Bug 2376396 (CVE-2025-38212)

Summary: CVE-2025-38212 kernel: ipc: fix to protect IPCS lookups using RCU
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 2025-07-04 14:03:45 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ipc: fix to protect IPCS lookups using RCU

syzbot reported that it discovered a use-after-free vulnerability, [0]

[0]: https://lore.kernel.org/all/67af13f8.050a0220.21dd3.0038.GAE@google.com/

idr_for_each() is protected by rwsem, but this is not enough.  If it is
not protected by RCU read-critical region, when idr_for_each() calls
radix_tree_node_free() through call_rcu() to free the radix_tree_node
structure, the node will be freed immediately, and when reading the next
node in radix_tree_for_each_slot(), the already freed memory may be read.

Therefore, we need to add code to make sure that idr_for_each() is
protected within the RCU read-critical region when we call it in
shm_destroy_orphaned().
Comment 1 Avinash Hanwate 2025-07-07 04:19:29 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025070422-CVE-2025-38212-5bd9@gregkh/T