Bug 2338815 (CVE-2025-21635)

Summary: CVE-2025-21635 kernel: rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: low    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-01-19 11:01:20 UTC
In the Linux kernel, the following vulnerability has been resolved:

rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy

As mentioned in a previous commit of this series, using the 'net'
structure via 'current' is not recommended for different reasons:

- Inconsistency: getting info from the reader's/writer's netns vs only
  from the opener's netns.

- current->nsproxy can be NULL in some cases, resulting in an 'Oops'
  (null-ptr-deref), e.g. when the current task is exiting, as spotted by
  syzbot [1] using acct(2).

The per-netns structure can be obtained from the table->data using
container_of(), then the 'net' one can be retrieved from the listen
socket (if available).

Comment 1 Avinash Hanwate 2025-01-20 07:42:12 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025011943-CVE-2025-21635-12e7@gregkh/T