In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix use-after-free due to delegation race
A delegation break could arrive as soon as we've called vfs_setlease. A
delegation break runs a callback which immediately (in
nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we
then exit nfs4_set_delegation without hashing the delegation, it will be
freed as soon as the callback is done with it, without ever being
removed from del_recall_lru.
Symptoms show up later as use-after-free or list corruption warnings,
usually in the laundromat thread.
I suspect aba2072f4523 "nfsd: grant read delegations to clients holding
writes" made this bug easier to hit, but I looked as far back as v3.0
and it looks to me it already had the same problem. So I'm not sure
where the bug was introduced; it may have been there from the beginning.
Metrics
Affected Vendors & Products
References
History
Mon, 04 Nov 2024 12:15:00 +0000
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-05-24T15:01:52.746Z
Updated: 2024-11-04T12:07:14.801Z
Reserved: 2024-05-22T06:20:56.205Z
Link: CVE-2021-47506
Vulnrichment
Updated: 2024-08-04T05:39:59.751Z
NVD
Status : Awaiting Analysis
Published: 2024-05-24T15:15:11.197
Modified: 2024-05-24T18:09:20.027
Link: CVE-2021-47506
Redhat