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  • [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-22:01.vt

    From FreeBSD Security Advisories@21:1/5 to All on Wed Jan 12 17:00:03 2022
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    ============================================================================= FreeBSD-SA-22:01.vt Security Advisory
    The FreeBSD Project

    Topic: vt console buffer overflow

    Category: kernel
    Module: vt
    Announced: 2022-01-11
    Credits: Oleg Bulyzhin
    Affects: FreeBSD 12.2 and FreeBSD 13.0
    Corrected: 2021-09-22 18:41:00 UTC (stable/13, 13.0-STABLE)
    2022-01-11 18:15:03 UTC (releng/13.0, 13.0-RELEASE-p6)
    2021-09-25 18:15:49 UTC (stable/12, 12.2-STABLE)
    2022-01-11 18:33:21 UTC (releng/12.2, 12.2-RELEASE-p12)
    CVE Name: CVE-2021-29632

    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

    FreeBSD's system console is provided by the vt(4) virtual terminal console driver.

    II. Problem Description

    Under certain conditions involving use of the highlight buffer while
    text is scrolling on the console, console data may overwrite data
    structures associated with the system console or other kernel memory.

    III. Impact

    Users with access to the system console may be able to cause system misbehaviour.

    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,
    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 amd64, i386, or
    (on FreeBSD 13 and later) arm64 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.

    # fetch https://security.FreeBSD.org/patches/SA-22:01/vt.patch
    # fetch https://security.FreeBSD.org/patches/SA-22:01/vt.patch.asc
    # gpg --verify vt.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

    This issue is corrected by the corresponding Git commit hash or Subversion revision number in the following stable and release branches:

    Branch/path Hash Revision
    - ------------------------------------------------------------------------- stable/13/ 9352de39c3dc stable/13-n247428 releng/13.0/ 3e0a1e124169 releng/13.0-n244773 stable/12/ r370674 releng/12.2/ r371491
    - -------------------------------------------------------------------------

    For FreeBSD 13 and later:

    Run the following command to see which files were modified by a
    particular commit:

    # git show --stat <commit hash>

    Or visit the following URL, replacing NNNNNN with the hash:

    <URL:https://cgit.freebsd.org/src/commit/?id=NNNNNN>

    To determine the commit count in a working tree (for comparison against
    nNNNNNN in the table above), run:

    # git rev-list --count --first-parent HEAD

    For FreeBSD 12 and earlier:

    Run the following command to see which files were modified by a particular revision, replacing NNNNNN with the revision number:

    # 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-2021-29632>

    The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-22:01.vt.asc> -----BEGIN PGP SIGNATURE-----

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