-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= 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----- iQIzBAEBCgAdFiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAmHd1f4ACgkQ05eS9J6n 5cIgEBAAkXpnKSElsT96dj4RYWJLkqB4+OBkGoOGrsZj8zd5Ei85oohhL38xiYAE jQpSwblgYCqmOxRL4hGgKN6fBPMnc/zXCdZhJzAfgkKXsn4eY5mObN1jus7owsmC RnFNOLSr1VVJZs8H1RAeAjJT2I6DF0oLb/f1u3ik+bPFJ8Y4hvPEliSH7rpzVBq7 hpmiH1HxAArVwtJ15N+7u6vNUce57dWSh4NzPHLduzMRpatPKVqtkC7UJIvqisxl bQTK46MYo454SgbZjRPistwnV9NFKjuKy5Rh38/FURbnBxg8w2HVkabidMy5lJyU geSOvV4wc2LraRdSvJHZlNXu1BJKnPpTpsl6XNr8ePzAl9rRPjZKo8cEBMmTlqK0 KdMeKsf1OfspA/8L6mCpg4NDeOoHktCrICWTi4/E6nGX/e1hZrCXKcxf0KYbhcfO xNvrYtKkCtCbEnbzZbW6rjY/RAmRwwMNngVw2FWRuSWU6BCmfKZndUXFO7aghj6Q JKISfctwtcHWn/QzI2BN9pNWZlzAJ8BfxR+/bV6VJNuRILOhrvgjnUzpies1xv7z GRN9JlpxzqihhlX8JED7jDOm99YflEG0Ep7Cr1OYXLDVx1xxh8dQLCOwl5qjnKgd ELae8IKnUn5pI1Og44AsjY9xWOvxxz28luwFxsbYf+3UMo6M4eE= =hcWy -----END PGP SIGNATURE-----