-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
=============================================================================
FreeBSD-SA-17:10.kldstat Security Advisory
The FreeBSD Project
Topic: Information leak in kldstat(2)
Category: core
Module: kernel
Announced: 2017-11-15
Credits: TJ Corley
Affects: All supported versions of FreeBSD.
Corrected: 2017-11-15 22:34:15 UTC (stable/11, 11.1-STABLE)
2017-11-15 22:49:47 UTC (releng/11.1, 11.1-RELEASE-p4)
2017-11-15 22:50:20 UTC (releng/11.0, 11.0-RELEASE-p15)
2017-11-15 22:35:16 UTC (stable/10, 10.4-STABLE)
2017-11-15 22:50:47 UTC (releng/10.4, 10.4-RELEASE-p3)
2017-11-15 22:51:08 UTC (releng/10.3, 10.3-RELEASE-p24)
CVE Name: CVE-2017-1088
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
The kldstat(2) syscall provides information about loaded kld files. The
syscall takes a userland argument of struct kld_file_stat which is then
filled with data about the kld file requested.
II. Problem Description
The kernel does not properly clear the memory of the kld_file_stat
structure before filling the data. Since the structure filled by the
kernel is allocated on the kernel stack and copied to userspace, a leak
of information from the kernel stack is possible.
III. Impact
Some bytes from the kernel stack can be observed in userspace.
IV. Workaround
No workaround is available.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.
Afterward, reboot the system.
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
Afterward, reboot the system.
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.
# fetch https://security.FreeBSD.org/patches/SA-17:10/kldstat.patch
# fetch https://security.FreeBSD.org/patches/SA-17:10/kldstat.patch.asc
# gpg --verify kldstat.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/ r325867
releng/10.3/ r325878
releng/10.4/ r325877
stable/11/ r325866
releng/11.0/ r325876
releng/11.1/ r325875
- -------------------------------------------------------------------------
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-2017-1088>
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-17:10.kldstat.asc>
-----BEGIN PGP SIGNATURE-----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=N2rs
-----END PGP SIGNATURE-----
