6tKtuEcKPHZbnW/wr+XzyrwcwYBXsNA xK1aGokHr7W0T2FTOZ9b9i4mfZLL8gfr70FBi7/INEbmQYPDylT2VCsoQO7Wox8o uhbXRxtlwZ1ix3POlhzTotjJSou8ny2PZnBVzu/64fGbIFWS4bCk35HmRIlN4lt6 ViAGBFJprJpcitFhOX51SBEgh689LKOuVUmucO2rpXAg53XzUR1xCvC3O2uY78AU fHp/0Gro0HeA45NY8zqQgv0VjbjTXw9mBOi2WCI9EKo+G3cYjOg= =kqz6 -----END PGP SIGNATURE-----
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