Bug 2383486 (CVE-2025-38460)

Summary: CVE-2025-38460 kernel: atm: clip: Fix potential null-ptr-deref in to_atmarpd().
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-07-25 16:01:53 UTC
In the Linux kernel, the following vulnerability has been resolved:

atm: clip: Fix potential null-ptr-deref in to_atmarpd().

atmarpd is protected by RTNL since commit f3a0592b37b8 ("[ATM]: clip
causes unregister hang").

However, it is not enough because to_atmarpd() is called without RTNL,
especially clip_neigh_solicit() / neigh_ops->solicit() is unsleepable.

Also, there is no RTNL dependency around atmarpd.

Let's use a private mutex and RCU to protect access to atmarpd in
to_atmarpd().