Bug 2338814 (CVE-2025-21648)

Summary: CVE-2025-21648 kernel: netfilter: conntrack: clamp maximum hashtable size to INT_MAX
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-01-19 11:01:16 UTC
In the Linux kernel, the following vulnerability has been resolved:

netfilter: conntrack: clamp maximum hashtable size to INT_MAX

Use INT_MAX as maximum size for the conntrack hashtable. Otherwise, it
is possible to hit WARN_ON_ONCE in __kvmalloc_node_noprof() when
resizing hashtable because __GFP_NOWARN is unset. See:

  0708a0afe291 ("mm: Consider __GFP_NOWARN flag for oversized kvmalloc() calls")

Note: hashtable resize is only possible from init_netns.

Comment 1 Avinash Hanwate 2025-01-20 07:46:16 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025011946-CVE-2025-21648-bcda@gregkh/T