-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-22:05.bhyve Security Advisory The FreeBSD Project Topic: Bhyve e82545 device emulation out-of-bounds write Category: core Module: bhyve Announced: 2022-04-06 Credits: Mehdi Talbi, Synacktiv Affects: All supported versions of FreeBSD. Corrected: 2022-04-05 22:59:52 UTC (stable/13, 13.1-STABLE) 2022-04-06 01:56:57 UTC (releng/13.1, 13.1-RC1-p1) 2022-04-06 03:04:14 UTC (releng/13.0, 13.0-RELEASE-p11) 2022-04-05 23:03:35 UTC (stable/12, 12.3-STABLE) 2022-04-06 03:06:28 UTC (releng/12.3, 12.3-RELEASE-p5) CVE Name: CVE-2022-23087 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background bhyve(8) is a hypervisor that supports running a variety of guest operating systems in virtual machines. It implements a number of device models, including an emulated Intel 82545 network interface adapter. II. Problem Description The e1000 network adapters permit a variety of modifications to an Ethernet packet when it is being transmitted. These include the insertion of IP and TCP checksums, insertion of an Ethernet VLAN header, and TCP segmentation offload ("TSO"). The e1000 device model uses an on-stack buffer to generate the modified packet header when simulating these modifications on transmitted packets. When checksum offload is requested for a transmitted packet, the e1000 device model used a guest-provided value to specify the checksum offset in the on- stack buffer. The offset was not validated for certain packet types. III. Impact A misbehaving bhyve guest could overwrite memory in the bhyve process on the host, possibly leading to code execution in the host context. The bhyve process runs in a Capsicum sandbox, which (depending on the FreeBSD version and bhyve configuration) limits the impact of exploiting this issue. IV. Workaround Only the e1000 device model is affected; the virtio-net device is not affected by this issue. If supported by the guest operating system, presenting only the virtio-net device to the guest is a suitable workaround. No workaround is available if the e1000 device model is required. V. Solution Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and restart bhyve virtual machines. 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 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install 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-22:05/bhyve.patch # fetch https://security.FreeBSD.org/patches/SA-22:05/bhyve.patch.asc # gpg --verify bhyve.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 . Restart the applicable bhyve virtual machines, or 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/ 53f722094798 stable/13-n250272 releng/13.1/ 5a28d8befda0 releng/13.1-n250078 releng/13.0/ b85c68857da3 releng/13.0-n244795 stable/12/ r371867 releng/12.3/ r371871 - ------------------------------------------------------------------------- For FreeBSD 13 and later: Run the following command to see which files were modified by a particular commit: # git show --stat Or visit the following URL, replacing NNNNNN with the hash: 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: VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAmJNDgYACgkQ05eS9J6n 5cJERBAAoqZXVIwucgIMLepm3hQdmYsuYGDhfp12ggOR8GO/a9oL9c21u5JSSNUq w966VU8u2Tv3JjKhNpXWSR9hbUSTuEWarkcrutNDe69GwcWv0Q8DU3DwhfrT6e9K +IO/yMNUUBL9LlWRW4XftiowNV2r9KvqzYsGbk8Wi+bN1Vd9gXo1r31Nu3Y3JBls EOjk8aoDuCCUqZKVjKw7VNXDjAo3MKnnt7s6nRLSJRvJH7iDGxttWGbAiREqLO07 Aqg0ZUbbtUs8PvOL38yj/eiC4tLdOGna+Nm7VNoiS+Ee2uL/tbGU079UCgqgSJ7k /0U8nrDss8NRirsFEbpYiNFs2zi+6dtRKjAzMGKxMU6TTnHodzfLBGsrOws5TmlS bblLVykXBT1egNT180gCNjBRdK2mYaF23wVEPbd8bg0+JPfG5MyylG137uJJw2B0 24RZpY3ciRCUw6xn9mRk//SOQh4fvtLSdNPfGtoYtHmzhao8wvWBqPw7SvkMkUP4 hsdNeutyIZjqTCDvtUD4Ge81BPLnW8fUkd7yNLbWFLGBqZGlCs/xBdmTqCS/XLF7 y9cPEsS7wb1sZS087uULgUrEDFPCnktozZ1ycCwoqCZy7dt6/zYFrYH1xu3AN+Ji hso4aoM18gVNadHfMRqHNClBDO0iaxuXPrg+SMqffOrdQCznQ3k= =CgB+ -----END PGP SIGNATURE-----