oss-security - Re: CVE-2021-20200: Linux kernel: close race between munmap() and expand

Follow @Openwall on Twitter for new release announcements and other news

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Wed, 10 Feb 2021 16:18:20 +0100
From: Alexandros Toptsoglou <atoptsoglou@...e.de>
To: oss-security@...ts.openwall.com, Rohit Keshri <rkeshri@...hat.com>
Subject: Re: CVE-2021-20200: Linux kernel: close race between
 munmap() and expand_upwards()/downwards()

Hi,

is the information listed here correct? Especially the CVE-2021-20200
assignment.

In project-zero reference at the last comment CVE-2020-29369 is mentioned.

Best regards,

Alexandros

On 2/10/21 4:04 PM, Rohit Keshri wrote:
> Hello Team,
> 
> A use-after-free flaw may be seen due to a race problem while in
> detach_vmas_to_be_unmapped() in mm/mmap.c in VMA access while
> munmap(). This flaw could allow a local attacker with a user privilege
> to crash the system, because VMA with VM_GROWSDOWN or VM_GROWSUP flag
> set may change their size under mmap_read_lock(). This vulnerability
> could even lead to a kernel information leak problem.
> 
> 
> 'CVE-2021-20200' was assigned by Red Hat.
> 
> References:
> https://bugs.chromium.org/p/project-zero/issues/detail?id=2056
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=246c320a8cfe0b11d81a4af38fa9985ef0cc9a4c
> 
> Thanks and Regards
> ..
> Rohit Keshri / Red Hat Product Security Team
> PGP: OX01BC 858A 07B7 15C8 EF33 BFE2 2EEB 0CBC 84A4 4C2D
> 
> secalert@...hat.com for urgent response
> 

-- 
Alexandros Toptsoglou <atoptsoglou@...e.de>
Security Engineer
OpenPGP fingerprint: C270 3848 AA4A 783A 9848  BB06 56A3 3D9C B652 1869

SUSE Software Solutions Germany GmbH
Maxfeldstr. 5
90409 Nuremberg
Germany
(HRB 36809, AG Nürnberg)
Managing Director: Felix Imendörffer



Download attachment "OpenPGP_signature" of type "application/pgp-signature" (841 bytes)

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.