FreeBSD Errata Notice FreeBSD-EN-23:15.sanitizer
1 December, 2023 by errata-notices@freebsd.org | freebsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-EN-23:15.sanitizer Errata Notice The FreeBSD Project Topic: Clang sanitizer failure with ASLR enabled Category: contrib Module: compiler-rt Announced: 2023-12-01 Affects: FreeBSD 14.0 Corrected: 2023-11-25 09:05:09 UTC (stable/14, 14.0-STABLE) 2023-12-01 00:38:35 UTC (releng/14.0, 14.0-RELEASE-p1) 2023-11-25 09:05:14 UTC (stable/13, 13.2-STABLE) 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 Compiler-RT is an implementation of various compiler runtime support routines, provided by the LLVM project. This library also provides a number of so-called Sanitizers, which help to catch buffer overruns, thread data races, and so on: AddressSanitizer, ThreadSanitizer, UndefinedBehaviorSanitizer, and more. II. Problem Description Some of the Sanitizers cannot work correctly when ASLR is enabled. Therefore, at the initialization of such Sanitizers, ASLR is detected via procctl(2). If ASLR is enabled, it is first disabled, and then the main executable containing the Sanitizer is re-executed, after printing an appropriate message. However, the Sanitizers work by intercepting various function calls, and by mistake the already-intercepted procctl(2) function was used. This causes an internal error, which usually results in a segfault. III. Impact Binaries linked to AddressSanitizer (using -fsanitizedress), MemorySanitizer (using -fsanitize=memory) or ThreadSanitizer (using -fsanitize=thread) can crash at startup with a segfault, if ASLR is enabled. Other binaries are not affected. IV. Workaround If ASLR is enabled system-wide, the problem can be worked around by running the specific binary with proccontrol(1), to temporarily disable ASLR for only that program. For example: proccontrol -m aslr -s disable /path/to/example_program V. Solution Upgrade your system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. No reboot is necessary, but Sanitized binaries must be re-linked, because the Sanitizer libraries are statically linked in. 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 and earlier, can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install No reboot is necessary, but Sanitized binaries must be re-linked, because the Sanitizer libraries are statically linked in. 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-23:15/sanitizer.patch # fetch https://security.FreeBSD.org/patches/EN-23:15/sanitizer.patch.asc # gpg --verify sanitizer.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile the operating system using buildworld and installworld as described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>. VI. Correction details This issue is corrected as of the corresponding Git commit hash or Subversion revision number in the following stable and release branches: Branch/path Hash Revision - ------------------------------------------------------------------------- stable/14/ 1e4798e9677f stable/14-n265803 releng/14.0/ 78b4c762b20b releng/14.0-n265381 stable/13/ 7c25a53a2cb9 stable/13-n256726 - ------------------------------------------------------------------------- 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'5270> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-23:15.sanitizer.asc> -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEthUnfoEIffdcgYM7bljekB8AGu8FAmVpPoYACgkQbljekB8A Gu+z2A//VhWVguaPhfTkV0jRrG/tD1iu+xhM7TSRcnnGYn7IIkzWzHkO5jrP9Oy5 aRueyAVvw048f4unEG36qBM+UO5LSCcDEj3OAhxhJzfTfXcRBYMRuvp5cC+Xjgji s6S7JlSTeHqJakj6UV58d4elppj5QN1b2IQtwahcwuBtlue4NaOg16z6GFDDbVKo Db8h+yOyQuwGj7uvahpuHpNB21pMfTwi4IWV2F9QOjQMO/+pcqia+leG53WOsB/A SFW3zNHdAl+Q7NBq6lRVTqyW69Ouh1gblQ57kMCdzyTF5BSzcDhX5QwiS9t2TIU9 gs2ulNxxIiSPmi7n/ZlDPRyH57C/+h6vSHVeXOVKZhIffrqvpqqhT0WKQfIUnNLb 0uhdmXLdXWWAAk1OvDkBAIiO6C8GxVvgZvHWFhELjnDK6+qmZD7xv3RVpJnRVk9X //U89b+zGNKhS+JFiTvXY90oUxoE72a9PuqvONZuKMGH+ooL9aRGEJujahCL2Swl jxymcZHduvsXbnzrmGZr8Lxl4DP+cHD688gc8KOgitb3MCupcx066KmX1Pem7PvX 2AULZrFBDTPEIgf0ZuGt5R3+zd+k/sDlPVGdkLpF1AVOOuwtfton6Vbd5CKDzDLR 0PqGdkk9CLpI0Mm8I1o+v69bopYua1ndo3G2YuKIK7V472sgrRw=EPbY -----END PGP SIGNATURE-----