From bippy-d3b290d2becc Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-47061: KVM: Destroy I/O bus devices on unregister failure _after_ sync'ing SRCU Description =========== In the Linux kernel, the following vulnerability has been resolved: KVM: Destroy I/O bus devices on unregister failure _after_ sync'ing SRCU If allocating a new instance of an I/O bus fails when unregistering a device, wait to destroy the device until after all readers are guaranteed to see the new null bus. Destroying devices before the bus is nullified could lead to use-after-free since readers expect the devices on their reference of the bus to remain valid. The Linux kernel CVE team has assigned CVE-2021-47061 to this issue. Affected and fixed versions =========================== Issue introduced in 5.9 with commit f65886606c2d and fixed in 5.10.37 with commit 03c6cccedd39 Issue introduced in 5.9 with commit f65886606c2d and fixed in 5.11.21 with commit 4e899ca84863 Issue introduced in 5.9 with commit f65886606c2d and fixed in 5.12.4 with commit 30f46c699373 Issue introduced in 5.9 with commit f65886606c2d and fixed in 5.13 with commit 2ee3757424be Issue introduced in 4.4.238 with commit f0dfffce3f4f Issue introduced in 4.9.238 with commit 840e124f89a5 Issue introduced in 4.14.200 with commit 40a023f681be Issue introduced in 4.19.148 with commit 19184bd06f48 Issue introduced in 5.4.66 with commit 41b2ea7a6a11 Issue introduced in 5.8.10 with commit 68c125324b5e Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2021-47061 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: virt/kvm/kvm_main.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/03c6cccedd3913006744faa252a4da5145299343 https://git.kernel.org/stable/c/4e899ca848636b37e9ac124bc1723862a7d7d927 https://git.kernel.org/stable/c/30f46c6993731efb2a690c9197c0fd9ed425da2d https://git.kernel.org/stable/c/2ee3757424be7c1cd1d0bbfa6db29a7edd82a250