In the Linux kernel, the following vulnerability has been resolved:
NFSD: Fix READDIR buffer overflow
If a client sends a READDIR count argument that is too small (say,
zero), then the buffer size calculation in the new init_dirlist
helper functions results in an underflow, allowing the XDR stream
functions to write beyond the actual buffer.
This calculation has always been suspect. NFSD has never sanity-
checked the READDIR count argument, but the old entry encoders
managed the problem correctly.
With the commits below, entry encoding changed, exposing the
underflow to the pointer arithmetic in xdr_reserve_space().
Modern NFS clients attempt to retrieve as much data as possible
for each READDIR request. Also, we have no unit tests that
exercise the behavior of READDIR at the lower bound of @count
values. Thus this case was missed during testing.
Metrics
Affected Vendors & Products
References
History
Mon, 04 Nov 2024 13:15:00 +0000
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ssvc
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-03-04T18:15:38.706Z
Updated: 2024-11-04T11:59:32.598Z
Reserved: 2024-03-04T18:12:48.835Z
Link: CVE-2021-47107
Vulnrichment
Updated: 2024-08-04T05:24:39.886Z
NVD
Status : Awaiting Analysis
Published: 2024-03-04T19:15:18.793
Modified: 2024-11-21T06:35:24.743
Link: CVE-2021-47107
Redhat