Bug 1356471 (CVE-2016-6213)
| Summary: | CVE-2016-6213 kernel: Overflowing kernel mount table using shared bind mount | ||
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| Product: | [Other] Security Response | Reporter: | Adam Mariš <amaris> |
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
| Status: | CLOSED ERRATA | QA Contact: | |
| Severity: | low | Docs Contact: | |
| Priority: | low | ||
| Version: | unspecified | CC: | aquini, arm-mgr, avagin, bhu, carnil, dhoward, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, kolyshkin, kstutsma, labbott, lgoncalv, madhu.chinakonda, matt, mchehab, mcressma, nmurray, plougher, qcai, rt-maint, rvrbovsk, slawomir, vdronov, williams |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: |
It was found that in Linux kernel the mount table expands by a power-of-two with each bind mount command. If a system is configured to allow non-privileged user to do bind mounts, or allows to do so in a container or unprivileged mount namespace, then non-privileged user is able to cause a local DoS by overflowing the mount table, which causes a deadlock for the whole system.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2019-06-08 02:56:15 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: | 1322495, 1356472 | ||
| Bug Blocks: | 1332565, 1356474 | ||
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Description
Adam Mariš
2016-07-14 08:09:18 UTC
Acknowledgments: Name: Qian Cai (Red Hat) Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1356472] It seems there is some debate on whether the CVE is actually something the kernel needs to fix. I'll hold off a bit on this one. Another reproducer using Docker: http://seclists.org/oss-sec/2016/q3/65 Another reproducer which doesn't use Docker, but it needs user namespaces to be enabled: http://seclists.org/oss-sec/2016/q3/75 I've reported this problem two years ago https://lkml.org/lkml/2013/6/20/709 (In reply to Andrew Vagin from comment #6) > I've reported this problem two years ago > https://lkml.org/lkml/2013/6/20/709 It's actually three years ago. Statement: This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and MRG-2 as of now due to the absence of unprivileged mount name spaces support. Nevertheless, the unprivileged mount name spaces might be added to a future RHEL-7 version as a supported feature, so future Linux kernel updates for the respective releases might address this issue. This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2017:2077 https://access.redhat.com/errata/RHSA-2017:2077 This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2017:1842 https://access.redhat.com/errata/RHSA-2017:1842 |