-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-EN-24:03.kqueue Errata Notice The FreeBSD Project
Topic: kqueue_close(2) page fault on exit using rfork(2) Category: core Module: kqueue Announced: 2024-02-14 Affects: All supported versions of FreeBSD. Corrected: 2023-12-05 00:43:27 UTC (stable/14, 14.0-STABLE) 2024-02-14 06:05:42 UTC (releng/14.0, 14.0-RELEASE-p5) 2023-12-05 00:44:13 UTC (stable/13, 13.2-STABLE) 2024-02-14 06:05:58 UTC (releng/13.2, 13.2-RELEASE-p10) For general information regarding FreeBSD Errata Notices and Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>. I. Background The kqueue(2) system call provides a generic method of notifying the user when an event happens or a condition holds. II. Problem Description Normally, when a process exits, all its kqueue fds will be destroyed at the moment p_klist is detached. However, if the process was created with rfork(2) with shared file descriptors, its signal knotes can survive. This can eventually result in a page fault when the process exits. III. Impact Using kqueue(2) with a process using rfork(2) can panic the system. IV. Workaround No workaround is available. V. Solution Upgrade your system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and reboot the system. Perform one of the following: 1) To update your system via a binary patch: Systems running a RELEASE version of FreeBSD on the amd64 or arm64 platforms, or the i386 platform on FreeBSD 13, can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install Reboot the system. 2) To update your 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/EN-24:03/kqueue.patch # fetch https://security.FreeBSD.org/patches/EN-24:03/kqueue.patch.asc # gpg --verify kqueue.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 as of the corresponding Git commit hash in the following stable and release branches: Branch/path Hash Revision - ------------------------------------------------------------------------- stable/14/ 24346a2f7775 stable/14-n265907 releng/14.0/ bb06104dce0b releng/14.0-n265404 stable/13/ 55e91944998c stable/13-n256837 releng/13.2/ 154dedade465 releng/13.2-n254656 - ------------------------------------------------------------------------- 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 VII. References <URL:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=275286> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-24:03.kqueue.asc> -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEthUnfoEIffdcgYM7bljekB8AGu8FAmXMYQwACgkQbljekB8A Gu+GSxAA5voCfr4a2LrMmBjQvgD7XwpCNH9yvYN3chKG07TTqNWkHbCxNvc4Brzm IXKGxvolrY3PZhXgN2KZhe/wAOf0I1ZazeW9wdk13O9G2SF5aaUYBkCvoMmPME42 f7lVXnkxhTQAovVFQRZAK6sYCVspIPQEpavoa7rq5dDDtO9g2AqB53aAbgdBpQ0j ClIcMzM2HdiYQBi4WuL36XVbeX6N++N5ouE8Hdz+pDcQSHuOm3VHUKlpRsEXLmYI 3uDJ8py+PGbtcLnSVALEcnreirJcCJ5em7Gaec2KXHDRis/dLW+DPlPyZp1mpIBZ l073AME8hEOxnJOUALvxTVHQS3L35JjFmxnSGwnLzXH16v/fGUKlnAZkOftNcRan JW1fLXB2EH+H+hdnOWiQeTCk8duIIvXuWEYf8dfP6SBMm9FfzBAoTv/K1mHxGFKZ s3iR4WyC7Y6r56meVdNfs/F4XtVh3edhVfOdjf/5I8+Ut9HGRNuHOCepLG9DASOd eQbhHAnHnUB21qq4Tme0eKoA130gVcBMr2NsE0lifNArLzEvvGB0Bw+9ZP9IfFeS /fPs4Yq1XIjpgk+TDdOPGexLWCIBl0ursjZMSuGyhXkDaD1oYzF3SKWrJRkahpUq +tN6jVPkG7Iy36myKSHofuPh641hSmk88IJPJHVrdNjo88hUti0= =xsIs -----END PGP SIGNATURE-----