Bug 2400737 (CVE-2022-50421)

Summary: CVE-2022-50421 kernel: rpmsg: char: Avoid double destroy of default endpoint
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-10-01 12:04:33 UTC 
In the Linux kernel, the following vulnerability has been resolved:

rpmsg: char: Avoid double destroy of default endpoint

The rpmsg_dev_remove() in rpmsg_core is the place for releasing
this default endpoint.

So need to avoid destroying the default endpoint in
rpmsg_chrdev_eptdev_destroy(), this should be the same as
rpmsg_eptdev_release(). Otherwise there will be double destroy
issue that ept->refcount report warning:

refcount_t: underflow; use-after-free.

Call trace:
 refcount_warn_saturate+0xf8/0x150
 virtio_rpmsg_destroy_ept+0xd4/0xec
 rpmsg_dev_remove+0x60/0x70

The issue can be reproduced by stopping remoteproc before
closing the /dev/rpmsgX.
Comment 1 Jon Moroney 2025-10-01 21:50:27 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100155-CVE-2022-50421-8bdc@gregkh/T