FreeBSD Errata Notice FreeBSD-EN-23:17.ossl
5 December, 2023 by errata-notices@freebsd.org | freebsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-EN-23:17.ossl Errata Notice The FreeBSD Project Topic: ossl(4)'s AES-GCM implementation may give incorrect results Category: core Module: ossl Announced: 2023-12-05 Affects: FreeBSD 14.0 Corrected: 2023-12-03 17:48:09 UTC (stable/14, 14.0-STABLE) 2023-12-05 18:27:34 UTC (releng/14.0, 14.0-RELEASE-p2) 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 ossl(4) is a kernel module which implements some cryptographic operations using implementations derived from OpenSSL. It integrated into the FreeBSD kernel's OpenCrypto Framework (OCF). II. Problem Description ossl(4) contains an implementation of AES-GCM for amd64. This implementation did not properly implement some aspects of the OCF interface. In particular, ossl(4) AES-GCM sessions were not thread-safe, and did not handle an AAD buffer outside of the main plaintext/ciphertext buffer. The former bug affects consumers which dispatch multiple requests in parallel on a single session, such as ZFS when encrypted datasets are configured. External AAD buffers are used by some network features such as ktls(4). III. Impact On amd64 systems, ossl(4) could give incorrect output for AES-GCM operations if consumers trigger either of the bugs described above. This could, for example, result in packet loss, if ossl is used to encrypt/decrypt tunnelled traffic, or data corruption if ossl is used to encrypt/decrypt filesystem data. Users are not affected by default, as ossl.ko is not loaded by default. To be affected, a system must either be running a custom kernel which contains ossl(4), or be configured to load ossl.ko via loader.conf(5). IV. Workaround Disable the use of ossl(4), either by removing it from loader.conf or the kernel configuration, and reboot the system. The built-in aesni(4) module currently implements all of the same operations as ossl, so consumers will not notice any functional difference. V. Solution Upgrade your system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. A reboot is required following the upgrade. 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 platfrom on FreeBSD 13 and earlier, can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install # shutdown -r now 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-23:17/ossl.patch # fetch https://security.FreeBSD.org/patches/EN-23:17/ossl.patch.asc # gpg --verify ossl.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 or Subversion revision number in the following stable and release branches: Branch/path Hash Revision - ------------------------------------------------------------------------- stable/14/ 118b866d9c39 stable/14-n265898 releng/14.0/ 433fe061fc59 releng/14.0-n265388 - ------------------------------------------------------------------------- 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'5306> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-23:17.ossl.asc> -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEthUnfoEIffdcgYM7bljekB8AGu8FAmVvmVoACgkQbljekB8A Gu/dvQ/+KCck7lbRZYax4QZ7JxLpbutOWDITGFVMtELT7njcMMpIH6TIKLwTDpcR XPz/znROLquDkTpke6uf0IZyC1nMHxaYwgiTImpA0ecd3Z5n6hNj2EEhOhlitDfc N+UNhpQa8689CYkcm4ofgb2MQdzc/0HDTX+6tUpLuwuLhqGxyJK5bgQo63MK2osb qlj5TntXjVIbd33dN97JZfV9JDSapS2xLBFShe0R9+do0ucvDVOiPErHvKsLSm9P iYxrezxw3X6fi1BbLVe7u3B3ELeNgKnreh7CakDn/UF3hhn138d4XQ2+3ppRaadG 81kbzMtHQHOKTRzVBrdi2sd7wDOgTapGmeeSr/87GYCOU2ZfXpZjr5k4tuD/RUOB 44ZxeWnaNKWa4C8xr1ESr3pebTF1la2tqNQwiG/9euUn3Kl/NZFRCzaruiEmaLaG DeOAu3VZCucHPowA3rr80J6XPx/295Bq/bN6J5/Qd+TzKjzbqzvelXXHsn5AMjur tPUtG5iCLQZvivM5Wd4jaOVrZvp0ps7qlugNnOZPr/qBcW04YdwCamzwUipIDNnP XrxmxJdhFJhy//hnTNgJiKS6LJP5lh2ogAN6tRnvKKZrb11OAcHPIUqIyI51Bieh w4Yqrq2cOxMDgi7jKlSi2DLWs56WWEDob8cHhRhKhI6Fre2Yizs=Vn8m -----END PGP SIGNATURE-----