Bug 1955695 (CVE-2021-3527)
| Summary: | CVE-2021-3527 QEMU: usb: unbounded stack allocation in usbredir | ||
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| Product: | [Other] Security Response | Reporter: | Mauro Matteo Cascella <mcascell> |
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
| Status: | CLOSED WONTFIX | QA Contact: | |
| Severity: | low | Docs Contact: | |
| Priority: | low | ||
| Version: | unspecified | CC: | berrange, cfergeau, dbecker, jen, jferlan, jforbes, jjoyce, jmaloy, jschluet, knoel, lhh, lpeer, m.a.young, mburns, mkenneth, mrezanin, mst, ondrejj, pbonzini, philmd, ribarry, rjones, sclewis, slinaber, virt-maint, virt-maint, yduan |
| 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 the USB redirector device (usb-redir) of QEMU. Small USB packets are combined into a single, large transfer request, to reduce the overhead and improve performance. The combined size of the bulk transfer is used to dynamically allocate a variable length array (VLA) on the stack without proper validation. Since the total size is not bounded, a malicious guest could use this flaw to influence the array length and cause the QEMU process to perform an excessive allocation on the stack, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2021-10-29 08:59:58 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: | 1956201, 1956221, 1956222, 1956223, 1956224, 1956225 | ||
| Bug Blocks: | 1949585, 1955699 | ||
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Description
Mauro Matteo Cascella
2021-04-30 16:52:07 UTC
Created qemu tracking bugs for this issue: Affects: fedora-all [bug 1956201] Statement: This issue affects the version of `qemu-kvm` as shipped with Red Hat Enterprise Linux 8 and Red Hat Enterprise Linux 8 Advanced Virtualization. A future update may address this flaw. Upstream patch series: https://lists.nongnu.org/archive/html/qemu-devel/2021-05/msg00564.html External References: https://www.openwall.com/lists/oss-security/2021/05/05/5 Acknowledgments: Name: Remy Noel (Blade Group) In reply to comment #5: > Upstream patch series: > https://lists.nongnu.org/archive/html/qemu-devel/2021-05/msg00564.html Note that the xhci patch was dropped [1] and a new USB patchset has been proposed without it [2]. As discussed upstream, this could leave room for unbound allocation on the heap, although more difficult to exploit by the guest to crash the QEMU process on the host. [1] https://lists.nongnu.org/archive/html/qemu-devel/2021-05/msg01372.html [2] https://lists.nongnu.org/archive/html/qemu-devel/2021-05/msg01373.html |