Bug 1903262 (CVE-2020-29369) - CVE-2020-29369 kernel: race condition between expand_downwards and expand_upwards and page-table free operations from an munmap call
Summary: CVE-2020-29369 kernel: race condition between expand_downwards and expand_upw...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2020-29369
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1903263 1903473 1903474 1903475 1903476 1903477 1903478 1903479 1903480 1903481 1903482 1903484 1903485 1903486 1903487 1903488 1903489 1903490 1903491 1903492 1903493 1903494 1903495
Blocks: 1903264
TreeView+ depends on / blocked
 
Reported: 2020-12-01 17:39 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-02-16 18:48 UTC (History)
54 users (show)

Fixed In Version:
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Doc Text:
A flaw was found in the Linux kernel. A race condition between certain expand functions and page-table free operations from an munmap call leading to ... FIXME. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Clone Of:
Environment:
Last Closed: 2020-12-07 15:36:09 UTC
Embargoed:

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Description Guilherme de Almeida Suckevicz 2020-12-01 17:39:43 UTC 
An issue was discovered in mm/mmap.c in the Linux kernel before 5.7.11. There is a race condition between certain expand functions (expand_downwards and expand_upwards) and page-table free operations from an munmap call.

Reference:
https://bugs.chromium.org/p/project-zero/issues/detail?id=2056

Upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=246c320a8cfe0b11d81a4af38fa9985ef0cc9a4c
Comment 1 Guilherme de Almeida Suckevicz 2020-12-01 17:40:32 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1903263]
Comment 6 Wade Mealing 2020-12-02 08:15:40 UTC 
Mitigation:


There is no mitigation available at this time.  Red Hat is investigating a kpatch as an option to fix this issue on kpatch supported streams.
Comment 8 Justin M. Forbes 2020-12-02 14:20:28 UTC 
This was fixed for Fedora with the 5.7.11 stable kernel updates.
Comment 15 Wade Mealing 2020-12-03 03:35:12 UTC 
Removing needinfo as I think most of them are no longer relevant.
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