FreeBSD Security Advisory FreeBSD-SA-19:24.mqueuefs
20 August, 2019 by firstname.lastname@example.org | freebsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-19:24.mqueuefs Security Advisory The FreeBSD Project Topic: Reference count overflow in mqueue filesystem 32-bit compat Category: core Module: kernel Announced: 2019-08-20 Credits: Karsten KÃ¶nig, Secfault Security Affects: All supported versions of FreeBSD. Corrected: 2019-08-20 17:45:22 UTC (stable/12, 12.0-STABLE) 2019-08-20 17:51:32 UTC (releng/12.0, 12.0-RELEASE-p10) 2019-08-20 17:46:22 UTC (stable/11, 11.3-STABLE) 2019-08-20 17:51:32 UTC (releng/11.3, 11.3-RELEASE-p3) 2019-08-20 17:51:32 UTC (releng/11.2, 11.2-RELEASE-p14) CVE Name: CVE-2019-5603 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/>. Note: This issue is related to the previously disclosed SA-19:15.mqueuefs. It is another instance of the same bug and as such shares the same CVE. I. Background mqueuefs(5) implements POSIX message queue file system which can be used by processes as a communication mechanism. 'struct file' represents open files, directories, sockets and other entities. II. Problem Description System calls operating on file descriptors obtain a reference to relevant struct file which due to a programming error was not always put back, which in turn could be used to overflow the counter of affected struct file. III. Impact A local user can use this flaw to obtain access to files, directories, sockets, etc., opened by processes owned by other users. If obtained struct file represents a directory from outside of user's jail, it can be used to access files outside of the jail. If the user in question is a jailed root they can obtain root privileges on the host system. IV. Workaround No workaround is available. Note that the mqueuefs file system is not enabled by default. V. Solution Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and reboot. Perform one of the following: 1) 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 # shutdown -r +10min "Security update" 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 https://security.FreeBSD.org/patches/SA-19:24/mqueuefs.patch # fetch https://security.FreeBSD.org/patches/SA-19:24/mqueuefs.patch.asc # gpg --verify mqueuefs.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/12/ r351255 releng/12.0/ r351261 stable/11/ r351257 releng/11.3/ r351261 releng/11.2/ r351261 - ------------------------------------------------------------------------- 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 vulnerability> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-5603> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-19:24.mqueuefs.asc> -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAl1cPglfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cIKGA/+Oh+ORvFs273SJwaYaf8LCJ21IJnzVxDp9vS6MSO79LmI6HeiqAy9apQs Ec4zOXvE5MzYfA+E9jyRa6c4h7OY7uSSym15wCjLLi+DWPJ1lcCPAv01JuAgSw9E GkLOprdk2aETTe1jc3DjXv0q56JZM79vegL2Nn/AJd7GZqSI4Qxf0M+87eWFMxd6 dFlvZtnh4QGuSC8w+ls5LpcGHfr8T6w4WwNv6hfvxu//Bg/6BRYKEIAnAu/P+udd LrZO5lY9IwdaLQckk44nCr02lHVG/G3JgyW2iWAn5tm0CPkQmbawbc6V2WN+lwYf ynn0ORfKWZpeLN6hd1QedlBhyEblUdjveVy9vaJI2KieHdRMlb56/HsPQqwZLdgV QrpambGJ4J+48gYcgOXsOn52kIG7iKLfyEsiH4mrQtlZEjfluWt0cGcNuMLNqgPc WZC1Kqpx3OI00u2M+85xnM8V4VL7iQnX7WWoe8qICZDksAsm4LDTwOP4HdfXkCgs iSibovwF9ZcKwZjB8AZ+smjRyHGb2KEs+WlGI+ASE5UF8jYshCEZWKfJFd59BJZx uw/lngCium0OgQ0Bzt0NnqR663kzSE1f7ZGLJtoc5+xaWbnTbifykYsM88hO/+/v LH/fYRdgXkDTtShiMgppx/YrfTF33+hea18CdNdtdPJmH99lPmE= =1dwe -----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"