Bug 2360979 (CVE-2025-37838)

Summary: CVE-2025-37838 kernel: HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition
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: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-04-18 15:01:12 UTC
In the Linux kernel, the following vulnerability has been resolved:

HSI: ssi_protocol: Fix use after free vulnerability in ssi_protocol Driver Due to Race Condition

In the ssi_protocol_probe() function, &ssi->work is bound with
ssip_xmit_work(), In ssip_pn_setup(), the ssip_pn_xmit() function
within the ssip_pn_ops structure is capable of starting the
work.

If we remove the module which will call ssi_protocol_remove()
to make a cleanup, it will free ssi through kfree(ssi),
while the work mentioned above will be used. The sequence
of operations that may lead to a UAF bug is as follows:

CPU0                                    CPU1

                        | ssip_xmit_work
ssi_protocol_remove     |
kfree(ssi);             |
                        | struct hsi_client *cl = ssi->cl;
                        | // use ssi

Fix it by ensuring that the work is canceled before proceeding
with the cleanup in ssi_protocol_remove().

Comment 1 Avinash Hanwate 2025-04-21 03:32:05 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025041858-CVE-2025-37838-2253@gregkh/T