Bug 2030747 (CVE-2021-44733) - CVE-2021-44733 kernel: use-after-free in the TEE subsystem
Summary: CVE-2021-44733 kernel: use-after-free in the TEE subsystem
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2021-44733
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2030754 2030755 2030756 2033206
Blocks: 2030292
TreeView+ depends on / blocked
 
Reported: 2021-12-09 15:55 UTC by Alex
Modified: 2022-06-16 11:23 UTC (History)
47 users (show)

Fixed In Version: kernel 5.16 rc7
Doc Type: If docs needed, set a value
Doc Text:
A use-after-free flaw in the Linux kernel TEE (Trusted Execution Environment) subsystem was found in the way user calls ioctl TEE_IOC_OPEN_SESSION or TEE_IOC_INVOKE. A local user could use this flaw to crash the system or escalate their privileges on the system. If the Linux system non configured with the CONFIG_PREEMPT option or CONFIG_CPU_SW_DOMAIN_PAN option enabled, then it is unlikely that a user can trigger this issue.
Clone Of:
Environment:
Last Closed: 2022-05-11 12:46:29 UTC
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2022:2229 0 None None None 2022-05-12 11:27:00 UTC
Red Hat Product Errata RHBA-2022:4630 0 None None None 2022-05-18 11:46:45 UTC
Red Hat Product Errata RHBA-2022:4693 0 None Closed RHEL 8.5 firefox has problems when smart cards are used 2022-06-08 21:08:39 UTC
Red Hat Product Errata RHBA-2022:4969 0 None None None 2022-06-08 18:40:22 UTC
Red Hat Product Errata RHBA-2022:5088 0 None None None 2022-06-16 11:23:39 UTC
Red Hat Product Errata RHSA-2022:1975 0 None None None 2022-05-10 14:40:32 UTC
Red Hat Product Errata RHSA-2022:1988 0 None None None 2022-05-10 14:46:36 UTC

Description Alex 2021-12-09 15:55:32 UTC 
There is use-after-free design issue with the lifetime tracking of the tee_shm:dmabuf object.
If dmabuf in the process of being destroyed, and at the same time other process do a call to the IOCTL command TEE_IOC_OPEN_SESSION or TEE_IOC_INVOKE referencing that shared memory, then exploitable use-after-free could happen.
It is hard to trigger the issue, so this is like race condition and to trigger it the CONFIG_CPU_SW_DOMAIN_PAN must be disabled and both the kernel must be configured with CONFIG_PREEMPT.

Reference and patch:
https://lore.kernel.org/lkml/20211214123540.1789434-1-jens.wiklander@linaro.org/
Comment 4 Alex 2021-12-15 13:05:09 UTC 
The candidate patch is:
https://lore.kernel.org/lkml/20211214123540.1789434-1-jens.wiklander@linaro.org/
Comment 7 Alex 2021-12-16 08:31:32 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2033206]
Comment 8 Justin M. Forbes 2022-01-05 14:34:34 UTC 
This was fixed for Fedora with the 5.15.12 stable kernel updates.
Comment 9 errata-xmlrpc 2022-05-10 14:40:30 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2022:1975 https://access.redhat.com/errata/RHSA-2022:1975
Comment 10 errata-xmlrpc 2022-05-10 14:46:32 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2022:1988 https://access.redhat.com/errata/RHSA-2022:1988
Comment 11 Product Security DevOps Team 2022-05-11 12:46:26 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-2021-44733
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