Bug 1817141 (CVE-2020-10690) - CVE-2020-10690 kernel: use-after-free in cdev_put() when a PTP device is removed while it's chardev is open
Summary: CVE-2020-10690 kernel: use-after-free in cdev_put() when a PTP device is remo...
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2020-10690
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1774657 1787568 1798395 1817354 1817355 1817356 1817357 1817358 1826223 1888688
Blocks: 1811167
TreeView+ depends on / blocked
 
Reported: 2020-03-25 16:45 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-02-16 20:23 UTC (History)
48 users (show)

Fixed In Version: kernel 5.5
Doc Type: If docs needed, set a value
Doc Text:
There is a use-after-free problem seen due to a race condition between the release of ptp_clock and cdev while resource deallocation. When a (high privileged) process allocates a ptp device file (like /dev/ptpX) and voluntarily goes to sleep. During this time if the underlying device is removed, it can cause an exploitable condition as the process wakes up to terminate and clean all attached files. The system crashes due to the cdev structure being invalid (as already freed) which is pointed to by the inode.
Clone Of:
Environment:
Last Closed: 2020-09-29 22:00:24 UTC
Embargoed:

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Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2020:4416 0 None None None 2020-10-29 15:10:21 UTC
Red Hat Product Errata RHBA-2020:4417 0 None None None 2020-10-29 15:08:50 UTC
Red Hat Product Errata RHBA-2020:4418 0 None None None 2020-10-29 15:14:14 UTC
Red Hat Product Errata RHBA-2020:4419 0 None None None 2020-10-29 15:12:40 UTC
Red Hat Product Errata RHBA-2020:4420 0 None None None 2020-10-29 15:51:34 UTC
Red Hat Product Errata RHSA-2020:4060 0 None None None 2020-09-29 20:53:36 UTC
Red Hat Product Errata RHSA-2020:4062 0 None None None 2020-09-29 18:59:29 UTC

Description Guilherme de Almeida Suckevicz 2020-03-25 16:45:25 UTC 
There was a use-after-free problem seen due to a race condition between the release of ptp_clock and cdev at the time of resource deallocation.

When a (high privileged) process allocates a ptp device file (like /dev/ptpX) and voluntarily goes to sleep. During this time if the underlying device is removed (a potential privilege escalation) by the user with administrator privilege, it can cause a denial of service (DoS) problem as the process wakes up to terminate and cleanup all attached files/resources. 

The system crashes due to the cdev structure being invalid (as already freed) which is pointed to by the inode.

Refer:
https://lore.kernel.org/linux-fsdevel/20191125125342.6189-1-vdronov@redhat.com/T/#u
Comment 5 Rohit Keshri 2020-03-26 08:38:39 UTC 
Mitigation:

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Comment 11 Rohit Keshri 2020-04-21 09:21:38 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1826223]
Comment 14 Petr Matousek 2020-04-21 13:18:42 UTC 
Statement:

This issue is rated as having Low impact as there is a need for high privilege access to trigger this problem. This will need an access to /dev/ptpX which is privileged operation, also removing the module is needed (again, privileged operation).
Comment 15 Hangbin Liu 2020-04-24 02:59:13 UTC 
Hi Rohit,

It looks RHEL7 has fixed this issue in bug 1774657. RHEL8 has fixed it in bug 1787568.
Should we close the RHEL7/8's CVE tracker bug 1817354, bug 1817355?

Thanks
Hangbin
Comment 18 Justin M. Forbes 2020-05-13 22:26:58 UTC 
This was fixed for Fedora with the 5.4.8 stable kernel updates.
Comment 19 errata-xmlrpc 2020-09-29 18:59:24 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:4062 https://access.redhat.com/errata/RHSA-2020:4062
Comment 20 errata-xmlrpc 2020-09-29 20:53:33 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:4060 https://access.redhat.com/errata/RHSA-2020:4060
Comment 21 Product Security DevOps Team 2020-09-29 22:00:24 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-10690
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