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Unrated severityNVD Advisory· Published Jul 29, 2024· Updated Nov 3, 2025

cachefiles: cyclic allocation of msg_id to avoid reuse

CVE-2024-41050

Description

In the Linux kernel, the following vulnerability has been resolved:

cachefiles: cyclic allocation of msg_id to avoid reuse

Reusing the msg_id after a maliciously completed reopen request may cause a read request to remain unprocessed and result in a hung, as shown below:

t1 | t2 | t3 ------------------------------------------------- cachefiles_ondemand_select_req cachefiles_ondemand_object_is_close(A) cachefiles_ondemand_set_object_reopening(A) queue_work(fscache_object_wq, &info->work) ondemand_object_worker cachefiles_ondemand_init_object(A) cachefiles_ondemand_send_req(OPEN) // get msg_id 6 wait_for_completion(&req_A->done) cachefiles_ondemand_daemon_read // read msg_id 6 req_A cachefiles_ondemand_get_fd copy_to_user // Malicious completion msg_id 6 copen 6,-1 cachefiles_ondemand_copen complete(&req_A->done) // will not set the object to close // because ondemand_id && fd is valid.

// ondemand_object_worker() is done // but the object is still reopening.

// new open req_B cachefiles_ondemand_init_object(B) cachefiles_ondemand_send_req(OPEN) // reuse msg_id 6 process_open_req copen 6,A.size // The expected failed copen was executed successfully

Expect copen to fail, and when it does, it closes fd, which sets the object to close, and then close triggers reopen again. However, due to msg_id reuse resulting in a successful copen, the anonymous fd is not closed until the daemon exits. Therefore read requests waiting for reopen to complete may trigger hung task.

To avoid this issue, allocate the msg_id cyclically to avoid reusing the msg_id for a very short duration of time.

Affected products

50

Patches

4
9d3bf4e9aa23
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
19f4f3990914
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
de045a82e1a4
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit
35710c6c4a1c
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.gitvia osv
commit

Vulnerability mechanics

Generated on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.

References

4

News mentions

0

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