|Summary:||CVE-2021-28038 xen: netback fails to honor grant mapping errors (XSA-367)|
|Product:||[Other] Security Response||Reporter:||Pedro Sampaio <psampaio>|
|Component:||vulnerability||Assignee:||Red Hat Product Security <security-response-team>|
|Status:||CLOSED UPSTREAM||QA Contact:|
|Version:||unspecified||CC:||jforbes, m.a.young, robinlee.sysu|
|Fixed In Version:||Doc Type:||If docs needed, set a value|
|Doc Text:||Story Points:||---|
|Last Closed:||2021-03-08 19:01:54 UTC||Type:||---|
|oVirt Team:||---||RHEL 7.3 requirements from Atomic Host:|
|Cloudforms Team:||---||Target Upstream Version:|
|Bug Depends On:||1936567|
Description Pedro Sampaio 2021-03-08 18:23:18 UTC
Xen Security Advisory CVE-2021-28038 / XSA-367 version 2 Linux: netback fails to honor grant mapping errors UPDATES IN VERSION 2 ==================== CVE assigned. ISSUE DESCRIPTION ================= XSA-362 tried to address issues here, but in the case of the netback driver the changes were insufficient: It left the relevant function invocation with, effectively, no error handling at all. As a result, memory allocation failures there could still lead to frontend-induced crashes of the backend. IMPACT ====== A malicious or buggy networking frontend driver may be able to crash the corresponding backend driver, potentially affecting the entire domain running the backend driver. In a typical (non-disaggregated) system that is a host-wide denial of service (DoS). VULNERABLE SYSTEMS ================== Linux versions from at least 2.6.39 onwards are vulnerable, when run in PV mode. Earlier versions differ significantly in behavior and may therefore instead surface other issues under the same conditions. Linux run in HVM / PVH modes is not vulnerable. MITIGATION ========== For Linux, running the backends in HVM or PVH domains will avoid the vulnerability. For example, by running the dom0 in PVH mode. In all other cases there is no known mitigation. RESOLUTION ========== Applying the attached patch resolves this issue. xsa367-linux.patch Linux 5.12-rc $ sha256sum xsa367* b0244bfddee91cd7986172893e70664b74e698c5d44f25865870f179f80f9a92 xsa367-linux.patch $ CREDITS ======= This issue was reported by Intel's kernel test robot and recognized as a security issue by Jan Beulich of SUSE. NOTE REGARDING LACK OF EMBARGO ============================== This issue was reported publicly, before the XSA could be issued.
Comment 1 Pedro Sampaio 2021-03-08 18:25:33 UTC
Created xen tracking bugs for this issue: Affects: fedora-all [bug 1936567]
Comment 2 Product Security DevOps Team 2021-03-08 19:01:54 UTC
This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.
Comment 3 Justin M. Forbes 2021-03-09 17:02:29 UTC
This was fixed for Fedora with the 5.10.21 stable kernel update.