Bug 2402224 (CVE-2023-53669)

Summary: CVE-2023-53669 kernel: tcp: fix skb_copy_ubufs() vs BIG TCP
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-10-07 16:03:53 UTC 
In the Linux kernel, the following vulnerability has been resolved:

tcp: fix skb_copy_ubufs() vs BIG TCP

David Ahern reported crashes in skb_copy_ubufs() caused by TCP tx zerocopy
using hugepages, and skb length bigger than ~68 KB.

skb_copy_ubufs() assumed it could copy all payload using up to
MAX_SKB_FRAGS order-0 pages.

This assumption broke when BIG TCP was able to put up to 512 KB per skb.

We did not hit this bug at Google because we use CONFIG_MAX_SKB_FRAGS=45
and limit gso_max_size to 180000.

A solution is to use higher order pages if needed.

v2: add missing __GFP_COMP, or we leak memory.
Comment 1 Jon Moroney 2025-10-07 17:54:28 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100705-CVE-2023-53669-f81f@gregkh/T