CVE-2019-5607

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-19:17.fd Security Advisory The FreeBSD Project Topic: File description reference count leak Category: core Module: unix Announced: 2019-07-24 Credits: Mark Johnston Affects: All supported versions of FreeBSD. Corrected: 2019-07-22 19:25:05 UTC (stable/12, 12.0-STABLE) 2019-07-24 12:57:49 UTC (releng/12.0, 12.0-RELEASE-p8) 2019-07-22 19:27:23 UTC (stable/11, 11.2-STABLE) 2019-07-24 12:57:49 UTC (releng/11.2, 11.2-RELEASE-p12) 2019-07-24 12:57:49 UTC (releng/11.3, 11.3-RELEASE-p1) CVE Name: CVE-2019-5607 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background UNIX-domain sockets are used for inter-process communication. It is possible to use UNIX-domain sockets to transfer rights, encoded as file descriptors, to another process. Rights are encapsulated in control messages, and multiple such messages may be transmitted with a single system call. II. Problem Description If a process attempts to transmit rights over a UNIX-domain socket and an error causes the attempt to fail, references acquired on the rights are not released and are leaked. This bug can be used to cause the reference counter to wrap around and free the corresponding file structure. III. Impact A local user can exploit the bug to gain root privileges or escape from a jail. IV. Workaround No workaround is available. V. Solution Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. 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 “Rebooting for a 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. [FreeBSD 11.2] # fetch https://security.FreeBSD.org/patches/SA-19:17/fd.11.2.patch # fetch https://security.FreeBSD.org/patches/SA-19:17/fd.11.2.patch.asc # gpg --verify fd.11.2.patch.asc [FreeBSD 11.3] # fetch https://security.FreeBSD.org/patches/SA-19:17/fd.11.patch # fetch https://security.FreeBSD.org/patches/SA-19:17/fd.11.patch.asc # gpg --verify fd.11.patch.asc [FreeBSD 12.0] # fetch https://security.FreeBSD.org/patches/SA-19:17/fd.12.patch # fetch https://security.FreeBSD.org/patches/SA-19:17/fd.12.patch.asc # gpg --verify fd.12.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 and reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/12/ r350222 releng/12.0/ r350286 stable/11/ r350223 releng/11.2/ r350286 releng/11.3/ r350286 - ------------------------------------------------------------------------- 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: VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAl04WnBfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cIOTQ/+KQMGXwNiuMVNib5ErewD9QdT48NYaU/hYUub3VMAfQltvWmbiPw7zXj7 yJGm9FxWrMvZ6hFnKskV60u9d7PMYkOv4nzcaFgPoadByXXlALQGd/ansrZFyTJr bDeBs7J3dM/VnH/lSlPc/LlbnH4iN+gj6SSqpsWAIdq99VIviAnzHTr7SniGfXul hP+5+xSlfAYOKuH7jM1+gpuld9kR2QzGObiUJ6gfJk+I41C90tSJHb3v+DCanyrM N2NXKbkgRtZoaIItiqZVIKHJP+VaHOnHCBq3uEbj2+OR7I5yFkDYdQbTiWVU1bl0 9Ps/5LPDEiQYQqgCGadzZyqyEHvoPFy2vWvc1GFya6cV1L3gtM51C713ci2Xa3NK ZknS4bIC2Nhtrf9PcFJRkMKW8OOdwYi/2vL9I4W/PAs2EV3thQivBB7dH9TYRTdC BWP2tFM+isibjezJfj2RAjdAq0Kln0U+4AkNWgNNToyzSNFJ0LBtvzlgS7mmtuN0 mA9n7tYyQM5vCXEQqcC3hIkJSeNE2Sj4/RVd8oo1Ngh1el0AFTJ2aq+QowG/lWO/ pK1lvOQXMPElbSSxCytqALWY995VRxmEUO/TF6pCgsRDIXxx+eSf1XrtT2d1+Na7 nzt511Ho9/F4Uwbih7u+IhnWReB2Da0djLBWUtOc+HsMLQZVAUk= =juJj -----END PGP SIGNATURE-----