Bug 1548412 (CVE-2017-13166)
| Summary: | CVE-2017-13166 kernel: v4l2: disabled memory access protection mechanism allowing privilege escalation | ||
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| Product: | [Other] Security Response | Reporter: | Vladis Dronov <vdronov> |
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
| Status: | CLOSED ERRATA | QA Contact: | |
| Severity: | high | Docs Contact: | |
| Priority: | high | ||
| Version: | unspecified | CC: | airlied, ajax, bskeggs, ewk, hdegoede, ichavero, itamar, jarodwilson, jforbes, jglisse, john.j5live, jonathan, josef, jwboyer, kernel-maint, labbott, linville, mchehab, mjg59, steved |
| 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 bug in the 32-bit compatibility layer of the ioctl handling code of the v4l2 video driver in the Linux kernel has been found. A memory protection mechanism ensuring that user-provided buffers always point to a userspace memory were disabled, allowing destination address to be in a kernel space. This flaw could be exploited by an attacker to overwrite a kernel memory from an unprivileged userspace process, leading to privilege escalation.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2019-06-08 03:41:04 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: | 1548413, 1548429, 1548430, 1548431, 1548432, 1548726, 1548727, 1548728, 1550058, 1550059, 1550060 | ||
| Bug Blocks: | 1548415 | ||
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Description
Vladis Dronov
2018-02-23 12:43:00 UTC
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1548413] details of the flaw impact per upstream commit a1dfb4c48cc1: ...As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. This was fixed for Fedora with the 4.15.4 stable updates. Mitigation: A systemtap script intercepting v4l2_compat_ioctl32() function of the [videodev] module and making it to return -ENOIOCTLCMD error value would work just fine, except breaking all 32bit video capturing software, but not 64bit ones. Alternatively, blacklisting [videodev] module will work too, but it will break all video capturing software. This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:0676 https://access.redhat.com/errata/RHSA-2018:0676 This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:1062 https://access.redhat.com/errata/RHSA-2018:1062 This issue has been addressed in the following products: Red Hat Enterprise MRG 2 Via RHSA-2018:1170 https://access.redhat.com/errata/RHSA-2018:1170 This issue has been addressed in the following products: Red Hat Enterprise Linux 7.4 Extended Update Support Via RHSA-2018:1130 https://access.redhat.com/errata/RHSA-2018:1130 This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Via RHSA-2018:1319 https://access.redhat.com/errata/RHSA-2018:1319 This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2018:2948 https://access.redhat.com/errata/RHSA-2018:2948 |