CVE-2022-42310

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Xen Security Advisory CVE-2022-42310 / XSA-415 version 2 Xenstore: Guests can create orphaned Xenstore nodes UPDATES IN VERSION 2 ==================== Public release. ISSUE DESCRIPTION ================= By creating multiple nodes inside a transaction resulting in an error, a malicious guest can create orphaned nodes in the Xenstore data base, as the cleanup after the error will not remove all nodes already created. When the transaction is committed after this situation, nodes without a valid parent can be made permanent in the data base. IMPACT ====== A malicious guest can cause inconsistencies in the xenstored data base, resulting in unusual error responses or memory leaks in xenstored. This can finally cause Denial of Service situations or long running error recoveries of xenstored. VULNERABLE SYSTEMS ================== Systems with Xen version 4.9 and newer running the C variant of Xenstore (xenstored or xenstore-stubdom) are vulnerable. Systems using the Ocaml variant of Xenstore (oxenstored) are not vulnerable. MITIGATION ========== Using oxenstored will avoid the vulnerability. CREDITS ======= This issue was discovered by Julien Grall of Amazon. RESOLUTION ========== Applying the appropriate attached patch resolves this issue. Note that patches for released versions are generally prepared to apply to the stable branches, and may not apply cleanly to the most recent release tarball. Downstreams are encouraged to update to the tip of the stable branch before applying these patches. xsa415.patch xen-unstable, Xen 4.16.x xsa415-4.15.patch Xen 4.15.x xsa415-4.14.patch Xen 4.14.x - 4.13.x $ sha256sum xsa415* ff973fd3d0af2b45ba46ba74410204a60fcba30b0d0830c591dc827eac9ae484 xsa415.meta bc5b33bbef18c0fb15d6da6760ece9ef7f6f2cfab78664aee533ff717b379e3b xsa415.patch 243e7e35ba94973252a6381977af2cf70774abfd0bfd5d0015179b94c832453e xsa415-4.14.patch 7b18b510b811551025cd2a86d654ee776b5003172ab468e7e86a0c6d892f4629 xsa415-4.15.patch $ DEPLOYMENT DURING EMBARGO ========================= Deployment of the patches and/or mitigations described above (or others which are substantially similar) is permitted during the embargo, even on public-facing systems with untrusted guest users and administrators. But: Distribution of updated software is prohibited (except to other members of the predisclosure list). Predisclosure list members who wish to deploy significantly different patches and/or mitigations, please contact the Xen Project Security Team. (Note: this during-embargo deployment notice is retained in post-embargo publicly released Xen Project advisories, even though it is then no longer applicable. This is to enable the community to have oversight of the Xen Project Security Team’s decisionmaking.) For more information about permissible uses of embargoed information, consult the Xen Project community’s agreed Security Policy: http://www.xenproject.org/security-policy.html -----BEGIN PGP SIGNATURE----- iQFABAEBCAAqFiEEI+MiLBRfRHX6gGCng/4UyVfoK9kFAmNg+6IMHHBncEB4ZW4u b3JnAAoJEIP+FMlX6CvZm88H/inrzV4zw8Po/g59rq1hUrCE/L4KwAemf5ZmWMK8 Unka74TyN2j47wous4EbBstzQQtOvf7GP2OT68qpIlqaZSAGcu+7x6TPx3M8q8kM ZFzqcDYvNye8KrUCNp9pVJIV2Y8b3JLAZXCvxxGK++yECGMjTh5ZkxzdiNK/t9NO +TmhH7CHFzkiO25Ch/8+vlwMs6eH/rKFLUVbEU/ZiD9L/P84xQr1EORhAhDJorx1 SLyprG0BlaCUIA/YbQVEftqHiG0J6ikuBYJGBHyQGVEV/MqSXGCUB/Eee6nzH4fH 1USXmeQ27OMsKwOJXyxFvrCgmKdeTNDcx0KSzSPFrED9rSc= =hu/k -----END PGP SIGNATURE-----