Bug 1851474 (CVE-2020-15566)
| Summary: | CVE-2020-15566 xen: incorrect error handling in event channel port allocation leads to DoS (XSA-317) | ||
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| Product: | [Other] Security Response | Reporter: | Dhananjay Arunesh <darunesh> |
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
| Status: | CLOSED NOTABUG | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | acaringi, ailan, bhu, bmasney, brdeoliv, dhoward, drjones, dvlasenk, fhrbata, hkrzesin, imammedo, jforbes, jshortt, jstancek, knoel, m.a.young, mrezanin, nmurray, pbonzini, ptalbert, robinlee.sysu, rvrbovsk, security-response-team, vkuznets, xen-maint |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: |
A flaw was found in Xen in the allocation of an event channel port. Under certain circumstances, a malicious guest user might be able to crash the host, resulting in a Denial of Service (DoS) condition.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2020-07-07 19:30:02 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1854465 | ||
| Bug Blocks: | 1851487 | ||
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Description
Dhananjay Arunesh
2020-06-26 16:37:39 UTC
Acknowledgments: Name: the Xen project Statement: Only Xen versions 4.10 and later are affected by this flaw. The default configuration, when guests are created with xl/libxl, is not vulnerable, because of the default event channel limit (see Mitigation). Mitigation: The issue can be avoided by reducing the number of event channels available to the guest to no more than 1023. For example, setting `max_event_channels=1023` in the xl domain configuration, or deleting any existing setting (since 1023 is the default for xl/libxl). For ARM systems, any limit no more than 4095 is safe. For 64-bit x86 PV guests, any limit no more than 4095 is likewise safe if the host configuration prevents the guest administrator from substituting and running a 32-bit kernel (and thereby putting the guest into 32-bit PV mode). External References: https://xenbits.xen.org/xsa/advisory-317.html Created xen tracking bugs for this issue: Affects: fedora-all [bug 1854465] This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2020-15566 |