Bug 2363269 (CVE-2025-37787)

Summary: CVE-2025-37787 kernel: net: dsa: mv88e6xxx: avoid unregistering devlink regions which were never registered
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 2025-05-01 14:01:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: dsa: mv88e6xxx: avoid unregistering devlink regions which were never registered

Russell King reports that a system with mv88e6xxx dereferences a NULL
pointer when unbinding this driver:
https://lore.kernel.org/netdev/Z_lRkMlTJ1KQ0kVX@shell.armlinux.org.uk/

The crash seems to be in devlink_region_destroy(), which is not NULL
tolerant but is given a NULL devlink global region pointer.

At least on some chips, some devlink regions are conditionally registered
since the blamed commit, see mv88e6xxx_setup_devlink_regions_global():

		if (cond && !cond(chip))
			continue;

These are MV88E6XXX_REGION_STU and MV88E6XXX_REGION_PVT. If the chip
does not have an STU or PVT, it should crash like this.

To fix the issue, avoid unregistering those regions which are NULL, i.e.
were skipped at mv88e6xxx_setup_devlink_regions_global() time.
Comment 1 Avinash Hanwate 2025-05-02 04:44:51 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025050119-CVE-2025-37787-746d@gregkh/T